越沙步行轮仿生设计及动力学性能仿真

为提高车轮在沙土介质环境的通过性能,基于鸵鸟足趾结构形貌与运动方式,设计出一种仿生越沙步行轮。该步行轮通过轮脚中的定立柱和动滑块相互配合实现对轮下沙土的限流紧固功能,同时自适应带动轮刺机构进入附着牵引工作状态与离沙减扰非工作状态。采用多刚体动力学分析软件,预测了仿生越沙步行轮轮腿各部件之间的活动范围和干涉情况。采用离散元软件,分析了轮脚底面/沙土相互作用关系,验证了该仿生越沙步行轮具有良好的固沙限流、牵引附着性的特点。该研究为提高松软地面中步行机构的通过性能提供了参考。

Bionic design and dynamics performance simulation of walking wheel to travel on sand

It is important to enhance the traveling ability of wheel in the loose sand circumstance.According to the morphology structure and the movement mode of ostrich foot, a new bionic walking wheel to travel on sand was developed, using the theory of bionic engineering and the design concept, which combined the traditional wheel walking mechanism that had the advantages of simple structure and high speed and leg foot type robot that had the advantage of resistance to sink.African ostrich is highly cursorial bipedal animal on land with a permanently elevated metatarsophalangeal joint supported by only 2 toes.They are also acknowledged as the fastest bipedal animal on land with extraordinary endurance during locomotion.The ostrich is capable of running at very high speeds and can run steadily for 30 min at a speed exceeding 50 km/h and move at a speed of 70 km/h for short sprints, with a step length reaching up to 5 m.Research showed that the toenail of ostrich has played a vital role in producing the propulsive force in high speed locomotion.Therefore, toenail surface shape had been applied to the structure design of wheel lug of bionic walking wheel that travelled on sandy terrain by using reverse engineering technology, which finally improved the traction performance of bionic walking wheel in sandy environment.By cooperating the static column with the dynamic slide block, wheel feet have effects of sand fixation and flow limitation.At the same time, the bionic walking wheel can adaptively drive wheel lug structure into the traction working state and the non-working state of reducing sand disturbance.In order to further analyze the movement performance and properties of bionic walking wheel travelling on sand, we performed the dynamics simulation and analyzed the interaction relation between wheel foot surface and sand with the discrete element method.Using rigid multi-body dynamics, the kinetic space and interference pattern among the wheel legs of bionic walking wheel were forecasted.During the period of 1.25-2.5 s, the simulation results showed that the displacement and speed curve of slide block were relatively smooth, which indicated there was no interference in slide block structure of bionic walking mechanism and our wheel design worked effectively.At the same time, the acceleration of slide block was almost zero, which showed the impact force between slide block and stand column could be ignored in locomotion.To objectively and clearly reflect the performance of bionic walking wheel travelling on sand terrain, this study used the comparative method, and bionic wheel feet and ordinary wheel feet with the same size were adopted.Through analyzing the interactions between wheel foot and sand by discrete element method, the superior traction performance with sand fixation and flow limitation and the driving and ride comfort were verified for bionic walking wheel.The study provides the fire-new design idea of walking machine for improving the traveling performance on sand.