Study On Autonomous Attitude Guidance Algorithm Of Deep-Space Probe

To increase the mission autonomy, the concept of Attitude Guidance was brought up for modern deep-space probe, in addition to the traditional autono-mous attitude determination and control. This concept was universally utilized in recent year's deep-space probes.With the supports of the Tenth Five-Year 863 Program'Autonomy Technol-ogy of Deep Space Exploration and Its Simulation and Demonstration System', this dissertation studied the problem that how to transform the high-level task command of attitude system, which is determined by the probe's mission behav-ior, to the reference attitude motion input for controller, i.e. the problem of autonomous attitude guidance. This dissertation laid emphasis on the structurized calculation method for attitude motion driven by the pointing task events, and the problems that how to give a feasible reference attitude motion under internal and external constraints. The mathematical simulation with multiple system network-ing, and standalone semi-physical simulation of autonomous attitude guidance and control of the deep-space probe, was also realized.The main contents of this dissertation are as follows.A structurized attitude pointing algorithm based on target vectors, was con-structed in an event-driven manner. To handle the multiple pointing tasks and so-phisticated target motion during deep-space exploration, a related vectors hierar-chy for deep-space attitude guidance, and a vector propagation algorithm that is adapt to onboard utilization were built. At these basis, to solve the calculation versatility problem for reference attitude motion of various three-axis attitude definition, an analytic vector algorithm for each order reference parameters was given according to onboard navigation information and ephemeris services. To further reduce calculation cost, multiple computing cycles were defined. The output reference attitude command was used to realize the attitude tracking con-trol of reference attitude trajectory.A spatially attitude constraints monitor method was described, and an atti-tude pointing mode reconfiguration algorithm was proposed to solve the con-straints problem with stabilization pointing mode. Celestial geometric constraints, attitude kinematics, and dynamics constraints during deep-space exploration were studied and summarized. The constraints were then abstracted into several classes of spatial representation form. To solve the problem of auxiliary pointing constraint or kinematic singularity, the method of attitude space planning and hodograph envelope of rigid-body vector were used. This achieved the justifica-tion of attitude pointing mode along with the satisfaction with primary pointing task. Several representative pointing modes were selected to make specific calcu-lation and kinematics analysis.Pre-planning method based on state-space search for attitude maneuver un-der complex constraints was studied. To the attitude maneuver suffering from multiple constraints in time-varying space environment, especially to the exter-nally celestial geometric constraints that are more prominent in deep-space envi-ronment, the autonomous global planning of attitude maneuver was engaged from these aspects: global planning, dynamic constraints accommodation, in-crease of computational efficiency, and optimization of the feasible solution. De-scribe attitude path and constraints boundary in Rodrigues parameters space. The problem is then transformed to a motion planning problem of point robot. A sim-plified attitude guidance law for Euler-rotation planning was designed. And the feasible path was obtained by using RRT algorithm to perform random search of path node. Finally, the path was optimized in the parameters space according to evaluate the cost of maneuver.Lastly, combining with'Autonomy Technology of Deep Space Exploration and Its Simulation and Demonstration System', designed an autonomous attitude control system scheme for deep-space probe, and constructed the autonomous attitude mathematical simulation subsystem based on MATLAB/Simulink, real-ized multisystem united simulation and 3-dimensional visualizing demonstration for flight process of deep-space exploration. By the semi-physical real-time con-trol simulation platform based on MATLAB/Simulink/dSPACE, the real-time performance of the proposed calculating method of reference attitude command is confirmed by merotype attitude control simulation.