根据大口径非球面光学元件研抛工艺的需求，基于行星式研抛装置设计了一种新型的双路气压平衡研抛压力控制系统。该系统利用低摩擦气缸,压力传感器和两个电气比例阀构建研抛气压闭环回路。分析了系统工作原理，建立了压力控制系统的非线性模型。为了实现恒压控制，运用前馈控制及双模态PID控制算法设计了复合控制器。实验结果表明，该系统能实现研抛压力的平缓过渡，可完成研抛压力的无级调节和柔性控制，输出研抛压力在0到350 N可调，稳态压力波动小于1 N，对气缸活塞位移波动干扰有较强的鲁棒性。该系统基本满足研抛系统对研抛压力稳定性和精确度的要求。

According to the demands of large-caliber aspherical optical elements for polishing technology, a kind of dual pressure balanced polishing pressure control system was proposed based on the planet type rotational structure. The closed-loop pressure control system was built by using a low friction cylinder, two electrical proportional valves and several pressure sensors. The nonlinear mathematical model of the pressure control system was built by analyzing experimental values. In order to output a constant pressure, a composite controller was developed by combining with a feedforward control and multiple sets of bimodal PID controls. Experimental results show that the control system achieves grinding pressure smooth transition and implements stepless adjustment and flexible control for the polishing pressure. The output of the pressure is adjustable within the range 0 to 350 N and the steady pressure fluctuation is less than 1 N. The system has stroger robustness against the enough disturbances of a cylinder piston. The system basically meets the stability and accuracy requirements of the polishing pressure.