Four-Wheel Independent Steering Swerve Drive for First Robotics Competition

Abstract

Swerve drive is a drive train that is designed to be omnidirectional, with the ability of a robot to move in any direction at any moment. A swerve drive module is composed of two motors, a gearbox, encoders, and a wheel. One of the motors drives the wheel, while the other motor controls the steering. The gearbox is what controls the rotation of the wheel. The encoders are placed in various places to detect the rotational position of the drive wheel. By combining these components, the swerve drive module can be programmed to rotate as fast as the encoders are able to read. The drawbacks of swerve drive include weight and cost. These drawbacks keep this drive train out of reach of many applications, including the FIRST Robotics Competition (FRC). The FRC is an international high school robotics competition. Each year, teams of high school students, coaches, and mentors work during a six-week period to build robots capable of competing in that year’s game that weigh up to 125 pounds. Our intention for this project is to design, prototype, build, and test a drive system comprised of four independent steering modules that are more cost-effective, compact, and have less weight than what is currently available on the market. It is expected that such a drive system with four swerve drive modules will provide a viable option for the teams with their robots in the FRC. It not only allows young adults in high school teams to expose to complex yet affordable drive systems but also gives them the opportunity to build or program this drivetrain for their robots. A team of three seniors took on this task to develop four viable swerve drive modules that are cost-effective, and light weighted to fulfill their senior capstone requirement. The project was broken into 3 major sub-sections: structure/frame, steering train, and drive train. This paper will discuss the development of such swerve drive using the engineering design process, including the illustration and description of three feasible design concepts and the selection of the best of three options. The integration of the best drive train design into the robot structure is also illustrated and discussed. The testing of the robot drive will be demonstrated, including speed, maneuverability, and structure analysis. The developed four swerve drive modules later were mounted to the robot built by a local high school team (Colerain High School) in their FRC in March 2022. The team experience and competition results during their FRC will be summarized at the end of this paper. It is evident that the swerve drive is the best overall option for the robotics teams from a competitive and compact design standpoint due to its complete maneuverability combined with the necessary torque and speed with less weight to compete at a high level.