For a pet project of mine, I'm interested in finding a tubular solenoid which force is spread linearly over a longer length. The project is based on IA and uses a programmed controller (and sensors) to feed several solenoids (the question is for one solenoid) quickly in order to "grab" something falling vertically, from below, this silently (done) but also a bit more smoothly (the problem). Currently, while the programming seems to work, the test prototype with two solenoids lack control. Basically the solenoids force goes from 0 / 1 [didn't try to control current yet].
I bought and tried from the Net, something like
but the force is basically 0 / 1… meaning the force grows exponentially over a short distance.
Ideally, the force would be linearly spread over a length I decide. Thus my question
Preferably with only one solenoid, how to choose/select the core and wires in order to spread the force over a longer length (i.e. not exponential growth)
If 2+ solenoids are necessary please explain how you would arrange them to reach such result (1 is preferable though).
Note: if that helps, the current applied to the solenoid can be precisely controlled from a chip.
Best Answer
The force of a solenoid is a function of both its position and the current. If you have position feedback, you should be able to control the current to achieve nearly constant force over some portion of its travel.
That said, there are linear actuators that don't involve rotary motors with gears or screws. They are basically linear BLDC motors, and they can be very quick. The downside is that they are rather expensive and require a relatively complex controller.