This is now at the prototype stage - i.e. stick it in a model and use it! I have wanted to do do this project for several years. Now there is a PIC microcontroller with a 10bit ADC with adjustable min/max references to measure the feedback pot position to better than 0.1% accuracy and EEPROM memory to store a failsafe position even when power is removed. The servo started as a JR 591 standard size ballrace servo. The digital servo amp PCB is 17mm x 19mm.
Precise and rapid control.
Position measured and motor driven 1000 times/second.
No overshoot - algorithm compensates for motor inertia.
High speed from MOSFET motor drivers.
Tight control - deadband less than gearbox slack.
Accurate control to better than 0.1% of pot.
Ignores pulses outside normal 1-2ms range.
Will not drive arm outside normal span of movement.
Servo span adjustable 70 - 90° via pot.
Bad pulses (outside 0.9 -2.1ms) trigger failsafe.
Absence of input pulses triggers failsafe.
Failsafe position securely programmed via simple special programmer.
A 16Mhz process control computer on a postage stamp!
Commercial enquiries welcome