Attitude control law design for moving mass control reentry vehicle based on sliding mode
Due to issues of aerodynamic ablation, complicated mechanical environment and serious nonlinear dynamics, the control system is difficult to achieve high accuracy. For nonlinear dynamics of moving mass control reentry vehicle, a design method based on sliding mode for pitch-yaw channel attitude control is proposed, which improves control accuracy and anti-disturbance capability. According to a reentry vehicle attitude control system, the pitch-yaw channel dynamic model of the nonlinear system is firstly given. Secondly, designed by using backstepping theory, a sliding mode controller with approach law is proposed. Besides, in order to reduce chattering of sliding mode control, an improved sliding mode controller is presented, in which relay characteristics is replaced with continuous functions. Finally, simulation results demonstrate the validity and feasibility.
The Research on Control System Design Method for Reentry Aircraft under Moving Mass/RCS Compound Control
The moving mass control is of benefit to reentry aircraft in shape maintenance,energy consuming reduction and load capability increase,but is sometimes inefficient to meet system performance requirement due to the highly relying on aerodynamic force,which is without other control systems combined.In this paper,a whole-airspace high-capability control system design for a reentry aircraft under moving mass/RCS compound control is proposed,which is based on the control capability analysis of the moving mass control system.According to the analysis results,the dynamic pressure and attack angle departure are used to be logic decision variables of the compound control mode and a moving centroid/RCS compound controller including a virtual controller and a moment allocation controller is developed.Two groups of simulations for a typical reentry aircraft achieving designed maneuver trajectory by tracking command attack angle are implemented to present the compound control capability in the whole reentry flight and show the advantages of the compound control compared with either of the control systems.The simulation results demonstrate the validity of proposed compound control mode and the high capability of the controller designed.
RIP - General Purpose Interactive Display at HHIRF
RIP is a general purpose interactive code for display and analysis of data acquired with the Holifield Heavy Ion Research Facility (HHIRF) accelerators at Oak Ridge National Laboratory. The HHIRF data acquisition system includes a version of RIP for on-line display of one-and two-dimensional histograms on color graphic terminals and hard copy on color printer/plotters. General features of the program and interactive techniques will be described.