集成式伺服作动器压力损失特性及其影响因素

针对集成式伺服作动器液压回路的特点和选择切换功能，分析了能源切换原理、选择活门的压力损失规律及其对作动器活塞运动速度的影响。电磁阀通过控制选择活门阀芯的位置以实现不同能源的切换。分析了选择活门压力损失的成因分布与特征。由分析可知，流道结构突变处的局部损失占比最大，沿程损失可忽略不计，选择活门压力损失与流入流量的平方呈比例关系。同时，拟合出了活塞伸出运动和收缩运动时的压力损失经验系数。建立了作动器左右腔流量、压力和活塞动力学模型，发现某型选择活门压力损失使作动器活塞伸出速度下降了4.9%，收缩速度下降了5.2%。由于活塞受力情况一致，选择活门的压力损失不影响负载力与活塞速度的关系，速度下降比例与负载力无关；阀芯开度直接影响着流经系统流量，系统流量影响着流体与流道的撞击强度和频率，进而影响了选择活门的压力损失程度，速度下降百分比随阀芯开度增大而增大。分析结果可为高可靠性、高精度航空作动器伺服控制系统的设计提供技术支持。

Analysis of Pressure Loss Characteristics and Influence of Integrated Servo Actuator

In view of the characteristics of the hydraulic circuit of the integrated servo actuator and the selection switching function, the principle of energy switching, the law of pressure loss of the selection valve and its influence on the movement speed of the piston of the actuator are analyzed. The solenoid valve controls the position of the selection valve spool to realize the switching of different energy sources. The distribution and characteristics of the pressure loss of the selection valve are analyzed, and it is found that the local loss at the sudden change of the flow channel structure accounts for the largest proportion, and the loss along the way is negligible. It is concluded that the pressure loss of the selection valve is proportional to the square of the inflow flow rate, and the pressure loss empirical coefficient during extension and contraction is fitted. The flow, pressure of the left and right chambers of the actuator and piston dynamics models are established. And it is found that the selection valve pressure loss reduces the extension speed of the actuator piston by 4.9% and the contraction speed by 5.2%. Because the relationship between piston speed and load force is constant, the pressure loss of the valve does not affect the relationship between the load force and the piston speed, and the percentage of speed decrease is independent of the load force. The spool opening directly affects the flow through the system. The system flow affects the impact intensity and frequency of the fluid and the flow channel, and then affects the degree of pressure loss of the selected valve. The percentage of speed decrease increases with the increase of the spool opening. The analysis results can provide technical support for the design of high-reliability and high-precision aviation actuator servo control system.