Mechanism Design And Kinematic Performance Research Of Snake-Like Robots With Orthogonal Active Wheels

Snake-like robots show broad application prospects in military inspection and emergency rescue because of their flexible mode of motion and high terrain adaptability. However, the lack of research on mechanism terrain adaptability and kinematics has restricted the practical application of snake-like robots for a long time. To solve these problems, this thesis creatively advanced a design concept of a snake-like robot with orthogonal active wheels. This concept integrates biomimetic parallel mechanisms with the wheeled walking mechanisms to keep the high redundancy characteristic of snake-like robots and enhance their ability to perform search and rescue missions. The main content is as follows.First, the orthogonal active wheel mechanism and2-UPS/U biomimetic parallel mechanism are designed through mechanism type synthesis. The dimensional type synthesis and degrees of freedom of the mechanism are analyzed and the positive effect of these mechanisms on the agility and adaptability of the robot is demonstrated. These mechanisms also develop several kinds of high-efficiency active wheel cord locomotion.Second, in response to the requirement of the joint output torque in actual missions, an integral formula of the general torque characteristics and kinematics constraints is established. The optimization for the joint mechanism is performed by the sequential quadratic programming algorithm and the results are further analyzed.Third, the key factors affecting the performance of the robot are investigated for laying the foundation of presenting the electromechanical fusion design theory. The mechanical system and electric control system of the prototype module are designed, which is based on the electromechanical fusion design theory. Kinematics and mechanical properties of the prototype module are tested. The semi-autonomous motion control system facing actual missions of snake-like robots is designed.At last, kinematics modeling approach of snake-like robot base on the screw theory is discussed. The head pose of snake-like robots in task environment is obtained using the method of imaginary mechanism. According to the characteristic of active wheel cord locomotion, the pose description and motion control strategy is established employing the method of function division and geometric modeling.This thesis makes efforts to research the mechanism and kinematics of orthogonal active wheel snake-like robots. The performance of lifting, the efficiency of locomotion and the mobility in complex terrain of the mechanism are demonstrated by theoretical analysis, experiment and simulation, which has high reference value to the research and design of search and rescue snake-like robots. The proposed kinematics modeling method lays a foundation of motion control in task environment.