Aimed at the problems of limited application range, single movement scene, inability of climbing, and limited space movement of the multi-terrain movement robot, a novel dual module soft robot with the multi-terrain movement ability is proposed. Each soft module is composed of a four-chamber omnidirectional bending soft pneumatic actuator. By establishing the bending model of the omnidirectional bending soft actuator, the variation law of the omnidirectional bending soft actuator is analyzed. A new rotary movement mode is proposed, which enables the robot to move in a variety of complex environments in the rotary movement mode. A gait control method based on pulse width modulation (PWM) is proposed to make the robot realize the multi-terrain movement function more simply and quickly, and its feasibility is verified by experiments. The experimental results show that the dual modular soft robot based on the four-chamber omnidirectional bending soft actuator can climb vertically along circular pipes, square pipes, and irregular rods (human forearms), and the crawling speed can reach 11.7 mm / s. It can also move rapidly in complex terrain such as flat ground, artificial turf, rugged road surface, and slope, and the crawling speed can reach 14.0 mm/s, which overcomes the shortcomings of the existing pipe climbing robot and multi-terrain movement robot. The modular soft robot can move stably and quickly in a variety of terrain, and has a strong adaptability. It has a potential application value in pipeline detection and complex terrain detection.
