Limit Cycle Prediction Conditions for a Class of Hydraulic Control System

1986 ◽  
Vol 108 (1) ◽  
pp. 17-23 ◽  
Author(s):  
C. S. Cox ◽  
I. G. French
Keyword(s):  
Control Systems ◽  
Limit Cycle ◽  
Coulomb Friction ◽  
Position Control ◽  
Viscous Friction ◽  
Cycle Performance ◽  
Working Fluid ◽  
Hydraulic Control ◽  
Electrohydraulic System ◽  
Hydraulic Control System

This paper presents the conditions necessary to sustain a limit cycle in hydraulic position control systems with displacement feedback. The limit cycle performance of the system is then examined when the temperature of the working fluid varies between 283K(10°C) to 343K(70°C). Results are presented for an electrohydraulic system driving a load comprising inertia, viscous friction, and coulomb friction.

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.

A Hydraulic Control System Design for Change-Wheel Garage of Light Rail Based on PLC

2012 ◽  
Vol 233 ◽  
pp. 76-79
Author(s):  
Yong Gang Yang ◽  
Jun Sun ◽  
Meng Tao Yang
Keyword(s):  
Control System ◽  
System Design ◽  
Servo Control ◽  
Light Rail ◽  
Control System Design ◽  
Hydraulic Control ◽  
Plc Control ◽  
Servo Control System ◽  
Hydraulic Servo ◽  
Hydraulic Control System

This paper introduces the hydraulic control system design for the change-wheel garage of Chongqing light rails through analysis of three-stage cylinder synchronization circuit for lifting bodies, and optimizing the design of the slewing mechanism with respect to the hydraulic servo control system of digital cylinder. The results improved the smoothness in the process of changing wheel lifting and the rotary accuracy of the rotary mechanism. Design on the PLC control system of the system is also included as part of this paper.

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