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Subsection 3.17.2: The math controller Up Section 3.17: LoadData Section Section 3.18: Output Section

### 3.17.3 The PID controller

The PID controller allows users to create simple control systems where the value of one model parameter is used to control the output of another model parameter. The PID controller calculates the output value as a sum of three terms: a term proportional to the error (i.e. the difference between a user-defined target value and the measurement), a derivative term, and an integral term.
This controller requires the following parameters:
• var: specify the model parameter that is used as process variable, i.e. the measurement.
• target: the target value for the process variable.
• Kp: weight factor for the proportional term.
• Kd: weight factor for the derivative term
• Ki: weight factor for the integral term.
For example:
<load_controller id="1" type="PID">
<var>fem.rigid_body[1].euler.z</var>
<target>1.5708</target>
<Kp>5</Kp>
<Kd>1</Kd>
<Ki>4</Ki>