Semi-active control of space manipulator soft contacting based on magnetorheological rotational damper

2015 ◽  
Vol 230 (14) ◽  
pp. 2390-2398 ◽  
Author(s):  
Xiaoping Du ◽  
Hang Chen ◽  
Zhengjun Liu ◽  
Chao Wang
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Active Control ◽  
Optimal Control Theory ◽  
Passive Control ◽  
Control Force ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Space Manipulator ◽  
Dynamic Formulation

A novel soft contacting technology is proposed to reduce the risks of contacts that space manipulator is on-orbit service. The magnetorheological (MR) rotational damper is considered and utilized for cushioning and vibration reduction in the space manipulator. Based on the extended manipulator model, a linear dynamic formulation of free-floating space manipulator is built. Subsequently, the mechanical property of magnetorheological rotational damper is analyzed by using Bingham model. Then, the optimal control force can be obtained by using the linear quadratic optimal control theory. Finally, the optimal control force is served as the parameters to achieve the semi-active control of soft contacting by employing the clipped optimal control theory. The hard contacting and passive control technology are introduced to make comparison with the results of soft contacting. Some numerical simulations are made to demonstrate the validity and capability of the proposed soft contacting technology.

The Design of High-Speed Dwell-Rise-Dwell Cams Using Linear Quadratic Optimal Control Theory

1994 ◽  
Vol 116 (3) ◽  
pp. 867-874 ◽  
Author(s):  
B. C. Fabien ◽  
R. W. Longman ◽  
F. Freudenstein
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Optimal Control Theory ◽  
High Speed ◽  
Numerical Procedure ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Trajectory Sensitivity ◽  
Cam Design ◽  
Quadratic Optimal Control

This paper uses linear quadratic optimal control theory to design high-speed Dwell-Rise-Dwell (D-R-D) cams. Three approaches to D-R-D cam design are compared. In the first approach the cam is designed to be optimal at a fixed operating speed, i.e., a tuned cam design is obtained. In the second approach the cam profile is determined by minimizing a sum of quadratic cost functions over a range of discrete speeds, thus producing a cam-follower system which is optimal over a range of speeds. The third technique uses trajectory sensitivity minimization to design a cam which is insensitive to speed variations. All design methods are formulated as linear quadratic optimal control problems and solved using an efficient numerical procedure. It is shown that the design techniques developed can lead to cams that have significantly lower peak contact stress, contact force and energy loss when compared to a polydyne cam design. Furthermore, the trajectory sensitivity minimization approach is shown to yield cams that have lower residual vibration, over a range of speeds, when compared to a polydyne cam design.

Active Control of Non-Linear System by a Fuzzy-Optimal Control Technique

2010 ◽  
Author(s):  
Takashi Mochio
Keyword(s):  
Optimal Control ◽  
Nonlinear System ◽  
Control Theory ◽  
Real Time ◽  
Active Control ◽  
Optimal Control Theory ◽  
Time Dependent ◽  
Control Technique ◽  
The Real ◽  
Non Linear System

The purpose of this paper is to estimate the real time vibration control of an actively-controlled nonlinear structure due to non-stationary external loads. When the optimal control theory is adopted as a control law against the concerned task, the derivation of time dependent optimal control gains may be required because of a remarkable non-stationarity of response amplitude. In addition, since the system is nonlinear, it takes more time to calculate those time dependent gains. This means that it is difficult to strictly execute the real time active control with optimal control theory as for the non-stationary and nonlinear system. In this paper, therefore, one approximate technique, coupled fuzzy-optimal control, is proposed in order to realize the real time control of non-stationary and nonlinear system. Finally, results by deterministic analysis based on numerical simulations are compared with those by stochastic analysis using statistical equivalent linearization technique.

On the Optimal Digital State Vector Feedback Controller With Integral and Preview Actions

1979 ◽  
Vol 101 (2) ◽  
pp. 172-178 ◽  
Author(s):  
Masayoshi Tomizuka ◽  
Dan E. Rosenthal
Keyword(s):  
Optimal Control ◽  
Control System ◽  
Optimal Control Theory ◽  
State Vector ◽  
Feedback Controller ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Future System ◽  
Control Situations ◽  
Quadratic Optimal Control

A digital state vector feedback controller with integral and preview actions, which can be called a proportional plus integral plus derivative plus preview (PIDP) controller, is derived based on linear quadratic optimal control theory. The preview action is a generalization of the feedforward concept which has been exercised in many process control situations. Preview of future system disturbance inputs is shown to be effective to improve the performance of the control system.

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