Limit Cycle Prediction Conditions for a Class of Hydraulic Control System

Abstract

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.

Characterization and quenching of friction-induced limit cycles of electro-hydraulic servovalve control systems with transport delay

“…The hydraulic fluid flowing into the cylinder drive is controlled by a four way electrohydraulic servovalve driven by a torque motor. This control system architecture is generally nonlinear and has four nonlinearities [7,8]. Two of these nonlinearities, which are associated with the spool valve, are the pressure/flow characteristics and the flow saturation effect that occur when the valve ports are fully exposed.…”

“…approximately linearize the friction force has been exploited and derived conditions which need to be satisfied by a class of electrohydraulic control system to sustain a limit cycle based on the Nyquist plot method. Besides, in [7] the effect of changing fluid temperature as well as the viscous and Coulomb friction on the limit cycle characteristics are also investigated. Extensions of the same method to the stability analysis of an electro-hydraulic servovalve control system subject to Stribeck-type friction using the non-simplified system representation is presented in [8].…”

“…The proposed method for synthesizing robust controller to achieve limit cycle amplitude suppression has some distinguished features and advantages comparing with other prevailing methods [7,8,[13][14][15]. First, the present work turns the view from the limit cycle analysis of nonlinear systems containing nonlinearity to the design of robust controller to achieve limit cycle amplitude suppression.…”

“…In order to investigate the system dynamics of electro-hydraulic servovalve control systems in the presence of friction, several methods have been proposed in the literature [7][8][9][10][11][12][13][14][15]. In one of such works [7], the describing function method [16,17] to * Tel.…”

“…In one of such works [7], the describing function method [16,17] to * Tel. : +886 2 86625925x336; fax: +886 2 26649082.…”