Distributed fault-tolerant strategy for electric swing system of hybrid excavators under communication errors

A distributed fault-tolerant strategy for the controller area network based electric swing system of hybrid excavators is proposed to achieve good performance under communication errors based on the adaptive compensation of the delays and packet dropouts. The adverse impacts of communication errors are effectively reduced by a novel delay compensation scheme, where the feedback signal and the control command are compensated in each control period in the central controller and the swing motor driver, respectively, without requiring additional network bandwidth. The recursive least-squares algorithm with forgetting factor algorithm is employed to identify the time-varying model parameters due to pose variation, and a reverse correction law is embedded into the feedback compensation in consecutive packet dropout scenarios to overcome the impacts of the model error. Simulations and practical experiments are conducted. The results show that the proposed fault-tolerant strategy can effectively reduce the communication-error-induced overshoot and response time variation.

基于自适应的延时与丢帧补偿,提出了一种分布式容错策略,用以确保基于CAN(controller area network)总线的混合动力挖掘机电动回转系统在通信出错时获得良好的运行性能。通过采用一种分别在中央控制器和电机驱动器上对反馈信号和控制信号进行补偿的全新延时补偿方法,可以在不增加通信带宽的情况下大大降低通信错误的不利影响。采用了带遗忘因子的递推最小二乘法对由姿态变化引起的时变模型参数进行辨识,并通过在连续丢帧情况下的反馈补偿中引入反向修正率来消除模型误差的不利影响。仿真和实验结果表明提出的容错策略可以有效第减小通信错误引起的系统超调和响应时间变化。