Research On Propulsion Characteristics Of Tracked-paddle Mechanism

Generally,the main propulsion force of amphibious or underwater vehicles in water is mostly generated by propeller,and the attitude of the vehicle is controlled by rudder.Although this method is more practical and reliable,there are still some shortcomings.For example,the direct transition in amphibious environments cannot be achieved by this type of propulsion.However,the addition of ground moving mechanisms will undoubtedly make the robot's power and control systems more complicated.In some special field environments,robots need to have amphibious functions while still simple in structure,which means high efficiency in the transition of the amphibious environments without power switching.As a classic ground moving mechanism,the track mechanism has long been used for amphibious equipment.But the application of this mechanism in large vehicles has been progressing slowly due to its low propulsion efficiency.Based on the traditional track mechanism,a new type of tracked-paddle underwater propulsion mechanism is studied in this paper.Receivable blade mounted on the track is used in this mechanism instead of the propeller to produce thrust in the state of full immersion without additional coverage.The propulsion characteristics of tracked-paddle mechanism are systematically studied and deeply explored in this paper.The following work is mainly carried out:(1)Firstly,the propulsion mechanism and working characteristics of different types of underwater propulsion mechanisms are compared and analyzed;then the underwater propulsion characteristics of the tracked-paddle propulsion mechanism are derived,and the relevant research methods and key points are clarified;The thrust of propeller under ideal condition is deduced and calculated,and the iterative rel ationship between the moving speed and the rotational speed of the mechanism is analyzed;(2)Various possibilities of blade contraction and their advantages and disadvantages are analyzed,and the structure of the blade studied in this paper is determined.The main components of the crawler mechanism are determined;on this basis,the kinematics and dynamics characteristics of the blades in the track mechanism are analyzed;the main structure design of the paddle-track propulsion mechanism was completed;based on these,the structure of a kind of dual-track underwater robot was designed,and the kinematics and dynamics modeling was carried out;(3)The propeller performance of track blades under different morphological parameters is simulated with the method of CFD,to provide some guidance for the optimal design of the track mechanism.Firstly,several parameters in the single blade state are researched by simulation.Then the influence of density of multi-blade arrangement on thrust was studied.Finally,the influence of track spacing and blade angle on thrust was studied.(4)Finally,the underwater propulsion performance of the designed paddle-tracked propulsion mechanism was experimentally verified,and the effects of the simulated morphological parameters were measured.The consistency between numerical simulation results and experimental data is verified,and several parameter ranges corresponding to the optimal propulsion efficiency were determined.