I have to build a motor to turn the front wheel steering of a small ATV. I would like 150 pounds of force, as fast as possible, 10+ inches / second. My goal for 150 pounds of force is from me taking a fishing scale, attach to steering arm and pulling the wheel at a dead-stop in moderately heavy sand - as my control test, so that I know my device would be strong enough to turn in harsh terrain.
Here is a picture of a the ATV:
There is no passenger. I’m building an autonomous R/C rover - so it’s going to have payload of lead batteries. I believe the strongest and fastest way would to create a leadscrew mounted to a motor, drive the steering arms. I can also just bolt a motor with a chain or pully to the steering shaft, except I think the amount of gears and pully’s it would take would use more space, than a rotation/linear solution. To go buy a pre-made linear servo assembly can be expensive, I want to build it with all my spare parts I’ve been salvaging over the years. I am not concerned with the feedback positioning at this point, I just want to make the motor/actuator.
I know how to calculate the rpm -vs- the screw pitch, will give me the speed. But I am confused on how to pick out my motor, test it’s lifting strength to drive the screw. There is information online, except - that I am dumb and when they start with the math and go on for paragraphs to explain about physics that I never learned, the information is not useful.
I know I can mount a stick with a weight to the shaft of a motor and spin it. Motor will stalls to give me AN ESTIMATE of the strength of a motor. Where I get confused, is the length of the stick with the weight, since the longer the stick acts like a lever and changes the rotational force.