0x2023 Notch filter

Implemented as IIR 2nd order filter configured by the center frequency and the bandwidth around it. Filter is placed on the output of the velocity controller so it filters the torque demand value. Frequency prewarping is applied. Filter formula in discrete domain

y_k = a₀ x_k + a₁ x_k-1 + a₂ x_k-2 + b₁ y_k-1 + b₂ y_k-2

where  a₀ = K, a₁ = -2Kcos(2pi*f), a2 = K, b1 = 2Rcos(2pi*f), b2 = -R² 

and K = (1 - 2Rcos(2pi*f) + R²) / (2-2cos(2pi*f))

       R = 1 - 3 * BW

f - center frequency and BW - bandwidth expressed relative to the sampling frequency, where f,BW = [0, 0.5]

 

Name	Index:Sub	Type	Bit Size	Options			Unit	Access	PDO Mapping
Enabled	0x2023:1	BOOL	1	Disabled 0 Enabled 1				readwrite
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Center frequency	0x2023:2	UINT	16	10	2000	100	Hz	readwrite
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Rejection band	0x2023:3	UINT	16	1	4000	1	Hz	readwrite