Attitude Control Schemes for the First Recovery Mission of India
- Paper number
IAC-07-C1.1.06
- Author
Dr. N.K. Philip, Control Systems Group, ISRO Satellite Centre, India
- Coauthor
Ms. Chinnaponnu S, Control Systems Group, ISRO Satellite Centre, India
- Coauthor
Mr. Natarajan P, Control Systems Group, ISRO Satellite Centre, India
- Coauthor
Dr. Agrawal V K, Control Systems Group, ISRO Satellite Centre, India
- Coauthor
Ms. Malik N K, India
- Coauthor
- Coauthor
Dr. E. Krishna Kumar, Indian Space Research Organisation (ISRO), Astronautical Society of India, India
- Year
2007
- Abstract
This paper describes the Attitude control schemes for the various phases such as Acquisition, on-orbit, orbit maneuver, and de-boost maneuvers and coast phases of the India’s first recovery mission Space Capsule Recovery Experiment-I (SRE-1). During the on-orbit phase, the SRE was configured to point the negative Roll axis to Sun. The attitude referencing of SRE was based on dry tuned gyros with updates using the attitude determined using on-board sun sensors and magnetometer. It was possible to hold the attitude to a fixed inertial orientation or to an orientation in which negative yaw axis pointed to deep space while the negative roll to the sun. The target orientation for the second case was determined on-board based on the satellite position vector and the sun vector. For attitude acquisition and attitude maneuvers, a set of 8 thrusters grouped in functionally redundant blocks were used. The same set of thrusters was configured in such a manner that they were providing the velocity correction for de-orbiting the module. The control scheme with thrusters was based on proportional derivative controller with a pulse width pulse frequency modulator (PWPFM). Based on the reference attitude quaternion (commanded or computed onboard) and the current attitude quaternion, the error quaternion was calculated on-board and fed to the controller. The required thrusters to be fired were based on the PWPFM outputs of the yaw, roll and pitch axes. In order to get micro-gravity environment during the on-orbit payload operations a linear quadratic regulator (LQR) based control scheme was designed to drive an orthogonal configuration of magnetic torquers which in turn produced three axis control torque with the interaction of Earth’s magnetic filed. In order to obtain the required precision on the impact point at touch down GPS aided navigation, closed loop guidance and control scheme was used for SRE-1. The navigation position and velocity output was used by the on-board guidance algorithm to generate the steering commands in terms of quaternions. The control system was designed to track the steering commands with tight tracking accuracy during the velocity reduction as well as during the costing phase. The casting phase of SRE was designed to ensure zero angle of attack at re-entry while maintaining the negative yaw axis toward deep space. The proportional derivative control scheme with PWPFM was used during the de-orbiting phase and the coasting phases. During the de-orbiting phase, in order to reduce the off-modulation in case of one thruster failure, a novel thruster failure detection, isolation and reconfiguration scheme was introduced. The detection scheme utilises the unique torque combination of all the 8 thrusters and based on the error biases the detection and isolation logic was designed. The logic for thruster failure in open and closed modes were designed separately. The performance of the all the control schemes for SRE-1 was excellent
- Abstract document
- Manuscript document
IAC-07-C1.1.06.pdf (🔒 authorized access only).
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