Linear Motion and Control 1

[eaolsen]

I am looking for a unique piece of hardware. It needs to provide controlled resistance to linear motion in one direction and linear motion in the other direction. It needs to be able to resist roughly 500lbs and move 50lbs. It needs to be able to move/resist at about 1 ft/sec. I need to be able to modulate the level of resistance through the motion. It also needs to be able to measure the amount of force being applied to it at each point through the motion.

I know that hydraulics would work great for this but we are steering away from that because of the mess. Pneumaics aren't an option because the system would be spongy.

Since the system is always pulling or resisting pulling, the force could be transferred by a cable.

 

[tygerdawg]

What kind of gizmo are you looking for? One option to consider: You might be able to apply an AC induction gearmotor + inverter drive + encoder to provide the torque necessary to resist the force and drive at the speeds you want. The resistive force would probably force the motor into the regenerative operation mode, so you'd need regen resistors to convert the regen voltage to heat.

This scheme could be used for rack & pinion, timing belts, ball screws, etc.

TygerDawg

 

[automatic2]

Sounds like a perfect application for a ball screw drive.

 

[solidworkswell]

see if this helps.

Have a leniar piston which pushes with a constant force and free slide on the back stroke. This way you can push 50lbs. For resisting use a damper (one way damper). you can adjust the damper such that u get 500lbs of resisting force with 1ft/s.

but the damper works of fluid for resistanc.

 

[unclesyd]

Here is one of many types of rodless or belt cylinders that we used all over the place. Like I stated this one of many types that we used, some were used of tables for very high speed machines were accurate and stationary position was a requirement.

http://www.isotechinc.com/prod13.htm

 

[alansimpson]

Pneumatics with hydraulic speed control can produce very controlable motion. Much cleaner than hydraulics on its own since the hydraylic circuit is closed. Festo used to have such a system, PHD also.

 

[sreid]

I would suggest a brushless PM servo motor and PWM amplifier. The mechanics would be a gear box (perhaps a cyclo-converter) followed by, say, a cable reel if the stroke is long.

The speed of the servo can be continously set by a speed command. The amount of torque can be continously set by varying the current limuit in the amplifier. The amount of torque can be monitored by looking at the current sense output of the amplifier.