Design and trajectory planning of 3+2 DOF manipulator for inspection robot

On the basis of the 3-DOF of the traditional track inspection robot manipulator, a mechanical arm with 3+2 DOF was designed by adding the telescopic and pawl rotational DOF, which expanded the working scene of the manipulator and met more inspection requirements. The improved D-H method was used to establish the kinematics equation of the manipulator. The 3+2 DOF manipulator was modeled by the Robotics Toolbox in Matlab, and the trajectory planning was carried out by quintic polynomial interpolation method. Then, the position model of the manipulator and the curves of joint angle, angular velocity, angular acceleration and angular acceleration change rate with time of each joint of the manipulator can be obtained. The simulation results show that the joint trajectory of the designed 3+2 DOF manipulator is smooth and continuous without mutation, which can effectively suppress the vibration of the manipulator and achieve safe and stable work in the underground environment.