Research On Constraint Characteristics Of Multi-section Towed Bicycle Robot

As an intelligent,novel and self-balancing vehicle,bicycle robot is the product of the integration of mechanism and control engineering,which has important theoretical research value.However,due to the limitation of inherent structure,the existing bicycle machines have insufficient load capacity.Aiming at this problem,this paper proposes a kind of multi-section drag-and-drop bicycle robot.The multi-section trailer bicycle robot is composed of a two-wheel tractor,which connects more than one articulated vehicle through the steering joint,and improves the system load capacity by increasing the number of articulated vehicles.To reveal the constraint characteristics of the robot system is the basis of establishing the system dynamics model and the premise of further realizing the balance and stability control.Based on this,this project takes the multi-section towed bicycle robot as the research object,focusing on its constraint characteristics.Mainly completed the following work:(1)Considering the general constraint characteristics of the multi-section towed bicycle robot,kinematics analysis is only conducted for the 0-section,1-section and2-section towed bicycle robot.Based on reasonable assumptions,the coordinate system of the robot is established,and the rotation transformation matrix between the coordinate systems is established accordingly.According to the geometric conditions and kinematic relations satisfied by the system,the constraint analysis of the system is carried out,and the complete constraint equation and the non-complete constraint equation of the robot system are finally established.(2)Analyze the degree of freedom of multi-section towed bicycle robot.Aiming at the tedious and unpractical problem of solving the degree of freedom of the robot system by using the grubler-kutzbach formula,a new method is proposed to introduce the mathematical induction method.By solving the velocity variable,qualitative constraint analysis was carried out on the system,and the law of freedom calculation of the robot system was deduced and summarized.The hypothesis was made,and the inductive proof was given by mathematical induction.Finally,it is concluded that the degree of freedom of multi-node towed bicycle has nothing to do with the number of articulated nodes,which is always 3.(3)Build a physical prototype of drag-and-drop bicycle robot,including mechanical system and measurement and control system.Based on an existing electric bicycle,the transmission scheme of the whole vehicle is designed and transformed.A steering joint is designed at the tail and a mounting wheel is attached.Based on this platform,a measurement and control system with ipc as the main control unit is built,including driver module,communication module,battery module,etc.,using encoder,gyroscope and other sensors to complete the data collection task.Finally,the signal transmission scheme and power supply scheme are defined.(4)Carry out virtual prototype simulation and physical prototype experiment verification for the established non-holonomic constraint equation.Established in the ADAMS,0,1,2,section pull-type bicycle robot virtual prototype model of establishing PID control link,control prototype realization of self balancing driving requirements within the given time,joint data,get the key motion parameters measured values,the joint data and geometric parameters into the nonholonomic constraint equations,and the key motion parameters calculated value.Finally,the measured curves of the key motion parameters are compared with the calculated ones,and the results show that the two curves are basically identical,which proves that the established nonholonomic constraint equation is correct.Physical prototype experiments also prove this point.