Specifications

Chapter 2 Functions
- 13 -
Chapter 2 Functions
2-1 Control system of the HA-655 driver
It is said that [plan, do, see] is essential to perform perfect
jobs. In other words, the [plan, do, see] is the repeating
cycle of command→action→result→feedback→modified
command → action → feedback →・・・・.
Driving machines precisely requires the same control as
the above job cycle, that is [Motion command→run→
feedback→modified command→・・・・].
For example, assume the required motion is rotation to a
target angle and stopping there. To perform the motion,
the motor must be equipped with an angular sensor to
detect a current position, and the position data must be
compared with the command. If the position data is
different than the command, the motor rotates until the
position data becomes equal to the command. This is an
example of a position servo system.
The speed control system is the same. The motor is
equipped with a speed sensor and the speed is compared
with the speed command. If the speed is different from the
command, the motor accelerates or decelerates until the
motor speed becomes equal to the command. This is an
example of the speed servo system.
The HA-655 driver realizes above both controls of position and speed with the same unit.
The fundamental configuration of servo system of the HA-655 driver is as follows:
The HA-655 driver function is consists of three parts: the position control block, the speed control block,
and the power amplifier.
In the position mode, a command position from a host is compared to a feedback position. If there is a
difference between them, the position control block commands the power amplifier through the speed
control block to flow current to the actuator until there is no difference.
In the speed mode, a speed command is directly inputted to the speed control block. The speed block
compares the command and current feedback speed. If there is a difference between them, the speed
control block commands to the power amplifier flow the current to the actuator until there is no
difference.
The HA-655 driver allows two types of encoder as a functional member of the feedback system,
optionally: an incremental encoder or an absolute encoder.
HA-655 driver
Position
command
Position
control block
Speed feedback
Actuator
Speed
control block
Speed
command
Position feedback
Driven machine
Encoder
Power
amplifier
Plan Do See
Perfect job cycle
Feedback
Com. Run Result
Feedback
Precise motion control