Tec de Monterrey, 2022

The project was born from an urgent need during the COVID-19 pandemic: hospitals were facing shortages of support staff, leaving gaps in patient care. To address this, the team envisioned an autonomous electric vehicle (AGV) capable of transporting food, supplies, and medical tools through hospital corridors without human intervention.

The engineering challenge focused on designing and manufacturing the chassis, the structural backbone of the AGV. The team was responsible for ensuring that the frame could withstand static and dynamic loads, impacts, and vibrations, while also housing all internal systems: batteries, suspension, motor, and electronics, amounting to more than 300 kg of components.

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The project began with an inherited design from a previous campus, which used round steel tubing. However, material limitations in the workshop forced a series of redesigns. Initial versions based on ⅝” tubing proved inadequate under simulation, often exceeding the yield strength of structural steel. Through iterative CAD modeling and ANSYS simulations, the team introduced triangular reinforcements, later transitioning to square steel profiles (PTR 1 ¼”) for greater rigidity and manufacturability. Each redesign sought to reduce stress concentrations, improve load distribution, and simplify fabrication. The final design combined longitudinal beams (largueros) with cross-bracing, resulting in a structure that remained well below the 250 MPa yield threshold under static loads, with minimal deformation (<0.2 mm).

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A full set of simulations validated the chassis:

• Static analyses confirmed that the floor could support the batteries and that lifting points (cáncamos) were structurally sound.

• Dynamic crash tests simulated frontal, lateral, and rear impacts at 30 km/h against a concrete post. Although localized plastic deformation occurred, the internal components were not compromised.

• Modal analysis revealed resonant frequencies, guiding future reinforcement strategies to avoid fatigue or failure.

The simulations highlighted a tradeoff: while ASTM A36 structural steel was accessible and weldable, it added unnecessary weight. Alternative materials like AISI 4130 chromoly steel were identified as more optimal, offering higher strength-to-weight ratios despite higher cost.

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With the final design validated, the team proceeded to manufacture a full-scale prototype in the workshop. Processes included:

• Measuring and marking steel profiles, including precise 45° cuts.

• Cutting with horizontal band saws and grinders.

• Surface treatments like polishing and automotive paint for corrosion protection.

• Joining through MIG and arc welding.

The prototype was then subjected to physical validation tests: compression and tension with battery loads, and suspension through lifting points. These confirmed the digital results.

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The prototype’s material cost was ~4,440 MXN, with total prototyping costs (including labor) reaching ~13,400 MXN. The team also analyzed assembly efficiency (DFA), measuring handling and insertion times, and projecting costs for small-scale production (100 units per year). Future scaling would require CNC laser cutting for precision and efficiency.

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The prototype fulfilled its purpose but was approximately 30% heavier than the ideal design, reducing vehicle efficiency and autonomy. Despite this, the project demonstrated the value of iterative design, simulation-driven validation, and hands-on prototyping in engineering.

Future improvements include switching to lighter, higher-performance materials, adding missing reinforcements, and completing integration with the other AGV subsystems (suspension, traction, and controls). In the end, the project not only produced a functional chassis but also served as a bridge between academic learning and professional engineering practice, preparing the team to face real-world challenges in vehicle design and automation

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Please find attached below the relevant documents to this project. (Note: most, if not all documents, are in Spanish)