Control strategies of energy optimization for an in-pipe robot with inclining-angle-adjustable screw rollers

Abstract

In the existing in-pipe robots based on screw drive, the inclining angle of rollers tipped on the elastic arms is usually invariable. The roller with an unchangeable inclining angle is an obstacle for changing load capacity and optimizing energy consumption of the robot. Therefore, a screw drive in-pipe robot with inclining-angle-adjustable rollers is proposed. While considering the constraint of motor performance, the adjustable inclining angle enhances large-scale environmental adaptability and the ability of optimizing energy consumption. The optimization of energy consumption is then discussed based on dynamic analysis and the model of energy consumption. Two control strategies of energy optimization: An energy optimization of point-approaching task and an energy suboptimization of inspection with constant traveling speed are proposed. The simulation results show that the two control strategies can respectively change the inclining angle and the motor speed based on the load. The energy consumption for a same distance is less than that of a robot without inclining-angle-adjustable rollers. In real pipelines with three different loads, the experiments verified the validity of the proposed control strategies.