Quanser 6 DOF Hexapod Laboratory Manual page 20

Figure 2.15: QUARC blocks used to interface to Hexapod actuators and sensors
The Hexapod IO API \Hexapod IO subsystem, shown in Figure 2.16, interfaces Hexapod position controller to the
the hardware I/O explained above. For instance, it converts the encoder counts to joint linear position (i.e., multiplied
by the encoder resolution and motor shaft circumference constant). Based on the force computed by the Hexapod
controller to reach the desired position, denoted as F , this subsystem computes the current required for the amplifier
drives (see Section 3.2 for the force to current conversion).
The current is converted to the PWM signals required. The PWM magnitude is applied to the QUARC HIL Write
block on PWM Channels #0 to #5 and the PWM direction is applied to DO Channel #0 to #5. Note that current
commands are saturated according the configured amplifier limits to help prevent the motors or amplifier drives from
over-heating (see Hexapod User Manual [2] for current limit specifications).
Figure 2.16: Hexapod IO subsystem
HEXAPOD Laboratory Guide 20