Wheel-legged Robots Based On Spatial Single-loop Mechanisms With Revolute Joints

In this thesis,three kinds of wheel-legged robots based on spatial single-loop mechanisms with revolute joints are designed,and the theoretical research and analysis are carried out based on these three kinds of robots,including: configuration analysis,motion analysis,dynamic analysis,motion stability analysis,simulation analysis,and prototype experiment,etc.First of all,the thesis proposes a wheel-legged robot based on Bennett mechanism,which could move with two different gaits by redesigning the links.The switch of the two gaits could be achieved by reversing the actuator.The locomotion path of the mechanism with two gaits are analyzed separately,and three cases of the motion during the actuator reversal are discussed in detail.The theoretical analysis of the motion stability during the actuator reversal is performed.The control method is presented based on the mechanism's locomotion path by which the robot could reach anywhere in a plane.Finally,a prototype is made and tested to verify the research.Secondly,a deformable biped wheel-legged robot based on Bricard mechanism is proposed.The robot can switch between wheel mode and leg mode through the deformable mechanism to improve the environmental adaptability through different motion modes.The input-output angle relation of the deformation mechanism of the robot is deduced.The singular position of the robot deformation mechanism was analyzed by SVD method.Then the kinematics analysis and dynamics analysis of the two motion modes of the robot are carried out.A virtual prototype is made in motion simulation to verify above analysis.Finally,a prototype is designed and fabricated to verify the theoretical analysis.Then,a deformable quadruped wheel-legged robot based on Sarrus mechanism is proposed.The robot could realize wheeled and quadruped motion through the deformable mechanism.The degree of freedom and singular position of Sarrus mechanism were analyzed by the screw theory,and the input-output angle relationship of the deformable mechanism was deduced.Then two gaits of the robot in the leg mode are analyzed,including crawling gait and trot gait.A virtual prototype is made in motion simulation to verify above analysis.Finally,the transmission structure of robot is designed.At the end of the paper,a summary is given,and the advantages and disadvantages of the proposed robot are compared comprehensively,and the future development direction of wheel-legged robot is discussed.