Analysis of control accuracy in the final phase of the rendezvous between the Automated Transfer Vehicle and the Space Station Freedom
Abstract
The Automated Transfer Vehicle (ATV) is an expendable unmanned vehicle launched by Ariane 5. The ATV's reference mission is to support the Space Station Freedom (SSF). The ascent part of the ATV's mission is to reach a given berthing point next to the SSF, within required accuracies. The vehicle must be able to hold this position in order to be grappled by the SSF's robotic arm. With the SSF's monitoring and authorizations, the ATV is designed to be able to achieve automatic rendezvous operations within the SSF's manned environment. During the final approach, the ATV's motion is a forced translation parallel to the SSF velocity axis. The control accuracy, estimated around this reference trajectory, is a key parameter for respect of safety requirements, and the purpose for this paper. After a brief description of the ATV's reference mission, we will focus on the last 100 meters of the rendezvous between the ATV and the SSF. We will begin by describing the modeling principles and the simplifying assumptions used to obtain a dynamic model for the relative distance between the ATV and SSF berthing points. The principles of the ATV rendezvous optical sensor and thruster architecture will also be discussed. The design of a control aimed at maintaining the reference trajectory will next be considered along with the effects of measurement and modeling disturbances, noise as well as bias, on the control accuracy. The results demonstrate that the accuracy achieved around the reference trajectory remains compliant with the berthing requirements and would even allow direct docking if needed.
- Publication:
-
NASA STI/Recon Technical Report A
- Pub Date:
- 1993
- Bibcode:
- 1993STIA...9585809C
- Keywords:
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- Accuracy;
- Command And Control;
- Orbit Transfer Vehicles;
- Rendezvous Guidance;
- Rendezvous Trajectories;
- Space Station Freedom;
- Dynamic Models;
- Error Analysis;
- Mission Planning;
- Optical Measuring Instruments;
- Velocity Distribution;
- Launch Vehicles and Space Vehicles