| Amphibious robot is a kind of equipment that can operate in the environments of land and underwater,it can perform such tasks as underwater items salvage,offshore platform construction and maintenance,detection and reconnaissance.At present,amphibious robots have the characteristics of large size and heavy weight.The miniaturized and lightweight amphibious robot is more convenient to be delivered and transported when carrying out detection,reconnaissance and other missions.In this paper,a tracked chassis of a small tracked amphibious robot is developed for working near the coast.The robot mainly performs underwater observation tasks.The main research contents are as follows:(1)Combined with the application scenarios and design indicators of the amphibious robot,determine the overall structure design scheme of the robot,the factors considered in scheme selection of the track chassis are discussed,the selection,design,theoretical calculation and simulation analysis of the components of the track chassis are completed.Finally,the track chassis is processed and assembled,and the prototype of the amphibious robot is built.(2)The track chassis is optimized.The optimization objects include side plate,bottom plate and motor bracket of the track frame.The process of multi-working condition topology optimization of the side plate is analyzed in detail.The methods of multi-working condition topology optimization are studied,and the different solving methods of weight coefficient are analyzed.The satisfaction method,grey comprehensive relational analysis method,average distribution method and analytic hierarchy process are used to carry out multi-working condition topology optimization of the side plate,and the optimization results of the are compared.The grey comprehensive relational analysis method is improved to reduce the workload of preparation before optimization.(3)The kinematic characteristics of the robot are analyzed,including five working conditions:turning on land,climbing slope,stepping over steps,crossing ditches and crawling on the sea floor.The steering parameters such as the steering radius and the steering angular velocity of the robot are solved,the maximum climbing Angle is deduced,process analysis arecarried out in step climbing condition and crossing ditches condition.Then,through the dynamics simulation,the smoothness of the straight driving conditions is analyzed,the steering parameters of the steering conditions are solved,and the motion process,driving torque and longitudinal Angle parameters of other conditions are solved.The water resistance characteristics of the robot crawling on the seabed are analyzed by fluid simulation.(4)The experiments of turning,climbing slope,climbing convex platform,crossing ditches and crawling on the sea floor are carried out.The theoretical values,simulation values and experimental values of steering radius and steering angular velocity are compared and analyzed.The ability of climbing slope,climbing over the convex platform,crossing the ditch obstacle are tested.The speed of underwater straight is tested.The movement performance of the robot is verified.Through the motion experiment,the actual motion performance of the robot is tested,which provides important reference for the motion control of the robot. |
