Actuator for science project?

Question

I am making a project and I need some type of electrically powered actuators that will move a tiny bit.. a fraction of an inch.. in a programmable manner, over and over. They need to be very reliable and longlasting. Is anyone familiar with anything like this?

Answer 1

You can buy linear actuators. Depending what you mean by a programmable manner and whether you want to control the position or just want them to move a set distance. If it's a set distance, the solenoid suggestion is fine. If you want to be able to control the movement to set positions in a controlled and reproducible manner there are two main methods.

The first method is to use a motor drive and use a sensor to measure the position in a feedback loop. The other method is to use a stepper motor. Both of these will need some way to make the rotary motion linear but that is just a gearbox and a linkage or a rack and pinion arrangement.

The advantage of the first method is that the motor can be as powerful as it needs to be. The positioning comes from the sensor. The disadvantage is it needs more electronics and the sensor needs to be somehow read or converted into a signal which either controls the motor or gives feedback to the computer or controller. Because the position is read from a position sensor, the position is absolute (ie it always knows exactly where it is)This is effectively how ships' rudders and aircraft ailerons are computer controller.

The advantage of the second method is that the stepper motor give controlled and defined steps, is easy to interface to and easily connected and controlled by a computer or stepper motor controller ic. The disadvantage is that stepper motors tend to be more expensive than normal motors and are generally lower power. Unlike the first method the stepper motor only gives relative movement and doesn't know where it is initially. It must therefore be zeroed in some way before it is used, usually by driving it against a stop or a zero sensor.

You can also make an actuator act over a different range by using levers to either increase or decrease the movement, but this will decrease and increase the force respectively.

Finally there are more custom designed solutions. The most obvious one is inside a disk drive moving the heads back and to. This uses a coil inside a magnetic field and is effectively a loudspeaker coil movement. You could also attach something to a speaker and drive that to get small movements, but you'll only get a very low force from it without destroying it and it may be physically bigger than you want.

Answer 2

Electric actuators are of various types. You get linear actuators and rotary actuators.

You have to select a modulating actuator ( usually servo controlled ie with position feedback) and you will also need a signal controller ( usually 4-20 mA).
They have provision for adjusting stroke( distance) over the control signal range)

All the best!

Answer 3

Use bateries and combine them with LED and a buzzer when the buzzer vibrates you can use it to move and object. Tis is quite complicated.

Well the best way is to use a spinig gear. When you apply a little force to a big gear the back small gear will move fast. Try combining a few gears together. A little force is only needed to move the object.

Answer 4

You can get servos for as little as $10 each. Price is dictated by accuracy, strength and speed.

To control them with a computer, I'd recommend the Lynxmotion SSC-32 servo controller.

Answer 5

Hi. For rotation use a servo-motor. For linear motion a solenoid.

Answer 6

Another idea is a stepper motor with a screw thread on its shaft.