Abstract
Oscillations caused by solid friction in a hydraulic driving system are treated theoretically. The system includes a table lying on a rectilinear sliding surface, an actuator cylinder, a 4-way servo valve, a relief valve, and an oil pump. The solid friction force considered is assumed to vary with the relative sliding velocities between the table and sliding surface, namely, the friction-velocity charscteristic is given by a polygon having two straight-line segments and the critical value of static friction is equal to the value of kinetic friction without slipping. The stick-slip motions of the table are analyzed considering the 4-way valve pressure-flow characteristic, the friction-velocity relation, oil compressibility and the sizes of the hydraulic driving elements. Several types of limit cycles and the regions in which they occur are shown in figures according to the parameters mentioned above. Lastly, the steady-state displacement waves of the table are described and the curves of amplitudes and their periods are given.
