Filter programming

Release Note

release_note

The availability of this function depends on the configuration and the scope of the version.

In order to achieve a high surface finish in free-form surface machining, any excitation of machine oscillations must be avoided as far as possible.

HSC axis filters provide the user with the possibility of smoothing the axis setpoints for the drives to minimise excitations in the machine. This may result in deviations from the programmed contour but the user is able to limit them. As opposed to conventional low-pass filters, HSC axis filters do not distort the contour, i.e. parallel paths in diametrically opposed directions remain parallel.

Attention

attention

A condition for the use of this functionality is the complete and correct parameterisation of axis-specific filter parameters [2]-3.

Example of settings in the axis lists:

filter[0].order

10

filter[0].time_constant

10000

filter[0].prototype

5           #Type HSC filter

filter[0].type

8

filter[0].fg_f0

20

filter[0].guete

100

filter[0].share_percent

100

The following NC command is provided for selecting filter programming:

#FILTER [ON | OFF] [ HSC [PATH_DEV <expr> [ORDER<expr>] [TIME_CONSTANT<expr>]
[SHARE <expr>] [FCUT<expr>] [DAMPING<expr>] [MODE<expr>]]                             (modal)

HSC

Keyword for selecting the HSC filter.

ON

Enable HSC filter.

OFF

Disable HSC filter.

PATH_DEV <expr>

Parameterisable path deviation in [mm, inch *]. This function only provides filter[].type 8 and filter[].type 12 when MODE 3.is used. Default 0 (no monitoring).

*with active P-CHAN-00439

ORDER<expr>

Specify filter order This function is similar to that of the axis parameter filter[0].order.

TIME_CONSTANT<expr>

Specify filter order in µs. This function is similar to that of the axis parameter filter[0]. time_constant. TIME_CONSTANT is only used when a valid ORDER > 0 value is not programmed at the same time.

Notice

notice

If neither ORDER nor TIME_CONSTANT are programmed, the program resorts to the axis parameters.

SHARE<expr>

Specify the fitter performance as a percentage. This function is similar to that of the axis parameter filter[0]. share_percent. If SHARE is not programmed, the configured axis parameter value is used.

FCUT<expr>

Specify the first natural frequency to be suppressed in Hz. Only effective when filter[0].type 12 is used. This requires an additional HSC licence. If FCUT is not programmed, the configured axis parameter value filter[0].fg_f0 is used.

DAMPING<expr>

 

Specify a damping factor of the first natural frequency as a dimensionless unit. Only effective when filter[0].type 12 is used. This requires an additional HSC licence.

The value range is valid between 0 and 1. Default value is 0.1.

 

Equation used for calculation:

 

A1, A2 two consecutive amplitudes at a damped oscillation

MODE<expr>

Specify the type of frequency suppression.

Only effective when filter[0].type 12 is used. This requires an additional HSC licence. Permitted values are 0.1, 2.3. Default value is 1.

The modes are distinct from one another:

  • In their ruggedness with deviations from the actual natural frequencies.
  • In the degree of deviation from the actual contour.
  • The higher the MODE, the more rugged the filter but the higher the contour deviation.

Contour error monitoring is provided for Mode 3 (cf. PATH_DEV).

Ruggedness

 

MODE 0

MODE 1

MODE 2

percentage residual oscillation < 5%

with fluctuations of up to +/-3% from actual natural frequency

with fluctuations of up to +/-14% from actual natural frequency

with fluctuations of up to +/-30% from actual natural frequency

Programing Example

prg_example

Filter programming

N1111 #FILTER ON [HSC]

N10 X0 Y0

N20 X0 Y1

N30 X1 Y1

N50 X1 Y0

N40 X0 Y0

N4001 #FILTER OFF [HSC]

Example of filter programming
Example of filter programming