The Robust Adaptive Control of Free-Floating Space Manipulator Systems

2001 ◽  
Author(s):  
Chen Li ◽  
Liu Yanzhu
Keyword(s):  
Adaptive Control ◽  
Jacobian Matrix ◽  
Robust Adaptive Control ◽  
Dynamic Equations ◽  
Generalized Jacobian ◽  
Space Manipulator ◽  
Floating Base ◽  
Inertial Parameters ◽  
Control Scheme ◽  
Robust Adaptive

Abstract In this paper, the kinematics and dynamics of free-floating space manipulator systems are analyzed, and it is shown that the Jacobian matrix and the dynamic equations of the system are nonlinearly dependent on inertial parameters. In order to overcome the above problems, the system is modeled as under-actuated robot system, and the idea of augmentation approach is adopted. It is demonstrate that the augmented generalized Jacobian matrix and the dynamic equations of the system can be linearly dependent on a group of inertial parameters. Based on the results, the robust adaptive control scheme for free-floating space manipulator with uncertain inertial parameters to track the desired trajectory in workspace is proposed, and a two-link planar space manipulator system is simulated to verify the proposed control scheme. The proposed control scheme is computationally simple, because we choose to make the controller robust to the uncertain inertial parameters rather than explicitly estimating them online. In particular, it require neither measuring the position, velocity and acceleration of the floating base with respect to the orbit nor controlling the position and attitude angle of the floating base.

Adaptive control of a class of non-linear systems preceded by backlash-like hysteresis

2014 ◽  
Vol 24 (5) ◽  
Author(s):  
JIANPING CAI ◽  
LUJUAN SHEN ◽  
FUZHEN WU
Keyword(s):  
Differential Equation ◽  
Adaptive Control ◽  
Linear Systems ◽  
Tracking Error ◽  
Robust Adaptive Control ◽  
Unknown Parameters ◽  
Control Scheme ◽  
Non Linear ◽  
Non Linear Systems ◽  
Robust Adaptive

We consider a class of uncertain non-linear systems preceded by unknown backlash-like hysteresis, which is modelled by a differential equation. We propose a new state feedback robust adaptive control scheme using a backstepping technique and properties of the differential equation. In this control scheme, we construct a new continuous function to design an estimator to estimate the unknown constant parameters and the unknown bound of a ‘disturbance-like’ term. The transient performance of the output tracking error can be guaranteed by the introduction of pre-estimates of the unknown parameters in our controller together with update laws. We do not require bounds on the ‘disturbance-like’ term or unknown system parameters in this scheme. The global stability of the closed-loop system can be proved.

Robust Variable Structure Control for Free-Floating Space Robot System With Dual-Arms in Joints Space

2009 ◽  
Author(s):  
Xiaoteng Tang ◽  
Li Chen
Keyword(s):  
Variable Structure Control ◽  
Variable Structure ◽  
Joint Space ◽  
Space Robot ◽  
Dynamic Equations ◽  
Robot System ◽  
Structure Control ◽  
Floating Base ◽  
Inertial Parameters ◽  
Control Scheme

In this paper, the kinematics and dynamics of free-floating space robot system with dual-arms are analyzed. It is shown that the dynamic equations of the system are nonlinearly according to inertial parameters. In order to overcome these problems, the system is modeled as under-actuated robot system, and the idea of augmentation approach is adopted. It is demonstrated that the dynamic equations of the system can be linearly depending on a group of inertial parameters. Based on this result, a robust variable structure control scheme for free-floating space robot system with dual-arms with uncertain inertial parameters to track the desired trajectories in joint space is proposed, and a planar space robot system with dual-arms is simulated to verify the proposed control scheme. The advantage of the control scheme proposed is that it requires neither measuring the position, velocity and acceleration of the floating base with respect to the orbit nor controlling the position and attitude angle of the floating base. In addition to this advantage, it is computationally simple, because of choosing the controller robust for the uncertain inertial parameters rather than explicitly estimating them online.

scholarly journals Robust Fractional Adaptive Control Based on the Strictly Positive Realness Condition

2009 ◽  
Vol 19 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Samir Ladaci ◽  
Abdelfatah Charef ◽  
Jean Loiseau
Keyword(s):  
Adaptive Control ◽  
Fractional Order ◽  
Robust Adaptive Control ◽  
Adaptive Controllers ◽  
Actuator Dynamics ◽  
Control Scheme ◽  
Positive Realness ◽  
Robust Adaptive ◽  
Model Reference Adaptive ◽  
Strictly Positive Realness

Robust Fractional Adaptive Control Based on the Strictly Positive Realness ConditionThis paper presents a new approach to robust adaptive control, using fractional order systems as parallel feedforward in the adaptation loop. The problem is that adaptive control systems may diverge when confronted with finite sensor and actuator dynamics, or with parasitic disturbances. One of the classical robust adaptive control solutions to these problems makes use of parallel feedforward and simplified adaptive controllers based on the concept of positive realness. The proposed control scheme is based on the Almost Strictly Positive Realness (ASPR) property of the plant. We show that this condition implies also robust stability in the case of fractional order controllers. An application to Model Reference Adaptive Control (MRAC) with a fractional order adaptation rule is provided with an implementable algorithm. A simulation example of a SISO robust adaptive control system illustrates the advantages of the proposed method in the presence of disturbances and noise.

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