Atmospheric Single-Arm Robot
Adjustments and Calibration
User’s Manual
Tuning PID Motor Parameters
Brooks Automation
Revision 1
7-9
Tuning PID Motor Parameters
This procedure helps you set the PID parameter tuning for any robot and track system
with a servo motor. While the robot goes to the commanded position, its motion is
controlled by a number of parameters. If the parameters are not tuned properly, there
is unwanted movements in the robot or the robot stops suddenly.
Several factors affect the motion of the robot. Among them, PID factors are the most
significant ones.
The PID filter is a combination of three functions.
KP
is the proportional element (KP) of the filter and acts as gain. GN is Brooks Auto-
mation’s equivalent command.
KI
is the integrator function (
KI
) represented by the parameter
KI.
It improves the sys-
tem accuracy. With the
KI
parameter, the motor does not stop until it reaches the exact
desired position, regardless of the level of friction or opposing torque. The integrator
also reduces or decreases the system stability. Brooks Automation uses the same com-
mand,
KI
.
KD
is the damping element (
KD
) of the filter. It reduces the delay associated with the
motor response. The delay in the servo system is between the application of the cur-
rent and its effect on the position. Brooks Automation uses the
ZR
command.
After you set up the system, you need to tune PID.
To tune the PID
1.
Set
KI
to 0.
2.
Set
KP
(
GN
) to 1.
3.
Set
KD
(
ZR
) to 100. (
KD
maximum = 4095)
Brooks
Commands
Galil
Commands
Property
GN
KP
Proportional gain
KI
KI
Integrator
ZR
KD
Damping (or Derivative)
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