Baldor Flex+DriveII, Руководство по установке, Страница: 111 / 126

Control System B-5 MN1902
B.1.4 Position control
Flex + Drive II only :
Setting the control mode to Position Control configures the Flex+Drive II as a full positioning
system, as shown in Figure 46. Here, the Flex+Drive
II
can be used to command many
different position profiles:
H
Preset moves
H
Absolute or relative moves
H
Incremental absolute or relative moves
H
Jog control
H
Following / Gearing
H
Homing
The profiler generates a position demand signal that smoothly changes between successive
targets. The profile also generates corresponding speed and acceleration demand signals.
The position and speed demand signals are fed into a position controller and used, together
with the position measured from the feedback device, to generate a suitable speed demand
signal. If the position controller is tuned correctly, the measured position will accurately track
the position demand.
The speed demand signal from the position controller is fed into the speed controller and used,
together with the speed measured from the feedback device, to generate a torque demand
signal. If the speed controller is tuned correctly, the measured speed will accurately track the
speed demand. To improve the tracking performance of the speed controller, the profiler
acceleration demand is fed in at this point.
Finally, the torque demand signal is fed into a torque controller, which determines the
appropriate amount of current to apply to the windings of the motor. This demand current is
compared with the actual winding current measured from sensors, and a suitable pulse width
modulation (PWM) signal is generated. This PWM signal is fed to the power electronics in the
drive.
Position
controller
Speed
controller
Torque
controller
Power stage
+ motor
Speed
demand
Torque
demand
PWM
Position
Speed
Accn
Profiler
Position
reference
data
Measured current
Measured speed
Measured position
Figure 46 - Control structure in Position control mode