Eliminating the Reaching Phase From Variable Structure Control

2000 ◽  
Vol 122 (4) ◽  
pp. 753-757 ◽  
Author(s):  
Cuneyt Yilmaz ◽  
Yildirim Hurmuzlu

In this paper, we present a variable structure control method that eliminates the reaching phase. The approach is based on modifying the sliding domain equations through the use of exponential functions. In addition, the proposed method insures optimal convergence parameters with respect to the tracking errors and control effort. [S0022-0434(00)02504-1]

1996 ◽  
Vol 118 (2) ◽  
pp. 327-332 ◽  
Author(s):  
Robert R. Y. Zhen ◽  
Andrew A. Goldenberg

This paper addresses the problem of robust hybrid position and force control of robot manipulators. Variable structure control with sliding mode is used to implement the hybrid control strategy. Two variable structure control algorithms are developed in task space. One of the algorithms is based on hierarchical control method, and the other is developed for control of robot manipulators used to carried out both unconstrained and constrained tasks.


2018 ◽  
Vol 37 (4) ◽  
pp. 1176-1187
Author(s):  
Xianglong Wen ◽  
Kang Yi ◽  
Chunsheng Song ◽  
Jinguang Zhang

The frequency components of vibration signal in vibration isolation system under multiple excitations are quite complex.Self-adaptive feedforward control method based on Least Mean Square algorithm has strict requirements for reference signal, which results in a certain restriction on its practical application. Sliding mode variable structure control method needs neither complicated reference signal nor accurate mathematical model. It has the strong robustness for external disturbance and system parameter perturbation, and the physical implementation is simple. To this end, application of sliding mode variable structure control method is studied. First, mathematical model of the control channel through system is established for identification. Second, the discrete sliding mode variable structure controller based on state-space model is designed to carry out simulation and experiment. The experimental result indicates that root mean square value of vibration signal after control is decreased by 57.90%, of which the amplitudes of two main frequency components 17 and 25 Hz reduce by 42.66 and 72.71%, respectively. This shows that sliding mode variable structure control is an effective control method for active vibration isolation of floating raft under multiple excitations.


1993 ◽  
Vol 115 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Tai-Heng Chang ◽  
Yildirim Hurmuzlu

A new variable structure control law based on the Lyapunov’s second method that can be used in trajectory planning problems of robotic systems is developed. A modified approach to the formulation of the sliding domain equations in terms of tracking errors has been presented. This approach possesses three distinct advantages: (i) it eliminates the reaching phase, (ii) it provides means to predict the entire motion and directly control the evolution of tracking errors, (iii) it facilitates the trajectory planning process in the joint and/or cartesian spaces. A planar, five-link bipedal locomotion model has been developed. Five constraint relations that cast the motion of the biped in terms of four parameters are developed. The new control method is applied to regulate the locomotion of the system according to the five constraint relations. Numerical simulation is performed to verify the ability of the controller to achieve steady gait by applying the proposed control scheme. Bifurcation diagrams of the periodic motions of the biped are used to demonstrate the improvements in controller performance that arise from the application of the proposed method.


2006 ◽  
Vol 315-316 ◽  
pp. 623-627
Author(s):  
P. Wei ◽  
Z.L. Wang ◽  
L.H. Qiu

In order to improve the robust performance for a type of nonlinear multivariable system, a new fuzzy variable structure control method is introduced in detail, which combined the features of traditional variable structure control method with the advantages of the fuzzy control theory. The present work realized the linearization of the nonlinear multivariable system, and then the new fuzzy variable structure control method is applied to control the linearization system. The robust experiments were carried out on the novel method. The results indicated that the required robust performance could be achieved with high efficiency by utilizing the new method.


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