Design And Implementation Of Foot Robot Based On AVR

Robot competition has become one of the scientific and technological innovation activities that college students in China are keen to participate in. Developing a contest robot platform which is suitable for college students has the practical significance. In the background of RoboCup, the subject is aimed at developing a biped walking robot platform for competition. According to the competition rules, the mechanical structure of the biped walking robot, the hardware of control system based on ATmegal28, stable gait, the software of control system and some others are designed and implemented. The biped walking robot is debugged and verified.Firstly, based of the understanding and the analysis of biped walking robot mechanism and the rules of the game, through the analysis and simplification of the joints and degrees of freedom of human body, the hips joints, knee joints and ankle joints of the biped walking robot are configured with degrees of freedom of forward movement. And the analog servo SR-403P is chosen as the joint drive element. Then the servo connecting pieces, top plate and feet plate are designed with the software Pro/Engineer. And the mechanical structure of the biped walking robot is designed and produced completely.Secondly, according to the control requirements of biped walking robot, the AVR MCU ATmegal28 is chosen as the control chip of the system. The high performance rechargeable batteries are selected as the power of servo and control circuits. To eliminate the interference, the control circuit and servos are insulated with the optocoupler. The infrared sensors are used to detect the ground. With the idea of modular design, the MCU minimum system circuit, peripheral isolation circuit, power circuit, infrared sensor circuit and some other circuits are designed. The feasibility of the circuit is tested by welding circuit on the pegboard. And the PCB is designed is fabricated.Thirdly, according to the action requirements of biped walking robot, with the gait planning method based on the principle of bionics, the human walking and flip process are simulated and analyzed. The process of human motion is simplified and improved, and then the changing angle dates of the hip, knee and ankle joint of robot are obtained. After repeated testing, the changing angle dates are set for the initial gait datas of the walk and roll motion of biped walking robot. The walking and tumbling action requirements of biped walking robot are achieved.Lastly, in terms of software design, the main function, walking function, infrared detection and interrupt trigger function and some other software functions are designed. In the walking function,6 PWM signals are generated with timer/counter. In accordance with the initial gait data, the changing PWM is calculated and outputed in a timely manner to driving 6 servos to rotate coordinately, and realizing walk, roll forward, roll backward and some other functions of biped walking robot. The walking speed regulation algorithm is designed, which makes the robot gait more stable on the basis of the guarantee of walking speed. In the infrared detection and interrupt trigger function, the infrared emitter transmit modulation signal, and the output of infrared receiver is detected with the external interrupt. In the interrupt handler, the correction method is used to correct the walking direction of robot. Through the software and hardware debugging, the initial gait is improved, the stable gait of biped walking robot is obtained, and the design requirements of the biped walking robot competition is reached.