Optimal Guidance Command Generation and Tracking for Reusable Launch Vehicle Reentry (Preprint). - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Optimal Guidance Command Generation and Tracking for Reusable Launch Vehicle Reentry (Preprint). write by . This book was released on 2006. Optimal Guidance Command Generation and Tracking for Reusable Launch Vehicle Reentry (Preprint). available in PDF, EPUB and Kindle. The objective of this work is to develop a robust guidance and control architecture for autonomous reusable launch vehicles that incorporates elements of recent advances in the areas of optimal trajectory generation and reconfigurable control. This work integrates three separately developed methods to form a coherent architecture with the potential to manage control effector failures, vehicle structural/aerodynamic degradation, uncertainty, and external disturbances. Outer-loop guidance commands in the form of body-frame angular rates (roll, pitch, and yaw) are generated from an optimal reference trajectory that is computed off-line with a direct pseudospectral method and then tracked by a reconfigurable inner-loop control law. The appropriate open-loop state histories from the pseudo-four-degree-of-freedom reference trajectory are converted using a modified backstepping approach that complements the inner-loop control law in a six-degree-of-freedom simulation. The inner-loop control law is capable of reacting and compensating for off-nominal conditions by employing nonlinear reconfigurable control allocation, dynamic inversion, and model-following/anti-windup prefilters. The results show that the inner loop control can adequately track the desired optimal guidance commands; thus, confirming that applicability of this control architecture for future development involving on-line, optimal trajectory generation and high-fidelity guidance and control for reentry vehicles.
Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT).
Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT). - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT). write by . This book was released on 2006. Optimal Guidance Command Generation and Tracking for the Reentry of a Reusable Launch Vehicle (PREPRINT). available in PDF, EPUB and Kindle. In this work, optimal outer-loop guidance commands are generated from an off-line reference trajectory and then tracked by a reconfigurable inner-loop control law. The primary motivation for this work is a "stepping-stone" towards online, optimal trajectory generation, footprint determination, and retargeting capabilities in the presence of control effector failures or vehicle structural/ aerodynamic degradation, uncertainty, and external disturbances. The presented guidance and control architecture uses a 6-degree-of-freedom simulation and an inner-loop controller to track body-name angular rates (roll, pitch, and yaw), generated from an optimal psuedo-4-degree-of-freedom reference trajectory that is computed using a direct pseudo spectral method. The innerloop control law is capable of reacting and compensating for off-nominal conditions by employing its nonlinear control allocation, dynamic inversion, and model-following/anti-windup prefilters. The results show that the inner-loop control can adequately track the desired optimal guidance commands; thus, confirming the applicability of this control architecture for future development involving on-line, optimal trajectory generation and high-fidelity footprint determination for reentry vehicles.
Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles
Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles write by Patrick J. Shaffer. This book was released on 2006. Fault Tolerant Optimal Trajectory Generation for Reusable Launch Vehicles available in PDF, EPUB and Kindle. Reconfigurable inner-loop control laws improve the fault tolerance of a vehicle to control effector failures; however, in order to preserve stability, the unfailed effectors may be deployed to off-nominal positions to compensate for undesirable perturbations caused by the failed effectors. The effectors acting under the influence of a reconfigurable control law can produce significant perturbations to the nominal forces produced by the wing and body and can also affect the range of flight conditions over which the vehicle can be controlled. Three degree-of-freedom (3 DOF) dynamical models used in trajectory optimization for aerospace vehicles typically include wing-body aerodynamic force effects but ignore the aerodynamic forces produced by the control surfaces. In this work, a method for including these trim effects as well as control induced trajectory constraints in a 3 DOF model is presented.
High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles
High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles write by Kevin P. Bollino. This book was released on 2006. High-Fidelity Real-Time Trajectory Optimization for Reusable Launch Vehicles available in PDF, EPUB and Kindle. Creating simplicity out of complexity, this research abandons the traditional guidance and control architecture for aerospace vehicles and embraces a revolutionary concept based on the principles of nonlinear optimal control theory. Motivated by the emerging needs of the next generation of reusable space vehicles, an autonomous integrated guidance and control system is developed that provides a safe approach to the highly constrained and nonlinear reentry problem. A pseudospectral-based optimal guidance scheme is used to generate high-fidelity, vehicle-tailored solutions to reentry trajectory optimization and guidance problems. To provide an autonomous, onboard capability of satisfying final-approach requirements, a new method is developed that includes an automatic generation of landing constraints given any runway geometry. This unique and simple approach avoids significant complexities arising from previous ideas of trajectory segmentation, trimmed flight, and trajectory tracking schemes. When demonstrating the new ideas, it is shown that the proposed approach can easily compensate for large uncertainties and disturbances consisting of hurricane-force wind gusts. An investigation of these new principles for the complete, nonlinear six degree-of-freedom system dynamics indicates that while the results are quite promising, a substantial amount of new theoretical and computational problems remain open, particularly in the area of over-actuated dynamical systems.
Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases
Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases write by Kenneth R. Horneman. This book was released on 2010. Automated Trajectory Generation and Guidance for a New Launch Vehicle Flight Phases available in PDF, EPUB and Kindle. Much effort has been put into developing technologies for next generation re-usable launch vehicles. Fully re-usable launch vehicles include a booster stage that is designed to land, usually near the launch site, after it has released the upper-stage, which continues to orbit. The fuel reserve needed to turn the booster stage around will usually be minimal For this reason, once the booster stage has completed a rocket-back maneuver, it will typically be at a high altitude (exo-atmospheric) but with low kinetic energy and a steep flight path angle on re-entry. Traditional re-entry guidance is designed for vehicles with a high velocity, and shallow flight path angle, and thus these traditional approaches are not appropriate for a low energy re-entry (LOER). The current research presents a set of guidance algorithms that will successfully guide a vehicle to landing starting from LOER condition. The guidance algorithms are designed to ensure the vehicle can achieve near optimal range performance when required and also to execute a sharp pull-up maneuver that balances the load factor constraint against the need to pull-up quickly before the dynamic pressure constraint is exceeded. The guidance approach has been tested for a wide variety of vehicles and mission scenarios, including more traditional initial conditions that would occur at the end of a High Energy Re-entry (HIER) from orbit. Thus, the guidance approach we have developed can be used as a more robust version of Terminal Area Energy Management (TAEM) guidance, as well as for LOER and has been tested for a wide range of vehicles, including the Space Shuttle and vehicles with a wide variety of L/D capability. Significant development has also gone into the engineering considerations needed to implement the guidance algorithms on a real vehicle. Program execution time, application of vehicle constraints, trajectory repeatability and other factors are all addressed in order to meet this need.
