RDS Control Panel
H000002007-RDS User Manual
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Version 5.0.0 (2018-09-17)
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D.8.1
REMINDER: THEORY ABOUT MOVING A MEASUREMENT DEVICE
To move the arm from one place to another one, Leap-Frog is using a script in RDS Data Collector: click
on “New”, RDS Data Collector appears, executing automatically a Leap-Frog script.
During a measurement, both parts that are the measurement system and the part to measure must be
imperatively interdependent from each other, that means any displacement is forbidden.
When the part to be measured is larger than the measurement device can do, it becomes necessary to find
a way to move one (arm or part) to be able to measure the inaccessible zone.
That means moving « without moving », having a perfect knowledge of the movement done (distance,
orientations, offsets…)
Technically, such a displacement is a reference change (from a system of axes N°1 to a system of axes
N°2), the start (Ref N°1), is then Machine reference. (RM).
To allow the software to know this displacement in all details, we use elements that will be accessible from
both positions of the measuring device: those elements measured from both positions, the software
comparing them, will calculate a displacement « matrix »: displacement in X, Y and Z, of the origin point,
and each rotation it underwent between both positions (along X, Y and Z).
Overlap points
The displacement method consists by an « Overlap » method, using geometric elements, probed identically
from both positions.
Depending on the accuracy of the measurement device, this displacement will necessary generate a loss
of accuracy, as it results from two measurements of the elements.
To minimize this lost, it is important to optimize the method. Here are the main rules:
Use the most accurate measurement device
Look for the positions of the measurement device as to have a lap area (accessible from both positions) as
large as possible, as to « stabilize « as best as possible the displacement. (as the 4 feet of a table are on
each extremities of the table, not at the centre).
Use a maximum number of elements (geometric elements used for this Leap-Frog) (a table is more stable
on 4 feet than on 3).
Use good quality elements (a machined bore will be much better than a tapping not clean).
The type of elements used will define the calculation method used by the software.
« Leapfrog » name is often used.
NB: moving the measurement device or moving the part comes to the same thing
RM
Pos2
P 1
P 2
