HTMod2

Status

Completed
Status date

2017-05-04
Activity Code

4C.036

Objectives

In the frame of the contract 4000110670/14/NL/US a 100 Volt High torque Wheel Drive Electronic with analogue interface for a Reaction Wheel was qualified. The design and qualification file was submitted for approval.

In the frame of this qualification, which was performed on Reaction Wheel Assembly level, several features of the heritage wheel drive electronics were improved and qualified. For example, on parts level the European N-channel MOSFETs have been validated and qualified in the Reaction Wheel Assembly. A new ESA-qualified PCB-supplier has been selected and qualified in the Reaction Wheel Assembly. The most stringent mechanical environmental conditions for the Reaction Wheel Assembly have been successfully qualified in the frame of this contract.

The qualification of the Reaction Wheel Assembly RSI 50-220/451 was successful and is now the baseline for the 100 Volt Off-The-Shelf Reaction Wheel Product Line at Rockwell Collins Deutschland GmbH.

Challenges

During preparation and performance of the Shock Test it was recognized that the specified shock levels were very challenging to be met by the test house. For future Shock Test campaigns, RCD will consider a test set-up and/or test house change in order to avoid not meeting the specification.

Driven by the design of the reaction wheel some tests were sensitive to the non-preferred “structure return” test set-up and few NCR’s were raised. As lessons learnt, RCD has drastically improved the test set-up descriptions to avoid re-test campaigns in the future.

Benefits

With this successful qualification campaign of the RSI 50-220/451 RCD has established a Reaction Wheel Assembly with a 100 Volt high torque WDE analogue interface as an off-the-shelf product which benefits all satellite manufacturer’s using a 100 Volt bus supply.

Features

The RSI 50-220/451 is a ball bearing momentum / reaction wheel for cw and ccw operation which has its control electronics completely contained within the wheel housing.

The RSI 50-220/451 provides an angular momentum storage capacity of 50 Nms and a nominal motor torque of  220Nmm in the speed range from +4500rpm to -4500rpm. The main dimensions of the RWA are 347mm diameter and (max.) 124mm height. The total mass is less than 9,5kg.

The following list presents the design features of the WDE:

Lightweight electronics integrated in the wheel housing
Supply voltage: 100 VDC
Current injection onto the power bus during wheel braking for high efficiency
Power consumption: < 20 W at nom. speed/steady state;
Interface isolation > 10kΩ for the telemetry signals (i.e. speed measurement (tacho puls-es), motor current, speed direction and status ON/OFF)
Interface isolation > 10kΩ for the telecommand signals (i.e., torque command and torque direction)
Two thermistor interfaces for bearing and electronics temperature monitoring
Over-speed, overvoltage and overcurrent limiter

Current status

A qualification test has been performed with a reaction wheel assembly of the type RSI 50-220/451 including functional tests at room temperature and at temperature extremes as well as sine and random vibration tests, a shock test, an EMC test and a microvibration test.