带流量前馈与工作腔压力反馈的电液负载敏感系统节能方法

基于流量前馈控制的电液负载敏感系统为容积节流复合调速系统,可将阀口全开以降低能量损失,但在超越工况下,系统速度特性会受阀口阻尼降低的影响,引发执行器超速下坠甚至安全事故等问题。据此,提出了适用于带阀后压力补偿的电液负载敏感系统的解决方法:将负载进油口容腔压力控制为一恒定值,并研制了相应的压力串级控制器。该控制器以速度反馈作为内环以提高系统抗负载干扰能力,并以带抗积分饱和补偿的PI 控制器作为外环以控制工作腔压力为一定值。基于2 t挖掘机不同负载工况下的试验结果表明:工作腔压力控制与传统手柄直接控制阀口的方法相比,可在降低比例阀阀口损失的同时保证执行器速度控制性能。

Energy Saving Method for Electro-hydraulic Load-sensing Systems with Flow Feed-forward and Working Chamber Pressure Feedback

The electro-hydraulic load-sensitive system based on feed-forward control is a volumetric throttling compound speed control system, which can open the valve port fully to reduce energy loss, but under overrunning conditions, the system speed characteristics can be affected by the reduced damping of the valve port, causing problems such as actuator overspeed drops and even safety accidents. To address this problem, a solution is proposed for electro-hydraulic load sensitive systems with post-valve pressure compensation: the load inlet cavity pressure is controlled to a constant value, and a corresponding pressure cascade controller is developed. The controller uses the speed feedback as the inner loop to improve the system's resistance to load disturbances and the PI controller with anti-windup compensation as the outer loop to control the working chamber pressure to a certain value. Test results based on different load conditions on a 2-ton excavator show that the working chamber pressure control can reduce the proportional valve orifice losses while maintaining the actuator speed control performance compared to the traditional direct control orifice by the handle.