Design And Analysis Of Omni-directional AGV Structure Based On Mecanum Wheel

AGV is widely used in material transportation,loading,unloading,sorting,assembly and other occasions to reduce labor costs.Traditional vehicles have only two degrees of freedom,which made flexibility is poor.The omni-directional AGV can replace people to work in narrow spaces,improving production efficiency and economic benefits.Mecanum wheels are a type of omni-directional wheels,and their mechanical properties and assembly accuracy affect the vehicle's sports performance and load-bearing capacity.At present,due to the high processing cost of the integrally formed hub,the discontinuous contact between the roller and the ground,which results in poor stability and affects the wide range of applications.Focusing on the problem,the combination of the hub and the roller support frame is used to improve the structure of the hub and reduce the manufacturing cost.At the same time,the length of the roller and the radius of the hub are shortened,the error of the roller generatrix is reduced,and the stability of the wheel movement is improved.The wheel set and the lifting mechanism module are designed to improve the ease of use of the Mecanum wheel,the paper mainly focuses on the following aspects:(1)Use the constant velocity spiral method and projection method to find the roller generatrix equation.Match the geometric parameters according to the design requirements,model in Solidworks,check that there is no interference,and the roller meets the requirements of the envelope to form a circle.Analyze the hub from the processing technology Machining method is proposed to reduce the cost of the two-piece wheel hub and roller support frame combination of the hub structure.Ansys software is used to conduct a static analysis of the Mecanum wheel before and after the improvement to verify that the improved Mecanum wheel has improved processability and reduced hub radius.After that,the performance of each component is improved under the premise of meeting the requirements of strength and rigidity.(2)According to the design requirements,determine the wheel set and lifting module scheme,match the parameters,select the appropriate motor,reducer,screw and synchronous belt.Use Solidworks to complete the vehicle modeling,interference evaluation,and verify that the design structure is reasonable.(3)Study the kinematics and dynamics,derive the motion relationship between the four-wheel speed and the vehicle speed.ADAMS software is used to simulate the AGV before and after the improvement under no-load and full-load conditions,to verify that the improved wheels have better omni-directional sports capabilities,and to analyze the cause of the curve error.Based on the principle of virtual displacement to derive,the relationship between the screw thrust of the lifting mechanism and the angle between the scissor arm and the horizontal angle.Using the STEP continuous ladder function in the ADAMS software to simulate the lifting process and verify the reasonable design parameters of the scissor lifting mechanism.(4)Based on the Hertz theory,study the contact area and the amount of stress and deformation at the contact point between the roller and the ground under heavy load.According to the theory of transient dynamics,use Ansys software to perform transient dynamics on the improved Mecanum wheel,analyze and verify that the contact surface is planarized during the movement of the Mecanum wheel,and the strength and rigidity of the roller made by the roller busbar are reasonable.According to the stress and deformation,an optimization method that can improve the stability of the roller motion is proposed.(5)Manufacture and test prototypes.The Mecanum wheel was tested for circular pulsation,omni-directional motion performance and design parameter verification to verify that the Mecanum wheel was enveloped into a circle,and the prototype performance and parameters met the design requirements.