Robust Adaptive Compensation for a Class of Nonlinear Systems

1998 ◽  
Vol 124 (1) ◽  
pp. 231-234 ◽  
Author(s):  
Hongliu Du ◽  
Satish S. Nair
Keyword(s):  
Nonlinear Systems ◽  
Adaptive Design ◽  
Sliding Mode ◽  
Design Method ◽  
Design Guidelines ◽  
Robust Adaptive Control ◽  
Control Law ◽  
Case System ◽  
Robust Adaptive ◽  
Adaptive Control Strategy

A robust adaptive design method is proposed for the on-line compensation of uncertainties, for a class of nonlinear systems. As an extension of previous work, the adaptive part of the control law uses a constructive Gaussian network without any prior training, and the control law provides robustness using a systematically designed sliding mode term. In the design, learning and control bounds are guaranteed by properly constructing the control architecture using the proposed methods. The robust adaptive control strategy, with the proposed design guidelines, has been validated using a hardware example case of a nonlinear robotic linkage system. Experiments have shown that the inclusion of the proposed stable learning and robust terms into the control design, using the proposed constructive methods, results in improved system performance for the example case system.

Robust adaptive tracking control for uncertain nonholonomic mobile manipulator

2021 ◽  
pp. 095965182110277
Author(s):  
Abdelkrim Brahmi ◽  
Maarouf Saad ◽  
Brahim Brahmi ◽  
Ibrahim El Bojairami ◽  
Guy Gauthier ◽  
...  
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Robust Adaptive Control ◽  
Convergence Time ◽  
Adaptive Sliding Mode Control ◽  
Mobile Manipulator ◽  
Control Law ◽  
Adaptive Tracking Control ◽  
Robust Adaptive ◽  
Manipulator Robot

In the research put forth, a robust adaptive control method for a nonholonomic mobile manipulator robot, with unknown inertia parameters and disturbances, was proposed. First, the description of the robot’s dynamics model was developed. Thereafter, a novel adaptive sliding mode control was designed, to which all parameters describing involved uncertainties and disturbances were estimated by the adaptive update technique. The proposed control ensures a relatively good system tracking, with all errors converging to zero. Unlike conventional sliding mode controls, the suggested is able to achieve superb performance, without resulting in any chattering problems, along with an extremely fast system trajectories convergence time to equilibrium. The aforementioned characteristics were attainable upon using an innovative reaching law based on potential functions. Furthermore, the Lyapunov approach was used to design the control law and to conduct a global stability analysis. Finally, experimental results and comparative study collected via a 05-DoF mobile manipulator robot, to track a given trajectory, showing the superior efficiency of the proposed control law.

scholarly journals A Novel Robust Adaptive Backstepping Method Combined with SMC on Strict-Feedback Nonlinear Systems Using Neural Networks

2019 ◽  
Vol 291 ◽  
pp. 01001
Author(s):  
Yahui Li ◽  
Feng Gao ◽  
Franco Bernelli-Zazzera ◽  
Zeyou Tong ◽  
Fugui Li ◽  
...  
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode ◽  
Design Method ◽  
The Novel ◽  
Backstepping Method ◽  
Adaptive Backstepping ◽  
Closed Loop Systems ◽  
Robust Adaptive ◽  
Derivatives Of ◽  
Strict Feedback

Adaptive backstepping methodology is a powerful tool for nonlinear systems, especially for strict-feedback ones, but its robustness still needs improvements. In this paper, combined with sliding mode control (SMC), a new backstepping design method is proposed to guarantee the robustness. In this method, based on the novel combining method, the auxiliary controller is introduced only in the final step of the real controller, unlike traditional methods, which usually all include an auxiliary controller in every de-signing step to guarantee the robustness of the closed-loop systems. The novel combing methods can avoid calculating multiple and high-order derivatives of the auxiliary controllers in the intermediate steps, low-ering the computational burden in evaluating the controller. The effectiveness of the proposed approach is illustrated from simulation results.

Robust Adaptive Control of Mildly Nonlinear Systems With Time Varying Input/Output Delays

2012 ◽  
Author(s):  
James P. Nelson ◽  
Mark J. Balas ◽  
Richard S. Erwin
Keyword(s):  
Adaptive Control ◽  
Nonlinear Systems ◽  
Adaptive Controller ◽  
Robust Adaptive Control ◽  
Control Law ◽  
Time Varying ◽  
Robust Adaptive ◽  
Input Delays ◽  
Persistent Disturbances ◽  
Adaptive Control Law

Many systems must operate in the presence of delays both internal to the system and in its inputs and outputs. In this paper we present a robustness result for mildly nonlinear systems. We use this result to show that, for small unknown time varying input delays, a simple adaptive controller can produce output regulation to a neighborhood with radius dependent upon the size of an upper bound on the delay. This regulation occurs in the presence of persistent disturbances and the convergence is exponential. We conclude with an example to illustrate the behavior of this adaptive control law.

Robust Adaptive Trajectory Control for an Omnidirectional Vehicle

2013 ◽  
Vol 284-287 ◽  
pp. 1919-1923
Author(s):  
Ya Chao Yang ◽  
Chi Cheng Cheng ◽  
Chin Yin Chen
Keyword(s):  
Sliding Mode ◽  
Trajectory Control ◽  
Robust Adaptive Control ◽  
Tracking Performance ◽  
Sliding Mode Controller ◽  
Vehicle System ◽  
Control Scheme ◽  
Asymptotic Tracking ◽  
Robust Adaptive ◽  
Adaptive Control Strategy

In this paper, a robust adaptive control strategy is proposed for trajectory control of an omnidirectional vehicle with three omni-wheels, which have the ability to move simultaneously with independently rotational motion. Actuators of the omnidirectional vehicle contain uncertainties and their parameters are unknown. By the Lyapunov stability, the asymptotic tracking performance can be assured. The proposed control scheme is demonstrated by actual tracking experiments using the omnidirectional vehicle system. Experimental results showed promising tracking performance for the proposed method as compared to traditional sliding mode controller.

scholarly journals Parameter Adaptive Sliding Mode Trajectory Tracking Strategy with Initial Value Identification for the Swing in a Hydraulic Construction Robot

2022 ◽  
Author(s):  
Jingwei hou ◽  
Dingxuan Zhao ◽  
Zhuxin Zhang
Keyword(s):  
Trajectory Tracking ◽  
Sliding Mode ◽  
Estimation Algorithm ◽  
Robust Adaptive Control ◽  
Identification Algorithm ◽  
Initial Value ◽  
Robust Adaptive ◽  
Adaptive Control Strategy ◽  
The Moment ◽  
Tracking Strategy

Abstract A novel trajectory tracking strategy is developed for a double actuated swing in a hydraulic construction robot. Specifically, a nonlinear hydraulic dynamics model of a double actuated swing is established, and a robust adaptive control strategy is designed to enhance the trajectory tracking performance. When an object is grabbed and unloaded, the inertia of a swing considerably changes, and the performance of the estimation algorithm is generally inadequate. Thus, it is necessary to establish an algorithm to identify the initial value of the moment of inertia of the object. To this end, this paper proposes a novel initial value identification algorithm based on a two-DOF robot gravity force identification method combined with computer vision information. The performance of the identification algorithm is enhanced. Simulations and experiments are performed to verify the effect of the novel control scheme.

Robust Adaptive Tracking Control of Uncertain Rehabilitation Exoskeleton Robot

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Brahim Brahmi ◽  
Abdelkrim Brahmi ◽  
Maarouf Saad ◽  
Guy Gauthier ◽  
Mohammad Habibur Rahman
Keyword(s):  
Sliding Mode ◽  
Robust Adaptive Control ◽  
Human Robot Interaction ◽  
Adaptive Sliding Mode Control ◽  
Control Law ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Control Approach ◽  
Exoskeleton Robot ◽  
Robust Adaptive

Abstract Rehabilitation robots have become an influential tool in physiotherapy treatment because they are able to provide intensive rehabilitation treatment over a long period of time. However, this technology still suffers from various problems such as dynamic uncertainties, external disturbances, and human–robot interaction. In this paper, we propose a robust adaptive control approach of an exoskeleton robot with an unknown dynamic model and external disturbances. First, the dynamics of the exoskeleton's arm is presented. Then, we design a robust adaptive sliding mode control in which the parameter uncertainties and the disturbances are estimated by the adaptive update methods. The proposed control ensures a good tracking of the system with a finite time convergence of sliding surface to zero. Throughout this paper, the designed control law and the global stability analysis are formulated and demonstrated based on the appropriate choice of the candidate Lyapunov function. The experimental and comparative results, performed for seven degrees-of-freedom (DOFs) exoskeleton arm with three healthy subjects to track a passive rehabilitation motion, confirm the effectiveness and robustness of the proposed control law compared with conventional adaptive approach.

Robust Adaptive Control of Nonlinear Systems With Input/Output Delays

2010 ◽  
Author(s):  
Mark J. Balas ◽  
Suraj Gajendar
Keyword(s):  
Adaptive Control ◽  
Nonlinear Systems ◽  
Adaptive Controller ◽  
Output Regulation ◽  
Robust Adaptive Control ◽  
Control Law ◽  
Robust Adaptive ◽  
Input Delays ◽  
Persistent Disturbances ◽  
Adaptive Control Law

Many systems must operate in the presence of delays both internal to the system and in its inputs and outputs. In this paper we present a robustness result for mildly nonlinear systems. We use this result to show that for small unknown input delays, a simple adaptive controller can produce output regulation to a neighborhood with radius dependent upon the size of the delay. This regulation occurs in the presence of persistent disturbances and the convergence is exponential. We conclude with an example to illustrate the behavior of this adaptive control law.

A Robust Adaptive Sliding Mode Control Method for Attitude Control of the Quad-Rotor

2014 ◽  
Vol 852 ◽  
pp. 391-395
Author(s):  
Yong Gao ◽  
Zhao Qing Song ◽  
Xiao Liu
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Robust Adaptive Control ◽  
Adaptive Sliding Mode Control ◽  
Control Law ◽  
Unknown Disturbances ◽  
Robust Adaptive ◽  
Uncertainty Parameters

Quad-rotor is a multi-variable and strong coupling system which has nonlinear and uncertainties. According to the quad-rotor, a dynamic model of attitude which included uncertainty parameters and unknown disturbances was established. The tracking error state was used to design a slide mode surface, and a Lyapunov function which includes slide mode surface and unknown parameter was built. Further more, a robust adaptive control law was designed. At last, the designed control law was simulated, and the results justify the feasibility of the proposed control law.

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