<p>The Automated Guided Vehicle (AGV) has recently become an essential part of the modern logistics system. Compared with the traditional AGV, the climbable AGV is capable of moving on the flat ground and vertical climbing with the aid of the track. Because of this unique advantage, the stacker might be replaced and the logistics efficiency will be improved. However, the mechanical condition of the supporting parts of the climbing AGV will change extremely when operating under different working conditions, which puts forward higher requirements for structure rigidity. In addition to the structure rigidity, the mass minimization also matters. The climbable AGV has to overcome not only goods weight but also its self-weight when vertical climbing, which limits its effective work durations. In this paper, the level set topology optimization was conducted in order to achieve better structure design of key body parts. According to the characteristics of the climbable AGV with multi-working conditions, the mechanical analysis of key body parts was carried out under typical working conditions which included the climbing transition condition, the climbing transition condition and the vertical climbing condition. And the boundary conditions for topology optimization of key supporting parts of vehicle body were obtained. In order to reflect the importance of each condition during the optimization process, the weight coefficient of each working condition was determined by analytic hierarchy process (AHP). And the drawing constraint was introduced to improve the manufacturability of results. The topology optimization model of static flexibility minimization under multi-working conditions was established based on level set method. The level set method implicitly embeds the dynamic evolution of the structure boundary into a level set function with a higher dimension. Due to the characteristic of the level set method, the optimization result with clear boundary which was convenient for manufacturing was obtained. Compared with the original structure, the weight of the optimized structure is greatly reduced by 42.64%. Finally, the obtained result was reconstructed reversely and analyzed by finite element method. The simulation result shows that although the strength and stiffness of the optimized structure have a certain reduction under the climbing transition condition and the climbing transition condition, the maximum stresses and displacements are still in small magnitudes and meet the design requirements. Nevertheless, the mechanical properties of the optimized structure have some improvement under the vertical climbing condition. The obtained result is helpful to achieve the lightweight design of climbable AGV and provides a further reference for the future prototype production.</p>

Muti-Working Conditions Topology Optimization of the Key Structure of the Climbable AGV Based on Level-Set Method

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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