混合动力挖掘机电动回转系统速度控制研究

Speed control of electric drive swing system in hybrid excavator

针对挖掘机回转平台转动惯量大、变化范围宽且外界干扰力矩较大,易造成速度波动的问题,对20 t混合动力挖掘机电驱动回转系统速度控制进行了研究。建立了其数学模型,提出了比例积分(PI)+扰动观测器补偿的速度控制方案,并设计了扰动观测器和PI控制系数;在转台最大和最小惯量,且施加阶跃干扰力矩的情况下,对PI+DOB方案以及PI控制方案进行了仿真对比。仿真结果表明:该回转系统在采用PI控制之外增加DOB环节后,使转台惯量变化对转速超调量的影响从3.1%下降到1%,外部干扰对转速波动的影响从1.3%下降到0.1%;扰动观测器环节减小了惯量变化对转速超调的影响,增强了速度控制的抗干扰能力,改善了回转作业的操作性。

Aiming at the rotary speed fluctuation of the excavator upper platform caused by the large and variable swing inertia and the large disturbance torque,the speed control of electric drive swing system of a 20-ton excavator upper platform was investigated.The mathematic model of the swing system was built and analyzed.The PI plus disturbance observer control scheme was presented and the disturbance observer was designed.The simulation was performed at the condition of the maximum,minimum swing inertia and the step disturbance torque.The simulation results indicate that the scheme of disturbance observer makes the impact of inertia variation of platform on rotary speed fluctuation drop from 3.1%to 1%,and the impact of external disturbance on rotary speed fluctuation drop from 1.3%to 0.1%.Therefore,the impact of inertia variation of platform on rotary speed is decreased,the ability of anti-disturbance is enhanced and the operability of the swing system is improved through the disturbance observer.