Velocity control of the parallel four-bar linkage-type pipeline robot in transition phase of elbow

In order to improve the passing capacity of the parallel four-bar linkage-type pipeline robot in the transition phase of elbow, a velocity control model based on the variety of deflexion angle when the robot passes in the elbow is proposed. By analyzing the movement of the robot in the transition phase, a pose model of the robot is established. Using this model the coordinates of the wheel centers and the contact points between the wheels and the pipeline surface can be calculated. Based on the pose model of the robot, and the relationship between the wheel speed and the driving angular velocity under the condition of no interference, the ratio relationship of the driving angular velocities of the wheels is obtained, that is the velocity control model. The proposed velocity control model is validated by simulation analysis. The simulation result is consistent with the theoretical calculation.