Optimal Tracking Control Method Research Of The Omni-directional Rehabilitation Walker

With the growing global population aging, the patients with lower-limb dysfunction haveincreased significantly, Correct rehabilitation for these patients plays an important role in additionto necessary treatments and drug treatments. The omni-directional rehabilitation walker as anauxiliary medical equipment have achieved good clinical results with the scientific and reasonabletraining mode according to the theory of rehabilitation medicine. However, the omni-directionalrehabilitation walker requires precise tracking of training path established by the doctors to achievegood recovery effect on the patients. Therefore, the study of the trajectory tracking control of theomni-directional rehabilitation walker has the extremely important significance. Further more, thesystem of the walker is an redundant system, how to rational allocate the force or torque of theomni-directional wheels to make the walker has minimum energy consume under the accuratetrajectory tracking control has an important practical significance. This paper carried out researchwork, specific content as follows:Firstly, we studied the optimal trajectory tracking control problem of the omni-directionalrehabilitation walker. It transfer the dynamic model to the error state model, and then quadraticperformance index based on the path tracking error、the speed tracking error and the energyquadratic. The original nonlinear system transfer to linear system according to the theory of theexact linearization and apply the optimal control theory of the linear system to solve the optimalcontroller.Secondly, we studied the robust optimal trajectory tracking control problem of theomni-directional rehabilitation walker. Due to the different quality of different patients, even thesame patient can have a different quality when he does the training process, and the extent of thecenter of gravity caused by the mass of the load change is also different. For the problem of the loadchange, a robust optimal control method when the mass of the load change bounded is proposed,and it meets the minimum of the path tracking error、the speed tracking error and the energyconsume.Finally, for the two kinds of control strategies, the simulation study according to the differenttrajectory routes verify the reliability and the validity of the proposed algorithm.