Design of admittance controller with sliding mode based on disturbance observer for elbow joint actuated by pneumatic muscles

2020 ◽  
Vol 47 (5) ◽  
pp. 657-667
Author(s):  
Binrui Wang ◽  
Jiqing Huang ◽  
Guoyang Shen ◽  
Dijian Chen
Keyword(s):  
Sliding Mode Control ◽  
Elbow Joint ◽  
Disturbance Observer ◽  
Position Control ◽  
Sliding Mode ◽  
Admittance Control ◽  
Compliance Control ◽  
Content Type ◽  
Joint Compliance ◽  
Active Compliance

Purpose Active compliance control is the key technology for Tri-Co robots (coexisting–cooperative–cognitive robots) to interact with the environment and people. This study aims to make the robot arm shake hands compliantly with people; the paper proposed two closed-loop-compliant control schemes for the dynamic identification of cascade elbow joint. Design/methodology/approach The active compliance control strategy consists of inner and outer loops. The inner loop is the position control using sliding mode control with disturbance observer (SMCDO), in which a new saturation function is designed to replace the traditional signal function of sliding mode control (SMC) law so as to mitigate chatter. The outer loop is the admittance control to regulate the dynamic behaviours of the elbow joint, i.e. its impedance. The simulation is carried out to verify the performance of the proposed control scheme. Findings The results show that the chatter of traditional SMC can be effectively eliminated by using SMCDO with this saturation function. In addition, for the handshake task, the value of threshold force and elbow joint compliance is defined. Then, the threshold force tests, impact tests and elbow-joint compliance tests are carried out. The results show that, in the impedance model, the elbow joint compliance only depends on the stiffness parameters, not on the position control loop. Practical implications The effectiveness of the admittance control based on SMCDO can improve the adaptability of industrial manipulator in different working environments to some degree. Originality/value The admittance control with SMCDO completed trajectory tracking has higher accuracy than that based on SMC.

Observer-based finite-time sliding mode control for reentry vehicle

2015 ◽  
Vol 8 (4) ◽  
pp. 345-362
Author(s):  
Xiangdong Liu ◽  
Xiaohuan Ren ◽  
Yongzhi Sheng
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Accuracy ◽  
Content Type ◽  
Reentry Vehicle ◽  
Integral Sliding Mode ◽  
Finite Time Convergence ◽  
Global Robustness

Purpose – The purpose of this paper is to design a disturbance observer-based finite-time global sliding mode control scheme for the attitude tracking control problem of the reentry vehicle with parameter uncertainties and disturbances. Design/methodology/approach – Feedback linearization is first introduced to transform vehicle model into three independent second order uncertain subsystems. Then a finite-time controller (FTC) is proposed for the nominal system on the basis of the homogeneity theory. Thereafter the integral sliding mode method is introduced for the vehicle with disturbances. The finite time convergence is achieved and global robustness is also assured by the combination of finite time control method and integral sliding mode strategy. Furthermore, to improve the attitude angle tracking accuracy a novel finite time disturbance observer (DO) is constructed. Findings – Simulation is made for the reentry vehicle with disturbances involved. And the results show the finite-time convergence, tracking accuracy and robustness of the proposed strategy. Originality/value – The proposed control strategy has three advantages. First of all it can achieve finite time convergence and avoid singularity. Moreover, it can also realize global robustness. Finally, a new kind of DO is introduced to improve the tracking accuracy.

Disturbance observer-based sliding mode control for multi-agent systems with mismatched uncertainties

2018 ◽  
Vol 38 (5) ◽  
pp. 606-614 ◽  
Author(s):  
Qing Wang ◽  
Changyin Sun ◽  
Xiaofeng Chai ◽  
Yao Yu
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Multi Agent Systems ◽  
Content Type ◽  
Agent Systems ◽  
Mode Control ◽  
Mismatched Uncertainties ◽  
Multi Agent

PurposeThis paper aims to develop sliding mode control (SMC) methods for second-order multi-agent systems (MAS) in the presence of mismatched uncertainties.Design/methodology/approachBased on the disturbance observer (DOB), discontinuous and continuous sliding mode protocols are designed to achieve finite-time consensus in spite of the disturbances.FindingsCompared with integral SMC, numerical simulation results show that the proposed control methods exhibit better performance with respect to reduction of chattering.Originality/valueThe main contributions are the following: MAS described with mismatched uncertainties are considered; both discontinuous and continuous sliding mode controllers are considered; with the proposed sliding mode controller, the desired sliding surface can be reached in finite time and the DOB is introduced in the controller to alleviate the chattering phenomenon.

Robust model reference adaptive backstepping sliding-mode control for quadrotor attitude with disturbance observer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nigar Ahmed ◽  
Mou Chen
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Model Reference ◽  
Content Type ◽  
Mode Control ◽  
Robust Model ◽  
Backstepping Sliding Mode Control ◽  
Model Reference Adaptive ◽  
Control Criterion

Purpose The purpose of this research paper is to design a disturbance observer-based control based on the robust model reference adaptive backstepping sliding-mode control for attitude quadrotor model subject to uncertainties and disturbances. Design/methodology/approach To estimate and reject the disturbance, a disturbance observer is designed for the exogenous disturbances with perturbation while a control criterion is developed for the tracking of desired output. To achieve the control performance, backstepping and sliding-mode control techniques are patched together to obtain robust chattering-free controller. Furthermore, a model reference adaptive control criterion is also combined with the design of robust control for the estimation and rejection of uncertainties and unmodeled dynamics of the attitude quadrotor. Findings The findings of this research work includes the design of a disturbance observer-based control for uncertain attitude quadrotor system with the ability of achieving tracking control objective in the presence of nonlinear exogenous disturbance with and without perturbation. Practical implications In practice, the quadrotor flight is opposed by different kinds of the disturbances. In addition, being an underactuated system, it is difficult to obtain an accurate mathematical model of quadrotor for the control design. Thus, a quadrotor model with uncertainties and disturbances is inevitable. Hence, it is necessary to design a control system with the ability to achieve the control objectives in the presence of uncertainties and disturbances. Originality/value Designing the control methods for quadrotor control without uncertainties and disturbances is a common practice. However, investigating the uncertain quadrotor plant in the presence of nonlinear disturbances is rarely taken into consideration for the control design. Hence, this paper presents a control algorithm to address the issues of the uncertainties and disturbances as well as investigate a control algorithm to achieve tracking performance.

scholarly journals Backstepping Sliding-Mode Control of Piezoelectric Single-Piston Pump-Controlled Actuator

Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 154
Author(s):  
Bin Wang ◽  
Pengda Ren ◽  
Xinhao Huang
Keyword(s):  
Sliding Mode Control ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Piezoelectric Pump ◽  
Mode Control ◽  
Control Precision ◽  
Backstepping Sliding Mode Control ◽  
Actuator System ◽  
The Mathematical Model

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the intermittent oil supplying and position control precision is essential when designing the controller. In order to accurately control the output of the actuator, a backstepping sliding-mode control method based on the Lyapunov function is introduced, and the controller is designed on the basis of establishing the mathematical model of the system. The simulation results show that, compared with fuzzy PID and ordinary sliding-mode control, backstepping sliding-mode control has a stronger anti-jamming ability and tracking performance, and improves the control accuracy and stability of the piezoelectric pump-controlled actuator system.

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