挖掘机动臂势能回收系统的压力滑模控制

Pressure sliding mode control of hydraulic excavator boom potential energy recovery

为了实现混合动力液压挖掘机动臂势能回收,保证动臂下降过程的平稳性,提出基于Super-twisting滑模控制的以稳定动臂液压缸上腔压力为目标的能量回收控制方法.在建立关键元件的数学模型讨论能量回收时挖掘机动臂下降的平稳条件的基础上,针对上腔压力控制和下腔压力控制2种情况,对比分析外力扰动对下降速度的影响;设计Super-twisting滑模能量回收控制器实现压力的稳定控制,证明压力稳定滑模控制器的稳定性.通过AMESIM进行系统仿真,结果表明:以下腔压力为控制目标和以上腔压力为控制目标的液压挖掘机动臂势能回收控制方法能够满足动臂势能回收时平稳下降,其中,以上腔压力为控制目标有较好的抗外力扰动能力,且更容易确定控制目标.

A new boom potential energy recovery schema for hydraulic excavator was proposed to maintain the stability of boom lowering down velocity based on the pressure super-twisting sliding mode control of the upper side on excavator boom cylintlers.The mathematical models of the key hydraulic elements were introduced,and the necessary stability condition of boom lowering down was discussed.The lowering down speed disturbance caused by the external force was analyzed for the upper side pressure control and the lower side pressure control of excavator boom cylinders.The super-twisting sliding mode controller was presented and the stability of them was proved for the two schemas.Simulation in AMESIM was conducted.Results show that both the upper side and the lower side excavator boom cylinder pressure control of the potential energy recovery are stable.The upper side pressure control method has better antidisturbance ability,and it is much object to set the control object.