User Manual

Table Of Contents
Motor Operating Features and Options
90 Advanced Digital Motor Controller User Manual V2.0, July 8, 2019
Forward and Reverse Power Adjustment Gain
This parameter lets you select the scaling factor for the power output as a percentage
value. This feature is used to connect motors with a voltage rating that is less than the
battery voltage. For example, using a factor of 50% it is possible to connect a 12V motor
onto a 24V system, in which case the motor will never see more than 12V at its input
even when the maximum power is applied.
Selecting the Motor Control Modes
For each motor, the controller supports multiple motion control modes. The controller’s
factory default mode is Open Loop Speed control for each motor. The mode can be
changed using the Roborun PC utility.
Open Loop Speed Control
In this mode, the controller delivers an amount of power proportional to the command
information. The actual motor speed is not measured. Therefore the motor will slow down
if there is a change in load as when encountering an obstacle and change in slope. This
mode is adequate for most applications where the operator maintains visual contact with
the robot.
Power Command
PWM
Motor
FIGURE 7-3: Open loop mode
Closed Loop Speed Control
In this mode, illustrated in Figure 7-4, an optical encoder (typical) or an analog tachometer
is used to measure the actual motor speed. If the speed changes because of changes in
load, the controller automatically compensates the power output. This mode is preferred
in precision motor control and autonomous robotic applications. Details on how to wire
the tachometer can be found in “Connecting Tachometer to Analog Inputs” on page 48.
Closed Loop Speed control operation is described in “Closed Loop Speed Mode” on page
133. On brushless motors, speed may be sensed directly from the motor’s Hall or other
internal Sensors and closed loop operation is possible without additional hardware.
Position Sensor
Gear box
Position Feedback
FIGURE 7-4. Motor with tachometer or Encoder for Closed Loop Speed operation