Academic literature on the topic 'Mobile vertical turning center'

The article introduction provides an overview of the historical development of mechatronic devices, from ancient times to the present. It is emphasized that the development of modern robotics in relation to work in aggressive environments is a very urgent task. Especially important is the creation of autonomous functioning robots to work in high radiation areas, chemically contaminated areas, demining, fire extinguishing, etc. Then this article presents material on the physics of a mechanical system motion, which is a mobile platform with three roller-bearing wheels, or so-called omni-wheels. This question is revealed on the basis of the derivation of the kinematic equations for the platform motion, based on transformation matrices, which allow to obtain the total dependences of the projections of the linear velocities of the roller-bearing wheels on the axis of the fixed (base) coordinate system. It is indicated that the transition to movement from the position at to the position at can be carried out in two ways. In the first method, the robot turns around on the center of mass by creating a torque about the vertical axis of the robot, followed by movement parallel to the axis . In the second method, by creating such a state of the wheels, i.e. the magnitude of the linear velocity and its direction, which will ensure a linear movement of the center of mass of the robot in a given direction without first rotating the body about the vertical axis. It is noted that the first method in relation to the second has both advantages and disadvantages. The advantages include ease of management and the ability to rigidly fix the camera of the review on the platform body. However, this method is more energy consuming and requires additional time for the implementation of the camera turn to a given direction. The second method is not deprived of these drawbacks, and the overview camera may have a turning mechanism, which ensures its independent functioning from the platform position control system. Given this, the kinematics of the movement of the platform according to the second method are considered. As an example, it is shown that by jointly solving the obtained kinematic equations, for example, for selected mutually perpendicular directions of the platform mass center movement, characterized by angles or , it is easy to explain the physics of platform moving in a given direction from any starting position without first turning to a given direction.

A computerized 360 degrees panorama allowed us to suppress most of the locomotion-induced visual feedback of a freely walking fly without neutralizing its mechanosensory system ('virtual open-loop' conditions). This novel paradigm achieves control over the fly's visual input by continuously evaluating its actual position and orientation. In experiments with natural visual feedback (closed-loop conditions), the optomotor turning induced by horizontal pattern motion in freely walking Drosophila melanogaster increased with the contrast and brightness of the stimulus. Conspicuously striped patterns were followed with variable speed but often without significant overall slippage. Using standard open-loop conditions in stationary walking flies and virtual open-loop or closed-loop conditions in freely walking flies, we compared horizontal turning induced by either horizontal or vertical motion of appropriately oriented rhombic figures. We found (i) that horizontal displacements and the horizontal-motion illusion induced by vertical displacements of the oblique edges of the rhombic figures elicited equivalent open-loop turning responses; (ii) that locomotion-induced visual feedback from the vertical edges of the rhombic figures in a stationary horizontal position diminished the closed-loop turning elicited by vertical displacements to only one-fifth of the response to horizontal displacements; and (iii) that virtual open-loop responses of mobile flies and open-loop responses of immobilized flies were equivalent in spite of delays of up to 0.1 s in the generation of the virtual stimulus. Horizontal compensatory turning upon vertical displacements of oblique edges is quantitatively consistent with the direction-selective summation of signals from an array of elementary motion detectors for the horizontal stimulus components within their narrow receptive fields. A compensation of the aperture-induced ambiguity can be excluded under these conditions. However, locomotion-induced visual feedback greatly diminished the horizontal-motion illusion in a freely walking fly. The illusion was used to assay the quality of open-loop simulation in the new paradigm.

Taking the high-speed CX series vertical milling compound machining center of CX8075 produced by Anyang Xinsheng Machine Tool Co., Ltd. as example, the machine three-dimensional simplified model is established, the source of the heat and the distribution of the important hot-points are analyzed, the machine temperature field distribution is derived which lays a foundation for the thermal error compensation. Taking into account the moving part-saddle of the machining center, its mathematic model is obtained, the important hot-points are studied, the thermodynamic parameters are determined. Based on ANSYS finite element method, the steady-state temperature field and the thermal deformation of saddle are presented, the optimal design of high-speed and high-accuracy machine tool is doned and its thermal deformation analysis is realized.

Abstract This paper proposes a system that allows the control of the lights in a house, building/edifice. The system can be controlled by an application that is made in MIT App Inventor for mobile devices that use Android OS(operating system). The application sends data, via Bluetooth, to the control center, the control center powers on the selected light by turning it on and setting its intensity based on the user preferences. The control center is made from an Arduino Nano programing board, the signal used for powering the lights and setting the brightness is a PWM (Pulse Width Modulation) signal. The system contains the Arduino Nano board, Bluetooth HC-05 module for communication with the mobile application and four LED’s that are used to simulate the lights.

The obstacle surmounting capability of traditional spherical mobile robot is limited, especially when the spherical mobile robot comes across vertical barrier. In this paper we design a new kind of spherical mobile robot with two-mass-one-spring mechanism based on tradition spherical mobile robot. This spherical robot could not only move agility and move with the zero turning radius like traditional spherical mobile robot but also jump in three-dimensional space. In this paper we build the mathematical model of robot jumping with friction. Numeric simulations are carried out for the model using Matlab and ADAMS, we get the similar curve. These simulation results verify the validity of the mechanics model. At last we design an experimental facility, verify the model of robot jumping by experiment. Our work will be the base of model machine designing.

Remarkable similarities in the vertical plane of forward motion exist among diverse legged runners. The effect of differences in posture may be reflected instead in maneuverability occurring in the horizontal plane. The maneuver we selected was turning during rapid running by the cockroach Blaberus discoidalis, a sprawled-postured arthropod. Executing a turn successfully involves at least two requirements. The animal's mean heading (the direction of the mean velocity vector of the center of mass) must be deflected, and the animal's body must rotate to keep the body axis aligned with the heading. We used two-dimensional kinematics to estimate net forces and rotational torques, and a photoelastic technique to estimate single-leg ground-reaction forces during turning. Stride frequencies and duty factors did not differ among legs during turning. The inside legs ended their steps closer to the body than during straight-ahead running, suggesting that they contributed to turning the body. However, the inside legs did not contribute forces or torques to turning the body, but actively pushed against the turn. Legs farther from the center of rotation on the outside of the turn contributed the majority of force and torque impulse which caused the body to turn. The dynamics of turning could not be predicted from kinematic measurements alone. To interpret the single-leg forces observed during turning, we have developed a general model that relates leg force production and leg position to turning performance. The model predicts that all legs could turn the body. Front legs can contribute most effectively to turning by producing forces nearly perpendicular to the heading, whereas middle and hind legs must produce additional force parallel to the heading. The force production necessary to turn required only minor alterations in the force hexapods generate during dynamically stable, straight-ahead locomotion. A consideration of maneuverability in the horizontal plane revealed that a sprawled-postured, hexapodal body design may provide exceptional performance with simplified control.

Training subjects to step in place on a rotating platform while maintaining a fixed body orientation in space produces a posteffect consisting in inadvertent turning around while stepping in place eyes closed (podokinetic after-rotation, PKAR). We tested the hypothesis that voluntary turning around while stepping in place also produces a posteffect similar to PKAR. Sixteen subjects performed 12 min of voluntary turning while stepping around their vertical axis eyes closed and 12 min of stepping in place eyes open on the center of a platform rotating at 60°/s (pretests). Then, subjects continued stepping in place eyes closed for at least 10 min (posteffect). We recorded the positions of markers fixed to head, shoulder, and feet. The posteffect of voluntary turning shared all features of PKAR. Time decay of angular velocity, stepping cadence, head acceleration, and ratio of angular velocity after to angular velocity before were similar between both protocols. Both postrotations took place inadvertently. The posteffects are possibly dependent on the repeated voluntary contraction of leg and foot intrarotating pelvic muscles that rotate the trunk over the stance foot, a synergy common to both protocols. We propose that stepping in place and voluntary turning can be a scheme ancillary to the rotating platform for training body segment coordination in patients with impairment of turning synergies of various origin.

In this work, the design, manufacturing, instrumentation, and application of a two-finger exoskeleton with force feedback are presented. The exoskeleton is based on remote center of motion mechanisms in order to avoid mechanical interference with the user’s fingers and is manufactured by three-dimensional printing. The developed exoskeleton is applied in a mobile robot teleoperation by mapping the finger movements in forward and turning commands for the robot. The presence of obstacles detected by the robot is sensed by the user by means of a feedback force. The problem of simultaneously communicating a data acquisition card and the robot hardware by MATLAB ® Simulink® was solved by using an external Wi-Fi module. The result is a lightweight exoskeleton which is able to communicate bidirectionally with a mobile robot by a personal computer for teleoperation tasks. The success of the system implementation is proven by a set of experiments presented in the final part of the article.

This paper proposes a real-time embedded system for joint space control of omnidirectional mobile robots. Actuators driving an omnidirectional mobile robot are connected in a line topology which requires synchronization to move simultaneously in translation and rotation. We employ EtherCAT, a real-time Ethernet network, to control servo controllers for the mobile robot. The first part of this study focuses on the design of a low-cost embedded system utilizing an open-source EtherCAT master. Although satisfying real-time constraints is critical, a desired trajectory on the center of the mobile robot should be decomposed into the joint space to drive the servo controllers. For the center of the robot, a convolution-based path planner and a corresponding joint space control algorithm are presented considering its physical limits. To avoid obstacles that introduce geometric constraints on the curved path, a trajectory generation algorithm considering high curvature turning points is adapted for an omnidirectional mobile robot. Tracking a high curvature path increases mathematical complexity, which requires precise synchronization between the actuators of the mobile robot. An improvement of the distributed clock—the synchronization mechanism of EtherCAT for slaves—is presented and applied to the joint controllers of the mobile robot. The local time of the EtherCAT master is dynamically adjusted according to the drift of the reference slave, which minimizes the synchronization error between each joint. Experiments are conducted on our own developed four-wheeled omnidirectional mobile robot. The experiment results confirm that the proposed system is very effective in real-time control applications for precise motion control of the robot even for tracking high curvature paths.

The paper sums up results achieved during in the last few years of the development and research of service robots aiming their use for service applications on vertically oriented walls with predominantly smooth contact surfaces having minimal altitude unevenesses within the range ± 5 mm. Two robot generations are described step by step, and both of them use the same mechanical principle of the patented system of motion. The system uses the intermittent motion when positions of the robot legs and body alternate cyclically, and the appropriate gripping force of a holding-down system is realized by vacuum. As compared with the first version, the current one allows legs to move independent in part. In that way it is possible to compensate better variations of parallelism between a contact plane of the robot holding-down system and a vertical wall. Moreover, the robot is provided with a rotary unit making possible a rotation on the axis going through the robot center and being perpendicular to the contact plane, which guarantees a change in the robot orientation in the plane. As for drives, very compact rotary actuating mechanisms (servo drives) are used, having a high ratio of power parameters in relation to weight and dimensions, combined with a control based on an industrial PC.