Gait Planning And Motion Control For Gait Training Robot

Gait Training Robot (GTR) is a kind of modern medical equipment for the rehabilitation training of individuals with locomotor disfunction of the lower limbs. Currently, performing the rehabilitation training with GTR has become a world recognized rehabilitation method with obvious treatment effects. In recent years, with the increase of individuals with locomotor disfunction of the lower limbs in China, the needs for the gait rehabilitation training have become more and more. Because the prices of the overseas GTR products are very high and there isn't home-made GTR product with mature technology, this medical equipment has not been used in domestic medical establishments. So development this kind equipment has great significance to improve domestic medical treatment level and to improve the patients'life quality.The dissertation is part of the study on the key techniques of Gait Training Robot System. The main works of this dissertation are establishing the gait planning method and motion control system for the Powered Gait Orthosis (PGO) of the GTR System. The main contents of this dissertation are as follows:(1) Testing and computing methods of the gait characteristic parameters. A gait characteristic parameter test bench is built, which consists of a motion capture system and a treadmill. The local coordinate system creation method, coordinate transformation method and the computing methods for the parameters of joint angles are studied. The feasibility and correctness of these methods have been tested by experiments.(2) Mathematical model creation method for the hip joint, knee joint and ankle joint angle data. The hip joint, knee joint and ankle joint angle data mathematical model are established by using non-linear curve-fitting methods and the residual analyses are made. The residual analyses results demonstrate that these created mathematical models can describe the human gait characteristics exactly and meet the demands of human natural gait planning for the PGO.(3) A set of overall gait planning methods for the PGO are established according to the PGO's work tasks and work environments. The overall walk training process consists of three gait phases: start gait, cycle gait and end gait. The gait of each gait phase is planed according to its motion characteristic and task demand. In the end, a set of overall gait planning for the PGO are established by combining the three gait phases in a certain sequence.(4) The motion control strategy and its data generation method for the PGO are studied and applied to the motion control system of the PGO. According to the operating principle of servo motor and structural features of PGO, the motion control strategy is confirmed and the closed loop position control method, which based on the joint angle data, is established. According to the joint structure and motion transmission order of the joint actuator, the motion transfer functions from motor axis to joint axis are derived. Based on the motion transfer functions, the motion control data generation program is programmed, which can transform the target motion trajectories to pulse instructions needed by the servo motor drivers.(5) The gait planning methods and motion control system for the PGO have been tested through experiments. First detect and calculate a set of joint angle data of cyclic gait, then plane the target motion trajectories of the three joints, and then transform the target motion trajectories to pulse instructions data. At last, the gait training experiments are carried out on the GTR prototype with a dummy. The experimental results show that the PGO is able to guide the dummy's legs to move in the planned gait pattern on treadmill and the motion trajectory errors are very small. The goal of driving the patient's legs to move in human natural gait pattern can be achieved by using the GTR prototype.