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Function rc_filter_pid

Function Documentation

int rc_filter_pid(rc_filter_t *f, double kp, double ki, double kd, double Tf, double dt)

Creates a discrete-time implementation of a parallel PID controller with high-frequency rolloff using the forward-Euler integration method.

This is equivalent to the Matlab function: C = pid(Kp,Ki,Kd,Tf,Ts)

It is not possible to implement a pure differentiator with a discrete transfer function so this filter has high frequency rolloff with time constant Tf. Smaller Tf results in less rolloff, but Tf must be greater than dt/2 for stability. Returns 0 on success or -1 on failure.

Parameters

  • f – Pointer to user’s rc_filter_t struct

  • kp – [in] Proportional constant

  • ki – [in] Integration constant

  • kd – [in] Derivative constant

  • Tf – [in] High Frequency rolloff time constant (seconds)

  • dt – [in] desired timestep of discrete filter in seconds

Returns

Returns 0 on success or -1 on failure.