With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potentia...With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental performance, as compared with some existing methods. results show that the designed controller can achieve better tracking展开更多
The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneum...The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneumatic system had disadvantages such as inherent non-linearity and variations of system parameters with working points. In order to improve the dynamic performance of the system, feed forward compensation self-tuning pole-placement strategy was adopted to place the poles of the system in a desired position in real time, and a recursive least square method with fixed forgetting factors was also used in the parameter estimation. Experimental results show that the steady state error of the pneumatic rotary position system is within 3% and the identified system parameters can be converged in 5 s. Under different loads, the controlled system has an excellent tracking performance and robustness of anti-disturbance.展开更多
A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused...A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused by asymmetric structures and different friction characteristics in two directions. On the basis of this algorithm, a traditional PID control is used to improve dynamic performance. Furthermore, a new asymmetric fuzzy PID control with α factor is advanced to improve the self-adaptability and robustness of the system. Both the theoretical analyses and experimental results prove that, with this control strategy, the dynamic performance of the system can be greatly improved. The system using this control algorithm has strong robustness and it obtains desired overshoot and repeatability in both transient and steady-state responses.展开更多
This paper provided a fuzzy-PI control. It makes use of the advantages of fuzzy controller for dynamic characteristics, and the advantages of PI control for steady characteristics of pneumatic position servo. Experime...This paper provided a fuzzy-PI control. It makes use of the advantages of fuzzy controller for dynamic characteristics, and the advantages of PI control for steady characteristics of pneumatic position servo. Experimental results show that positioning accuracy meets the conventional industrial needs, and prove that the fuzzy-PI controller to be correct and more effective than the usual PID controller. The control method improve the dynamic and steady characteristics of the system.展开更多
A method of error analysis on the positioning accuracy of a pneumatic vibration isolator was proposed.First,the necessity of positioning accuracy was studied,in addition to the key factors associated with positioning ...A method of error analysis on the positioning accuracy of a pneumatic vibration isolator was proposed.First,the necessity of positioning accuracy was studied,in addition to the key factors associated with positioning accuracy.These analyses indicated that the positioning accuracy of the pneumatic vibration isolator was mainly attributed to the position error of the push button and the gap between the spindle and valve stem.Second,the error model of the positioning accuracy of the pneumatic vibration isolator was established through geometric simplification and geometric calculation.There are different methods used to calculate the position error of the push button for the different valves.Finally,an example analysis evaluating the impact of a specific two-position three-way valve on the positioning accuracy was given by means of error distribution.Experimental results validated the accuracy of the error model and the example analysis.This error model can be used to guide the structural parameter optimization design according to the requirements for positioning accuracy.展开更多
The PID, fuzzy, self-organized fuzzy and self-organized fuzzy-PID controllers are adopted in the position control of single pneumatic muscle actuator. Experiments show that the self-organized fuzzy-PID is obviously ef...The PID, fuzzy, self-organized fuzzy and self-organized fuzzy-PID controllers are adopted in the position control of single pneumatic muscle actuator. Experiments show that the self-organized fuzzy-PID is obviously effective for the position control of single pneumatic muscle actuator, which can realize precision within 0.3 mm and withstand 18?N variable load plus about 36?N fixed load. It is relatively precise and robust.展开更多
Pneumatic driven system is widely used in industrial automation, mainly for relatively simple tasks with open-loop control. Because of the pneumatic system’s compressibility and few stop positions, it was considered ...Pneumatic driven system is widely used in industrial automation, mainly for relatively simple tasks with open-loop control. Because of the pneumatic system’s compressibility and few stop positions, it was considered hard to control in a precise motion control system. With the help of newly developed pneumatic servo control technology, using servo-pneumatic positioning controller now is just as easy as using electro-servo system. This article discusses Web-based servo-pneumatic manipulator control and object recognition and positioning. The authors built a three-degrees-of-freedom (3 DOF) pneumatic manipulator with a servo-pneumatic closed-loop control system and machine vision system in their lab. Web-based tele-operation was a basic ability in this experimental system. After installing a CCD camera, video capture card, and related software developed by the authors, the robot could recognize the user specified object through the Web page and find its position. The remote user could command the robot to move to the position and to grab the object. The critical issues of Web-based control are to integrate hybrid open-architecture mechatronic system through the Web and develop a software language environment characterized by the script. The authors’ experiment showed that pneumatic devices could serve as accurate position control and be controlled through the Web.展开更多
Pneumatic artificial muscles (PAMs) currently possess a high power-to-weight ratio, a high power-to-volume ratio, and a high degree of safety. They have therefore been applied to many power assist devices and position...Pneumatic artificial muscles (PAMs) currently possess a high power-to-weight ratio, a high power-to-volume ratio, and a high degree of safety. They have therefore been applied to many power assist devices and positioning mechanisms such as bionic robots, welfare devices, and parallel manipulators. However, the significant nonlinear characteristics of PAM mechanisms limit their positioning accuracies. The accuracies are generally lower than 5 μm, which preclude the PAM from precision systems. Nevertheless, enhancing the positioning accuracy is desired to extend the application fields of PAMs. This study aims to clarify a practical controller design method to achieve the precise positioning of PAM systems. As the first step of this research, a linear motion mechanism with a pair of McKibben PAMs was constructed and a conventional dynamic model for this system is introduced. The dynamic model is used to explain the basic characteristics of the PAM mechanism and discuss the necessary characteristics for precise positioning. Then open-loop step and sinusoidal responses of the PAM mechanism were examined by experimental and simulated results. Next, for precise positioning, the practical controller design procedure is discussed and determined based on the measured open-loop responses. The proposed controller design procedure can be easily implemented into PAM mechanisms without an exact dynamic model. The positioning performance of such a system was experimentally evaluated. The experimental results show that although the positioning accuracy depends on the target position, the positioning error is lower than 1 μm even in the worst case and the positioning resolution can be set to 0.5 μm.展开更多
For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for p...For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for precise positioning of a pneumatic system.This Scheme is tested by simulation and experiment and is shown to be effective.展开更多
By applying a nonlinear control and arranging a transient process, the initiative error of the pneumatic servo positioning system is reduced largely, and a larger gain of the controller is used to improve the respondi...By applying a nonlinear control and arranging a transient process, the initiative error of the pneumatic servo positioning system is reduced largely, and a larger gain of the controller is used to improve the responding speed of the system at the same damping ratio. Therefore, a compromise is made among the responding speed, overshoot, robustness, adaptability and stability. In addition, a dynamic output feedback controller, including position velocity and acceleration （PVA） feedback, is designed to improve the performance of the system. And a nonlinear controller is reconstructed based on the linear output feedback controller to decrease noises and disturbances. The dynamic responses of the system are simulated and tested. Results show that the error is kept within 0.02 mm under different mass loads and the positioning transient process is smooth, without overshoot and speedy.展开更多
The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,go...The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,good bionics and flexibility.A kind of bionic leg driven by PAMs is designed.The proportional-integral-derivative(PID)algorithm and radial basis function neural network(RBFNN)algorithm are combined to design RBFNN-PID controller,and a low-pass filter is added to the control system,which can effectively improve the jitter phenomenon of the joint during the experiment.It is verified by simulation that the RBFNN-PID algorithm is better than traditional PID algorithm,the response time of joint is improved from 0.15 s to 0.07 s,and the precision of joint position control is improved from 0.75°to 0.001°.The experimental results show that the amplitude of the change in error is reduced from 0.5°to 0.2°.It is verified by jumping experiment that the mechanism can realize jumping action under control,and can achieve the horizontal displacement of 500 mm and the vertical displacement of 250 mm.展开更多
Aiming to suppress the influence of uncertain disturbances in the drive control of permanent magnet synchronous machines(PMSM),such as the parameter uncertainties and load disturbance,a robust anti-interference contro...Aiming to suppress the influence of uncertain disturbances in the drive control of permanent magnet synchronous machines(PMSM),such as the parameter uncertainties and load disturbance,a robust anti-interference control for the angular position tracking control of a PMSM servo system has been proposed in this paper.During the position tracking,uncertain system disturbances being regarded as a lumped unknown term will be online observed by a nonlinear disturbance observer(NDOB),of which the influence will consequently be counteracted by a robust backstepping compensator(RBC).The asymptotical stability of proposed control scheme is analyzed and designed according to the Lyapunov stability criterion,and its convergence against the system uncertain disturbance is verified on a prototype PMSM servo platform and shows good performance in rotor angular position tracking and anti-interference.展开更多
In this paper, a novel control law is presented, which uses neural-network techniques to approximate the affine class nonlinear system having unknown or uncertain dynamics and noise disturbances. It adopts an adaptive...In this paper, a novel control law is presented, which uses neural-network techniques to approximate the affine class nonlinear system having unknown or uncertain dynamics and noise disturbances. It adopts an adaptive control law to adjust the network parameters online and adds another control component according to H-infinity control theory to attenuate the disturbance. This control law is applied to the position tracking control of pneumatic servo systems. Simulation and experimental results show that the tracking precision and convergence speed is obviously superior to the results by using the basic BP-network controller and self-tuning adaptive controller.展开更多
The control of single pneumatic muscle actuator is studied, as one basic partof research on the parallel-robot arthrosis actuated by pneumatic muscle actuators. Experimentsshow that a self-modified fuzzy-PID controlle...The control of single pneumatic muscle actuator is studied, as one basic partof research on the parallel-robot arthrosis actuated by pneumatic muscle actuators. Experimentsshow that a self-modified fuzzy-PID controller is obviously effective for its position servo and asimple PID controller is good for its force track.展开更多
Precise position tracking control of the single-rod pneumatic actuator is considered and a nonlinear cascade controller is developed.The proposed controller comprises an extended disturbance observer(EDOB)and a nonlin...Precise position tracking control of the single-rod pneumatic actuator is considered and a nonlinear cascade controller is developed.The proposed controller comprises an extended disturbance observer(EDOB)and a nonlinear robust control law synthesized by the backstepping method.The EDOB is designed to estimate not only the influence of disturbances but also the parameter uncertainties.With the use of parameter and disturbance estimates,the nonlinear cascade controller,which consists of an outer position tracking loop and an inner load pressure loop,is further designed to attenuate the effects of parameter and disturbance estimation errors.The stability of the closed-loop system is proven by means of Lyapunov theory.Extensive comparative experimental results obtained verify the effectiveness of the proposed nonlinear cascade controller and its performance robustness to parameter and external disturbance variations in practical implementation.展开更多
In order to design a low-cost pneumatic force servo system with large output forces,a scheme of a booster cylinder controlled by high speed solenoid valves is proposed.A nonlinear model of the system is established,in...In order to design a low-cost pneumatic force servo system with large output forces,a scheme of a booster cylinder controlled by high speed solenoid valves is proposed.A nonlinear model of the system is established,in which the hysteresis of high speed solenoid valve is considered.In order to deal with parameter uncertainty and disturbances of noise and friction,a feed-forward control method based on a disturbance observer is proposed.A practical pneumatic force servo system is used to testify the feasibility of the proposed controller.The experimental results show that pneumatic force servo system based on the proposed controller has high force tracking accuracy and quick response.展开更多
In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry （e.g., service, medical, and aging care）. Such robots must be safe and flexible ...In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry （e.g., service, medical, and aging care）. Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds.展开更多
A new learning control law is presented which can obtain learning gain matrices from a recursive identifier along the learning axis. The system convergence is proved when disturbances exist in the system. Finally it i...A new learning control law is presented which can obtain learning gain matrices from a recursive identifier along the learning axis. The system convergence is proved when disturbances exist in the system. Finally it is applied to pneumatic servo control system, the experiment results show its validity.展开更多
基金Supported by National Key Scientific and Technological Project(Grant No.2010ZX04001-051-031)Key Program of National Natural Science Foundation of China((Grant No.61533014)the Innovative Research Team of Shaanxi Province,China(Grant No.2013KCT-04)
文摘With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental performance, as compared with some existing methods. results show that the designed controller can achieve better tracking
基金Project(50375034) supported by the National Natural Science Foundation of China
文摘The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneumatic system had disadvantages such as inherent non-linearity and variations of system parameters with working points. In order to improve the dynamic performance of the system, feed forward compensation self-tuning pole-placement strategy was adopted to place the poles of the system in a desired position in real time, and a recursive least square method with fixed forgetting factors was also used in the parameter estimation. Experimental results show that the steady state error of the pneumatic rotary position system is within 3% and the identified system parameters can be converged in 5 s. Under different loads, the controlled system has an excellent tracking performance and robustness of anti-disturbance.
文摘A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused by asymmetric structures and different friction characteristics in two directions. On the basis of this algorithm, a traditional PID control is used to improve dynamic performance. Furthermore, a new asymmetric fuzzy PID control with α factor is advanced to improve the self-adaptability and robustness of the system. Both the theoretical analyses and experimental results prove that, with this control strategy, the dynamic performance of the system can be greatly improved. The system using this control algorithm has strong robustness and it obtains desired overshoot and repeatability in both transient and steady-state responses.
文摘This paper provided a fuzzy-PI control. It makes use of the advantages of fuzzy controller for dynamic characteristics, and the advantages of PI control for steady characteristics of pneumatic position servo. Experimental results show that positioning accuracy meets the conventional industrial needs, and prove that the fuzzy-PI controller to be correct and more effective than the usual PID controller. The control method improve the dynamic and steady characteristics of the system.
基金Supported by National Science and Technology Major Project(2013ZX02104003)the Natural Science Foundation of Hubei Province(2018CFC889)
文摘A method of error analysis on the positioning accuracy of a pneumatic vibration isolator was proposed.First,the necessity of positioning accuracy was studied,in addition to the key factors associated with positioning accuracy.These analyses indicated that the positioning accuracy of the pneumatic vibration isolator was mainly attributed to the position error of the push button and the gap between the spindle and valve stem.Second,the error model of the positioning accuracy of the pneumatic vibration isolator was established through geometric simplification and geometric calculation.There are different methods used to calculate the position error of the push button for the different valves.Finally,an example analysis evaluating the impact of a specific two-position three-way valve on the positioning accuracy was given by means of error distribution.Experimental results validated the accuracy of the error model and the example analysis.This error model can be used to guide the structural parameter optimization design according to the requirements for positioning accuracy.
文摘The PID, fuzzy, self-organized fuzzy and self-organized fuzzy-PID controllers are adopted in the position control of single pneumatic muscle actuator. Experiments show that the self-organized fuzzy-PID is obviously effective for the position control of single pneumatic muscle actuator, which can realize precision within 0.3 mm and withstand 18?N variable load plus about 36?N fixed load. It is relatively precise and robust.
基金Project (No. ZD0107) supported by Natural Science Foundation of Zhejiang Province, China
文摘Pneumatic driven system is widely used in industrial automation, mainly for relatively simple tasks with open-loop control. Because of the pneumatic system’s compressibility and few stop positions, it was considered hard to control in a precise motion control system. With the help of newly developed pneumatic servo control technology, using servo-pneumatic positioning controller now is just as easy as using electro-servo system. This article discusses Web-based servo-pneumatic manipulator control and object recognition and positioning. The authors built a three-degrees-of-freedom (3 DOF) pneumatic manipulator with a servo-pneumatic closed-loop control system and machine vision system in their lab. Web-based tele-operation was a basic ability in this experimental system. After installing a CCD camera, video capture card, and related software developed by the authors, the robot could recognize the user specified object through the Web page and find its position. The remote user could command the robot to move to the position and to grab the object. The critical issues of Web-based control are to integrate hybrid open-architecture mechatronic system through the Web and develop a software language environment characterized by the script. The authors’ experiment showed that pneumatic devices could serve as accurate position control and be controlled through the Web.
文摘Pneumatic artificial muscles (PAMs) currently possess a high power-to-weight ratio, a high power-to-volume ratio, and a high degree of safety. They have therefore been applied to many power assist devices and positioning mechanisms such as bionic robots, welfare devices, and parallel manipulators. However, the significant nonlinear characteristics of PAM mechanisms limit their positioning accuracies. The accuracies are generally lower than 5 μm, which preclude the PAM from precision systems. Nevertheless, enhancing the positioning accuracy is desired to extend the application fields of PAMs. This study aims to clarify a practical controller design method to achieve the precise positioning of PAM systems. As the first step of this research, a linear motion mechanism with a pair of McKibben PAMs was constructed and a conventional dynamic model for this system is introduced. The dynamic model is used to explain the basic characteristics of the PAM mechanism and discuss the necessary characteristics for precise positioning. Then open-loop step and sinusoidal responses of the PAM mechanism were examined by experimental and simulated results. Next, for precise positioning, the practical controller design procedure is discussed and determined based on the measured open-loop responses. The proposed controller design procedure can be easily implemented into PAM mechanisms without an exact dynamic model. The positioning performance of such a system was experimentally evaluated. The experimental results show that although the positioning accuracy depends on the target position, the positioning error is lower than 1 μm even in the worst case and the positioning resolution can be set to 0.5 μm.
文摘For a pneumatic actuator,precise positioning is difficult to obtain because of the compressibility of air and the static friction and Coulomb friction.This paper develops a nonlinear friction compensation scheme for precise positioning of a pneumatic system.This Scheme is tested by simulation and experiment and is shown to be effective.
基金The National Natural Science Foundation of China (No.50085002)
文摘By applying a nonlinear control and arranging a transient process, the initiative error of the pneumatic servo positioning system is reduced largely, and a larger gain of the controller is used to improve the responding speed of the system at the same damping ratio. Therefore, a compromise is made among the responding speed, overshoot, robustness, adaptability and stability. In addition, a dynamic output feedback controller, including position velocity and acceleration （PVA） feedback, is designed to improve the performance of the system. And a nonlinear controller is reconstructed based on the linear output feedback controller to decrease noises and disturbances. The dynamic responses of the system are simulated and tested. Results show that the error is kept within 0.02 mm under different mass loads and the positioning transient process is smooth, without overshoot and speedy.
基金Supported by the National Natural Science Foundation of China(No.51775323).
文摘The bionic legs are generally driven by motors which have the disadvantages of large size and heavy weight.In contrast,the bionic legs driven by pneumatic artificial muscles(PAMs)have the advantages of light weight,good bionics and flexibility.A kind of bionic leg driven by PAMs is designed.The proportional-integral-derivative(PID)algorithm and radial basis function neural network(RBFNN)algorithm are combined to design RBFNN-PID controller,and a low-pass filter is added to the control system,which can effectively improve the jitter phenomenon of the joint during the experiment.It is verified by simulation that the RBFNN-PID algorithm is better than traditional PID algorithm,the response time of joint is improved from 0.15 s to 0.07 s,and the precision of joint position control is improved from 0.75°to 0.001°.The experimental results show that the amplitude of the change in error is reduced from 0.5°to 0.2°.It is verified by jumping experiment that the mechanism can realize jumping action under control,and can achieve the horizontal displacement of 500 mm and the vertical displacement of 250 mm.
基金The work is supported by the financial support of National Natural Science Foundation of China under Grant 51877075 and 51575167the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body(No.71865008)+1 种基金Hunan University,and the State Key Laboratory of Reliability and Intelligence of Electrical Equipment(No.EERIKF2018007)Hebei University of Technology.
文摘Aiming to suppress the influence of uncertain disturbances in the drive control of permanent magnet synchronous machines(PMSM),such as the parameter uncertainties and load disturbance,a robust anti-interference control for the angular position tracking control of a PMSM servo system has been proposed in this paper.During the position tracking,uncertain system disturbances being regarded as a lumped unknown term will be online observed by a nonlinear disturbance observer(NDOB),of which the influence will consequently be counteracted by a robust backstepping compensator(RBC).The asymptotical stability of proposed control scheme is analyzed and designed according to the Lyapunov stability criterion,and its convergence against the system uncertain disturbance is verified on a prototype PMSM servo platform and shows good performance in rotor angular position tracking and anti-interference.
基金Guangdong-Hong Kong Technology Cooperation Funding Scheme (No.2005A10207005, IID 2004-0005)the Research Grants Council of Hong Kong (No.9040407)
文摘In this paper, a novel control law is presented, which uses neural-network techniques to approximate the affine class nonlinear system having unknown or uncertain dynamics and noise disturbances. It adopts an adaptive control law to adjust the network parameters online and adds another control component according to H-infinity control theory to attenuate the disturbance. This control law is applied to the position tracking control of pneumatic servo systems. Simulation and experimental results show that the tracking precision and convergence speed is obviously superior to the results by using the basic BP-network controller and self-tuning adaptive controller.
文摘The control of single pneumatic muscle actuator is studied, as one basic partof research on the parallel-robot arthrosis actuated by pneumatic muscle actuators. Experimentsshow that a self-modified fuzzy-PID controller is obviously effective for its position servo and asimple PID controller is good for its force track.
基金Project(51505474)supported by the National Natural Science Foundation of ChinaProject(2015XKMS020)supported by the Fundamental Research Funds for the Central Universities,China+1 种基金Project(2016T90520)supported by the China Postdoctoral Science FoundationProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Precise position tracking control of the single-rod pneumatic actuator is considered and a nonlinear cascade controller is developed.The proposed controller comprises an extended disturbance observer(EDOB)and a nonlinear robust control law synthesized by the backstepping method.The EDOB is designed to estimate not only the influence of disturbances but also the parameter uncertainties.With the use of parameter and disturbance estimates,the nonlinear cascade controller,which consists of an outer position tracking loop and an inner load pressure loop,is further designed to attenuate the effects of parameter and disturbance estimation errors.The stability of the closed-loop system is proven by means of Lyapunov theory.Extensive comparative experimental results obtained verify the effectiveness of the proposed nonlinear cascade controller and its performance robustness to parameter and external disturbance variations in practical implementation.
基金Supported by the National Natural Science Foundation of China(51375045)the State Key Laboratory Program of Fluid Power and Mechatronic Systems of China(GZKF-201214)
文摘In order to design a low-cost pneumatic force servo system with large output forces,a scheme of a booster cylinder controlled by high speed solenoid valves is proposed.A nonlinear model of the system is established,in which the hysteresis of high speed solenoid valve is considered.In order to deal with parameter uncertainty and disturbances of noise and friction,a feed-forward control method based on a disturbance observer is proposed.A practical pneumatic force servo system is used to testify the feasibility of the proposed controller.The experimental results show that pneumatic force servo system based on the proposed controller has high force tracking accuracy and quick response.
文摘In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry （e.g., service, medical, and aging care）. Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds.
文摘A new learning control law is presented which can obtain learning gain matrices from a recursive identifier along the learning axis. The system convergence is proved when disturbances exist in the system. Finally it is applied to pneumatic servo control system, the experiment results show its validity.
