In order to eliminate the disturbance of speed and external load in pump controlled motor system, a constant speed control system which composes of variable displacement pump and fixed displacement motor as a research objective is established. The control principle of pump controlled motor system was expatiated,and then mathematical models of the hydraulic pressure system were derived. A kind of compound control was adopted for the system which based on optimized incremental proportion integral derivative (PID)and feedforward control technology. Simulation models were established for the system's responding situation with Matlab/Simu-link software. According to the result,it is shown that control system has a swift response under the two disturbances which are the mo-tor output speed keeps stable as required. The laboratory table is built,with the load-box was used to simulate the change of load and using transducer to simulate the change of speed. When the input speed is kept at 800 r/min and 1 500 r/min,the motor speed returns to the setting value in two seconds,the stable state fluctuation ratio is 0.5% and transient adjustment ratio is 5.33%,while speed and load changed suddenly. Analysis experimental results show that speed control system can satisfy the design index with better regulation ability,and also provide the effective reference significant for the achievement of vehicle-based electric generator system.%针对泵控马达系统存在转速和外接负载扰动的问题,以变量泵-定量马达恒速控制系统为研究对象,阐明了系统的控制原理,建立相应液压系统的数学模型;采用了优化后的增量式PID与前馈相结合的复合方式对系统进行控制.通过Matlab的Simulink模块对系统的响应情况进行仿真,仿真结果表明:控制系统在两种扰动下反应迅速,马达输出转速能保持在较理想的状态.采用负载箱来模拟负载变化,变频器控制来模拟转速变化,进行了试验台的搭建.在输入转速为800、1500 r/min时,当突变转速和负载时,马达输出转速能在2 s内恢复到稳定值,稳态转速偏差为0.5%,瞬时转速偏差为5.33%.分析实验结果表明该系统调速能力较好,为车载发电系统的实现提供了借鉴意义.
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