Experimental Investigation And Analysis On Moving Performance Of The Crablike Robot

Amphibious environment is always complex. The working environment is often covered by rugged rocks or loose gravel on land, or full of currents and plankton underwater, which puts forward higher requirements for the robot. Most traditional robots only can work underwater or on land with a low efficiency under such a harsh environment. As amphibious creatures living on shallow sea with superior amphibian exercise performance, the crab can walk on land or seabed with walking legs or swim underwater with swimming legs. Through the observation and analysis of crab's physiological structure and motion law,this paper develops the crablike robot which can walk on land and swim underwater. Based on the structure design of the robot,the motion performance on land and underwater are verified by simulation and experiment.In this paper, the function of different parts of crab is summarized first. The crablike robot body is designed referencing to the shell, body and arrangement mode of crab. Through the observation and analysis of crab walking leg, the leg of crablike robot is developed with planar 5-bar linkage. And the joint torque is compared under the same load with serial structure. We designed the crablike robot's swimming leg through simplified and extracted the swimming leg of crab. In order to keep the stability of robot when moving under water, the influence of buoyancy must be considered.This paper studies the motion performance of walking legs. Based on establishing kinematics and dynamics equations of parallel mechanism, the paper solves the motion space and Jacobian Matrix. The walking legs which are the execution unit of crawling on land and seabed not only provide support but also have a decisive effect on the motion performance. The paper analyzes the performance of crawling with ADAMS and establishes the Co-simulate system of ADAMS and MATLAB which is used to verify the performance of sheer. The result shows that the walking legs can meet the requirement of robot assignmentSwimming legs are the main underwater robot motion units. The robot can realize different attitudes with different motion laws. The paper analyzes the propulsion performance of swimming legs with the method of computational fluid dynamics. The hydrodynamic model is established to analyze the swimming speed, power consumption with Fluent. The hydrodynamic performance of swimming legs flapping in different frequencies and flapping under constrain are compared.At the end of this paper, mechanism realize experiment is carried out on single walking leg to ensure moving flexibly without collision and interference between parts. The experiment about swimming legs flapping in different frequencies and phases between left and right swimming legs is also carried out to discuss the swimming performance.