I was looking into the servo control circuit you have available on your site and was wondering if it could be used to control a servo that drives a throttle body? We have a customer that is a parapalegic and we are setting up a hand control Kart for him. We currently are using a cable throttle but we cannot perfect the pull, throw and the cable twist as he turns the wheel so we are looking into making a "drive by wire" system. We cannot rely on a radio controlled servo due to possible interferences on the track and the kart so we need an actual wire conection from the potentiometer on the steering wheel to the throttle body. Anyone have any advice?...
The servo control on this site is the simplest form of open loop control. The circuit has actually no way of knowing how far the servo has moved, it just sends a pulsewidth and doesn't care about the result.
For any kind of vehicle, you need closed loop control with some kind of intelligent failure mode. A TPS should monitor the position of the throttle plates and be constantly compared by a microcontroller to the position of the control pot to make sure that the amount of throttle added is being commanded. The server also needs to fight against a strong string so that if it does fail off, the throttle returns to a closed position. If it was to fall full on, the system will realize this based on the TPS vs. control pot position and also shut down. But to be properly safe, you must have two control pots and two TPSs which are all used to validate one another.
Drive by wire
Posted - Apr 30 2010 : 4:46:04 PM
