RoboteQ AX2850 - Manual (Page 43)

AX2550 Motor Controller User’s Manual 43
Selecting the Motor Control Modes
Closed Loop Speed Control
In this mode, illustrated in Figure 18, an analog tachometer or an optical encoder (AX2850
only) 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 64.
Closed Loop Speed control operation is described in “Closed Loop Speed Mode” on
page 97.
Close Loop Position Control
In this mode, illustrated in Figure 18, the axle of a geared down motor is coupled to a
potentiometer that is used to compare the angular position of the axle versus a desired
position. This AX2550 feature makes it possible to build ultra-high torque “jumbo servos”
that can be used to drive steering columns, robotic arms, life-size models and other heavy
loads. Details on how to wire the position sensing potentiometers and operating in this
mode can be found in “Closed Loop Position Mode” on page 85.
Controller
FIGURE 16. Effect of commands to motors examples in
mixed mode
FIGURE 17. Motor with tachometer or Encoder for Closed Loop Speed operation