液压机械传动装置模式切换优化控制

Optimal control of mode shifting of hydro-mechanical transmission device

针对液压机械传动装置(HMT)模式切换时易出现动力中断、冲击度大且切换前后稳定输出转速不一致等问题,提出了一种排量预测及转矩协调控制的模式切换方法。该方法通过建立HMT模式切换数学模型,基于二次型最优控制理论,对切换过程离合器转矩进行了协调控制;根据模式切换前后液压调速系统流量平衡方程,建立了基于所处工况信息(输入转速、负载转矩)的排量预测模型,通过控制变量液压泵排量阶跃调节至预测值,实现了模式切换前后稳定输出转速的基本一致。仿真结果表明:与传统方法相比,该方法可使HMT模式切换过程最大输出转矩损失系数降低29.85%、切换时间减少17.82%、切换冲击度控制在合理范围内,同时,排量调节有效减小了切换前后稳定输出转速的误差,模式切换品质得到明显提高。

In view of the problems of power interruption,high impact,and inconsistent rotation speed before and after shifting,during the mode shifting of hydro-mechanical transmission device(HMT),a mode shifting method of displacement prediction and torque coordinated control is proposed.By establishing the mathematical model of HMT mode shifting,the method based on the quadratic optimal control theory coordinates the clutch torque during the shifting process;according to the flow balance equation of the hydraulic speed control system before and after the mode shifting,a displacement prediction model based on the working condition information(input speed,load torque)is established,and by step-adjusting the displacement of the controlled variable hydraulic pump to the predicted value,the output speed before and after the mode shifting is basically consistent.The simulation results indicate that,compared with the traditional method,this method can decrease the maximum output torque loss coefficient of the HMT mode shifting process by 29.85%,the mode shifting time is reduced by 17.82%,the shifting impact is controlled within a reasonable range,displacement adjustment effectively reduces the error of output speed before and after shifting,and the mode shifting quality is significantly improved.