桥式起重机定位防摆改进型自抗扰控制

Modified active disturbance rejection control for positioning and anti-swing of bridge crane

中文关键词  桥式起重机  新型跟踪微分器  扩张状态观测器  改进型自抗扰控制

英文关键词  bridge crane  novel tracking differentiator  extended state observer  modified active disturbance rejection control

中文摘要

      为解决严重外界干扰下桥式起重机长距离运输过程中定位困难、消摆时间长的问题, 根据起重机先加速、 再匀速、后减速的远程运输特点, 利用两段Sigmoid函数, 设计了可按需调整各阶段速度且高阶连续的新型跟踪微 分器; 采用Sigmoid函数构造了增益时变且连续可微的扩张状态观测器, 使其具有“大误差小增益, 小误差大增 益”特性, 克服了经典ESO增益在切换点处的突变问题, 抑制了观测信号的微分峰值现象, 实现了位移和摆角控制 回路间的解耦; 利用tanh函数改进了误差反馈控制律, 避免了大扰动下的控制量饱和问题; 综合形成了适用于起重 机长距离运输、且能最大程度抑制振动和冲击的改进型自抗扰控制器, 并对闭环系统的稳定性进行了严格的理论 证明. 仿真及实验结果表明, 改进型自抗扰控制器在大干扰影响下可全过程平稳且基本无摆地将负载搬运到目标位 置.

英文摘要

      To solve the problems of difficult positioning and long anti-swing time during long-distance transportation of bridge cranes with severe disturbance, according to the long-distance transportation characteristics of bridge crane that first accelerates, then operates uniformly, and finally decelerates, a new high-order continuous tracking differentiator (TD), which can adjust the speed of each stage as needed, is designed by using two sigmoid functions. The sigmoid function is used to construct an extended state observer (ESO) with time-varying gain, so that it has the characteristics of “large error and small gain, small error and large gain”, which overcomes the sudden change of gain at the switching point, restrains the derivative peaking phenomenon, and achieves a decoupling between the position and the swing angle control loop. To avoid the saturation of the control variable under large disturbances, the tanh function is used to improve the classic error feedback control law. Combining the above measures, a modified active disturbance rejection controller (MADRC) is formed, which is suitable for long-distance transportation of cranes and can minimize vibration and shock. The stability of the closed-loop feedback system is strictly proved theoretically. The simulation and experimental results show that the MADRC can transport the load to the target position smoothly and basically without swing under large disturbance.