Document Type

Restricted Campus Only

Publication Date

4-26-2023

Abstract

This report documents the 2022-2023 Autonomous Planetary Rover Team’s work. The main focus and goal of our team was to improve the locomotion of the rover through mechanical improvements to the suspension and steering systems. The final expectation for the rover given by our sponsor, Dr. Kevin Nickels, was for the rover to complete an obstacle course where it drives over obstacles the height of the radius of its wheel, traverses uneven terrain, and completes turns with a 12-inch turn radius. The main inspirations for our design of the suspension and steering systems come from previous planetary rovers that have completed missions on Mars and the Moon, specifically Curiosity and Sojourner. We have done substantial research on the mechanics of the rocker-bogie suspension system and have chosen this as our method of robust suspension. We also researched different methods of steering and settled on an independent steering system. In terms of primary subsystems, we have focused on suspension and steering, though we will also discuss design choices related to the chassis material and electronic components.

This project has been evolving and changing for multiple iterations—four previous teams have worked on the rover, each team focusing on different aspects of improvement. Our team is focusing on improving the mechanical aspects of the rover while making use of previous teams’ additions to the project, but will not focus on any systems related to the autonomous navigation of the rover. This year, the design problem was to mechanically improve the rover so that it was capable of going around and over obstacles in a simple obstacle course. Requirements of the design also included the Rover’s ability to carry a 100-pound load (to simulate experimental equipment) and to traverse over obstacles as tall as 5.1 inches (the radius of the wheels). These design requirements fed into project-specific requirements from our sponsor, which included having a rocker-bogie suspension system and independent steering. Another requirement was the capability of the rover to pass through a standard door frame in Trinity University’s CSI Building. These requirements reflect constraints of real planetary rover design, and will force us to consider environmental factors on the design. In this document, we will discuss all conducted tests and to what extent these tests showed that our prototype fulfilled each requirement.

Though individual design components of the rover proved to be successful, the overall prototype was unable to complete the required obstacle course due to issues with stability. The clearance, dimensions, and obstacle construction requirements were successful based on testing, and are important for the next steps of the rover. Some tests showed partial achievement of requirements, which demonstrate that the rover has been improved this year and is on the right track. The team concludes that the suspension system design is a partial success, as similar to the steering system design, because it functioned as expected though not integrated perfectly. The rover was able to be controlled by a joystick, and was capable of making wide turns - showing success for the desired independent steering design. The rover’s ability to overcome obstacles was also deemed a partial success, as though it could statically handle being on top of an obstacle without tipping excessively, it was difficult for it to dynamically climb the obstacle. The team believes that each subsystem of the rover prototype shows promise, and look forward to seeing future iterations.

Comments

Dr. Keith Bartels, Team Adviser

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