Mechanism Design Of An Ihchworm-like Climbing Robot And Gait Planning Based On CPG

The inspection and maintenance of the wind turbine blades is very important for the stable operation of the wind turbines. Wall-climbing robot can take the detection equipments anywhere on the blades, which is the study focus of the blade inspection. Considering that there is a lack of robots climbing on the blades, a climbing robot for the blades inspection is developed and the climbing gait on the curved surface of the blades is designed with a CPG method.Firstly, an inchworm-like climbing robot with 5 DOF is designed, including three T type joints and two I type joints, which is driven by DC servo motors. The vacuum sucker is composed of three suction cups. Based on the static force analysis, The static displacement of the parts is analyzed through Solid Works Simulation, which is used to improve the parts’ strength design. In view of the adsorption safety, the radius threshold of the suction cup is derived based on the static force equilibrium equations.Secondly, based on D-H method, the homogeneous transformation matrix of the kinematics model is established. The forward and inverse kinematics analyses of the robot are derived. Based on the characteristic of the robot’s structure, three gaits are designed including inchworm type, flip and rotation. Through Adams dynamic simulation of three gaits, the maximum torques of the joints are obtained, verifying the correctness of the motor selection.Thirdly, based on geometric method, the adaptability of the vacuum sucker to the arc surface is analyzed. Based on circular trajectory planning method, the similarities and differences between plane flip gait and curved surface flip gait are analyzed. The plane flip gait can adapt to the circular arc surface by adjusting the angle amplitudes of corresponding joints. What’s more, based on supervised learning method and adaptive frequency Hopf oscillator, an adaptive CPG network learning plane flip gait is established. The online adjustment method is designed based on correlation. The convergence of CPG network parameters adjustment is proved by the simulation. Further on, the steady-state value of the parameters can be the initial values of the parameters of the CPG network, and then the curved surface flip gait is established by adjusting the angle amplitudes online. The coordinated simulation of the curved surface flip gait based on MATLAB and Adams is carried out,which validates the efficacy of this method.The physical prototype robot is developed, and the distributed control system based on PC is realized. The flip gait experiments on the plane and the curved surface are carried out. The experimental results are consistent with the results of simulation, it shows that the rationality of mechanism design and of the effectiveness of the gait planning method.