Journal articles: 'Quadruped Robots'

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Zhang, Chunsong, and Jian S. Dai. "Continuous Static Gait with Twisting Trunk of a Metamorphic Quadruped Robot." Mechanical Sciences 9, no. 1 (January 4, 2018): 1–14. http://dx.doi.org/10.5194/ms-9-1-2018.

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Abstract. The natural quadrupeds, such as geckos and lizards, often twist their trunks when moving. Conventional quadruped robots cannot perform the same motion due to equipping with a trunk which is a rigid body or at most consists of two blocks connected by passive joints. This paper proposes a metamorphic quadruped robot with a reconfigurable trunk which can implement active trunk motions, called MetaRobot I. The robot can imitate the natural quadrupeds to execute motion of trunk twisting. Benefiting from the twisting trunk, the stride length of this quadruped is increased comparing to that of conventional quadruped robots. In this paper a continuous static gait benefited from the twisting trunk performing the increased stride length is introduced. After that, the increased stride length relative to the trunk twisting will be analysed mathematically. Other points impacting the implementation of the increased stride length in the gait are investigated such as the upper limit of the stride length and the kinematic margin. The increased stride length in the gait will lead the increase of locomotion speed comparing with conventional quadruped robots, giving the extent that natural quadrupeds twisting their trunks when moving. The simulation and an experiment on the prototype are then carried out to illustrate the benefits on the stride length and locomotion speed brought by the twisting trunk to the quadruped robot.

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Li, Tengfei, Chunsong Zhang, Shengjie Wang, and Jian S. Dai. "Jumping with Expandable Trunk of a Metamorphic Quadruped Robot—The Origaker II." Applied Sciences 9, no. 9 (April 29, 2019): 1778. http://dx.doi.org/10.3390/app9091778.

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Most of the traditional quadruped robots are assembled with rigid trunks that make no active contributions to their locomotion performances. However, in the natural world, some quadrupeds expand their trunks when jumping. This paper proposes a metamorphic quadruped robot, named the Origaker II, with an expandable trunk that can implement the motion of contracting-stretching. Benefitting from the expandable trunk, this robot achieves a longer jumping distance than that of the traditional quadruped robots. The structure of the robot is introduced. Its jumping motion is designed based on the observation of a frog. The effect of the expandable trunk on this robot will be mathematically analyzed. At last, contrast simulations are conducted to verify the benefits of the expandable trunk to the robot.

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Yao, Ligang, Hao Yu, and Zongxing Lu. "Design and driving model for the quadruped robot: An elucidating draft." Advances in Mechanical Engineering 13, no. 4 (April 2021): 168781402110090. http://dx.doi.org/10.1177/16878140211009035.

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Recent developments in driving mode have heightened the need for quadruped robots. However, it is still a challenge to improve the dynamic characteristics. This paper makes a comprehensive review of the quadruped robot driving mode, from two aspects: hydraulic drive and motor drive. The application of hydraulic drives in quadruped robots is relatively mature. As motor performance is improving, interest in motor driving mode for quadruped robots is growing rapidly. Specific quadruped robots of milestone significance are presented in different driving modes. The performance in load capacity and motion characteristics, in different driving modes, are compared. Finally, the research difficulties in the field of quadruped robots are analyzed, while future development of the quadruped robot shows high prospects. The purpose of this paper is to summarize and analyze the previous research results and provide useful guidance for robot designers in developing more efficient driving modes for quadruped robots.

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Li, Zhi, Hong Kai Li, Hao Zhang, and Zhen Dong Dai. "Analysis and Design of Hydraulic System of a Hydraulically Actuated Quadruped Robot." Applied Mechanics and Materials 461 (November 2013): 861–68. http://dx.doi.org/10.4028/www.scientific.net/amm.461.861.

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Abstract.Quadruped not only possess excellent kinetic speed and stability but also can adapt to various complex terrains, with the result that hydraulically actuated quadruped bionic robots with high load and outstanding adaptability have become the research hotspot. Hydraulic system, which is regarded as the dynamic part of a hydraulic quadruped robot, has a direct effect on the kinetic capability of robots. Based on dog’s structure bionics, hydraulically actuated quadruped robot was designed. In accordance with distribution modes of hydraulic cylinders which drive robot’s kinetic joints, a hydraulic oil-line system of the robot was designed in this paper. Combining the maximum design kinetic velocity, trotting movement pattern within foot’s work space was planned. Velocity curve of each joint’s hydraulic cylinder was obtained through simulation analysis of dynamic analysis software. According to the structure of asymmetrical hydraulic cylinder, minimum flux which the oil hydraulic pump theoretically requires at the robot’s maximum kinetic speed was calculated. With practical experience, the oilsource parameter which could meet the demands of hydraulic quadruped robot were determined.

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Sutyasadi, Petrus, and Manukid Parnichkun. "Gait Tracking Control of Quadruped Robot Using Differential Evolution Based Structure Specified Mixed SensitivityH∞Robust Control." Journal of Control Science and Engineering 2016 (2016): 1–18. http://dx.doi.org/10.1155/2016/8760215.

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This paper proposed a control algorithm that guarantees gait tracking performance for quadruped robots. During dynamic gait motion, such as trotting, the quadruped robot is unstable. In addition to uncertainties of parameters and unmodeled dynamics, the quadruped robot always faces some disturbances. The uncertainties and disturbances contribute significant perturbation to the dynamic gait motion control of the quadruped robot. Failing to track the gait pattern properly propagates instability to the whole system and can cause the robot to fall. To overcome the uncertainties and disturbances, structured specified mixed sensitivityH∞robust controller was proposed to control the quadruped robot legs’ joint angle positions. Before application to the real hardware, the proposed controller was tested on the quadruped robot’s leg planar dynamic model using MATLAB. The proposed controller can control the robot’s legs efficiently even under uncertainties from a set of model parameter variations. The robot was also able to maintain its stability even when it was tested under several terrain disturbances.

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Jia, Yan, Xiao Luo, Baoling Han, Guanhao Liang, Jiaheng Zhao, and Yuting Zhao. "Stability Criterion for Dynamic Gaits of Quadruped Robot." Applied Sciences 8, no. 12 (November 25, 2018): 2381. http://dx.doi.org/10.3390/app8122381.

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Dynamic-stability criteria are crucial for robot’s motion planning and balance recovery. Nevertheless, few studies focus on the motion stability of quadruped robots with dynamic gait, none of which have accurately evaluated the robots’ stability. To fill the gaps in this field, this paper presents a new stability criterion for the motion of quadruped robots with dynamic gaits running over irregular terrain. The traditional zero-moment point (ZMP) is improved to analyze the motion on irregular terrain precisely for dynamic gaits. A dynamic-stability criterion and measurement are proposed to determine the stability state of the robot and to evaluate its stability. The simulation results show the limitations of the existing stability criteria for dynamic gaits and indicate that the criterion proposed in this paper can accurately and efficiently evaluate the stability of a quadruped robot using such gaits.

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Yoneda, Kan. "Light Weight Quadruped with Nine Actuators." Journal of Robotics and Mechatronics 19, no. 2 (April 20, 2007): 160–65. http://dx.doi.org/10.20965/jrm.2007.p0160.

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Quadruped robots, which tend to be heavy can be made lighter by carefully considering the number of actuators and required power. This paper discusses the relationship of the moving functions of quadruped locomotion and the required number of actuators. Using fewer actuators than conventionally need not prevent the quadruped robot from satisfactory locomotion. At the same time, energy saving brings a lighter design, because required actuators and batteries are smaller. This paper discusses several techniques to reduce energy consumption. Combining these discussions, examples of 3-, 5-, and 9-actuator quadrupeds are designed, and experimentally performed good locomotion.

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He, JingYe, JunPeng Shao, GuiTao Sun, and Xuan Shao. "Survey of Quadruped Robots Coping Strategies in Complex Situations." Electronics 8, no. 12 (November 27, 2019): 1414. http://dx.doi.org/10.3390/electronics8121414.

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As an important branch of mobile robots, quadruped robots have high flexibility, high adaptability, and high dynamics, which provide excellent maneuverability and environmental adaptability. In the past ten years, researchers have done a lot of research on the ability of the quadruped robot to cope with the complex environment and published many results in order to make the working environment of the quadruped robot closer to reality. This paper collected these research results and divided these literatures into three categories according to different situations: crossing challenging terrain, walking on slope, and coping with interference, respectively, introducing representative methods. The purpose of this review is to summarize and analyze the previous research results and provide guidance for future research on quadruped robots in complex situations.

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Chatzakos, Panagiotis, and Evangelos Papadopoulos. "Self-Stabilising Quadrupedal Running by Mechanical Design." Applied Bionics and Biomechanics 6, no. 1 (2009): 73–85. http://dx.doi.org/10.1155/2009/748719.

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Dynamic stability allows running animals to maintain preferred speed during locomotion over rough terrain. It appears that rapid disturbance rejection is an emergent property of the mechanical system. In running robots, simple motor control seems to be effective in the negotiation of rough terrain when used in concert with a mechanical system that stabilises passively. Spring-like legs are a means for providing self-stabilising characteristics against external perturbations. In this paper, we show that a quadruped robot could be able to perform self-stable running behaviour in significantly broader ranges of forward speed and pitch rate with a suitable mechanical design, which is not limited to choosing legs spring stiffness only. The results presented here are derived by studying the stability of the passive dynamics of a quadruped robot running in the sagittal plane in a dimensionless context and might explain the success of simple, open loop running controllers on existing experimental quadruped robots. These can be summarised in (a) the self-stabilised behaviour of a quadruped robot for a particular gait is greatly related to the magnitude of its dimensionless body inertia, (b) the values of hip separation, normalised to rest leg length, and leg relative stiffness of a quadruped robot affect the stability of its motion and should be in inverse proportion to its dimensionless body inertia, and (c) the self-stable regime of quadruped running robots is enlarged at relatively high forward speeds. We anticipate the proposed guidelines to assist in the design of new, and modifications of existing, quadruped robots. As an example, specific design changes for the Scout II quadruped robot that might improve its performance are proposed.

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Han, Shuo, Yuan Chen, Guangying Ma, Jinshan Zhang, and Runchen Liu. "Gait Planning and Simulation Analysis of a New Amphibious Quadruped Robots." Journal of Robotics and Mechatronics 30, no. 2 (April 20, 2018): 257–64. http://dx.doi.org/10.20965/jrm.2018.p0257.

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In order to allow quadruped robots to adapt to the complex working environment in the field of fisheries and aquaculture, a new type of quadruped robot with linear and rotary driving is proposed, and the kinematic inverse solution of the leg of the quadruped robot is deduced. For achieving quadruped robot smooth walking, the straight gait of the quadruped robot is planned according to the stability margin principle of motion, so that the stability margin of the machine is 20 mm when three legs supporting it. The planning gait is simulated by ADAMS software, the kinematics and dynamics analysis of the four main driving mechanisms of the robot leg were carried out, and the feasibility of using the STEP5 driving function to execute the planning gait in the quadruped robot was verified. The theoretical and simulation curve analysis results show that, the quadruped robot according to the planned gait can complete the cycle and have a stable walking. The results of this study can provide a reference for the practical application of the new amphibious quadruped robot in the fields of complex and uneven ground in the field of fisheries and aquaculture to realize exploration, fishing and transportation.

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PASTOR, ROBERT, ZDENKO BOBOVSKY, PETR OSCADAL, JAKUB MESICEK, MAREK PAGAC, ERIK PRADA, LUBICA MIKOVA, and JAN BABJAK. "OPTIMIZING A QUADRUPED ROBOT: A COMPARISON OF TWO METHODS." MM Science Journal 2021, no. 2 (June 2, 2021): 4348–55. http://dx.doi.org/10.17973/mmsj.2021_6_2021008.

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Robots that have been optimized in simulation often underperform in the real world in comparison to their simulated counterparts. This difference in performance is often called a reality-gap. In this paper, we use two methods, genetic algorithm and topology optimization, to optimize a quadruped robot. We look at the original and optimized robots’ performance in simulation and reality and compare the results. Both methods show improvement in the robot’s efficiency, however the topology optimization behaves in a more predictable manner and shows similar results in simulation and in real laboratory testing. Modifying robot morphology with a genetic algorithm, although less predictable, has a potential for more improvement in efficiency.

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Huang, Wenkai, Junlong Xiao, Feilong Zeng, Puwei Lu, Guojian Lin, Wei Hu, Xuyu Lin, and Yu Wu. "A Quadruped Robot with Three-Dimensional Flexible Legs." Sensors 21, no. 14 (July 19, 2021): 4907. http://dx.doi.org/10.3390/s21144907.

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As an important part of the quadruped robot, the leg determines its performance. Flexible legs or flexible joints aid in the buffering and adaptability of robots. At present, most flexible quadruped robots only have two-dimensional flexibility or use complex parallel structures to achieve three-dimensional flexibility. This research will propose a new type of three-dimensional flexible structure. This passive compliant three-dimensional flexibility reduces the weight and complex structure of the robot. The anti-impact performance of the robot is verified by a side impact experiment. The simulation and experiments show that the robot still has good stability even under a simple algorithm and that the flexible leg can reduce the impact on the quadruped robot and improve the environmental adaptability of the robot.

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13

Zhong, Yuhai, Runxiao Wang, Huashan Feng, and Yasheng Chen. "Analysis and research of quadruped robot’s legs: A comprehensive review." International Journal of Advanced Robotic Systems 16, no. 3 (May 1, 2019): 172988141984414. http://dx.doi.org/10.1177/1729881419844148.

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As an important basic component of quadruped robots, mechanical legs provide the robots with excellent maneuverability and versatility, which determine the core application performance such as job adaptability, walking speed, and load capacity. A large number of robotics institutes for the last few decades have studied mechanical legs used by quadruped robots and published many research results. In this article, we collect these research results and classify them into three categories (prismatic legs, articulated legs, and redundant articulated legs) according to the degrees of freedom and then introduce and analyze them. On this basis, we summarize and study the design methods of the actuators and mechanical leg structures. Finally, we make some suggestions for the development of quadruped robot’s legs in the future. The motivation of this review is to summarize and analyze previous research efforts and provide useful guidance for future robotic designers to develop more efficient mechanical legs of quadruped robots.

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Vatau, Steliana, Valentin Ciupe, and Inocentiu Maniu. "Java Simulator for Quadruped Walking Robot." Solid State Phenomena 166-167 (September 2010): 445–50. http://dx.doi.org/10.4028/www.scientific.net/ssp.166-167.445.

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With advances in science and technology, the interest to study the animals walking has developed the demand for building the legged robots. Physics-based simulation and control of quadruped locomotion is difficult because quadrupeds are unstable, under actuated, high-dimensional dynamical systems. We develop a simple control strategy that can be used to generate a large variety of gaits and styles in real-time, including walking in all directions (forwards, backwards, sideways, turning). The application named JQuadRobot is developed in Java and Java3D API. A Graphical User Interface and a simulator for a custom quadruped leg's robot and the main features of the interface are presented in this paper. This application is developed in Java and is essential in a development motion for legged robot. The friendly interface, allows any user to define and test movements for this robot. The cross-platform capability was the first reason to choose Java language for developing this application.

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Cao, Shao Yong. "The Mechanical Structure Design of Bionic Quadruped Walking Robot." Applied Mechanics and Materials 851 (August 2016): 484–91. http://dx.doi.org/10.4028/www.scientific.net/amm.851.484.

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This paper aims to design a flexible, efficient, reliable and long-term working quadruped robot, which can be operating in complex environment such as carrying cargoes over rough terrains. The robot’s body shape is constructed by using bionic methodology after observation and analysis of the four-legged animal’s bone structure and body proportion. And the robot’s gait, step length and stride frequency are determined by studying four-leg animal’s movements. Moreover, the robot’s working space can be known by studying the joint form and activity scope of four-legged animals. Finally, the overall structure of this robot can be designed and eventually the desired objectives are achieved. The results turned out to be useful for the research of quadruped robots

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Zhu, Xue Biao, Kui Shen Chen, and Yuan Yuan Mei. "Dynamic Simulation of Hydraulic Driving Mechanism Based on ADAMS." Advanced Materials Research 875-877 (February 2014): 2143–47. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.2143.

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It establishes the model of hydraulic driving quadruped walking robot by Lagranges equation according to mechanism parameter. It determines the relationship between joint space and operating space. Comprehensive using the software Pro/E and ADAMDS, then build its virtual model and present dynamics simulation. It analyses the robots walking tracks and stability of motion. It provides theory reference for optimized out reasonable quadruped walking robots structure parameter.

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Yang, Kun, Yibin Li, Lelai Zhou, and Xuewen Rong. "Energy Efficient Foot Trajectory of Trot Motion for Hydraulic Quadruped Robot." Energies 12, no. 13 (June 29, 2019): 2514. http://dx.doi.org/10.3390/en12132514.

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Quadruped robots can be used to transport loads or conduct rescue missions on tough terrain. In addition to flexibility and adaptability to complex terrain, the hydraulic driven quadruped robots also have the important characteristic of energy consumption. This paper studies the trot gait motions of the quadruped robot SCalf. The energy model including the mechanical power and heat rate is established, which can be used to obtained the energy consumption of the robot. Compared with a cubic spline interpolation reference trajectory, a foot trajectory based on Fourier series is studied to reduce the joints energy consumption, and the parameters of the foot trajectory are acquired by the Pattern Search method. The effectiveness of the energy efficient trajectory is verified by simulations and verified on the robot prototype.

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Chen, Xuedong, Keigo Watanabe, and Kiyotaka Izumi. "Joint Positions and Robot Stability of the Omnidirectional Crawling Quadruped Robot." Journal of Robotics and Mechatronics 11, no. 6 (December 20, 1999): 510–17. http://dx.doi.org/10.20965/jrm.1999.p0510.

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Determination of joint positions, judgment of robot stability, and selection of the consequential swing leg are keys to crawling control for quadruped robots. We derive an efficient way to obtain actuation variables of joint positions to satisfy the gait for quadruped robots. By defining the statically stable area for foot placement, a new approach on analysis of robot stability is presented. Unlike conventionally, we avoid solving complicated direct robot kinematics as an overall kinematic chain and simultaneously show information on robot stability and the stable range of foot placement. Effectiveness is shown in practical crawling experiments.

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Hao, Qian, Zhaoba Wang, Junzheng Wang, and Guangrong Chen. "Stability-Guaranteed and High Terrain Adaptability Static Gait for Quadruped Robots." Sensors 20, no. 17 (August 31, 2020): 4911. http://dx.doi.org/10.3390/s20174911.

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Stability is a prerequisite for legged robots to execute tasks and traverse rough terrains. To guarantee the stability of quadruped locomotion and improve the terrain adaptability of quadruped robots, a stability-guaranteed and high terrain adaptability static gait for quadruped robots is addressed. Firstly, three chosen stability-guaranteed static gaits: intermittent gait 1&2 and coordinated gait are investigated. In addition, then the static gait: intermittent gait 1, which is with the biggest stability margin, is chosen to do a further research about quadruped robots walking on rough terrains. Secondly, a position/force based impedance control is employed to achieve a compliant behavior of quadruped robots on rough terrains. Thirdly, an exploratory gait planning method on uneven terrains with touch sensing and an attitude-position adjustment strategy with terrain estimation are proposed to improve the terrain adaptability of quadruped robots. Finally, the proposed methods are validated by simulations.

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Kang, Ru, Fei Meng, Xuechao Chen, Zhangguo Yu, Xuxiao Fan, Aiguo Ming, and Qiang Huang. "Structural Design and Crawling Pattern Generator of a Planar Quadruped Robot for High-Payload Locomotion." Sensors 20, no. 22 (November 16, 2020): 6543. http://dx.doi.org/10.3390/s20226543.

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Load capacity is an important index to reflect the practicability of legged robots. Existing research into quadruped robots has not analyzed their load performance in terms of their structural design and control method from a systematic point of view. This paper proposes a structural design method and crawling pattern generator for a planar quadruped robot that can realize high-payload locomotion. First, the functions required to evaluate the leg’s load capacity are established, and quantitative comparative analyses of the candidates are performed to select the leg structure with the best load capacity. We also propose a highly integrated design method for a driver module to improve the robot’s load capacity. Second, in order to realize stable load locomotion, a novel crawling pattern generator based on trunk swaying is proposed which can realize lateral center of mass (CoM) movement by adjusting the leg lengths on both sides to change the CoM projection in the trunk width direction. Finally, loaded crawling simulations and experiments performed with our self-developed quadruped robot show that stable crawling with load ratios exceeding 66% can be realized, thus verifying the effectiveness and superiority of the proposed method.

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Srinivas, Taarun, Adithya Krishna Karigiri Madhusudhan, Lokeshwaran Manohar, Nikhit Mathew Stephen Pushpagiri, Kuppan Chetty Ramanathan, Mukund Janardhanan, and Izabela Nielsen. "Valkyrie—Design and Development of Gaits for Quadruped Robot Using Particle Swarm Optimization." Applied Sciences 11, no. 16 (August 13, 2021): 7458. http://dx.doi.org/10.3390/app11167458.

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Over the past decades, developments and scientific breakthroughs in the field of robotics have shown the replacement of wheeled robots with legged robots, which are often inspired by the biological characteristics of legged animals. Many industries and urban-based applications promote quadruped robots because of their dexterous ability to efficiently handle multiple tasks in the working environment. Motivated from the recent works in the field of quadruped robots, this research aims to develop and investigate gaits for a 2 DoF mammal-inspired quadruped robot that incorporates 4 hip and 4 knee servo motors as its locomotion element. Forward and inverse kinematic techniques are used to determine the joint angle required for the locomotion and stability calculation are presented to determine the center of mass/center of gravity of the robot. Three types of gaits such as walk, trot, and pace are developed while keeping the center of mass inside the support polygon using a closed-loop control system. To minimize errors and improve the performance of the robot due to its non-linearity, a meta-heuristic algorithm has been developed and addressed in this work. The fitness function is derived based on the Euclidean distance between the target and robot’s current position and kinematic equations are used to obtain the relation between joints and coordinates. Based on the literature, particle swarm optimization (PSO) was found to be a promising algorithm for this problem and is developed using Python’s ‘Pyswarms’ package. Experimental studies are carried out quantitatively to determine the convergence characteristics of the control algorithm and to investigate the distance traveled by the robot for different target positions and gaits. Comparison between experimental and theoretical results prove the efficiency of the proposed algorithm and stability of the robot during various gait movements.

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P., Murali Krishna, and Prasanth Kumar R. "Energetics of constant height level bounding in quadruped robots." Robotica 34, no. 2 (June 24, 2014): 403–22. http://dx.doi.org/10.1017/s0263574714001532.

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SUMMARYIn this paper, we investigate the energetics of constant height level bounding gaits in quadruped robots with asymmetric body-mass distribution along the longitudinal axis. Analytical expressions for mechanical specific resistance for two cases of bounding are derived: bounding with equal front and rear leg step lengths, and bounding with unequal front and rear leg step lengths. Specific resistance is found to be independent of mass distribution in the first case, and dependent in the second case. The quadruped robot has average nonzero acceleration/deceleration due to unsymmetric distribution of mass when front and rear leg step lengths are equal. Results show that lower body lengths, lower step lengths, and higher heights from the ground level give lower specific resistance. The effect of body-mass asymmetry is to accelerate in the first case, and to reduce specific resistance in the second case. This result provides some insight into why certain quadrupedal animals in nature evolved to have body-mass asymmetry.

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Yamaguchi, Tomohiro, Keigo Watanabe, Kiyotaka Izumi, and Kazuo Kiguchi. "Obstacle Avoidance for Quadruped Robots Using a Neural Network." Journal of Advanced Computational Intelligence and Intelligent Informatics 7, no. 2 (June 20, 2003): 115–23. http://dx.doi.org/10.20965/jaciii.2003.p0115.

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Legged mobile robots, which differ from wheeled and crawler, need not avoid all obstacles by altering the path in the obstacle avoidance task. Because, legged mobile robots can get over or stride some obstacles, depending on the obstacle configuration and the current state of the robot. Legged mobile robots muse have suitable motion for each leg. We propose body motion control of a quadruped robot using a neural network (NN) for an obstacle avoidance task. Each leg motion is calculated by robot kinematics using body motion from the NN. NN design parameters are tuned off-line by a genetic algorithm (GA). Effectiveness of the present method is proved through an experiment.

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Yang, Kun, Xuewen Rong, Lelai Zhou, and Yibin Li. "Modeling and Analysis on Energy Consumption of Hydraulic Quadruped Robot for Optimal Trot Motion Control." Applied Sciences 9, no. 9 (April 28, 2019): 1771. http://dx.doi.org/10.3390/app9091771.

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Energy consumption is an important performance index of quadruped robots. In this paper, the energy consumptions of the quadruped robot SCalf with a trot gait under different gait parameters are analyzed. Firstly, the kinematics and dynamics models of the robot are established. Then, an energy model including the mechanical power and heat rate is proposed. To obtain the energy consumption, a cubic spline interpolation foot trajectory is used, and the feet forces are calculated by using the minimization of norm of the foot force method. Moreover, an energetic criterion measuring the energy cost is defined to evaluate the motion. Finally, the gait parameters such as step height, step length, standing height, gait cycle, and duty cycle that influence the energy consumption are studied, which could provide a theoretical basis for parameter optimization and motion control of quadruped robots.

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Bazeille, Stéphane, Jesus Ortiz, Francesco Rovida, Marco Camurri, Anis Meguenani, Darwin G. Caldwell, and Claudio Semini. "Active camera stabilization to enhance the vision of agile legged robots." Robotica 35, no. 4 (November 17, 2015): 942–60. http://dx.doi.org/10.1017/s0263574715000909.

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SUMMARYLegged robots have the potential to navigate in more challenging terrains than wheeled robots. Unfortunately, their control is more demanding, because they have to deal with the common tasks of mapping and path planning as well as more specific issues of legged locomotion, like balancing and foothold planning. In this paper, we present the integration and the development of a stabilized vision system on the fully torque-controlled hydraulically actuated quadruped robot (HyQ). The active head added onto the robot is composed of a fast pan and tilt unit (PTU) and a high-resolution wide angle stereo camera. The PTU enables camera gaze shifting to a specific area in the environment (both to extend and refine the map) or to track an object while navigating. Moreover, as the quadruped locomotion induces strong regular vibrations, impacts or slippages on rough terrain, we took advantage of the PTU to mechanically compensate for the robot's motions. In this paper, we demonstrate the influence of legged locomotion on the quality of the visual data stream by providing a detailed study of HyQ's motions, which are compared against a rough terrain wheeled robot of the same size. Our proposed Inertial Measurement Unit (IMU)-based controller allows us to decouple the camera from the robot motions. We show through experiments that, by stabilizing the image feedback, we can improve the onboard vision-based processes of tracking and mapping. In particular, during the outdoor tests on the quadruped robot, the use of our camera stabilization system improved the accuracy on the 3D maps by 25%, with a decrease of 50% of mapping failures.

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Khorram, Mahdi, and S. Ali A. Moosavian. "A 3D stable trot of a quadruped robot over uneven terrains." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 3 (November 14, 2016): 555–73. http://dx.doi.org/10.1177/0954406215617492.

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Legged robots have superior advantages rather than wheeled robots for moving over uneven terrains in the presence of various obstacles. The design of an appropriate path for the main body and legs is an important issue for such robots especially on the uneven terrains. In this paper, the focus is to develop a stable gait for a quadruped robot to trot on uneven terrains. First, a stability condition is developed for a whole-body quadruped robot over uneven terrains based on avoiding the tumbling. By using a simple model, a point with zero moments is calculated in the three-dimensional space. Then, the reference path of this point is determined so that the tumbling moments become zero. The path of the main body will be calculated by using an optimal controller. The main feature of the proposed gait generation framework is that the height of robot can change continuously and stably on uneven terrains. To evaluate the robot stability, the tumbling moments around diagonal lines are calculated and some methods are proposed to reduce these moments to improve the robot stability. The tip of swing foot is also planned to avoid any collision with the environment. The proposed method will be demonstrated using an 18-Degrees of freedom (DOF) quadruped robot in simulation and experimental studies. The experimental setup is a small-size quadruped robot, which is composed of a rectangular plate as its main body with four legs that each one has three active joints with DC servo motors. Obtained results reveal that the robot can trot on uneven terrains stably. Besides, the comparison with the previous methods approves the merits of proposed algorithm on uneven terrains.

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Gor, Mehul M., PM Pathak, AK Samantaray, Jung Ming Yang, and SW Kwak. "Fault-tolerant control of a compliant legged quadruped robot for free swinging failure." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 232, no. 2 (November 24, 2017): 161–77. http://dx.doi.org/10.1177/0959651817743410.

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Quadruped robots are designed to work in remote or hazardous environments which are unreachable or harmful for humans. In these situations, reliability and adaptability are the most critical issues for the quadruped robot. During the failure of any actuator, the performance of quadruped robot is severely affected. The failure can lead to joint locking or free joint. In the case of free joint, leg joint loses actuator torque and also the capability to support the robot body on the ground. Leg joint also loses resistance to external load and acts as a free rotating hanging link. This article presents strategies for controlling a compliant legged quadruped robot in the presence of free swinging failure. The strategy is motivated by the natural crawling by infants and adapted crawling by persons with specific disabilities. Bond graph has been used for dynamic modeling of the system. The control strategy has been tested both through simulations and experiments conducted on a prototype quadruped robot.

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KOBAYASHI, Yuichi, Hideo YUASA, and Tamio ARAI. "Amusement and Engineering. Robot Soccer Using Quadruped Robots." Journal of the Japan Society for Precision Engineering 66, no. 2 (2000): 185–88. http://dx.doi.org/10.2493/jjspe.66.185.

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Khorram, Mahdi, and S. Ali A. Moosavian. "Push recovery of a quadruped robot on challenging terrains." Robotica 35, no. 8 (June 30, 2016): 1670–89. http://dx.doi.org/10.1017/s0263574716000394.

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SUMMARYLegged robots may become unstable when subjected to unexpected disturbances such as external pushes and environmental irregularities mostly while moving on natural terrains. To enhance the mobility performance, legged robots should be able to keep or restore their balanced configuration when a sudden disturbance is exerted. The aim of this article is to design a controller for a quadruped robot to restore its balanced configuration despite exerting external pushes. This is achieved based on developing a full-dynamics model of the robot moving over even and uneven terrains. The proposed controller is based on a PD module which calculates the required accelerations for restoring the robot equilibrium. However, these accelerations may make the robot unstable and also cause the slippage of stance feet. Therefore, an optimization algorithm is used to compute the maximum admissible accelerations. The constraints of the optimization problem are the conditions which guarantee the robot stability and the stance feet slippage avoidance. The optimization algorithm is transformed into a linear constrained least-squares problem to be solved in real-time. The main contributions of this article are the development of a push recovery algorithm for quadruped robots and also the introduction of an appropriate condition which guarantees the stability of the robot even on uneven terrains. This stability condition is developed based on a full-dynamics model of the robot. The proposed algorithm is applied on an 18-DOF quadruped robot when the robot is standing over both even and uneven terrains. The obtained results show that the robot can successfully restore its balanced configuration by precise adjustment of the position and orientation of its main body while a massive external disturbance is exerted.

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Tang, Zhao, Peng Qi, and Jian Dai. "Mechanism design of a biomimetic quadruped robot." Industrial Robot: An International Journal 44, no. 4 (June 19, 2017): 512–20. http://dx.doi.org/10.1108/ir-11-2016-0310.

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Purpose This paper aims to introduce a novel design of the biomimetic quadruped robot, including its body structure, three structural modes and respective workspace. Design/methodology/approach By taking a metamorphic 8-bar linkage as the body of a quadruped robot, the authors propose a reconfigurable walking robot that can imitate three kinds of animals: mammals (e.g. dog), arthropods (e.g. stick insect) and reptiles (e.g. lizard). Furthermore, to analyze the three structural modes of this quadruped robot, the workspace is calculated and studied. Findings Based on experimental data analyses, it is revealed that the metamorphic quadruped robot can walk in all its three structural modes and adapt to different terrains. Research limitations/implications Because the body of the quadruped robot is deformable and reconfigurable, the location of payload is not considered in the current stage. Practical implications The relative positions and postures of legs of the metamorphic robot can be rearranged during its body reconfiguration in such a way to combine all the features of locomotion of the three kinds of animals into one robot. So, the metamorphic quadruped robot is capable of maintaining wider stability margins than conventional rigid-body quadruped robots and conducting operations in different environments, particularly the extreme and restricted occasions due to the changeable and adaptable trunk. Originality/value The main contribution is the development of a reconfigurable biomimetic quadruped robot, which uses the metamorphic 8-bar linkage. This robot can easily reshape to three different structural modes and mimic the walking patterns of all mammals, arthropods and reptiles.

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Ren, Dongyi, Junpeng Shao, Guitao Sun, and Xuan Shao. "The Complex Dynamic Locomotive Control and Experimental Research of a Quadruped-Robot Based on the Robot Trunk." Applied Sciences 9, no. 18 (September 18, 2019): 3911. http://dx.doi.org/10.3390/app9183911.

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The research of quadruped robots is fundamentally motivated by their excellent performance in complex terrain. Maintaining the trunk moving smoothly is the basis of assuring the stable locomotion of the robot. In this paper we propose a planning and control strategy for the pacing gait of hydraulic quadruped robots based on the centroid. Initially, the kinematic model between the single leg and the robot trunk was established. The coupling of trunk motion and leg motion was elaborated on in detail. Then, the real-time attitude feedback information of the trunk was considered, the motion trajectory of the trunk centroid was planned, and the foot trajectory of the robot was carried out. Further, the joint torques were calculated that fulfillment minimization of the contact forces. The position and attitude of the robot trunk were adjusted by the presented controller. Finally, the performance of the proposed control framework was tested in simulations and on a robot platform. By comparing the attitude of the robot trunk, the experimental results show that the trunk moved smoothly with small-magnitude by the proposed controller. The stable dynamic motion of the hydraulic quadruped robot was accomplished, which verified the effectiveness and feasibility of the proposed control strategy.

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Shen, Haocheng, Jason Yosinski, Petar Kormushev, Darwin G. Caldwell, and Hod Lipson. "Learning Fast Quadruped Robot Gaits with the RL PoWER Spline Parameterization." Cybernetics and Information Technologies 12, no. 3 (September 1, 2012): 66–75. http://dx.doi.org/10.2478/cait-2012-0022.

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Abstract Legged robots are uniquely privileged over their wheeled counterparts in their potential to access rugged terrain. However, designing walking gaits by hand for legged robots is a difficult and time-consuming process, so we seek algorithms for learning such gaits to automatically using real world experimentation. Numerous previous studies have examined a variety of algorithms for learning gaits, using an assortment of different robots. It is often difficult to compare the algorithmic results from one study to the next, because the conditions and robots used vary. With this in mind, we have used an open-source, 3D printed quadruped robot called QuadraTot, so the results may be verified, and hopefully improved upon, by any group so desiring. Because many robots do not have accurate simulators, we test gait-learning algorithms entirely on the physical robot. Previous studies using the QuadraTot have compared parameterized splines, the HyperNEAT generative encoding and genetic algorithm. Among these, the research on the genetic algorithm was conducted by (G l e t t e et al., 2012) in a simulator and tested on a real robot. Here we compare these results to an algorithm called Policy learning by Weighting Exploration with the Returns, or RL PoWER. We report that this algorithm has learned the fastest gait through only physical experiments yet reported in the literature, 16.3% faster than reported for HyperNEAT. In addition, the learned gaits are less taxing on the robot and more repeatable than previous record-breaking gaits.

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Inoue, Yukinari, and Noriaki Maru. "Gait of Quadruped Robot Including Positioning Control Using Linear Visual Servoing." International Journal of Automation Technology 5, no. 5 (September 5, 2011): 649–54. http://dx.doi.org/10.20965/ijat.2011.p0649.

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Quadruped robots walking in discrete environments conventionally control leg swinging using either simple potentiometer-based feedback or feed forward. We think accurate positioning control for a safe landing using visual servoing is required. Conventional visual servoing, however, has problems such as requiring complex nonlinear calculation with exact camera and joint angles. To solve these problems, we propose Linear Visual Servoing (LVS) for positioning the quadruped robot leg in a gait. We show that the robot can make minor adjustments despite error between planned and safe landing points.

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Lin, Chyi Yeu, Yi Pin Chiu, Li Chieh Cheng, Chun Chia Huang, Po Chia Jo, and Wei Lung Lin. "Panda Robot: Kinematic Design and Simulation for Quadrupedal Walking." Applied Mechanics and Materials 284-287 (January 2013): 1888–93. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.1888.

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For most quadruped robots, their waist joints can usually pitch or yaw, but cannot roll. Thus, their gaits can only be simulated by a simple motion model based on single-legged mechanisms. When pandas move on their four feet, they swing their hips and rear legs from side to side. Thus, the purpose of this study is to develop a quadruped robot which is equipped with a waist joint of one degree of freedom (DOF) for rolling so as to imitate the waist-swinging motion of a real panda. This research starts at editing the predetermined motion conditions with lengths of all panda body parts and the mechanism model with corresponding degree-of-freedom in the CAE software. The related simulation parameters of leg motions are acquired as a reference for gait controls. The quadrupedal walking process was tested in simulators to verify important design variables and simulation validity was also verified on the actual panda robot after their buildup. With this approach, this study has effectively and successfully developed a panda robot with a waist joint that can roll.

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Fujita, Masahiro. "Human Friendly Robots. Robot Entertainment: A Small Quadruped Autonomous Robot." Journal of the Robotics Society of Japan 16, no. 3 (1998): 313–14. http://dx.doi.org/10.7210/jrsj.16.313.

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Ha, Sehoon, Stelian Coros, Alexander Alspach, Joohyung Kim, and Katsu Yamane. "Computational co-optimization of design parameters and motion trajectories for robotic systems." International Journal of Robotics Research 37, no. 13-14 (June 5, 2018): 1521–36. http://dx.doi.org/10.1177/0278364918771172.

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We present a novel computational approach to optimizing the morphological design of robots. Our framework takes as input a parameterized robot design as well as a motion plan consisting of trajectories for end-effectors and, optionally, for its body. The algorithm optimizes the design parameters including link lengths and actuator placements whereas concurrently adjusting motion parameters such as joint trajectories, actuator inputs, and contact forces. Our key insight is that the complex relationship between design and motion parameters can be established via sensitivity analysis if the robot’s movements are modeled as spatiotemporal solutions to an optimal control problem. This relationship between form and function allows us to automatically optimize the robot design based on specifications expressed as a function of actuator forces or trajectories. We evaluate our model by computationally optimizing four simulated robots that employ linear actuators, four-bar linkages, or rotary servos. We further validate our framework by optimizing the design of two small quadruped robots and testing their performances using hardware implementations.

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Wang, Peng, Jixiang Li, and Yuan Zhang. "The Nonfragile Controller with Covariance Constraint for Stable Motion of Quadruped Search-Rescue Robot." Advances in Mechanical Engineering 6 (January 1, 2014): 917381. http://dx.doi.org/10.1155/2014/917381.

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The problem of a stable motion for the quadruped search-rescue robots is described as a variance constrained uncertainty in the discrete systems. According to the model structure of the quadruped search-rescue robot, the kinematics of the robot is analyzed on the basis of the D- H parameter. Each joint of the robot angular velocity is planned using the Jacobian matrix, because the angular velocity is directly related to the stability of walking based on the ADAMS simulation. The nonfragile control method with the covariance constraint is proposed for the gait motion control of the quadruped search-rescue robot. The motion state feedback controller and the covariance upper bounds can be given by the solutions of the linear matrix inequalities (LMI), which makes the system satisfy the covariance constrain theory. The results given by LMI indicate that the proposed control method is correct and effective.

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Kim, Joonyoung, Taewoong Kang, Dongwoon Song, and Seung-Joon Yi. "Design and Control of a Open-Source, Low Cost, 3D Printed Dynamic Quadruped Robot." Applied Sciences 11, no. 9 (April 22, 2021): 3762. http://dx.doi.org/10.3390/app11093762.

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In this paper, we present a new open source dynamic quadruped robot, PADWQ (pronounced pa-dook), which features 12 torque controlled quasi direct drive joints with high control bandwidth, as well as onboard depth sensor and GPU-equipped computer that allows for a highly dynamic locomotion over uncertain terrains. In contrast to other dynamic quadruped robots based on custom actuator and machined metal structural parts, the PADWQ is entirely built from off the shelf components and standard 3D printed plastic structural parts, which allows for a rapid distribution and duplication without the need for advanced machining process. To make sure that the plastic structural parts can withstand the stress of dynamic locomotion, we performed finite element analysis (FEA) on leg structural parts as well as a continuous walking test using the physical robot, both of which the robot has passed successfully. We hope this work to help a wide range of researchers and engineers that need an affordable, highly capable and easily customizable quadruped robot.

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Chen, Guangrong, Sheng Guo, Bowen Hou, and Junzheng Wang. "Virtual Model Control for Quadruped Robots." IEEE Access 8 (2020): 140736–51. http://dx.doi.org/10.1109/access.2020.3013434.

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Shakourzadeh, Shabnam, and Mohammad Farrokhi. "Fuzzy-backstepping control of quadruped robots." Intelligent Service Robotics 13, no. 2 (January 6, 2020): 191–206. http://dx.doi.org/10.1007/s11370-019-00309-3.

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Adachi, Hironori, Noriho Koyachi, Tatsuya Nakamura, and Eiji Nakano. "Development of Quadruped Walking Robots and Their Gait Study." Journal of Robotics and Mechatronics 5, no. 6 (December 20, 1993): 548–60. http://dx.doi.org/10.20965/jrm.1993.p0548.

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This paper describes the quadruped walking robots developed at the Mechanical Engineering Laboratory and their gait analysis. Legged locomotion has the potential to adapt itself to changes in walking conditions, but also has problems such as complexity. To overcome these problems, a new link mechanism called ASTBALLEM is used for the legs of the robots, and highly rigid and easily controllable legs are constructed by using this mechanism. To make a legged robot walk stably, it is necessary to provide a suitable gait. In this paper, two kinds of gaits are considered. One is the periodic gait, and it is systematically classified by two parameters. By using this classification method, suitable gaits for static walking and dynamic walking are selected. The other is the adaptive gait. In order to realize their potentials, walking robots must sense the walking conditions and change their gaits. Two adaptive gait schemes are proposed in this paper. One is a gait which adapts to the position of the center of gravity, and the other is a gait for incline terrain. Both gaits use force sensor data for detecting changes in the walking conditions. All the gaits discussed in this paper are experimentally evaluated.

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Zeng, Xuanqi, Songyuan Zhang, Hongji Zhang, Xu Li, Haitao Zhou, and Yili Fu. "Leg Trajectory Planning for Quadruped Robots with High-Speed Trot Gait." Applied Sciences 9, no. 7 (April 11, 2019): 1508. http://dx.doi.org/10.3390/app9071508.

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In this paper, a single leg platform for quadruped robots is designed based on the motivation of high-speed locomotion. The leg is designed for lightweight and low inertia with a structure of three joints by imitating quadruped animals. Because high acceleration and extensive loadings will be involved on the legs during the high-speed locomotion, the trade-off between the leg mass and strength is specifically designed and evaluated with the finite element analysis. Moreover, quadruped animals usually increase stride frequency and decrease contact time as the locomotion speed increases, while maintaining the swing duration during trot gait. Inspired by this phenomenon, the foot-end trajectory for quadruped robots with a high-speed trot gait is proposed. The gait trajectory is planned for swing and stance phase; thus the robot can keep its stability with adjustable trajectories while following a specific gait pattern. Especially for the swing phase, the proposed trajectory can minimize the maximum acceleration of legs and ensure the continuity of position, speed, and acceleration. Then, based on the kinematics analysis, the proposed trajectory is compared with the trajectory of Bézier curve for the power consumption. Finally, a simulation with Webots software is carried out for verifying the motion stability with two trajectory planning schemes respectively. Moreover, a motion capture device is used for evaluating the tracking accuracy of two schemes for obtaining an optimal gait trajectory suitable for high-speed trot gait.

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Lei, Jing Tao, and Feng Wang. "Energy Consumption Analysis of Quadruped Robot with Trot Gait." Applied Mechanics and Materials 271-272 (December 2012): 1531–35. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.1531.

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Energy consumption is one of the important evaluating indicators for walking robots. In this paper, the kinematics modeling of quadruped robot with trot gait was analyzed firstly. And then the dynamics modeling was analyzed, which considering periodic contact force between foots and ground during walking, and considering the elastic elements. Finally, the total energy consumption of walking robot during whole gait cycle was derived based on the dynamic model. The specific resistance was proposed to evaluate energy efficiency of quadruped robot with trot gait, and the relationship between specific resistance and gait parameters was presented, which will be used to analyze the energy efficiency and influencing factors, and then determine the reasonable gait parameters.

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Zhe, Xu, Gao Junyao, Li Hui, Liu Huaxin, Li Xin, Liu Yi, Sun Wentao, and Zhao Wenxue. "The modeling and controlling of electrohydraulic actuator for quadruped robot based on fuzzy Proportion Integration Differentiation controller." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 14 (January 21, 2014): 2557–68. http://dx.doi.org/10.1177/0954406213519613.

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Hydraulic actuators are widely used in various kinds of industrial applications. High-power density is key parameters for engineering applications especially for quadruped robots applied in the outdoor environment. Therefore, an increasing number of advanced robots are equipped with hydraulic actuators. In this paper, to compensate the inherent nonlinearities and enhance the performance of the quadruped robot, a hybrid fuzzy controller composed of fuzzy logic controller and Proportion Integration Differentiation controller is evaluated both in simulations and experiments. The control strategy is developed based on the accurate mathematical model. The Matlab Simulink and Fuzzy Logic Toolbox are implemented to accomplish the simulations under flexible loads. Single hydraulic actuator and single leg experiments are accomplished on the specific platforms. Both the simulations and the experimental results indicate that the fuzzy Proportion Integration Differentiation control strategy is capable of fulfilling the specific position tracking under diverse loads. Compared with the conventional Proportion Integration Differentiation controller, the fuzzy Proportion Integration Differentiation controller provided a desirable performance under heavy load with comparatively little response and settling time. Results show that the fuzzy Proportion Integration Differentiation control strategy can effectively achieve the objective of enhancing position tracking robustness under flexible loads and improve the performance of quadruped robot.

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Raheem, Firas A., and Murtadha Khudhair Flayyih. "Creeping Gait Analysis and Simulation of a Quadruped Robot." Al-Khwarizmi Engineering Journal 14, no. 2 (March 14, 2019): 93–106. http://dx.doi.org/10.22153/kej.2018.12.004.

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A quadruped (four-legged) robot locomotion has the potential ability for using in different applications such as walking over soft and rough terrains and to grantee the mobility and flexibility. In general, quadruped robots have three main periodic gaits: creeping gait, running gait and galloping gait. The main problem of the quadruped robot during walking is the needing to be statically stable for slow gaits such as creeping gait. The statically stable walking as a condition depends on the stability margins that calculated particularly for this gait. In this paper, the creeping gait sequence analysis of each leg step during the swing and fixed phases has been carried out. The calculation of the minimum stability margins depends upon the forward and inverse kinematic models for each 3-DOF leg and depends on vertical geometrical projection during walking. Simulation and results verify the stability insurance after calculation the minimum margins which indicate clearly the robot COG (Center of Gravity) inside the supporting polygon resulted from the leg-tips.

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Ha, Sehoon. "Quadrupedal robots trot into the wild." Science Robotics 5, no. 47 (October 21, 2020): eabe5218. http://dx.doi.org/10.1126/scirobotics.abe5218.

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Ikeda, Masahiro, and Ikuo Mizuuchi. "Analysis of the Energy Loss on Quadruped Robot Having a Flexible Trunk Joint." Journal of Robotics and Mechatronics 29, no. 3 (June 20, 2017): 536–45. http://dx.doi.org/10.20965/jrm.2017.p0536.

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[abstFig src='/00290003/09.jpg' width='300' text='Energy flow in legged robot' ] As a method of robot movement, legs have the advantage of traversability on rough terrain. However, the motion of a legged robot is accompanied by energy loss. The main causes for this loss could be negative work and contact between the legs and ground. On the other hand, animals with legs are considered to reduce energy loss by using the elasticity of their body. In this study, we analyze the influence of walking, using an elastic passive joint mounted on the trunk of a quadruped robot, on the energy loss. Additionally, we study the energy flow between legs and elastic components. In this study, we clarify a control method for quadruped robots in order to reduce the energy loss of walking. The results of simulating a quadruped walking robot, which has passive joints with elastic components on the trunk, are analyzed and the relationship between each kind of energy loss and the trunk joint’s elasticity is clarified.

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Hua, Zisen, Xuewen Rong, Yibin Li, Hui Chai, Bin Li, and Shuaishuai Zhang. "Analysis and Verification on Energy Consumption of the Quadruped Robot with Passive Compliant Hydraulic Servo Actuator." Applied Sciences 10, no. 1 (January 2, 2020): 340. http://dx.doi.org/10.3390/app10010340.

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The hydraulic servo actuator with passive compliance (HPCA) is designed for hydraulically-driven quadruped robots. It is characterized by an accumulator that connects to the piston chamber of the hydraulic cylinder to buffer impact forces between a robot’s feet and the ground. This paper studies the energy efficiency of this actuator in the dynamic locomotion of a quadruped robot. Different from the traditional methods of storing potentially recyclable energy using accumulators, the energy-saving principle of HPCA is to utilize the pressure-transition characteristics of the asymmetric hydraulic cylinder with control of the symmetrical valve. The accumulator can store and release oil during the switching of the transition point in each gait cycle of the robot, thereby improving the energy efficiency of the actuator. The influence of the initial inflation pressure and working volume of the accumulator on the energy efficiency of the HPCA is studied by simulation and physical experiments. The results show that the HPCA has a higher energy efficiency that is independent of the physical parameters of the accumulator.

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FUJIOKA, Toru, Hisashi OSUMI, and Ryosuke NAKAMURA. "1A1-P02 Curved Walking for Quadruped Robots(Walking Robot (1))." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2013 (2013): _1A1—P02_1—_1A1—P02_4. http://dx.doi.org/10.1299/jsmermd.2013._1a1-p02_1.

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SUZUKI, Yuhdai, and Takeshi AOKI. "2A2-Q10 Study of Quadruped Robot with Spherical Shell : Development of quadruped robots to allow locomotion." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2015 (2015): _2A2—Q10_1—_2A2—Q10_2. http://dx.doi.org/10.1299/jsmermd.2015._2a2-q10_1.

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Journal articles on the topic 'Quadruped Robots'

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