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1
Fahlén, Daniel, and Ludvig Fri. "Modelling and Control of a Forklift’s Hydraulic Lowering Function." Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-139247.
Повний текст джерелаАнотація:
Material handling and logistics are fundamental parts of today’s global societyand forklifts are a crucial part of the material handling process. Making these asefficient and reliable as possible are therefore of great interest. In this master thesis, an effort has been made to improve the control of the hydraulic lowering function of a specific forklift. Today the lowering function iscontrolled through an open-loop control scheme making the control performancesensitive to disturbances and system changes. One disturbance of special interestis the temperature of the hydraulic fluid. The goal of this thesis was therefore todesign a controller with improved robustness as well as improved performance. To solve this a model-based control design approach was used and a nonlineargrey-box model was derived, implemented and validated. The model parameterswere estimated using a nonlinear least-squares optimisation problem. The resulting model captures most of the system dynamics and the model fit is higher than 70% which was deemed good enough to use for control design. A PID controller was designed based on the estimated model and the controllerparameters were optimised. Furthermore, the controller was evaluated in simulations and implemented in a real forklift. The proposed controller was compared to the original controller for various scenarios. The results reveal improvedsteady state behaviour with enhanced temperature robustness compared to theoriginal controller.Materialhantering och logistik är viktigt för att dagens globala samhälle ska fungera. En grundläggande del i materialhanteringsprocessen är gaffeltruckar, därför är det av intresse att göra gaffeltruckar så effektiva och pålitliga som möjligt. I det här examensarbetet har ett försök gjorts till att förbättra styrningen av den hydrauliska sänkningsfunktionen hos en specifik gaffeltruck. Dagens lösning använder sig av öppen styrning vilket gör reglerprestandan känslig för störningar och systemförändringar. En störning av extra intresse är temperaturen av hydraulvätskan. Målet med detta arbete var därför att designa en regulator med ökad robusthet och prestanda. För att lösa detta har en modellbaserad metod för regulatordesign använts där en olinjär gray-box modell härleddes, implementerades och validerades. Modellparametrarna skattades genom att ställa upp och lösa ett ickelinjärt minsta-kvadrat optimeringsproblem. Den resulterande modellen fångar det mesta av systemdynamiken och modellpassningen till uppmätt data var högre än 70\% vilket ansågs bra nog för att kunna använda modellen som en bas för regulatordesign. En PID regulator designades och regulatorparametrarna optimerades med hjälp av modellen. Regulatorn utvärderades i simuleringar och för att sedan implementeras den på en riktig gaffeltruck. Den föreslagna regulatorn jämfördes med den ursprungliga regulatorn i flera olika testfall. Resultaten visade ett bättre steady-state beteende och ökad robusthet mot temperaturförändringar för den designade regulatorn jämfört med den ursprungliga regulatorn.
2
Скворчевський, Олександр Євгенович, та Христина Михайлівна Віленська. "Електрогідравлічні мехатронні модулі поступального руху: історія, сучасний стан, перспективи розвитку". Thesis, Харківський національний автомобільно-дорожній університет, 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/28258.
Повний текст джерелаАнотація:
Метою робота є аналіз існуючих електрогідравлічних мехатронних модулів поступального руху, виявлення основних напрямків їх розвитку та перспектив подальшого вдосконалення. В результаті прослідковано еволюцію таких систем. Запропоноване схемне рішення мехатронного модуля для проведення подальших науково-дослідних та проектно-конструкторських робіт в цьому напрямку.The aim is to analyze existing electro-mechatronic modules translational motion, identifying the main areas of development and prospects for further improvement. The result followed the evolution of such systems. The proposed schematics mechatronic module for further research and design work in this direction.
3
Bodin, Erik, and Henric Davidsson. "Model-Based Design of a Fork Control System in Very Narrow Aisle Forklifts." Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138049.
Повний текст джерелаАнотація:
This thesis explains the model-based design of a fork control system in a turret head operated Very Narrow Aisle forklift in order to evaluate and push the limits of the current hardware architecture. The turret head movement consists of two separate motions, traversing and rotation, which both are hydraulically actuated. The plant is thoroughly modeled in the Mathworks softwares Simulink/Simscape to assist in the design of the control system. The control system is designed in Simulink/Stateflow and code-generated to be evaluated in the actual forklift. Optimal control theory is used to generate a minimum-jerk trajectory for auto-rotation, that is simultaneous traversing and rotation with the load kept in centre. The new control system is able to control the system within the positioning requirements of +/- 10 mm and +/- 9 mrad for traversing and rotation, respectively. It also shows good overall performance in terms of robustness since it has been tested and validated with different loads and on different versions of the forklift. However, the study also shows that the non-linearities of the system, especially in the hydraulic proportional valves, causes problems in a closed-loop control system. The work serves as a proof of concept for model-based development at the company since the development time of the new control system was significantly lower than for the original control system.
4
Kontz, Matthew Edward. "Haptic Control of Hydraulic Machinery Using Proportional Valves." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19876.
Повний текст джерелаАнотація:
Supplying haptic or force feedback to operators using hydraulic machinery such as excavators has the potential to increase operator capabilities. Haptic, robotic, human-machine interfaces enable several enhancing features including coordinated motion control and programmable haptic feedback. Coordinated or resolved motion control supplies a more intuitive means of specifying the equipment's motion. Haptic feedback is used to relay meaningful information back to the user in the form of force signals about digging force acting on the bucket, programmable virtual constraints and system limitations imposed by the mechanism, maximum pressure or maximum flow. In order to make this technology economically viable, the benefits must offset the additional cost associated with implementation. One way to minimize this cost is to not use high-end hydraulic components. For smaller backhoes and mini-excavators this means that the hydraulic systems are comprised of a constant displacement pump and proportional direction control valves. Hydraulic and haptic control techniques suitable for backhoes/excavators are developed and tested on a small backhoe test-bed. A virtual backhoe simulator is created for controller design and human evaluation. Not only is the virtual simulator modeled after the test-bed, but the control algorithm used in the simulator is the same as the actual backhoe test-bed. Data from human subject tests are presented that evaluate the control strategies on both the real and virtual backhoe. The end goal of this project is to incorporate coordinated haptic control algorithms that work with low-cost systems and maximize the enhancement of operator capabilities.
5
Hoferek, Martin. "Řízení proporcionálního hydraulického ventilu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316385.
Повний текст джерелаАнотація:
The thesis deals with design and implementation of proportional hydraulic valve, which will be integrated to hydraulic system of small hydro in Rájec - Jestřebí. This valve will be used to control one of the wicket gates of double Francis turbine. The thesis is processed for the company Mavel a.s., which is the owner of SH. The goal of this thesis is to create control of the valve according to the client's requirements, its implementation to the control system and commissioning.
6
Vácha, Ondřej. "Testovaní charakteristiky proporcionální hydraulické kostky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400453.
Повний текст джерелаАнотація:
Goal of this thesis is to verify functions of hydraulic manifolds from new supplier, measure characteristics of pressure loss relative to flow rate and for proportional blocks also characteristics of flow rate relative to control voltage at constant inlet pressure. Verification will be carried out with proportional manifolds and on/off manifolds with different failure functions.
7
André, Simon. "Design and Optimization of Controllers for an Electro-Hydraulic System." Thesis, Linköpings universitet, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-107620.
Повний текст джерелаАнотація:
Electro-Hydraulic (EH) systems are commonly used in the industry for applications that require high power-weight ratios and large driving forces. The EH system studied in this master thesis have recently been upgraded with new hardware components and as a part of this upgrade a new controller was requested. The system consists of a controller that computes a control signal for an electric motor. The motor drives a gear pump that generates a flow of hydraulic fluid. The flow is then directed to a cylinder. The movements of a piston in the cylinder is affected by the flow and the piston position can be measured. The measured piston position is then fed back to the controller and the control loop is complete. The system was previously controlled using a Proportional-Integral-Derivative (PID) controller and the purpose of this thesis is to compare the old controller with alternative control strategies suitable for this application. The evaluation of the controllers is based on both software and hardware simulations and results in a recommendation for final implementation of the best suited controller. The control strategies chosen for investigation are: a retuned PID controller, a PID controller with feed forward from reference, a PID based cascade controller, a Linear Quadratic (LQ) controller, and a Model Predictive Controller (MPC). To synthesize the controllers an approximate model of the system is formed and implemented in the software environment Matlab Simulink. The model is tuned to fit recorded data and provides a decent estimation of the actual system. The proposed control strategies are then simulated and evaluated in Simulink with the model posing as the real system. These simulations resulted in the elimination of the cascade controller as a possible candidate since it proved unstable for large steps in the reference signal. The remaining four controllers were all selected for simulation on the real hardware system. Unfortunately the MPC was never successfully implemented on the hardware due to some unknown compatibility error and hence eliminated as a possible candidate. The three remaining control strategies, PID, PID with feed forward from reference and the LQ controller, were all successfully implemented and simulated on hardware. The results from the hardware simulations compared to simulations made with the old controller, as well as the results from the software simulations, were then evaluated. Depending on the purpose one of two control strategies is recommended for this application. The LQ controller achieved the best overall performance and is presented as the control strategy best suited for this application.
8
Vintr, Pavel. "Lineární jednotka s hydraulickým pohonem pro robot s paralelní kinematickou strukturou." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230468.
Повний текст джерелаАнотація:
This Master thesis deals with the design of linear unit with hydraulic actuator for the robot with parallel kinematic structure. One of the objectives is to get an overview of the differences related to characteristics of design and construction between serial and parallel kinematic structure (PKS) of the industrial robots, as a new type of technical objects in robotics. In addition the aim is to create an original structural design of linear unit, as the basic constructional assembly and operational node of robot with PKS, according to the specified input values, such as power, pressure, speed and stroke, important for the design of linear hydraulic actuator.
9
Huang, Szu-Wei, and 黃思維. "Hydraulic Characteristics of Detention Dam with Linear Proportional." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/11039002092875420986.
Повний текст джерелаАнотація:
碩士國立中興大學
土木工程學系
92
Abstract A detention pond is practically set to reduce the peak flow, delay the peak time and alleviate the amount of excess flood due to the upstream development. Linear proportional weirs are used in this study. The outlet has a rectangular base over which a fitting shape is designed. This special arrangement allows a rapid discharge prior to the arrival of peak flow thus leaves a greater capacity to accommodate the income flood. A numerical hydrological routing model is proposed to investigate the characteristics of flood detention with six linear proportional weirs considering six triangular and five trapezoidal inflow hydrographs. The detention pond experiments are also carried out to verify the suitability of proposed numerical model. The results of the study are outlined as follow: 1. Based on the hydrology continuity equation (3-15) and linear proportional weir discharge equation (3-17), we can calculate the governing equations (3-29) to (3~31) of triangular and trapezoidal inflow hydrographs. By using the Runge-Kutta numerical method together with the verified results from the detention pond experiment, the numerical model can provide a good way for flow prediction. 2. In this research, the regression formulas for peak reduction κ of linear proportional weir in equations (5-2), (5-3) with triangular hydrographs and in equations (5-6), (5-7) representing trapezoidal hydrographs are obtained. By using these regression formulas, we can ratiocinate the value of κ is less when the bottom width b or height a of rectangular outlet is larger, while the value of κ becomes larger when the ratio of shape a/b is greater. As for the dimensionless peak lag time Ts , it increases when the characteristic parameter of the triangular or trapezoidal inflow hydrograph increases. In addition, Ts is larger than zero when the value of κ approaches zero. It means that the peak time can have a lag although peak discharge is not reduced. Equations (5-4) and (5-8) are the regression formulas of Ts with κ and characteristic parameters 、 for references. 3. With comparison of the differences of storage volume between triangular and trapezoidal inflow hydrographs, it can be seen that the detention pond of trapezoidal hydrograph needs larger dimensionless storage volume than that of the triangular hydrograph when peak outflow is the same. Figures 5-20 and 5-33 show the storage volume for the linear proportion weir is less than that of the rectangular spillway. It is implied that the outlet for the linear proportional weir has a better detention effect. Also, the regression formulas for with κ of triangular and trapezoidal inflow hydrographs in equations (5-5) and (5-9) are provided for references.
10
XIE, YI-ZHE, and 謝佾哲. "CFD Simulation and Experimental Investigation of Hydraulic Proportional Damper." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/f5gm3e.
Повний текст джерелаАнотація:
碩士國立雲林科技大學
機械工程系
107
In this paper, the CFD simulation of the hydraulic proportional suspension damper is used to analyze various fluid phenomena such as fluid pressure, flow, flow line and shock absorber damping force inside the electronically controlled proportional valve. Firstly, it is practicall impossible to get the corresponding value of the correct opening of the main and pilot stage inside the electronically controlled proportional valve. This parameter is an important boundary condition when executed CFD simulation analysis. On the other hand, it is also clear that the CFD simulation cannot be executed if the boundary conditions for the simulation are unknown. To solve this problem, the force equilibrium equation for the main stage is derived. From this equation, the corresponding value of the correct opening of the main and pilot stage can be determined by trial-and-error approach. This study also focuses on the three critical dimensions inside the electronically controlled proportional valve, and explore the influence of the dimension changes on the damping force of the shock absorber and the evaluation of the soft and hard design of the shock absorber. Finally, this study tests the performance of the shock absorber through the shock absorber test bench. The relationship between the damping force and velocity of the shock absorber obtained by the experimental results is compared with the results of CFD simulation analysis. After comparison, although the experimental and CFD analysis results are slightly deviated, but the curilinear trend is very close. From this result, the reliability of the CFD simulation analysis method in this paper is verified. It is expected that the research results in this paper will make a concrete contribution to the research and development of domestic shock absorbers in the future.
11
Rangaraj, C. "Optimization And Design Of Proportional Weirs." Thesis, 1997. http://etd.iisc.ernet.in/handle/2005/1857.
Повний текст джерела
12
HSIAU, GWO-RONG, and 蕭國榮. "Application of fuzzy control to a hydraulic position servo system using proportional valve." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/82180241863740178889.
Повний текст джерела
13
Wu, Zun-Min, and 吳俊民. "Design and analysis of an open-loop P/Q hydraulic proportional valve with integrated amplifier." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/05926799339894391918.
Повний текст джерела
14
Jiunn-Min, Wu, and 吳俊民. "Design and Analysis of an open-loop P/Q hydraulic proportional valve with integrated amplifier." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/14148964646507769708.
Повний текст джерелаАнотація:
碩士國立雲林科技大學
機械工程技術研究所
86
The purpose of this paper is to design and analyze an open-loop P/Q hydraulic proportional valve with integrated amplifier. Two major areas in this paper are summarized as follows: First, a CAD simulation program will be developed to design and analyze theconfiguration and dimension of the spool which meets the requirements of P/Qcontrol.Futhermore,a valve-controled cylinder will also be established to evaluate the performance of the designed valve. Second,an unipolar current amplifier will be designed such that it can bedirectly intergrated into the valve-body design.To do this,the dimension ofthe driver must be designed to be acceptable small. Finally,a prototype of an open-loop P/Q hydraulic proportional valve withintegrated amplifier will be develop. To test the performance of this prototypeexperimentally,the test device developed in ITRI will be utilized.
15
Ye, Kuo Ann, and 葉國安. "Comparison of using proportional and servo valves on position control in a hydraulic servo system." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/82052559507003332329.
Повний текст джерела
16
CHEN, Che-Pin, and 陳哲斌. "Development of Vehicle Proportional Hydraulic Brake Actuator and Control of Anti-lock Braking System for the Motorcycle." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/e757ve.
Повний текст джерелаАнотація:
博士國立臺灣大學
工程科學及海洋工程學研究所
106
In the motorcycle industry, the safety of motorcycles operating at high speeds has drawn increasing attention. If a motorcycle is equipped with an anti-lock braking system (ABS), it can automatically adjust the brake force to prevent the wheels from locking for achieving optimal braking effect and ensuring operation stability. In an ABS, the brake force is controlled by an electro-hydraulic brake (EHB). The control valve of EHB was fitted with a proportional pressure valve in this study, which differed from the general use of a solenoid valve in order to precisely control the brake force and prevent hydraulic pressure oscillation in the pipes. This research developed a novel proportional pressure control valve of hydraulic braking actuators for an automobile and a motorcycle. The simulation analysis of solenoid driving force of the pressure control valves is implemented, and the pressure relief capability test of electromagnetic thrust with the proportional valve body is verified. Considering the high controllability and ease of production, the solenooid of this proportional valve was designed with a small volume and higher driving force to adjust the braking pressure and flow. Next, this study used MATLAB/Simulink to develop the overall motorcycle ABS simulation model, including a proportional electro-hydraulic brake (PEHB), motorcycle motion, tire, and controller models of bang-bang, PID, and fuzzy sliding-mode. The simulation results showed that this actuator had achieved a stable adjustment of depressurization control as well as satisfactory linear precision and repeatability. Therefore, it can be applied to the ABS for slip control. Additionally, an overall motorcycle ABS simulation model was established and perfomed for simulation and analyse of the wheel speed, slip, and brake force of the EHB and PEHB on different road surfaces during braking. According to the simulation results, it was demonstrated that the PEHB canreach more satisfactory stability and response during braking for slip control and effectively reduce braking distance. Finally, the open-loop and Hardware in the Loop (HIL) testing of the PEHB system of motorcycle were performed. The open-loop test commands confirmed the response time, tracking performance and linearity. Subsequently, In the HIL testing, PID (Bang-Bang) and fuzzy sliding-mode controller were used for slip control test in PEHB. The test results demonstrated that the proportional pressure control valve can perform wellin EHB systemto make the ABS achieve more precise slip control and improve motorcycle safety.
17
Kumar, M. Prasanna. "Studies On Application Of Control Systems For Urban Water Networks." Thesis, 2008. http://hdl.handle.net/2005/874.
Повний текст джерелаАнотація:
Management and supply of water in an urban water distribution system is a complex process, which include various complexities like pressure variations across the network depending on topography, demand variations depending on customers’ requirement and unaccounted water etc. Applying automatic control methods to water distribution systems is a way to improve the management of water distribution. There have been some attempts in recent years to develop optimal control algorithms to assist in the operation of complex water distribution systems. The difficulties involved by these hydraulic systems such as non-linearity, and diurnal demand patterns make the choice of a suitable automatic control method a challenge. For this purpose, this study intends to investigate the applicability of different controllers which would be able to meet the targets as quickly as possible and without creating undue transients.
As a first step towards application of different controllers, PD and PID linear controllers have been designed for pump control and valve control in water distribution systems. Then a Dynamic Inversion based nonlinear controller has been designed by considering the non-linearities in the system. Here, different cases considering the effects of initial conditions used, linearization methods used, time step used for integration and selection of gains etc., have been studied before arriving at best controller. These controllers have been designed for both the flow control problems and level control problems. It is found that Dynamic Inversion-based nonlinear controller outperforms other controllers.
It is well known that the performance of controllers is much dependent on the tuning of the gains (parameters). Thus in this study various alternative techniques such as Ziegler--Nichols rules (ZNPID), Genetic algorithms (GAPID) and fuzzy algorithms (FZPID) have been studied and a comparative study has been made Although with all the three gain tuning methods, required states have reached their target values, but the responses vary much in reaching to final targets. The self-tuned FZPID controller outperforms other two controllers, especially with regard to overshoots and the time taken to tune the gains for each problem.
Further, an optimal DI controller is developed for the over determined case with more controls and less targets. Energy loss is considered as an objective function and normal DI controller equations are considered as constraints. Hence, an attempt is made to reduce the energy minimization in water distribution system by formulating an optimal control problem using optimal Dynamic Inversion concept.
Finally, leakage reduction model is developed based on excessive pressure minimization problem by locating valves optimally as well as by setting valves optimally. For this purpose, optimization problem is solved using Pattern search algorithms and hydraulic analysis is carried out using EPANET program.