CL Controller (PD with FF)

Parent Polymorphic VI: CL Controller

Requirements: Quanser Rapid Control Prototyping Toolkit, LabVIEW 2020 or newer, Control Design and Simulation Module

Description

Produces a control signal that drives the system to the reference value based on the deviation between the measured value and the reference using Proportional-Derivative (PD) and Acceleration Feed-Forward control.

Recommended Inputs or Dialog Box Options Recommended inputs need not to be wired. They may be selected to appear as terminals or dialog parameters, but show up as terminals by default. They appear in simple text in the context help window for the VI.

cut-off frequency is the high-pass filter cut-off frequency (in rad/s) used to determine the velocity of y.

reference, r is the reference signal, e.g. desired position or velocity of a DC motor.

measured, y is the measured signal, e.g. motor position.

proportional gain, kp is multiplied by the error between the reference and measured signals and added to the final output.

integral gain, ki is multiplied by the integral of the error between the reference and measured signals and added to the final output.

feed-forward gain, ka is multiplied by the acceleration of the reference point and added to the final output.

Outputs

	error is the difference between the reference and measured signals, i.e. e = r - y.
	output, u is the controller output signal.

Details

The PD+FF control loop is depicted below and has the following structure: u = k_p (r-y) + k_d s (r-y) + k_a s² r. The direct derivative is not taken to minimize the noise in the control output. Instead, the first-order high-pass filter ω_f s/(s+ω_f) is used to compute the velocity of the error, where ω_f is the cut off frequency. Using the acceleration of the reference signal can lead to improved response time.

Feedthrough Behaviour

All input/output pairs of this function have direct feedthrough behaviour.

Examples

RCP CL Controller PV Example

This example demonstrates the use of RCP CL Controller using PV gains.

Targets

Target	Supported	Comments
RCP Windows (64-bit) Target	Yes	Fully supported.

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