A controller is provided as a way to try and reach a desired (target) value by means of a feedback control loop.

Motors and actuators use a controller by default, but have an option on the microdialog that allows you to disable the controller.
Figure 1. Controller Option for Motors

Figure 2. Controller Option for Actuators

Types of Controllers

There are two types of controllers available from the Property Editor:
  • PID
  • Soft Constraint (available for angle motors and displacement actuators only)
Note: In general it is recommended to use a controller, but if your controller is not doing what you want, try turning it off. The selected profile function will be used directly with no feedback loop involved.

PID Controller

PID is a conventional Proportional-Integral-Derivative (PID) control scheme. If the controller does not respond the way you expect, you can adjust the gains in the Property Editor:
  • Proportional Gain
  • Integral Gain
  • Derivative Gain

Soft Constraint Controller

A soft constraint is not a conventional controller, but more like a mathematical constraint with some violation allowed. (That is why it is a soft constraint, as opposed to a hard constraint which allows no violation.)

You can change the behavior of a soft constraint by adjusting the factors in the Property Editor:
  • Proportional Factor
  • Derivative Factor


This plot shows a case of a soft constraint controller overshooting the desired step-dwell-step profile function.