ADLINK PCI-8258 - Manual (Page 150)

136 Motion Control Theory
4.8 Interpolation
Interpolation is a multi-axes locus movement based on given locus
properties, e.g. center of circle and end point, and velocity data.
The controller then calculate relations between path and time. Axis
involved in interpolation start up at the same time and end at the
same time after operation completed.
This controller supports couple of interpolation including straight line
interpolation of any 2~6 axes, arc interpolation of any 3 axes and
spiral interpolation of any 3 axes.
The interpolation usually requires two or more axes to complete.
Required axes are assigned by array input. Here the axes array is
defined by assuming the first axis ID to be the reference axis.
Axis parameters of the reference axis is used as the basis for
setting up speed profiles of interpolation while settings of speed
profile are all in vector (composite). Take example. To execute a 2
axes straight line interpolation by Axis 1 and Axis 2, the axis ID
array can be declared as described below. In example below, the
first axis ID in axes_array is Axis 1. Then the interpolation
movement required initial speed, maximum speed, ending speed,
and acceleration rate are all set up relative to axis parameters of
Axis 1. If Axis 2 is the first element in axes_array then Axis 2 is the
reference axis.
I32 axes_array[2] = { 1, 2 };
Sections below describe straight line, arc, and spiral interpolation
mechanism and operation and followed by continuous interpolation.
4.8.1 Linear Interpolation
This controller supports up to six axes straight line interpolation.
After the straight line interpolation command is received, all
relevant axes start up at the same time and move according to
specified (relative or absolute) position, speed, and acceleration
profiles, all relevant axes stop concurrently. The speed profiles are
set by synthetic vector.
Assume you want to make a N (N=2~6) axes straight line
interpolation with offset of each axes represented by ΔX0,ΔX1…
ΔXN-1 then the synthetic shift ΔP shall be: