# 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 Tsampling 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.

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