0x2501 - Velocity control parameters set

Index	Sub Index	Name	Data Type	Acc.	Pdo Map.	NVM	Value range	Default value	Units
0x2501	0x01	Proportional constant	UINT32	RW	No	Yes	UINT32	4000	‰ rated torque / (increments * s)
0x2501	0x02	Integral constant	UINT32	RW	No	Yes	UINT32	50	‰ rated torque / (increments * s²)
0x2501	0x03	Derivative constant	UINT32	RW	No	Yes	UINT32	0	‰ rated torque / increments
0x2501	0x04	Integral antiwindup constant	UINT32	RW	No	Yes	UINT32	0	increments / (‰ rated torque * s)
0x2501	0x05	Acceleration feedforward constant	UINT32	RW	No	Yes	UINT32	0	(‰ rated torque * s²) / increments
0x2501	0x06	Integral limit	UINT32	RW	No	Yes	UINT32	10	‰ rated torque

The filter implemented in the velocity control loop is a parallel PID with acceleration feedforward and also with antiwindup control. Next Figure shows a diagram of the loop.

The equivalent equation of control loop is the following one (to simplify the anti-windup term has been eliminated):

The equation could be expressed in digital space as following:

The simplified equivalent equation of the implemented PID (without feedforwards) is:

Where:

Due to optimization of computational time we consider the T_sampling included into the constants value. We also include an additional scaling value to give more resolution. Therefore, the constants sent to the controller will be related with the internal ones in the following way:

Where

Giving a final scaling of

The integral limit is also scaled as stated in the following equation:

So, if we want a constant Kp' with a 0.4 value we must set a 26214 into register 0x2500 SubIndex 1 that corresponds to the Kp constant in position loop.

Any theoretical and/or empirical adjustment (Ziegler-Nichols, Tyreus-Luyben, etc) must be based on the use of the internal constant of the loop (Kp', Ki', Kd', etc.)

This object defines the constants of the velocity control loop.

For further information about meaning of each parameter see Position control parameters set.