基于Mecanum轮的电动轮椅与路面耦合系统振动特性分析

Vibration characteristic analysis of electric wheelchair-pavement coupling system based on mecanum wheel

为了分析基于Mecanum轮的全方位移动轮椅的振动特性,建立Mecanum轮与地面接触模型和7自由度移动平台模型,利用轮子与路面接触点的位移协调方程及轮椅与路面之间相互作用力的平衡关系构建轮椅与路面耦合振动方程,通过模拟仿真,研究轮子与路面接触的起始位置、转速以及负载大小对轮椅振动特性的影响规律。搭建了全方位移动试验台,通过试验验证了数值仿真的准确性。分析结果表明:从乘坐的舒适性出发,应尽量保持轮子与路面起始接触位置相同。轮椅的振动频率和幅值随着转速的增加而增大,当转速介于150 r/min和200 r/min之间时,轮椅的振动频率与人体固有生物波(8 Hz)接近,会引起乘坐者的强烈不适感。乘坐者的体重对轮椅振动特性影响较小但对振动的幅值有一定的抑制作用。

In order to analyze the vibration characteristics of omni-directional mobile wheelchair based on Mecanum wheel,the contact model between Mecanum wheel and ground and the mobile platform model with 7 degrees of freedom were established,and the coupling vibration equation between wheelchair and road surface was established by using the displacement coordination equation of the contact point between wheel and road and the balance relationship of interaction force between wheelchair and road surface.The effects of the starting position,rotational speed and load of the wheel in contact with the road surface on the vibration characteristics of the wheelchair were studied.An omni-directional mobile test rig was built,and the accuracy of numerical simulation was verified by experiments.The analysis results show that in order to improve the ride comfort,the initial contact position between the wheel and the road surface should be kept the same as far as possible.The vibration frequency and amplitude of the wheelchair increase with the increase of the rotational speed.When the rotational speed is between 150r/min and 200r/min,the vibration frequency of the wheelchair is close to the inherent biological wave(8Hz)of the human body,which will cause strong discomfort.The weight of the passenger has little effect on the vibration characteristics of the wheelchair,but has a certain inhibitory effect on the amplitude of the vibration.