Kinematics’ Analysis Of The Multi-motion Mode Wheel-leg Robot

Biomimetic robots’ research has always been a very active field in the last decades.Mechanism of the movement plays an important role in biomimetic robots’ research. Some of theresearchers, combine the feature of wheeled robots and the legged robots, formed the wheel-legrobots, enhancing the robot’s adaptability in different kinds of terrains. The object of thisdissertation is a kind of wheel-leg robot. This robot has six legs with the same mechanism. Thisrobot has differnt kinds of movment model. With the joints’ deformable ability, this kind ofbiomimetic mobile robot can travel by legs or wheels, so this kind of biomimetic mobile robotcan walk in different kinds of ways, so this robot can not only drive very fast but also hasenhanced the adaptability in complex grounds furtherly.In this dissertation, we firstly analyze the kinematics of one leg of the multi-motion modewheel-leg robot, establish the kinematic model using D-H rule, solve and simulate the forwardand inverse kinematics of the legged mechanism of the multi-motion mode wheel-leg robot; Thetraditional approach for constructing the kinematic model of serial mechanisms is to solve thecoordinate transformations of the kinematic equations by using D-H rule, however, this approachhas been proved to be less efficient in constructing some complex kinematic mechanisms, andthe analysis processes for coordinate transformations are usually not easy to determine.Therefore, the redundant coordinare system is proposed and established homogeneoustransformation matrices of Y axis to simply the transforming and calculating process.Simultaneously, we introduce the definition of Jacobian matrix, vector multiplicationmethod, differential transform method, and solve the Jacobian matrix with the vectormultiplication method, and simulate the final result with mathematical software and3D modelsoftware; we also solve the jacobian matrix with differential transform method, and at last wetest the vector multiplication method with the differential transform method, the analysis resultssupply a better way for the kinematic analysis of the robot studied by us.The study of the flexibility can provide a better solution for the locomotion ability, and theavoidance ability of the multi-motion mode robot in this dissertation. By introudcing the definition of flexibility, workspace of flexibility etc, we use geometric composition method andnumerical analysis method to study the flexibility of the legged mechanism of the multi-motionmode robot. Based on analyzing the planar flexibility, we solve the spatial flexibility of thelegged mechanism in this paper, and in the end, we solve the service sphere of the leggedmechanism of the robot to give the flexibility simulation results.In this dissertation, we also have studied the dynamics model of the legged mechanism ofthe robot. The final results show that the lagrange’s equations of the second kind is complicatedfor solving the dynamics model of the legged mechanism, and is not a convenient method forcalculation and real-time control.We continue to construct the parallel mechanism of the multi-motion mode robot using thecoordinate transformation methods. By constructing the geometric model of the end-effectors ofthe parallel mechanism, we solve the position and orientation of the bottom platform, and weconstruct the forward kinematics mode of the parallel mechanism. And we solve the forwardkinematics mode of the parallel mechanism of the multi-motion mode robot using artificial fishswarm algorithm (AFSA). Finally, we simulate the results of the forward kinematics of theparallel mechanism.We construct the inverse kinematic model of the multi-motion mode wheel-leg robot tosolve the analytical solution of the inverse kinematics, and solve the singular solution of theinverse kinematics by using geometric method. When the input of the top platform areorientation and position respectively, we can solve and simulate the inverse kinematics mode.Based on solution of the inverse kinematics, we can generate the straight walking gait, thetruning gait and the spinning gait to supply enough support fot the automatic gait generationmethod.