SVP324 - PID Value

Hi everybody

I have project about line folloer robot. I use Orangutan SVP 324, and QTR-8A Sensor, and 1500 rpm motors. I done something, but it s not completely. Because it vibrates too much. I think I can fix with PID, but ı can not find information in datasheet. And I dont have osilloscope ı can not take value. How can I find PID value(kp,ki, kd)?

Thank you for help :slight_smile:

The tried-and-true way is to just take a guess, and see how it goes. Then tweak the values up and down until it works alright.

Typically, you’ll start with a reasonable P value, and see if that works OK. You’ll often end up being somewhat off in the direction of load, or oscillating like a spring.
If you’re off in the direction of load, you then add some I value. Start medium-to-low, test, and tune until it works OK. You will likely end up with some overshoot in the correction, which in turn leads to oscillation.

So, once you have oscillation, you dampen it by turning up the D gain. Start medium-low, and tune from there. You’ll typically want the oscillation to slightly overshoot, and then settle to the line – look for “critically dampened spring” to see some graphs of what that looks like in a general control systems.

Now, if you know how often the control loop runs, and you know the units of the input values, and you know the range of the input values, and you have a model of your output system (latency, backlash, force, etc) then you can attempt to solve the system analytically as a differential equation. Typically, this only actually works in textbooks, or for expensive industrial motion control systems where the vendors have taken the time to build really good models of their systems, though :slight_smile: