Operation
Theory of Operation
232 MagneMotion
Rockwell Automation Publication MMI-UM007F-EN-P - September 2020
For general transport and conveyance applications, cogging effects are not observable or per-
ceptible if the vehicle, track, and payload design do not exhibit a sharp resonance within the
0–30 Hz range. However, for payloads susceptible to vibration, these cogging effects can have
an impact and require special attention to suppress them. See Motor Cogging on page 71 for
installation methods to minimize cogging.
Motor Blocks
A motor block is a discrete motor section within each QuickStick HT motor as shown in
Figure 6-2 and Figure 6-3. Each block is a set of independently controlled copper windings
that are driven by one inverter, with multiple blocks creating the motor primary (stator). Each
of the copper windings has an iron core, which creates an attractive force between the magnet
array and motor even when the motor is not powered.
Block Acquisition
The drive for each motor takes ownership of vehicles when they enter the motor or are identi-
fied during startup and maintains that ownership the entire time the vehicle is on the motor.
Ownership includes identification of the final destination, maximum acceleration, and maxi-
mum velocity as defined in the current motion order and determination of the interim destina-
tion for the vehicle and current acceleration and velocity setpoints.
The drive makes sure that the vehicle has acquired sufficient empty blocks ahead of the vehi-
cle in the direction of motion to maintain brick-wall headway with the current motion profile.
The vehicle is said to own these blocks until they are released. Headway is maintained by
communicating with the motors ahead of the vehicle to make sure that sufficient blocks can be
acquired to define new interim destinations.
• The vehicle master uses the position of the most recently acquired block farthest from
the vehicle as an interim destination (target) to calculate the next profile setpoint (P
set
,
V
set
, and A
set
).
• A new interim destination (target) block is only granted if the block has not been allo-
cated to another vehicle (that is, permission is granted for only one vehicle per motor
block).
• A new target is requested only immediately before the vehicle must start slowing
down for its current target to minimize the number of committed blocks and to make
sure brick-wall headway is maintained.
• Permission to enter a motor block is only granted after the previous vehicle has exited
the block and released ownership.
• Each vehicle is controlled in such a manner that it is always able to stop in the last
motor block it was granted permission to enter.
To Next Page
Loading...
Need help?
General
