Analyzing Nonlinear System Stability of a New Hydraulic Bilateral Rolling Shear

Abstract

New hydraulic bilateral rolling shear is a composite connecting rod shearing mechanism with the upper blade driven by servo-cylinders. This new creative system would be unstable because of interaction between the mechanical dynamics and hydraulic dynamics of the machine. What's more, the positive feedback between hydro-cylinder & mechanic, which produces instability phenomenon. In this model, all instabilities result from the control of the fuel. In this study, by using the unsymmetrical valve to control unsymmetrical cylinder, this hydraulic servo model could get the nonlinear equation of the state between force and cylinder flow. Lyapunov stability theory is also used to analyze the stability of system to prove the consequence. According to the recorded data, actual trajectory agree well with given trajectory, which show that method in this paper can meet the practical demand in engineering. In addition, the experimental results show that the nonlinear system with multiple degrees of freedom is stable and its performance is outstanding.

Pressure-Relief Impact Control of Open Circuit Hydraulic Pump-Controlled Forging Press System

“…Consensus on the formation and development mechanism of pressure relief has not yet been reached. At present, researches mainly focus on the valve-controlled hydraulic press system, including analyzing the transmission rule of the pressure wave in the pipeline [19,20], proposing the active compensation method for the pressure-impact prediction of the directional valve [21,22], using the electro-hydraulic proportional cartridge valve as the pressure-relief valve [23], and designing an energy sinusoidal pressure-relief curve [24]. However, research on the pressure-relief process of pump-controlled hydraulic presses has rarely been reported.…”