0x2013 Gain Scheduling

Depending on the application, the “optimal” tuning for the cascaded PID controller may differ between different operating points. If there is only one tuning available, it has to be a compromise not using the full potential of the hardware.

This feature allows the user to apply controller gains which will change dynamically regarding the current velocity. This technique can be used within the cascaded position controller to compensate for nonlinear effects, especially stiction/friction in the mechanics.

For velocities (in rpm) below a user-defined value, a set of PID values determined best for slow motion is used. Likewise, for velocities (in rpm) above a user-defined value, a set of PID values determined best for fast motion is used.

The PID values between these values are interpolated linearly.

 

Name	Index:Sub	Type	Bit Size	Options			Unit	Access	PDO Mapping
Enabled	0x2013:1	BOOL	1	Disabled 0 Enabled 1				readwrite
Enables or disables the gain scheduling feature.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Threshold Velocity 0	0x2013:2	UDINT	32	0		0		readwrite
Velocity that determines the lower threshold. Underneath this value, controller gains set 0 is used. Beyond it, linear interpolation begins.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Kp 0	0x2013:3	REAL	32	0		0		readwrite
The P-gain of the Position Control Loop of area 0 (low velocity, below threshold velocity 0) [rpm/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Ki 0	0x2013:4	REAL	32	0		0		readwrite
The I-gain of the Position Control Loop of area 0 (low velocity, below threshold velocity 0) [rpm/(inc*s)]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Kd 0	0x2013:5	REAL	32	0		0		readwrite
The D-gain of the Position Control Loop of area 0 (low velocity, below threshold velocity 0) [rpm*s/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Integral Limit 0	0x2013:6	UDINT	32			0		readwrite
The integrator limit of the Position Control Loop of area 0 (low velocity, below threshold velocity 0). The technique used for preventing the windup is clamping and it prevents the integral term from accumulating above or below pre-determined bounds. The limit should always be set in the driving shaft units, this is especially important when a gearbox is used in the setup.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Kp 0	0x2013:7	REAL	32	0		0		readwrite
The P-gain of the Velocity Control Loop of area 0 (low velocity, below threshold velocity 0) [mNm/rpm]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Ki 0	0x2013:8	REAL	32	0		0		readwrite
The I-gain of the Velocity Control Loop of area 0 (low velocity, below threshold velocity 0) [mNm/(rpm*s)]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Kd 0	0x2013:9	REAL	32	0		0		readwrite
The D-gain of the Velocity Control Loop of area 0 (low velocity, below threshold velocity 0) [rpm*s/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Integral Limit 0	0x2013:10	UDINT	32			0		readwrite
The integrator limit of the Velocity Control Loop of area 0 (low velocity, below threshold velocity 0). The technique used for preventing the windup is clamping and it prevents the integral term from accumulating above or below pre-determined bounds.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Threshold Velocity 1	0x2013:11	UDINT	32	0		0		readwrite
Velocity that determines the upper threshold. Above this value, controller gains set 1 is used. Up to this velocity linear interpolation is performed.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Kp 1	0x2013:12	REAL	32	0		0		readwrite
The P-gain of the Position Control Loop of area 1 (high velocity, above threshold velocity 1) [rpm/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Ki 1	0x2013:13	REAL	32	0		0		readwrite
The I-gain of the Position Control Loop of area 1 (high velocity, above threshold velocity 1) [rpm/(inc*s)]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Kd 1	0x2013:14	REAL	32	0		0		readwrite
The D-gain of the Position Control Loop of area 1 (high velocity, above threshold velocity 1) [rpm*s/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Position Loop Integral Limit 1	0x2013:15	UDINT	32			0		readwrite
The integrator limit of the Position Control Loop of area 1 (high velocity, above threshold velocity 1). The technique used for preventing the windup is clamping and it prevents the integral term from accumulating above or below pre-determined bounds. The limit should always be set in the driving shaft units, this is especially important when a gearbox is used in the setup.
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Kp 1	0x2013:16	REAL	32	0		0		readwrite
The P-gain of the Velocity Control Loop of area 1 (high velocity, above threshold velocity 1) [mNm/rpm]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Ki 1	0x2013:17	REAL	32	0		0		readwrite
The I-gain of the Velocity Control Loop of area 1 (high velocity, above threshold velocity 1) [mNm/(rpm*s)]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Kd 1	0x2013:18	REAL	32	0		0		readwrite
The D-gain of the Velocity Control Loop of area 1 (high velocity, above threshold velocity 1) [rpm*s/inc]
Name	Index:Sub	Type	Bit Size	Min Data	Max Data	Default Data	Unit	Access	PDO Mapping
Velocity Loop Integral Limit 1	0x2013:19	UDINT	32			0		readwrite
The integrator limit of the Velocity Control Loop of area 1 (high velocity, above threshold velocity 1). The technique used for preventing the windup is clamping and it prevents the integral term from accumulating above or below pre-determined bounds.