Elmo HARSFEN0602, HARmonica software manual 161, Xt = 10000 ⋅ cos2πt + ct

HARSFEN0602ElmoHARmonicaSoftwareManual PRELIMINARYDRAFT

Example:

This example illustrates working on a moving object. Consider the application depicted below:

Moving conveyer

Circle to

draw

10000	axis
	Y

Cake

X axis

161

In this application, an x-y stage draws a chocolate picture on a cake while the cake travels on a conveyer.

The drawing has to be accurate with respect to the cake.

In order to draw a circle of radius 10000 encoder counts on the cake in one second, the x- axis motor must follow the trajectory

x(t) = 10000 ⋅ cos(2πt) + c(t)

Where c(t) is the position of the conveyer. If the conveyer has an encoder, we can use the conveyer encoder to compensate its motion. Suppose that the resolution of the conveyer encoder is similar to the resolution of the x-axis encoder.

For drawing an exact circle on the moving cake, we program the motion 10000 ⋅ cos(2πt) as PVT, and set RM=1, FR[3]=1.

	4
x 10
4		x motor motion command
3	Conveyer position, as measured
	by the auxiliary encoder input
2
1
0		x motion
		relative to cake
-1				Time (sec)
0	0.2	0.4	0.6	0.8	1