scholarly journals Sliding Mode Control of Cable-Driven Redundancy Parallel Robot with 6 DOF Based on Cable-Length Sensor Feedback

2017 ◽  
Vol 2017 ◽  
pp. 1-21 ◽  
Author(s):  
Wei Lv ◽  
Limin Tao ◽  
Zhengnan Ji

The sliding mode control of the cable-driven redundancy parallel robot with six degrees of freedom is studied based on the cable-length sensor feedback. Under the control scheme of task space coordinates, the cable length obtained by the cable-length sensor is used to solve the forward kinematics of the cable-driven redundancy parallel robot in real-time, which is treated as the feedback for the control system. First, the method of forward kinematics of the cable-driven redundancy parallel robot is proposed based on the tetrahedron method and Levenberg-Marquardt method. Then, an iterative initial value estimation method for the Levenberg-Marquardt method is proposed. Second, the sliding mode control method based on the exponential approach law is used to control the effector of the robot, and the influence of the sliding mode parameters on control performance is simulated. Finally, a six-degree-of-freedom position tracking experiment is carried out on the principle prototype of the cable-driven redundancy parallel robot. The experimental results show that the robot can accurately track the desired position in six directions, which indicates that the control method based on the cable-length sensor feedback for the cable-driven redundancy parallel robot is effective and feasible.

2012 ◽  
Vol 468-471 ◽  
pp. 758-766
Author(s):  
Guo Qin Gao ◽  
Wei Wang ◽  
Xue Mei Niu ◽  
Hai Yan Zhou

Relative to serial robot, parallel robot gets more and more attention of scholars because of its many advantages. However, there are some problems in the current research such as the chains’ coordination and coupling control, which has became one of the key problems in the motion control of parallel robot. To further enhance the motion control performances, a novel sliding mode control method base on synchronization error is proposed in this paper. The simulation and experiment results show that the designed control system has good tracking performance, small system error and strong robustness, which can satisfy the high-precision requirements of the parallel robot control.


2021 ◽  
Vol 5 (2) ◽  
pp. p9
Author(s):  
Gao Hang

In order to overcome the trajectory tracking distortion caused by the friction mutations of the sandblasting and rust removal parallel robot based on the Stewart parallel mechanism, a fuzzy adaptive sliding mode control method that compensates for the friction mutations is designed. Firstly, the kinematics of the mechanism is analyzed by analytic method and the dynamic model of the Stewart parallel mechanism is established based on Lagrange method. Then, the robust adaptive term of the sliding mode is designed based on the sliding mode variable to estimate the uncertain term in real time, replacing the sliding Switching items of mode control to compensate for the influence of uncertain factors such as unmodeled dynamics, external disturbances and time-varying parameters, and to effectively suppress chattering of sliding mode control; Next, by designing fuzzy control based on sliding mode variable and sliding mode variable derivative, the dynamic adjustment of the sliding mode robust adaptive term gain is realized to compensate for the interference of the frictional force mutation, thereby eliminating the trajectory tracking distortion problem of the Stewart mechanism joint commutation. Finally, using MATLAB control method for numerical simulation and verify the effectiveness of the proposed fuzzy adaptive sliding mode control method to compensate for friction mutations.


Author(s):  
Muhammet Aydin ◽  
Oguz Yakut

Purpose The purpose of the study is to design a three-dimensional (3D) triglide parallel robot with a different approach and to control the manufactured robot via sliding mode control method that has not been applied to the robot before. Design/methodology/approach The x, y and z coordinates of the end effector of the robot have been given as a reference. The x, y and z reference values are transformed as new reference values of the vertical movement of the robot on the endless screw by using the inverse kinematic equations of the robot. The control of the robot over these reference values is provided by a sliding mode control. The MATLAB/real-time toolbox has been used for creating the interface. The real-time control of the triglide robot has been carried out with a sliding mode controller in the Simulink environment. Findings When the results of the sliding mode control are examined, it is seen that the desired reference values are provided in about 0.6 s. The velocity of the sliding limbs in each arm of the robot is approximately 50 mm/s. The reference values have been reached using the sliding mode control method, with an average error of 0.01 mm. In addition, the problem of chattering in the system caused by using the sign function has been relatively eliminated by using the saturation function instead of the sign function. Thus, the sliding mode control method with saturation function is more feasible. Originality/value In this study, the triglide parallel robot was manufactured using a 3D model after taking into consideration the dimensions of the 3D model. After production, the necessary hardware connections were provided, and a real-time sliding mode control method was implemented to the robot by using the interface program in MATLAB/Simulink environment. The literature contribution of the paper is the real-time control of the triglide robot with the sliding mode control method.


2014 ◽  
Vol 39 (9) ◽  
pp. 1552-1557 ◽  
Author(s):  
Xi LIU ◽  
Xiu-Xia SUN ◽  
Wen-Han DONG ◽  
Peng-Song YANG

Author(s):  
Sara Gholipour P ◽  
Sara Minagar ◽  
Javad Kazemitabar ◽  
Mobin Alizadeh

Background: A novel type of control strategy is presented for control of chaotic systems particularly a chaotic robot in joint and workspace which is the result of applying fractional calculus to dynamic sliding mode control. Objectives: To guarantee the sliding mode condition, control law is introduced based on the Lyapunov stability theory. Methods: A control scheme is proposed for reducing the chattering problem in finite time tracking and robust in presence of system matched disturbances. Conclusion: Also, all of chaotic robot's qualitative and quantitative characteristics have been investigated. Numerical simulations indicate viability of our control method. Results: Qualitative and quantitative characteristics of the chaotic robot are all proven to be viable thru simulations.


Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 154
Author(s):  
Bin Wang ◽  
Pengda Ren ◽  
Xinhao Huang

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.


Author(s):  
D W Qian ◽  
X J Liu ◽  
J Q Yi

Based on the sliding mode control methodology, this paper presents a robust control strategy for underactuated systems with mismatched uncertainties. The system consists of a nominal system and the mismatched uncertainties. Since the nominal system can be considered to be made up of several subsystems, a hierarchical structure for the sliding surfaces is designed. This is achieved by taking the sliding surface of one of the subsystems as the first-layer sliding surface and using this sliding surface and the sliding surface of another subsystem to construct the second-layer sliding surface. This process continues till the sliding surfaces of all the subsystems are included. A lumped sliding mode compensator is designed at the last-layer sliding surface. The asymptotic stability of all of the layer sliding surfaces and the sliding surface of each subsystem is proven. Simulation results show the validity of this robust control method through stabilization control of a system consisting of two inverted pendulums and mismatched uncertainties.


Author(s):  
N. I. Rajapakse ◽  
G. S. Happawana ◽  
Y Hurmuzlu

The current paper presents a robust control method that combines sliding-mode control (SMC) and quantitative feedback theory (QFT) for designing a driver seat of a heavy vehicle to reduce driver fatigue. A mathematical model is considered to analyse tracking control characteristics through computer simulation in order to demonstrate the effectiveness of the proposed control methodology. The SMC is used to track the trajectory of the desired motion behaviour of the seat. However, when the system enters into sliding regime, chattering occurs owing to switching delays as well as vehicle system vibrations. The chattering is eliminated with the introduction QFT inside the boundary layer to ensure smooth tracking. Furthermore, using SMC alone requires higher actuator forces for tracking than using both the control schemes together, and causes various problems in selecting hardware. Problems with noise amplification, resonances, presence of uncertainties, and unmodelled high-frequency dynamics can largely be avoided with the use of QFT over other optimization methods. The main contribution of the present paper is to provide guidance in designing the controller to reduce heavy vehicle seat vibration so that the driver's sensation of comfort maintains a certain level at all times.


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