Wireless Distributed Robotics
Senior Design Project: EECS 473 (Advanced Embedded Systems) | August 2021 - December 2021

I was part of a team that created a unique sub-GHz wireless protocol for use in connecting low-level robot components. The output of our project was a fully functioning custom wireless protocol demonstrated on two robots capable of docking and undocking to drive in either independent or coupled mode. These robots were successfully demonstrated with full functionality at our senior design expo.

I was responsible for the design, fabrication, assembly, and testing for the full mechanical and electrical systems while another student developed the software.

Video of robot docking: Docking Video
Video of robot navigation during expo (driving is a bit sloppy): Maze Driving

Electronics:

• Project utilized 24 custom designed and assembled printed circuit boards
  • Wireless communications board containing the 940MHz communications hardware and microprocessor (11x)
  • Motor driver board containing a custom H-bridge, current sense hardware, and encoder input (8x)
  • Controller board containing a joystick, button, and IMU (2x)
  • Servo driver containing servo power output and current sense hardware (1x)
  • Power distribution board with independent fuses for each connected device (2x)
• The wireless communications board acted as a base to provide wireless functionality to each of our other boards
• Each motor driver, controller, and processing unit communicated wireless, which means the only wires to each node are power
• Magnetic sensors to sense when the robots have completed docking

Mechanical:

• Two holonomic drivebase robots capable of 2D planar strafing and independent rotation
• Custom independently suspended transmissions for each wheel
• Docking mechanism to lock the robots together

Software:

• 940MHz Communications protocol to communicate between nodes
  • Achieved sub 1ms latency in normal operating conditions up to 50 feet away
  • No dropped packets during normal operating conditions up to 50 feet away
  • Robust header-data organization allows for the addition of a wide variety of types of nodes
• Single overseeing node coordinates communication between every node
• Control kinematics of robot motion change between docked and undocked mode

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