top of page
conference paper.png

Design, Analysis and Optimization of Chassis for Mobile Robotic Platform for Supermarkets

Problem Statement:

Super markets have narrow space between their shelves, which creates congestion when two or more people want to pass through. Also the waiting time for billing carrying a large shopping cart is inconvenient as a whole. Since lot of people shop in and out all day long, the shopping cart has to be structurally rigid while also being light weight at the same time. 

Goal:

  • To design and analysis of electric motor-powered compact trolley chassis with high strength to weight ratio.

  • To make comparisons among the suitable martials and select the best one for the design and purpose based on Ashby charts

  • Modal analysis to avoid resonance

Approach:

  • Design of cart using space frame structure & static structural analysis with boundary conditions including payload of 20kg

  • Calculate performance index in terms of stress, density & cost of material

  • Optimizing the dimensions of cross-section to have deformation less than 0.5mm while minimizing the mass of chassis as well

Results:

  • The calculated reaction force for front and rear wheels are 125.33N and 131.44N respectively.

Untitled.png
image.png

  • Of the different types of cross-sections, hollow square tubes was selected for this application as it had the highest area moment of inertia of 7872mm

  • Beam elements were used and mesh convergence from 10mm to 4.5mm for top members, 10mm to 6.5mm for side members (5% convergence)

  • Materials for Analysis: ABS, Alloy steel, Aluminum 6061-T6,  Fiber Composite(Kevlar), Wood(mahogany). The performance index is given as the ratio of density to yield strength as below

     â€‹

​

​

​

  • The performance index for materials is calculated  in Table 5 and it is found that Aluminum 6063-T6 is the best material for the application as it has the highest performance index when cost is considered

image.png

  • The vibration inducing part of the cart is the motor, which creates vibration at 3.33Hz. the modal analysis yields the 1st and 2nd mode as 41.71Hz and 48.82Hz respectively. 

  • We can conclude that the design is safe from resonance since the disturbance frequency is too low when compared to the first natural frequency.

stress.png

Stress: Al 6061-T6

deformation.png

Deformation: Al 6061-T6

Tools Utilized:

  • Solid works

  • Ashby charts

  • Optimization

  • Modal analysis

bottom of page