Research On The System Of Small Morphing Leg-wheel Quadruped Robot

With the rapid development of science and technology,mobile robots play an increasingly important role in the progress of society.Because of their large size,poor obstacle surmounting capacity and no operation or detection capability,the existing robots have too much restriction in complex unknown environment.According to the demand of unknown environment exploration,this paper has developed a small morphing leg-wheeled robot,and planned the multi-legged diagonal gait and wheeled motion.Then the embedded control system is designed and the prototype experiment is carried out.Aiming at the requirement of unknown environmental detection,the function and performance indexes of the leg-wheeled robot system are determined.Based on this,a small morphing leg-wheeled robot system is developed,which has the advantages of multi-legged and wheeled robots.The robot consists of four identical 3-DOF series limbs and a torso that can achieve the waist bending,and the interchange of legged and wheeled motion can be achieved under the coordination of each joint.The morphing robot can not only utilize the barrier ability of the legged movement,but also take advantage of the motion speed,high efficiency of wheeled movement,two kinds of movement can achieve autonomous transformation flexibly.When the robot moves in the wheeled mode,the lifted biped can achieve the coordinated operation similar to dual arms,and complete the corresponding task.The front end has ultrasonic ranging module and WIFI camera module,which can realize the real-time perception of the external environment.Additionally,the adopted wireless communication mode can realize remote control.After completing the design of the morphing robot system,the gait of the robot is planned.Based on its structural characteristics,the forward and inverse kinematics equations are derived by D-H method,and the trajectory of the end of the limb is generated by 6 polynomial interpolation.The corresponding diagonal gaits and the transformation gait patterns of the wheeled and legged motion are formulated.Furthermore,the formula of centroid position,stability margin and turn angle of the robot are deduced,and the gait is verified by Adams and Matlab co-simulation.In order to realize the motion control of robot,an embedded controller based on ARM processor is developed,and a multi-task real-time operating system uCOS II is embedded.In addition,the host computer software realized the bluetooth communication with embedded controller,and it can receive real-time image from WIFI camera,and control robot to complete the task with the perception of the robot environment.Based on the above work,the integration of the morphing robot prototype and the experiments under typical working conditions are carried out,including legged movement,wheeled movement,leg-wheel motion transformation experiment,environment detection,forearm operation and other experiments.The robot's function and performance are verified.