Study On Dynamic Characteristics Of Double Push Rod Leg Mechanism With Clearance

In order to adapt to the harsh working conditions,the traveling machinery system is developing towards the direction of large-scale,high precision,and high reliability.The theoretical and experimental research on the traveling machinery system has become the focus of the research at home and abroad.As the walking part of a new type of research robot,the double push rod limb and leg mechanism can realize the movement bearing function in extreme terrain.However,under the influence of low temperature,wear,machining,and assembly,the joint clearance of the mechanism will change,which will seriously affect the dynamic characteristics and operation accuracy of the double-push rod limb mechanism.Therefore,it is necessary to reveal the influence law of joint clearance on the kinematics and dynamics characteristics of such mechanisms.In this paper,the double-push rod limb-leg mechanism with clearance is taken as the research object.Aiming at the adverse effects of the clearance joint on the movement of the double-push rod limb-leg mechanism,the dynamic characteristics of the mechanism are analyzed and simulated,and experimental verification is carried out.The main research contents are as follows:First,a geometric model of the double push rod leg mechanism with clearance was established.According to the situation of the clearance joint,establish a mathematical model of the clearance joint.The contact force model and the friction model were used to describe the collision of the clearance joint,use the state transition discriminant equation to relate the different motions in the clearance joints,analyze the collision characteristics of the clearance joint in the process of moving.Second,based on the Newton-Euler method,the clearance model was inserted into the dynamics model of the double push rod leg mechanism without clearance,established the dynamics model of the double push rod leg mechanism with clearance,carried out the dynamics simulation.According to the simulation data,the effects of different clearance sizes,clearance positions,clearance quantities,and movement conditions on the dynamic characteristics of the double push rod leg mechanism with clearance were explored,provides a theoretical basis for the dynamic characteristics of the double push rod leg mechanism with clearance.In order to verify the rationality of the dynamics model and the reliability of the simulation results of the double push rod leg mechanism with clearance,built an experimental platform of the double push rod leg mechanism with clearance,Experimental study on the effects of the clearance joint on the angular change of legs relative to the X-axis direction,the motion trajectory,velocity and acceleration of the end of the double push rod leg mechanism.The dynamic characteristics of the double push rod leg mechanism under different clearance sizes,clearance positions,clearance quantities,and movement conditions were tested,compared with the simulation results in this paper,explored off the influence of different parameters on the dynamic characteristics of the double push rod leg mechanism.