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Miniature Integrated Stepper Motor Controller(
which is not described in the above figures though. Please note that for the non-linear
acceleration/deceleration, as there are knee points in its trajectory, is not suitable for
applications requiring motion smoothness. In this case, user can set the maximum start
speed
and
acceleration/deceleration. This process is shown in figure 7-11.
Figure7-11: S-curve Displacement Control (case 3)
Speed
Max. Start Speed
Angular
Displacement
Stop Position
Start Position
7.6 Direction Control and Position Counter
When the user enables the advanced motion control module, the actual motor direction is
controlled by the module. This is because if the user input commands a motion direction
different from the current motion direction, the desired direction cannot be executed
immediately.
UIM2842 has two types of position counters: absolute position counter and displacement
counter.
Absolute position counter is used for recording the absolute position of motor. The actual
angular displacement is also relative to micro stepping. The value recorded in absolute
position counter will be stored automatically on Power Failure situation and can only be
cleared on user instruction or preset sensor event. The counter will increase or decrease
according to ICFG.CWW and the actual direction of motor. Absolute position counter value
can be read through POS instruction.
Displacement counter is mainly used for displacement control. The former information is
cleared when it receives a new displacement instruction. It can also be used to record the
displacement since last time it was cleared.
7.7 Backlash Compensation
Backlash is a ubiquitous matter for mechanical system (e.g.: screw nut transmission or
gear rack transmission). For example, there is a gap between screw and nut, once the
UI Robot Technology Co. Ltd.
maximum
cessation
Uniform Accelaration
Trajectory
Knee point
M4220170607EN
speed
at
zero
Desired Speed
Closed-loop
to
disable
non-linear
Uniform Deceleration
Max. Cessation Speed
T（Time）
Knee point
T（Time）
)
Page 39
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