Abstract:

Mathematical models were built for the flow and pressure control of the direct drive electro-hydraulic servo system to realize the optimal pressure and flow compound control of the system. A constant pressure and limited flow control method was proposed based on the parameter switch by the pressure difference, and on this basis the pressure and flow switch control method was corrected. This method enhances significantly the system response under the prerequisite of meeting the system stability. The experimental results show that, by means of reasonable integral and dead zone regulation, both methods can make the pressure and flow switch smoothly, the system sensitivity to the changes of actuators and load parameters was declined, and the system response was improved. These results confirme the validity of the proposed method.

Key words: automatic control technology, direct drive electro-hydraulic servo system, pressure and flow compound control, constant pressure and limited flow control, pressure and flow switch control