Kinematic Characteristics And Applications Of Snake-Like Winding Soft Rod-Climbing Robot

Climbing robots have long been fascinating to the researchers for their potential capabilities in special environments.Although a number of rigid climbing robots have been developed with good performances in unstructured environment such as ladder,wall,tube and rod,they generally rely on complicated mechanisms composed of rigid actuators and transmission components.The resulting designs,however,contain several disadvantages including being segmented,inflexible,complex,heavy and high cost etc.Soft robots have recently attracted widespread attention due to their impressive attributes,including inherent compliance,unprecedented agility,and interacting with environments safely and adaptively.Soft climbing robots have attracted much attention of researchers for their potential applications on the wall or inside the tube.However,achieving a soft robot to climb on outer surface of rod or tube by agile and efficient motions has long been a challenge.Inspired by winding climbing locomotion of arboreal snakes,a tethered pneumatic-actuated winding-styled soft rod-climbing robot that consists of two winding actuators and a telescopic actuator is proposed in this work.Two kind of soft actuators are both designed by the same foldable bellows.We proposed six gaits of the robot based on the analysis of the climbing mechanism of arboreal snake.Based on constant curvature assumption,we built the kinematic model of the soft actuators,and develop a theoretical model to analyze bending motions of winding actuators and linear motion of telescopic actuator,respectively.Then,we evaluate the deformability of soft actuators and the key parameters(the number of winding rings and rotation directions of winding actuators,the number of segments of telescopic actuators,the payload and the frequency)to locomotion ability.We demonstrate that our robot can perform climbing locomotion like snakes,including turning around a corner along a rod,climbing a vertical rod with a maximum speed of 30.85 mm/s(0.193 body length/s),carrying larger payload(weight,500 g)than existing soft climbing robots do on a vertical surface,and climbing different friction surface and variable diameter rods.In addition,the experimental tests exhibit the potential applications of the robot in special environments such as high voltage cables,nuclear power plants,and underwater sites.