Model Reference Position Control of an Elastic Two-Mass System with Compensation of Coulomb Friction

1993 ◽  
Author(s):  
U. Schafer ◽  
G. Brandenburg
Keyword(s):  
Coulomb Friction ◽  
Position Control ◽  
Mass System ◽  
Model Reference ◽  
Reference Position

Pulse Width Control for Precise Positioning of Structurally Flexible Systems Subject to Stiction and Coulomb Friction

2004 ◽  
Vol 126 (1) ◽  
pp. 131-138 ◽  
Author(s):  
David B. Rathbun ◽  
Martin C. Berg ◽  
Keith W. Buffinton
Keyword(s):  
Limit Cycle ◽  
Pulse Width ◽  
Coulomb Friction ◽  
Closed Loop ◽  
Position Control ◽  
Industrial Robot ◽  
Sufficient Conditions ◽  
Position Error ◽  
Mass System ◽  
Precise Positioning

Pulse width control refers to the use of a control law to determine the duration of fixed-height force pulses for point-to-point position control of a plant that is subject to mechanical friction, including stiction. The use of constant-gain pulse width control laws for precise positioning of structurally flexible plants subject to stiction and Coulomb friction is analyzed. It is shown that when the plant is a simple two-mass system subject to stiction and Coulomb friction, a position error limit cycle can result. Sufficient conditions for stability and self-sustained oscillation of this closed-loop system are derived. The sufficient conditions for stability are used to determine conditions on the plant parameters and the control gain that guarantee closed-loop stability and thus limit-cycle-free operation and zero steady-state position error. The analysis methods that are introduced are demonstrated in applications to the control of the position of the end-effector of an industrial robot.

scholarly journals Sliding Mode Position Control of an Actuator with Backlash and Coulomb Friction

1995 ◽  
Vol 28 (8) ◽  
pp. 103-108
Author(s):  
J.C. Cadiou ◽  
N.K. M'Sirdi ◽  
P. Blazevic
Keyword(s):  
Coulomb Friction ◽  
Position Control ◽  
Sliding Mode

Design of a Disturbance Accommodating Adaptive Control System and Its Application to a DC-Servo Motor System With Coulomb Friction

1988 ◽  
Vol 110 (4) ◽  
pp. 343-349 ◽  
Author(s):  
P. N. Nikiforuk ◽  
K. Tamura
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Coulomb Friction ◽  
Motor System ◽  
Position Control ◽  
Adaptive Controller ◽  
Analog Computer ◽  
Adaptive Control System ◽  
Servo Motor ◽  
Analytical Functions

This paper discusses the design of a model reference type of adaptive control system for a linear unknown plant with system and observation disturbances. The disturbances are assumed to be approximately expressed by step, sinusoidal, and other analytical functions. The design of a controller, called a disturbance accommodating adaptive controller (DAAC), which eliminates the effect of these disturbances at the plant output, is described. Two types of bias DAAC are given as examples and are applied to the adaptive control of a DC-servo motor system. The plant (the DC-servo system) consists of two unknown loads connected through an electrical clutch and Coulomb friction. The effect of the friction on the plant is considered as an unknown bias disturbance and the DAAC is implemented on an analog computer. Experimental results for the position control of the DAAC system are given.

A non-linear model of a rotary pneumatic servo system

1997 ◽  
Vol 211 (2) ◽  
pp. 123-133
Author(s):  
N D Tillett ◽  
N D Vaughan ◽  
A Bowyer
Keyword(s):  
Coulomb Friction ◽  
Position Control ◽  
Servo System ◽  
Experimental System ◽  
Simulation Performance ◽  
Novel Device ◽  
Non Linear ◽  
Pneumatic Servo System ◽  
Linear Elements ◽  
Low Levels

A simulation model of a rotary pneumatic servo system has been developed and verified against an experimental system. The double-acting rotary actuator is a novel device utilizing flexible inflatable bladders. The device differs from conventional pneumatic cylinders in that it exhibits low levels of friction, as it has no sliding seals, but it does suffer from hysteresis caused by bladder distortion. The objective of this study was to develop a tool with which to investigate the effect of various forms of hysteresis and other parameters on system performance. The dynamic model utilizes a linearized analysis of pneumatic components based on earlier studies. The principal advance described in this paper relates to the inclusion of non-linear elements. These are hysteresis caused by friction or the distortion of flexible components, and a digital controller implementation. The simulation successfully predicted all major modes of behaviour. Simplified models of rubber and coulomb friction-induced hysteresis modified simulation performance in line with experimental results. An investigation in simulation showed that coulomb friction-induced hysteresis had a greater damping effect than that caused by distorting the bladders. This result applies only to position control, as hysteresis has been shown not to provide damping in trajectory control applications.

scholarly journals On the Stability of Digital Position Control with Viscous Damping and Coulomb Friction

2017 ◽  
Vol 61 (4) ◽  
pp. 266 ◽  
Author(s):  
Csaba Budai ◽  
László Kovács L.
Keyword(s):  
Discrete Time ◽  
Dry Friction ◽  
Coulomb Friction ◽  
Control Parameter ◽  
Position Control ◽  
Viscous Damping ◽  
Sampled Data ◽  
Stable Domain ◽  
The Stability ◽  
Parameter Values

In this paper, we investigate the combined effect of viscous damping and Coulomb friction on sampled-data mechanical systems. In these systems, instability can occur due the sampling of the applied discrete-time controller which is compensated by the two different physical dissipation effects. In order to investigate the interplay between these, we focus on how the stable domain of operation is extended by the dry friction compared to viscous damping. We also show that dry friction causes concave envelope vibrations in this extended region. The analytical results, presented in the form of stability charts, are verified by a detailed set of simulations at different representative control parameter values.

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