We are about halfway through the "Docking Logic" research project after this weekend. It appears to be quite clear at this point, it requires four sensors to successfully dock your robot to a beacon localized charger, with a high percentage of success. These sensors are:
1. An omni directional "system" which detects proximity to the charger.
2. A precise becon homing sensor for final homing.
3. A frontal contact switch (could be bumper) to determine physical contact with the charger. Could also be a photocell.
4. A distance sensing device, such as IR ranging or sonar that allows the robot to slow to a fractional speed when very close to the charger to prevent it from "ramming" it at full speed. (you wont beleive how important this is!)
We have finished the omni cone prox sensor docking, and we are now replacing it with a multiple sensor ring around the robot to give it a rough idea which direction the beacon is when in the prox mode. The cone was fun, but this may be a better solution. (?)
The design of the shape and technique of electrical contacts is next, the two best contenders at this point are frontal contact plates which contact a pair of hoops at any angle, or whiskers that V into a post with contacts.
It must be remembered here that while any one can make a robot dock with its charger, doing it successfully and in a totally repeatalbe manner is lacking in the home robot world at this point. (and Im not talking about the horrendous helter skelter way robot vacs dock)
Write me about your docking experiences!