Control System Design And Experiment Research Of Under-actuated Biped Robot

So far the development of biped walking robot, mechanism unnatural gait didn't change any more. Generally, the robot often depends on the drive system and up level trajectory planning and the control of gait balance of high torque and high gain feedback to obtain stable biped walking. For using complex control and drive system, the robot's energy efficiency is very low. It is goes against studying human's nature and efficiency walking. Against such a background, McGeer firstly proposed the concept of"passive dynamic walking"in the early 90 century. He designed the first simple passive dynamic walking robot .In recent years, with the developing of the theory about passive dynamic walking, the under-actuated scientists all the world have achieved long-term progress in prototype design and the control system exploitation .They discovered that the passive dynamic theory does great indeed on human's walking pattern. We can always walk stably and efficiency. The theory provides new ideas about the design of mechanism and control policy of humanoid robot. At the same time, using the theory and human's regulator we can design assisted convenience short out and low energy consumption walking devices. The gait of under actuated robot becomes a important offset of humanoid robot. The gain of the study of humanoid robot is walking stably and efficiency.1. Introduce the structure and the framework of the under-actuated biped robot PADW- JLU II which is independently designed by Jilin University. PADW-JLU II is a three dimension biped robot which is designed with knees. The robot weight 10.29kg, high 1.34 meter and ten degrees of freedom, which of the hip and the knees is under control. Each feet contained an inactivated degree of freedom and a sideway degree of freedom. The upper body can keep on the angle bisector of the legs through the linkage to the legs. We can evaluate the parameters'of the motor according to the kinematics model of the robot when its one leg stands on the floor and the other leg swings in the air.2. Aimed at the under-actuated robot PADW-JLU II, we employer a control system wh- ich is similar to human's nervous system. On the one hand, from the point of view of bionics, we have made use of the intelligent grade step control design method create the hardware system of the under-actuated robot. We also used the ARM7 microprocessor as the core controller of the organizing level and the corresponding level. To establish the drive circuit of DC motor, we used BTS7960 chips for the actuating level. Added initiative control on hip, the robot can walk on the horizontal plane. The angle of each joint can be obtained by the high precision absolute encoder. The current values can feedback by the exactitude resistance. In accordance with the needs of the control system and the characteristics of abs- olute encoder, we designed telecommunicate interface which has the automatic send and receive function. On the other hand, we designed the software frame with grade model. The frame consists of three parts, which we say the telecommunicate level of people and compu- ter, the management and the control level and the hardware driven level. Utilizing embedded real-time operating systemμC/OS-II, we layout the function on each level and divided the functions into same tasks. Pretreatment the current sampling data of the DC motor. We also designed the nerve net PID controller which is based on the Hebb supervised learning.3. The periodic walking gait of under actuated robot is consisting of swing stage and stance stage. So its dynamic walking is a mixed system contained continuous and discrete stage. Using limit stage mechanism theory, we divided the walking state into many stages. At the following time, we made the experiment of the robot walking and analyses the experience result. Consequently, the rationalization of the physical construction is demonstr- ated right. And we know the mechanism of the robot walking gait.