Bumpless Control Transfer with a Two-Degree-of-Freedom PID Controller

This example shows how to use signal tracking to achieve bumpless control transfer in a system that switches between a PID Controller (2DOF) block and another controller. You can make the PID controller track the output of the other controller by connecting the signal you want to track to the TR port of the PID Controller block. For example:

The input Ref takes a reference signal, and the input y takes the measured feedback from the plant. These signals feed the 2DOF controller, and the difference between them feeds the Active controller block (a Zero-Pole block). The output u drives the plant. A switch transfers control between the active controller and the PID Controller (2DOF) block. When the Active controller is in the loop, the PID Controller (2DOF) block tracks its output. Thus, the two controllers have the same output when you switch to PID control, ensuring smooth operation.