Study On The Ultrasonic Obstacle Avoidance And Inertial Navigation System Of Mobile Robot

As a correspondingly active research branch of robotics, the mobile robot has being drawn more attention in this field all the time. The obstacle avoidance and navigation of mobile robot was an important research field, as a key technique as well. As the development of information technique, automation technique, computer technique and navigation technique, each field has been continuously intercrossing and syncretizing with others. It impelled the researching development of mobile robot in obstacle avoidance and navigationThis thesis took the robot which worked under partly unknown or absolutely unknown environment as research object, and briefly focused on the design of hardware.Comparing the existing literature both domestic and overseas, we designed a kind of mobile robot navigation system platform which integrated the ultrasonic obstacle avoidance and inertial navigation system. This navigation platform had the function such as ultrasonic obstacle avoidance detecting, analog signals acquisition, MEMS inertial navigation module and communicating with GPS module. In order to satisfy the system requirement and low the cost, we selected the MSP430F135 as the Signal Processor. Basing on completing the peripheral circuit designing, we selected the T/R40 as the ultrasonic sensor and designed the ultrasonic eradiating circuit and receiving circuit. The analog signals acquisition module was composed of high frequency and low frequency analog signals acquisition. Thereinto, the high frequency acquisition system was implemented by that AT89S52 controlled the high-speed 8-bit analog-to-digital converter, while the low frequency acquisition system was implemented by MSP430F135 which integrated a 12-bit ADC. In order to build the communication between the master and MEMS inertial navigation module, the synchronous SPI was used as the communication mode between the master and slavery. In addition, in order to extent the system function, the RS232 communication interface was used to implemented the communication between the master CPU and GPS module. And then, basing on the completed hardware design, we did some system software simulation and debugging to implement every module function. Finally, after finishing the every module function, we made some simple system synthetically debugging. At the end, in order to enhance the navigation precision, we analyzed the random drift of the MEMS gyroscope in inertial system and the drift of Kalman filter,and did some research on how to eliminate the drift and a Kalman filter arithmetic which could properly compensate the drift.