Fuzzy Wavelet Neural Network Control for Coordinated Motion of Free-Floating Space Manipulator System in Joint Space

2009 ◽  
Author(s):  
Huang Dengfeng ◽  
Chen Li
Keyword(s):  
Neural Network ◽  
Lagrange Equation ◽  
Joint Space ◽  
Wavelet Neural Network ◽  
Dynamic Equations ◽  
Back Propagation Algorithm ◽  
Coordinated Motion ◽  
Space Manipulator ◽  
Control Scheme ◽  
Fuzzy Wavelet Neural Network

The dynamic control for coordinated motion of free-floating space manipulator system in joint space is discussed. According to the geometrical relationship and the linear momentum conservation law, the dynamic equations of space manipulator system are established through Lagrange equation of the second kind. Based on the above, a fuzzy wavelet neural network scheme is designed to control the base’s attitude and the joint angle of manipulator to track desired trajectories synchronously in joint space. The control scheme needs neither linearly parameterize the dynamic equations of the system, nor know any dynamic parameters. Moreover, its network weight is learning by back propagation algorithm online so the training time is saved. Numerical simulations are presented to verify the feasibility and effectiveness of the proposed control scheme.

GAIT SYNTHESIS BASED ON FWN FOR A FIVE-LINK BIPED ROBOT

2007 ◽  
Vol 05 (01) ◽  
pp. 197-211
Author(s):  
PENGFEI LIU ◽  
JIUQIANG HAN ◽  
JIANMEI MA ◽  
DONGLIN WANG
Keyword(s):  
Neural Network ◽  
Biped Robot ◽  
Wavelet Neural Network ◽  
Reference Trajectory ◽  
Back Propagation Algorithm ◽  
Double Support ◽  
Neural Network Controller ◽  
Network Controller ◽  
Fuzzy Wavelet Neural Network ◽  
Support Phase

This paper presents a new reference trajectory and a fuzzy wavelet neural network controller to synthesize the gait of a five-link biped robot when walking on the level ground. Both the single support phase (SSP) and the double support phase (DSP) are considered. The gait of the biped can be determined when the trajectories of the hip and the swing limb are designed. The trajectories of the hip and the swing limb are approximated with the time polynomial functions. The coefficients of the functions are determined by the constraint equations cast in terms of coherent physical characteristics, such as repeatability, continuity, stability, and minimization of the effect of impact. The fuzzy wavelet neural network controller is trained by error back-propagation algorithm. Given the certain gait parameters such as the step length, maximum step height, walking speed, and so on, the control scheme can generate the smooth gait profiles. The simulation results show that the designed controller can follow the reference trajectories well.

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.

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.

Robust Control for Coordinated Motion of Flexible Space Manipulator Based on the Augmentation Approach

2010 ◽  
Author(s):  
Zhiyong Chen ◽  
Li Chen
Keyword(s):  
Robust Control ◽  
A Priori ◽  
Joint Space ◽  
Momentum Conservation ◽  
Network Control ◽  
Coordinated Motion ◽  
Space Manipulator ◽  
Assumed Mode Method ◽  
Uncertainty Bound ◽  
Mode Method

In this paper, the coordinated control of a flexible space manipulator system with a front flexible link is discussed. With the assumed mode method and linear momentum conservation of the system, the dynamics of the manpulator is derived in Lagrangian formulation. By using the augmentation approach, a robust control scheme for the coordinated motion between the spacecraft’s attitude and arm’s joints of the flexible space manipulator with bounded external disturbances and uncertain parameters to track the desired trajectories in joint space is proposed. It is designed based on a priori knowledge about the uncertainty-bound and possesses the advantage that it can greatly reduce the calculation time needed by the adaptive or neural network control schemes. Simulation results show that the presented controller can stabilize the system to track the desired trajectories and keep the vibration amplitude of the flexible arm to be relatively low-level.

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