Centre of Gravity measurement unit WR12
General Description
The purpose of the WR12 facility is the measurement of the CoG coordinates of a test object (mostly at unit-level) up to 40 kg object mass.
The principle of the machine is based on the balancing of a table, which has one degree of freedom: the tilting about a horizontal axis.
The test validates the prediction of the physical properties of the test object, which is of great importance for the attitude control of the spacecraft. The test object is installed on the mounting table. The unbalance is induced by the position of the CoG of the object with respect to the tilting axis of the table.
The unbalance is compensated by a combined effect of:
- A movable counterweight of a given mass
- A set of masses (depending on the test object's properties) to be applied at a given distance from the horizontal axis.
The facility has a L-shape adapter device for measurements to be performed with the test object axis in horizontal position.
Mechanical Interface
The mechanical interface with the test object
is a circular horizontal stainless steel table with:
The mechanical interface with the test object
is a circular horizontal stainless steel table with:
Diameter 250 mm
12 x M8 threaded holes on 2 concentric circles (125 mm and 200 mm PCD)
Centring hole 25 mm H7 (to centre the test object)
An additional square I/F plate (330 mm x 330 mm) can be installed. A hole patterns can be drilled in this plate according to the specific I/F requirements of the test object.
TECHNICAL PARAMETERS
Description
Test object mass (nominal capacity) [kg]
40
Test object diameter (max) [mm]
600
Situated in class 100 000 clean room area (FED-STD-209)
Allowable overload [kg]
< 63
Accuracy [mm]
± 0.5/M, with M=mass test object in kg
Accuracy limit [mm]
± 0.1