Position-Based Impedance Control of Cylinder for Oil Hydraulic Servo Systems

摘要

The oil hydraulic cylinder has been used as industrial actuators, because it is inexpensive and also has a high power to weight ratio. However the accurate control of the oil hydraulic actuators is difficult because of very complex and high nonlinearity due to flow-pressure relationship and large friction force. Recently, to overcome those problems an impedance or hybrid force/position control concept has been suggested. This study proposes an impedance control of an oil hydraulic servo system with a position-based approach where an optimal servo system using the LQ optimization technique is constructed inside the force feedback loop. And also to attain the desired impedance over extensive operating conditions, we use an impedance parameter modulation law. From some experiments, an impedance parameter modulation law incorporating the optimal servo system shows good static force control ability and excellent performance in dynamic tasks such as collision force reduction.