How to reproduce internal RC servo electronics but for a much higher amp output

I've researched this quite a bit without much luck. I'm looking for something very specific that may be rare, but should exist as an off-the-shelf product...

Do any of the following items already exist? If not, what would be the simplest, lowest number of separate parts, lowest cost, simplest to reproduce method to produce one of the systems described below?

  1. A DC motor controller that acts exactly like the internal electronics of a RC servo except that it controls a motor of 12v or more, at an amperage of 5A or more. More generally,
  • Requested absolute position: takes a single-wire, 1.3v or 5v [u]absolute position[/u] input as PWM, serial, or simple byte commands
  • Current absolute position: also takes input from a 5v potentiometer or 10 to 12 bit absolute encoder (used for closed loop, absolute position data)
  • outputs variable voltage to control a DC motor, both directions, at 12v or more, at up 5A or more (exactly like the internals of a RC servo but higher voltage and amperage) and directs the DC motor's speed and direction until the potentiometer or absolute encoder indicates that the motor is at the desired position indicated by the other (first) input
  1. A Stepper motor controller that acts exactly like the internal electronics of a RC servo except that it controls a stepper motor of 12v or more, at an amperage of 5A or more. More generally,
  • Requested absolute position: takes a single-wire, 1.3v or 5v [u]absolute position[/u] input as PWM, serial, or simple byte commands
  • Current absolute position: also takes input from a 5v potentiometer or 10 to 12 bit absolute encoder (used for closed loop, absolute position data)
  • outputs the necessary pulses to control a stepper motor, both directions, at 12v or more, at up 5A or more (functionally, exactly like the internals of a RC servo but higher voltage and amperage) and directs the stepper motor's pulses and direction until the potentiometer or absolute encoder indicates that the motor is at the desired position indicated by the other (first) input

Whew! Hopefully that is clear enough!

Google "wiper motor servo". Is that close to #1?

groundfungus: Google "wiper motor servo". Is that close to #1?

You're a genius :o I've used wiper motors before for other projects and I'm fairly familiar with how RC servos work. The missing piece of the puzzle was that an H bridge could be used to simply amplify the original output of the servo. You're the man! Too bad this setup doesn't already exist as an off-the-shelf product...