| 英文摘要 | Mobile Robotics is one of the most important research areas of Robotics. A mobile robot is composed of moving structure, sensing system and control system. Focusing on the sensing system and control system for wheeled mobile robot working in an unknown environment, the research of the architecture, sensor signal processing and fusion, motion control, localization and obstacle avoidance are presented in this thesis. Firstly, the research on the history, trend, architecture and motion control for mobile robots are reviewed, and the background, main research contents, and the research significance of this thesis are introduced at the same time. Secondly, the characteristics and application limitations of the Sense-Model-Plan-Act structure and behavior-based structure are analyzed in this thesis. By combining the Sense-Model-Plan-Act structure with behavior-based structure, a hybrid structure based on multi-DSP parallel processing for a mobile robot is put forward. On the basis of this hybrid architecture, the hardware and software implementations, and communication network for the mobile robot CASIA-I designed by us is given in this thesis. Thirdly, a multi-DSP-based system with CAN communication bus is put forward, to control the sensors and process their signals for mobile robots. As for CASIA-I, the principle and its implementation of signal processing of infrared, ultrasonic and tactile sensors are given. The processed data of the above sensors are fused with the Dempster-Shafer theory. Fourthly, The servo system of CASIA-I is designed and implemented with the adaptive fuzzy PID algorithm. Kinematics for differential drive robots is analyzed, and then formulas are induced to describe forward kinematics for straight, rotating and arc motion. As an example of solving the inverse kinematics for differential drive robots, the left and right driving wheels’ velocities and their difference, which are needed to move around a circle with radium of r, are obtained. The motion control software of the mobile robot CASIA-I is programmed with assembly language of DSP. Fifthly, the localization principle based on odometer is analyzed for a wheeled differential drive robot, and formulas are induced to locate the straight, rotating and arc motion for CASIA-I. On the basis of the research results mentioned above, the methods to locate the coordinates and orientation of CASIA-I are presented. In order to solve the accumulation error problem of odometer localization, a new localization method combining odometer localization with CCD localization is put forward for CASIA-I. Sixthly, a dynamic obstacle avoidance algorithm based on the information of infrared and tactile sensors is put forward, which can work in the unknown environment with static and dynamic obstacles. The obstacle avoidance of CASIA-I is implemented with the above algorithm. Finally, the obtained research results are summarized and future work is addressed. |
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