Reserach About A Variable Structure Bicycle Robot

As the Representative of two-wheeler automobile, bicycle robot is widely researched in its unique properties of balance. From the modeling study, to the balance control, from the traditional rear-wheel drive, to the emerging front-wheel drive, from the basic straight line moving, to the track stand motion and circle motion, the research of bicycle robot has been extending. On the other hand, a kind of vehicle called Segway caused widespread concern recently. Segway is very different in the shape of the structure and the balance control method with the bicycle, but it has two-wheels and dynamic balance property as same as bicycle. Therefore, it is necessary to develop a structure variable bicycle robot, so it can move as either bicycle or Segway, and can switch between the two states in the different driving conditions. The research not only has theoretical value, but also has broad practical application prospect.A novel variable structure self-balancing bicycle robot was proposed in the paper. The researches based on it are the structural design, the kinematics analysis, the nonholonomic constraint analysis, the dynamics model analysis, and the balance control algorithm. The studies in the paper are specifically as the following aspects:Firstly, the design of the variable structure bicycle robot and the virtual model of the robot system were proposed in the paper. Secondly, nonholonomic constraint equations were deduced by means of recursion based on the assumption of rolling wheels without slipping. Computer simulations were carried out on a virtual prototype to verify the nonholonomic constraint equations. Thirdly, based on the nonholonomic constraint the dynamics equations of the system were deduced by means of Kane method. Fourthly, a balance control algorithm based on the kinematics was designed for the bicycle state. The centrifugal force generated in circular motion was considered as virtual equilibrium torque. The fork angel and the speed of the front wheel were taken as the input of the control system. The control parameters were selected under equilibrium conditions. Computer simulations were carried out on a virtual prototype by using Adams and Matlab. The simulations under different frame roll angels verified the effectiveness of the controller. Finally a physical prototype of the variable structure bicycle robot was constructed. It contains four group of the DC motor to provide drive force. The digital signal processor TMS320F28335is utilized as the core controller. The microcontroller C8051F040is utilized as data acquisition. The microcontroller C8051F410is utilized as motor control. Inertial reference system (MTI), photoelectric encoder and current sensors compose the sensor modular of the variable structure bicycle robot system.