Robust adaptive stick-slip friction compensation

1995 ◽  
Vol 42 (5) ◽  
pp. 474-479 ◽  
Author(s):  
Seon-Woo Lee ◽  
Jong-Hwan Kim
Keyword(s):  
Friction Compensation ◽  
Stick Slip ◽  
Robust Adaptive

Active control of flexible one-link manipulators using wavelet networks

Robotica ◽  
2013 ◽  
Vol 31 (8) ◽  
pp. 1275-1283 ◽  
Author(s):  
V. I. Gervini ◽  
E. M. Hemerly ◽  
S. C. P. Gomes
Keyword(s):  
Dead Zone ◽  
Flexible Manipulator ◽  
Friction Compensation ◽  
Control Law ◽  
Wavelet Network ◽  
Stick Slip ◽  
Control Laws ◽  
Operational Conditions ◽  
Structure Control ◽  
Wavelet Networks

SUMMARYThe design of control laws for flexible manipulators is known to be a challenging problem, when using a conventional actuator, i.e., a motor with gear. This is due to the friction of the nonlinear actuator, which causes torque dead zone and stick-slip behavior, thereby hampering the good performance of the control system. The torque needed to attenuate the vibrations, although calculated by the control law, is consumed by the friction inside the actuator, rendering it ineffective to the flexible structure control. Nonlinear friction varies with different operational conditions of the actuator and a friction compensation mechanism based on these models cannot always keep a good performance. This study proposes a new control strategy using wavelet network to friction compensation. Experimental results obtained with a flexible manipulator attest to the good performance of the proposed control law.

A learning approach to stick-slip friction compensation

1999 ◽  
Vol 32 (2) ◽  
pp. 1184-1189
Author(s):  
Seong-Il Cho ◽  
In-Joong Ha
Keyword(s):  
Friction Compensation ◽  
Learning Approach ◽  
Stick Slip

Robust adaptive deadzone and friction compensation of robot manipulator using RWCMAC network

2011 ◽  
Vol 25 (6) ◽  
pp. 1583-1594 ◽  
Author(s):  
Seong Ik Han ◽  
Kwon Soon Lee ◽  
Min Gyu Park ◽  
Jang Myung Lee
Keyword(s):  
Robot Manipulator ◽  
Friction Compensation ◽  
Robust Adaptive

High-accuracy robust adaptive motion control of a torque-controlled motor servo system with friction compensation based on neural network

2018 ◽  
Vol 233 (7) ◽  
pp. 2318-2328 ◽  
Author(s):  
Jian Hu ◽  
Yuangang Wang ◽  
Lei Liu ◽  
Zhiwei Xie
Keyword(s):  
Neural Network ◽  
Motion Control ◽  
Servo System ◽  
High Accuracy ◽  
Robust Adaptive Control ◽  
Lyapunov Theory ◽  
Parametric Estimation ◽  
Friction Compensation ◽  
Nonlinear Friction ◽  
Robust Adaptive

In this paper, a high-accuracy motion control of a torque-controlled motor servo system with nonlinear friction compensation is presented. Friction always exists in the servo system and reduces its tracking accuracy. Thus, it is necessary to compensate for the friction effect. In this paper, a novel controller that combines robust adaptive control with friction compensation based on neural network observer is proposed. An improved LuGre friction model is applied into the friction compensation as it is known as a good model to express the nonlinear friction. A single hidden-layer network is utilized to observe the immeasurable friction state. Then, the robust adaptive controller is used to handle the parametric uncertainty, the parametric estimation error, friction compensation error, and other uncertainties. Lyapunov theory is utilized to analyze the stability of the closed-loop system. The experimental results demonstrate the effectiveness of the proposed algorithm.

Friction compensation control of an electropneumatic servovalve by using an evolutionary algorithm

2000 ◽  
Vol 214 (3) ◽  
pp. 173-184 ◽  
Author(s):  
S H Choi ◽  
C O Lee ◽  
H S Cho
Keyword(s):  
Search Algorithm ◽  
Static Friction ◽  
Open Loop ◽  
Friction Model ◽  
Experimental Results ◽  
Friction Compensation ◽  
Stick Slip ◽  
Air Contamination ◽  
Compensation Control ◽  
Friction Models

A poppet-type electropneumatic servovalve developed in this study utilizes a poppet directly operated by a moving-coil actuator in the metering stage and is controlled by a digital controller. This servovalve is insensitive to air contamination and has no problem of air leakage at null, but it has relatively large friction between the O-rings installed in the peripheral grooves of the balance pistons and the valve sleeve. For friction compensation control, a static friction model that enables simulation of the stick-slip phenomena and a dynamic model that captures the friction behaviour such as presliding displacement and varying break-away force are presented. The parameters for the friction models are identified by utilizing an evolution strategy, one of the evolutionary algorithms, which is a probabilistic global search algorithm based on the model of natural evolution. These friction models are then used in designing a non-linear friction compensation controller. It is found in the experiment that the electropneumatic servovalve has almost no hysteresis and that the friction compensation control significantly improves valve performance. The experimental results of the open loop test on poppet positioning agree well with simulation results of the valve model with identified friction parameters. It is also shown that the experimental results of friction compensation control using a static friction model show a small steady state error but those using a dynamic friction model show almost no such error.

Sign in / Sign up

Export Citation Format

Share Document