Rockwell Automation Publication 750-AT006D-EN-P - January 2022
33
Chapter 2 Product Features
Figure 31 - Load Observer Only Configuration
Load Observer with Velocity Estimate
10:2020 [LdObs Mode] = LdObs VelEst (2) – This mode is recommended for position control applications. It performs well in situations with
changing inertia and unknown levels of compliance and backlash. It compensates for most loads that are connected to the motor, providing
high disturbance rejection and dynamic stiffness, and allows gains to be increased for quicker system response. It is not desirable for
Velocity mode applications because a steady state velocity error could be present that is hard to detect. This mode applies both Torque and
Velocity Estimate signals to the control loops. It replaces the default filtered Velocity Feedback signal with the Velocity Estimate signal.
Figure 32 - Load Observer with Velocity Estimate Configuration
Velocity Estimate Only
10:2020 [LdObs Mode] = Vel Est Only (3) – This mode can be used in some position control applications. It removes phase lag associated with
velocity feedback filtering and allows gains to be increased for quicker system response. It is not desirable for Velocity mode applications
because a steady state velocity error is present that is hard to detect. This mode applies the Velocity Estimate signal to the control loops but
not the Torque Estimate signal. It replaces the default filtered Velocity Feedback signal with the Velocity Estimate signal.
Figure 33 - Velocity Estimate Only Configuration
System Under Control
Load
Observer
Power Converter
Control Loops
Fs
Unloaded Motor
Acceleration
Reference
Torque
Estimate
Velocity
Estimate
Position
Feedback
Torque Load
P
REF
Velocity
Feedback
Filter
System Under Control
Load
Observer
Power Converter
Control Loops
Fs
Unloaded Motor
Acceleration
Reference
Torque
Estimate
Velocity
Estimate
Position
Feedback
Torque Load
P
REF
Velocity
Feedback
Filter
System Under Control
Load
Observer
Power Converter
Control Loops
Fs
Unloaded Motor
Acceleration
Reference
Torque
Estimate
Velocity
Estimate
Position
Feedback
Torque Load
P
REF
Velocity
Feedback
Filter