User`s manual

5-29

Functions

5. Functions

5.9.3 Adjusting the position control loop

(1) Parameter constants used for position control

Parameter constants used for position control are described below.

(a) Position control cut-off frequency (Fd-09)

This parameter constant determines the response of the position control loop.

Setting Fd-09 to a high value improves the response and shortens the positioning

time.

Note 1: Robot might oscillate if the Fd-09 setting is too large.

(b) Speed control cut-off frequency (Fd-01)

This parameter constant determines the response of the speed control loop. Set it

within a range where no mechanical vibration occurs. Setting to a high value

improves the response. If the "Mover mass" (Fd-00) of the mechanical system

(including robot) was set correctly, then the speed control cut-off frequency is

largely equivalent to the value set in Fd-01.

The speed PI control proportional gain is automatically determined according to

the "Speed control cut-off frequency" (Fd-01). However, fine adjustments to the

speed PI control proportional gain can be made by setting Fd-02.

(d) Speed PI control integral gain (Fd-03)

The speed PI control integral gain is automatically determined according to the

"Speed control cut-off frequency" (Fd-01). However, fine adjustments to the speed

PI control integral gain can be made by setting Fd-03.

Note 1: Robot might oscillate if the Fd-03 setting is too large.

(2) Adjustment method

1. Set the "Position control cut-off frequency" (Fd-09) somewhat low, and set the

"Speed control cut-off frequency" (Fd-01) in a range where no abnormal noise or

oscillation occurs.

2. Set the "Position control cut-off frequency" (Fd-09) to a large value in a range where

overshoot and vibrations do not occur. As a general guide, set to 1/6th or less of the

"Speed control cut-off frequency" (Fd-01).

3. Lastly, fine-adjust the "Speed PI control proportional gain" (Fd-02) and "Speed PI

control integral gain" (Fd-03) while monitoring the settling characteristics and

movement, and search for the optimal point.