Distance Tracking Accuracy

For the accuracy achieved by this function, see the after mentioned experiment results.

However, the accuracy of the distance tracking function may differ depending on the robot model, speed, and workpiece shape.

Experiment conditions

• Robot: Vertical 6-axis robot C4L
• Laser displacement meter: 2 types (see table below for specifications)

	Medium speed/medium accuracy laser displacement meter	High speed/high accuracy laser displacement meter
Measured distance (mm)	20 to 30	7.2 to 8.8
Spot diameter (um)	Approx. 25×1200	Approx. ⌀20
Repeatability (um)	1	0.02
Sampling cycle	0.33, 1, 2, 5 ms (4 levels available)	20, 50, 100, 200, 500, 1000 us (6 levels available)
Light source (Laser class)	Class 2	Class 1

Experiment environment

Start point and target point have been taught in advance.

• Without the distance tracking function: Robot moves in a straight line from the start point to the target point.
• With the distance tracking function: The robot moves on a trajectory to keep a constant distance to the workpiece like the blue arrow (robot trajectory) shown in the above figure.

Experiment results

Values of the distance tracking accuracy are the width of variations in the distance measured values between the start point and end point of the distance tracking function. Two types of the laser displacement meter are used. (See the tables below for the experiment results.)

Distance tracking accuracy of medium speed/medium accuracy laser displacement meter

Robot SpeedS(mm/s)	Robot AccelS(mm/s*s)	Workpiece tilt (mm)
		5 deg.	10 deg.	15 deg.
10	100	±0.03	±0.04	±0.06
30	300	±0.06	±0.09	±0.14
50	500	±0.09	±0.15	±0.32
100	1000	±0.15	±0.30	±0.48

Distance tracking accuracy of high speed/high accuracy laser displacement meter

Robot SpeedS(mm/s)	Robot AccelS(mm/s*s)	Workpiece tilt (mm)
		5 deg.	10 deg.	15 deg.
10	100	±0.02	±0.04	±0.05
30	300	±0.04	±0.06	±0.13
50	500	±0.06	±0.11	±0.20
100	1000	±0.13	±0.20	±0.35