Development Of Autonomous Cleaning Robot Powered By Ultrasonic Motors

Ultrasonic motor is a new type motor. Features such as high torque, low speed and high standstill torque what it has are enough for it to be better driver of small robots. The driving principle of ultrasonic motor is, however, different from that of electromagnetic motors, so it is necessary to study and adopt various control theories and methods for quick, precise and steady control of ultrasonic motors. At present, ultrasonic motors of overseas have already come into market, but the internal research on ultrasonic motors is later, lower level, and there is few application research on it.This paper use ultrasonic motors as the driver of an autonomous cleaning robot, to test and investigate the servo-control characteristics of internal ultrasonic motors, and do some researches on the development of cleaning robot.Autonomous cleaning robot prototype powered by ultrasonic motors directly, based on core controller DSP is designed and implemented. Three-wheel mobile machine of circular shape, suited size, flexible movement is designed as mechanical base of the robot. Detection and control system circuits of the robot, including power supply circuit, ultrasonic motor control circuit, pulse coding circuit, infrared acquisition circuit, bump switches circuit and photo resistor circuit, based on DSP TMS320LF2407A are designed, developed and debugged. In the process of infrared detection circuit debugging, some characteristics of infrared signal modulating are summarized.Methods of speed modulating by frequency modulation and PI servo-control are adopted, and closed loop control of motors and dual-differential drive walk of robot are achieved. Considering the task requirements and the actual sensatory system of robot, a path planning scheme base on obstacle avoiding of cleaning robot in unknown environments is proposed, and practical walk of robot in partial environments, according to the planning scheme, is realized by C language programme.