Research On Key Technology Of Fluid Driven Modular Soft Robot

Traditional robots typically work in a structured environment to perform repetitive tasks However,robots working in highly variable environments or requiring human-machine cooperation,such as detection robots,disaster relief robots,medical robots,etc.,require not only with sufficient strength and motion accuracy,but also with sufficient adaptability to ensure mission reliability and human security.In the current field of robotics research,there are two ways to achieve the adaptability of robot.The first one is to use the impedance control method to actively realize the compliance of the robot system;the other is to passively realize the compliance of the system through flexible mechanical components and materials.The latter strategy has been the latest focus in the field of soft robotics,using flexible materials such as silicone rubber to make the main structures and actuators of robots The advantage of the latter strategy is that it can utilize the flexibility of the material,reduce the complexity of the control,and realize the adaptive behavior of the robot.In this field,various forms of soft pneumatic actuators(SPA)driven by fluid pressure have been developed which produce mechanical work by expansion or deformation of an elastic chamber.However,fluid-driven soft actuators have inherent contradictions between power efficiency and material compliance,and usually have only one single motion mode and poor reusability.Based on the previous research work,this work proposes the design idea of modular soft robot to overcome the shortcomings of fluid-driven soft actuators.Three fluid-driven soft actuators are designed,including(1)Aiming at the problem of single movement mode of the soft robot,a bionic reconfigurable omnidirectional motion soft robot based on caterpillar gait is designed.Using the idea modular design,simple basic components are combined into a complex robot system The robot's soft actuator only performs the telescopic movement,and the combined robot array can realize the movement of three degrees of freedom(X,Y and rotation)on a plane The robot's modules can be reassembled,and multiple robot arrays can be combined by themselves and retain multiple degrees of freedom.Besides,the design of the fully flexible telescopic unit driven by negative pressure is an important complement to the type of motion of the soft actuator.(2)A soft linear actuator enhancement technique based on granular jamming is proposed for the contradiction between the driving efficiency and the compliance of the fluid-driven soft actuator.In this part,we designed a vacuum-powered soft linear actuator based on granular j amming(J-VSLA).This soft actuator greatly increases output efficiency while maintaining flexibility.The experimental results show that the granular jamming actuator J-VSLA can lift up to four times the weight(20%strain)compared to a full-soft actuator.(3)Aiming at the problem that the traditional drive actuator has only a single motion mode,a multi-motion mode soft actuator(CUBE)based on layer j amming is designed.This part of the work enriches the design idea of the soft robot from the level of the actuator,Using laminar jamming to achieve localized sti:ffness tuning,a single chamber pneumatic actuator has four motion modes that can be switched between eight different states.With the CUBEs work as the core components,a variety of soft robot systems are built to demonstrate that the novel design improves space utilization and flexibility,including a walking robot with omni-directional movement,hyper-redundant arms with multiple motion modes,hyper-redundant arms with self-assembled function and a steerable tube crawling robot.Besides,the proposed connection method based on the mortise and tenon structure realizes self-assembly between the modules compared to the existing bonding and magnetic connection modesFinally,on the basis of summarizing the full text,the future work of the soft robot field is prospected.