MPIAxisPreFilterConfig

Definition

typedef struct MPIAxisPreFilterConfig {
	MPIAxisPreFilterForm       form;
	long                   length;
	long                   coeffDelay[MPIAxisPreFilterCoeffsMAX];
	double                 coeff[MPIAxisPreFilterCoeffsMAX];
	long                   delay;
                           /* number of samples it takes for positions to propagate thru prefilter */
} MPIAxisPreFilterConfig;

Required Header: axis.h

Change History: Added in 03.04.00.

Description

PreFilters are used to filter motion trajectories. The command positions generated by the controller firmware during a move are passed through the filter before being used as set points by the control algorithm. PreFilters are useful for removing unwanted frequencies from the motion profile or for smoothing out motion generated by joysticks or other manual input devices.

Two forms of PreFilters are supported: BOXCAR and SHAPING. The BOXCAR filter is a simple averager where the output of the filter is the of average a number of previous command positions. The number of points is determined by the length parameter. For BOXCAR filters the coeff[] array is ignored.

The SHAPING PreFilter passes the trajectory through a special filter type patented by Convolve, Inc.® (www.convolve.com). This filter can greatly enhance the performance of mechanical systems with resonances or flexible hardware. The length and coefficients of the SHAPING filter are generated by Convolve® for the specific system using the filter. See the Convolve website for information about the advantages of Input Shaping®.

form The type of filter (NONE, BOXCAR, or SHAPING).
length The filter length (number of stages).
coeffDelay Used only for SHAPING filters. The coefficients are generated by Convolve®, Inc. software (see www.convolve.com).
coeff Used only for SHAPING filters. The coefficients are generated by Convolve®, Inc. software (see www.convolve.com).
delay The number of controller samples for the positions to propagate through the preFilter.

See Also

MPIPreFilterForm | MPIAxisConfig