液压机械复合传动系统模式切换过程同步控制

Synchronous Control of Mode Switching Process for Hydro-Mechanical Compound Transmission Systems

针对双模式液压机械复合传动(DHMT)系统在进行模式切换过程中易出现动力中断、稳定性差的问题,提出一种DHMT系统模式切换同步控制方法。该方法通过分析DHMT系统模式切换动力学约束条件,建立了系统输入转速总扰动量的计算方程;采用小信号线性化方法对液压元件角速度扰动进行线性化处理,以系统输入角速度总扰动量作为液压调速系统的前馈输入,建立液压元件角速度扰动与排量补偿增量方程,得到液压元件的转矩补偿传递函数;构建以液压元件角速度为状态变量、模式切换机构转矩为控制变量的状态空间方程,通过求解最优反馈增益矩阵二次型,实现对模式切换机构转矩的补偿控制,有效消除了模式切换机构结合过程中产生的转矩冲击。仿真与实验结果表明,与未采用同步控制方法相比,该方法可使DHMT系统模式切换品质得到大幅度提高;在两种不同的实验工况下,该方法可使DHMT系统最大输出转矩损失系数降低25.15%左右,切换时间平均减少0.455 s,冲击度控制在合理范围之内,具有良好的抗干扰能力和稳定性。

A synchronous control method of mode switching process for the dual-mode hydro-mechanical compound transmission (DHMT) systems is proposed to improve the problem that a DHMT system is prone to power interruption and poor stability during mode switching. An equation is established to calculate the total disturbance of the input angular speed of the system by analyzing the dynamic constraints of the DHMT mode. The speed disturbance of the hydraulic components is linearized using a small signal linearization method, and the total disturbance of the system input angular speed is used as a feedforward input of the hydraulic adjustment. Incremental equations of the hydraulic component angular speed disturbance and the displacement compensation are established to obtain a torque compensation transfer function of the hydraulic component. An equation of state space with the hydraulic component angular speed as a state variable and the mode switching mechanism torque as a control variable is constructed. An optimal feedback gain matrix quadratic form is solved to realize the compensation control of the mode switching mechanism torque and to effectively eliminate the torque shock combined with the mode switching mechanism. Simulation and experimental results and a comparison with the non-synchronous control method show that the proposed method greatly improves the quality of DHMT mode switching. Under two different experimental conditions, the method reduces the loss coefficient of the DHMT maximum output torque by about 25.15%, decreases the switching time by 0.455 s on average, and keeps the impact degree within a reasonable range. These results show that this method has a good anti-interference ability and stability.