Robot Chassis Design
Project Details
Type
Class
Start Date
End Date
Members
Grade
Academic Project
ME2331 — Introduction to Mechanical Design
Nov 2018
Dec 2018
3
A
Objective
The assignment was to create a robot chassis to hold a robotic arm that is provided and controlled by the professor. The chassis is to be able to autonomously move and avoid obstacles. Access to the robotic arm was not given, only the radius of the robotic arm base is given.
Responsibility
This was the first design course that mechanical engineering students had to take. Most people decided to go with wheels, but our team wanted to push the limit and try going with legs. The team settled on a bug-like design with 6 legs and using servo motors. The leg uses a parallel linkage system to keep the leg orientation normal to the floor as well as directing the force in a way to prevent slippage.
The chassis utilizes 12 servos (2 per leg) and a PCA9685 board to drive the servos with PWM. I was in charge of calibrating each servo motor to find their minimum and maximum pulses to accurately control the motors. To minimize wire management, I designed and soldered a custom PCB board together for better cable management and to eliminate the hassle of trying to figure out which wires were what.
Results
The servos were severely under-powered and were not able to achieve the desired torque. The chassis crawled instead of walked. Motor testing should have been done to obtain the usable torque values.