Controlling a Servo using PID control.

Hi Guys,

Wonder if you could help me.

I am learning about Simulink and the Arduino. I am trying to use PID feedback control with PWM but I'm not sure that makes sense due to the results.

I have a continuous servo that reads a value from 0 to 180 and a pot as an analog in and they work fine together and it is calibrated nicely.

Now I am trying to improve the response time mimicking an experiment that I did at Uni to control a servo using PID control.

So I have my input value going into a sum through a PID controller to the servo with the input signal going to a scope. From the servo read, the signal goes into the sum as a minus, and that signal also goes to the scope.

But trying to tune the PID controller, the signal just goes from high to low as PWM of 5Hz.

I am clearly missing something here.

Sample rate is set to 0.01

P = 1 I = 0 D = 0

Let me know what other info I need to give. D

[Robert]

Ok, I found my answer, and yes it was a stupid question, but if anyone stumbles upon this question and is stuck like I was. Servo motors have inherent feedback control in the form of a PID controller, but enerally for positional control it is only the 'P' proportional and 'D' derivative that used.

[Gaurav Pipersaniya]

can you tell me how can i do this project. actually i have to do project on pid controller similar to yours using simulink so if u can help in detail?

[Steve]

Do you have a mathematical model for the servo you were using(assuming it was a hobby servo) ?

Did you get through Gaurav Pipersaniya ?