The Attitude Control Test Bed is an on-going project and has been built up and used in several of our student projects and Space Grant Fellowship projects. This test bed allows attitude determination and control algorithms to be written and tested in a simulated magnetic and near frictionless environment. The test bed comprises three major student project efforts:
This cage allows us to tune and manipulate the magnetic field within its volume. One use is to effectively cancel out the Earth’s magnetic field for tuning and characterization of sensors. The magnetic field can be easily increased to three times the Earth’s magnetic field to greatly increase the torque provided by magnetic attitude actuators.
Any sensors, actuators, and control pieces used on in the test bed must be put on a platform. After final parts placement and securing wiring, the platform can then be neutrally balanced to allow for 3-axis attitude control. This is often a tedious and time consuming process, but provides for the most flexibility in attitude control options. We plan to have a future student project to automatically balance the platform, thus simplifing modifications.
Hemispherical Air Bearing
Our air bearing is a highly accurate, near friction-free precision instrument. Spherical air bearings are commonly used for zero-g satellite research, and they have also been used in systems for precision chip bonding and optical alignment. This bearing is capable of providing excellent load capacity and stiffness while allowing three axes of inherently frictionless rotational motion. Its features include:
- Freedom of rotation in 3 directions
- Center of rotation stability of ±5 millionths of an inch
- Range of motion up to +/- 45 degrees in two axes, 360 degrees along third axis
- Load capacity from 1 lb to 450 lbs
- Operating pressure from 10 psi to 90 psi
- Constructed out of black hard-coat Anodized Aluminum
The combination of these three items allow us to perform attitude control testing in an environment which simulates operation in space. This test bed will be continuously upgraded as more students pass on lessons learned, and new students advance the implementation.
In 2014, we installed a new state-of-the-art Attitude Determination and Control System Test Bed (ADCSTB) in the clean room. The new test bed incorporates the features seen above, but with high precision features, and will be targeted toward satellites undergoing its final flight validation.