Velocity PID Tuning¶

Tuning the parameters of velocity controller is pretty straight forward. In this section, the basic steps of tuning the velocity controller are explained.

PID Parameter Range¶

The constants k_P, k_I, and k_D should be between 0 and 10 with the precision of 6-digit floating point.

Measuring units of gains are: k_P [mNm/rpm],

k_I [mNm/(rpm*s]

k_D [mNm*s/rpm]

To find the proper values of PID constants of velocity controller the following steps are recommended:

Recommended Tuning Steps¶

Step 1.: Check if all constants k_P, k_I, and k_D are set to 0. After that activate the velocity controller. By default, the integral limit of velocity controller should be set to the maximum torque of selected motor in [milli-Nm].
Step 2.: Set the reference velocity to 50% of rated motor velocity [rpm].

Fig. 1: setting the reference value of velocity to 50% of its rated value¶

Step 3.: Increase k_P until the measured speed is around 70% of the reference speed. As a suggestion start with k_P equal to 0.1, and in each step increase k_P with a factor of 2.

Fig. 2: increasing k_P to increase the actual speed¶

Step 4.: From this step forth, step response of the system should be checked. Increase k_I step by step to increase the speed of velocity controller (as a suggestion start with k_I equal to 0.01 and in each step increase it by a factor of 2).

Fig. 3: Increasing k_I until proper step response is generated by velocity controller¶

At this point, the parameters k_P and k_I of the velocity controller are tuned. The parameter k_D of the velocity controller can be kept at its default value (0).