行为受限下Acrobot起摆平衡控制研究

Acrobot是一种典型的二自由度欠驱动机械系统,针对实际中可能存在的杆二摆角及驱动力矩受限的问题,研究了行为受限下系统的起摆与平衡控制问题.将整个过程分为起摆和平衡2个阶段,首先利用垂直向上不稳定平衡点处近似线性模型,设计了基于LQR方法的平衡控制器,并以减小平衡控制过程力矩为目标讨论了切换姿态的优化问题；起摆控制采用了基于参考路径的能量泵入法,提出了一个改进的参考路径,采用部分反馈线性化方法实现对参考路径的跟踪,可以保证摆角在一定范围内摆动的情况下系统机械能不断增加,使起摆结束时具有更优的切换姿态,从而更容易切换至平衡控制阶段,同时使得平衡控制过程更加平稳,所需力矩更小.最后给出了实物实验结果,证明了所提控制策略的有效性.

Swing-up and Balance Control Problem for the Acrobot with Limited Behavior

Acrobot is a typical underactuated mechanical system with two degrees of freedom.To the problem of limited swing angles of second link and driving torque in a real Acrobot,the swing up and balance control problem of Acrobot with limit behaviour is studied.The whole process is divided to swing up phase and balance phase.Firstly Based on the approximate linearization of the Acrobot around the unstable equilibrium point,a LQR balance controller is designed.To decrease the torque in the balance phase,the optimum problem of the switching gesture is studied;The swing up control is based on energy pumping method which follows a reference path.An improved reference path is proposed and the partial feedback linearization method is used to track the reference path which can guarantee that the energy is increasing while the swing angle is in the given range and can lead to a better switching gesture: easier to switch to balance control,smoother balance process and smaller driving torque.Finally the experiment results are given to show the effectiveness of the proposed control strategy.