I would like to source a linear actuator ‘system’ capable of the following:
1.) Measuring how far a mechanical lever has been moved
2.) Measuring how quickly said mechanical lever has been moved
3.) Have a ‘home’ position set at one half of its travel
4.) Output a 10K Ohm analog signal based on its home position -1 = retracted position, 0 = home position, 1 = extended position, with all positions in between being linear between the extremes]
5.) System should be ‘plug and play’ as much as possible
I want to be able to move a lever to various positions at various velocities and have the linear actuator follow the lever. If the lever is held in one position the linear actuator should hold its position.
The linear actuator should have four inches of travel with a velocity of two inches per second. The force required is approximately 25 pounds.
Hi,
As far as we know, we do not currently offer any device that does what you have described.
For points #1,#2 and #3 you could simply attach to your lever a linear variable resistor along its travel path (or other linear encoding methods). Connect the linear resistor to a voltage divider in such a way to make its half-way point provide 50% of your input voltage that that should cover those.
For point #4, connect the output of that voltage divider to a microcontroller. In it, you can code a routine to obtain that analog voltage value (through an ADC interface) and map it to a float/double of -1 to 1. This should be rather straightforward.
Concerning #5, since no ready-made product exists, it will not be plug and play at all and more along the lines of DIY.
Sincerely,
Thank you for your reply. I think I can cobble together the necessary items to accomplish most of the task.
Can you recommend an appropriate servo linear actuator?
Well, most servo linear actuators use a screw with a threaded rod, which makes it very hard to move the actuator, especially if powered.
Also, since you wish for the actuator to follow the motion (but hold the position, I’m assuming?), its controller would basically need to be in a “torque follow” mode, which is not the default way a linear actuator controller works.
You would most likely need to build your own torque-bsed controller from a linear actuator that provides position feedback. You will most likely need extra sensors for current measurement, too. Lets just say upfront that this is not trivial.
By default, most linear actuators either simply extend/retract (with or without limit switched) or they have a position position feedback, but no control. Those that do have a controller embedded normally only do position control, using as much torque as needed to reach and keep the target position.
For a physical setup, you may want to look at this and this product. Of course, when powered, they wont allow movement easily (like you seem to be needing).
If we misunderstood what you are trying to do, please do provide more details or clarification where needed.
Sincerely,
