The Improved Integrated Quadrature Encoder
Entry ID #: 1422
Created: Mon, Jan 12, 2015 6:50 PM
After many issues with the current encoders I have decided to improve them to everyone's benefit. The original Quad-encoders were bulky, but reliable, however often got in the way of some of our designs. The Integrated Motor Encoders were unreliable and difficult to debug. We have decided to redesign the IME to function more like the Quad-Encoder, but have the form factor of an IME. The design is in its simplest form a miniature quad-encoder, but what improves it further is the use of many electronic measures to eliminate the possibility of failing for false values caused by electromagnetic interference generated by the motor. To do this, we took the reading of the light flashes out of the case of the motor, and dedicated them to a small junction box on the cable going to the Cortex. The light pulses are transmitted through small fiber-optic cables, and connected to photo-resistors. The signal from the resistors is then run through a low pass filter, which siphons off high frequencies than can cause faulty readings. Finally the cables are run through a toroid which eliminates even more interference generated by the motor module. This new design is also extremely easy to add to VEX systems, as it functions the exact same way as a normal Quad-encoder, meaning no code changes. We used Autodesk Inventor 2014 to design our VEX part throughout the process. Inventor allowed us to take parts that already existed (the gear and Motor case) and modify them to convey our design. We had help from our coach ( who was an Electrical Engineer) on ideas of how to reduce noise on electrical signals; knowledge which we used to develop an electrical diagram of how the encoder works to reduce error.
This a an Engineering notebook page describing the morale behind our design and giving some diagrams to demonstrate what the design does.