Your assignment is to build a mobile robot base using the kit you were given in lab. It should have two large wheels, each driven by a motor, and another wheel for balance. You'll have to include the batteries in your base, and design a space for the controller boards and for mounting sensors in the front and back. You're likely to decide to rebuild your robot at least once during this course, but you might as well try to come up with a lasting design.
In order to test your robot base, you should use the motor test board (small PC board with 4 switches) included in your kit. Plug your motors and batteries into that board and you can use it as a simple manual controller. You will not be using the microcontroller board or the sensors for this lab!
The lab may have some spare charged-up battery packs. If you need fresh batteries and don't have time to charge yours, you can come to the lab and possibly make a trade. In order to take advantage of this opportunity, you have to design your base so that the battery pack is easily removable.
You are allowed to supplement the basic kit with rubber bands if you think they will aid structural stability. But remember the CS148 motto: No Glue!
The major goals for this base are robustness and straight driving.
To achieve robustness, follow some of the hints in the Lego building handout. The tradi tional Lego building technique of bricks atop bricks doesn't make a very robust structure. Be sure to cross-brace your structures. To test for robustness, you should be able to drive your base around for half an hour and sustain repeated mild collisions with walls without serious disintegra tion. When you pick it up, the base should feel solid, not flexible.
To achieve straight driving, make sure that the drive wheels are even with each other and that the axles are well supported (so that they don't splay out). Be sure that your gear assemblies don't have too much (or too little) play in them. You should probably gear these motors down once or twice to get a good balance between speed and torque. The speed you get with the motor plugged into the test board will be somewhat faster than the maximum speed available from the micro-controller. Faster robots are more exciting, harder to control, and able to apply less force.
You're welcome to add cool aesthetic elements, but you should do so only after your base is driving reliably.
Rather than hand in this assignment, you will give a demo during your lab section. You will be graded by your section TA as follows:
Happy robot building!