Project #2 - Team Chassis Design and Fabrication

In this project, your team will complete the design and fabrication of the chassis for your robot.

Your robot must satisfy three primary specifications: (1) it will run a balancing controller on a differential steering drive system, (2) it will balance itself on two wheels, drive, and steer; (3) it will incorporate an odometry systems and use it to estimate it's position by counting wheel rotations so that it can execute a test trajectory in the Precision Challenge, and (4) it will incorporate a range sensor to detect walls and complete the Maze Challenge in which it finds it's way out of a maze.

Your goal is to fabricate a chassis with motors and wheels for a differential steering/drive that allows the robot to balance, move, and turn. Care must be taken to plan the size, mass distribution, and layout of the vehicle. It will use the Arduino Mega as the Embedded controller.

      Arduino IDE - tell it which arduino you're using, i.e. the Mega 2560

      Motor Shield
              You must build the connectors on the motor shield board. The shield is stacked onto the Mega.
              Motor Shield User Manual
              Shield Software Library
                  from IDE:
                      Sketch > Include Library > add .ZIP Library
                      File > Examples > DualMC33926MotorShield > Demo   (motor demo hook up your motors)
      Maxon Motor data sheet

The 11.1 V LiPo battery pack is provided as your recommended power supply. With the power jumper on the shield, it will power both the shield and the Mega adequately. Later, you may choose to use 2 batteries in series to produce a 22.2 V supply voltage---this will exceed the rated voltage on the Mega. Therefore, if you do this, you should remove the jumper coupling the power for the two boards and use a separate 9V battery to power the Mega. You must fabricate a chassis with motors and a temporary 3rd point of contact, mount the Arduino, batteries and motors, and fabricate and mount the motor shield for driving the motors, and enough space to mount the peripheral sensors and cabling for future projects.

You will also write your first embedded control application to drive the motors so that your robot executes open-loop circular patterns. Your robot should execute counter clockwise circles of varying radii.

  • plexiglass chassis that implements the inverted pendulum
  • 2 - motors and motor brackets mounted precisely in a colinear, differential drive geometry
  • Arduino Mega
  • stranded ribbon cable for fabricating motor cables to PWM outputs.
  • 2 - wheels and a temporary 3rd point of contact
Final Report (one per team):
  • a short verbal description of the design concept, including a diagram "as built" and the concept as it might look when the whole robot is done---guess.
  • experimental evaluation of the open-loop controller at two important turn radii: zero, and approximately 10 cm. Have the robot execute 10 circles at these radii on a piece of paper and record the approximate position of a reference point on the robot each time it returns to its initial heading.
  • a brief description of these results (mean and variance).