How to link RPM and PWM?

Question

Electronics

There is a robot, I calculated its kinematic model, as a result I get for each engine (DPT) the rotational speed in PRM (revolutions per minute), how this value can be connected with the PWM at the controller output (ps output 8 bit = 256 gradation).

Answer 1

Well, how, how -> if there is no documentation, then you apply the frequency, measure the result of the rotation, give the frequency to your friend, measure another result. You collect statistics, build a relationship model, maybe linear, maybe not linear, you need to figure it out, in any case, you will have a rough model that can only be used together with PID regulation to set the initial values.

Answer 2

"robots" use ready-made servos or self-made ones with custom feedback. the mythical kinematic model is an abstract pretentious slag, which is not applicable in this case, because where it can be applied, the authors know the correct spelling of PRM.
but even in very cool products, a certain translation of shim-PRM never appears anywhere. control laws are used, where the value of the control signal (in this case, the duty cycle of the PWM signal) is the final result of calculations, which is not used numerically in any way and is stupidly given out.
it is also impossible to use a direct "transfer" due to the discrepancy between the parameters of the engine, power source and blunt wires calculated, compensation is needed.

Answer 3

need feedback from the engine. If you take a brushless motor, then you can get it there. But it is difficult to make a speed controller. If you take a conventional engine, then you need a rev counter, you can use an optical one on phototransistors or some other one. Nothing without this.