I need a variable speed linear actuator for my senior design project.?

Question

Preferably one that's easy to interface with a PC. Any help is appreciated; they don't give us biomed engineers much training in this area

Any suggestions on vendors that would have something cheap?

Answer 1

It depends on your exact situation, but I'd probably use a pneumatic system with a solenoid valve and a pressure transducer. I'd control the speed with a viscous damper and pulse width modulation at the solenoid. If you know your pressure, you can calculate your force. It's often even better to know the force than the displacement. I'd control the solenoid with some kind of high-current transistor with a good heat sink on it, interfacing it to the PC parallel port. (They're typically rated at 5mA, so you'll probably need a Darlington high-gain transistor.)

A simpler method might be to use a stepper motor with a rack and pinion with a Darlington array. Use a heavy flywheel and a short gear ratio (perhaps gearing it down before the rack and pinion) if you want smooth speed increments.

Answer 2

Best one I can think of is an x-y plotter, but I don't think they're very cheap.