A computer program calculates an optimal allocation of control effort in a system that includes redundant control actuators.
The program implements an iterative (but otherwise single-stage) algorithm of the quadratic-programming type. In general, in the quadratic-programming problem, one seeks the values of a set of variables that minimize a quadratic cost function, subject to a set of linear equality and inequality constraints. In this program, the cost function combines control effort (typically quantified in terms of energy or fuel consumed) and control residuals (differences between commanded and sensed values of variables to be controlled). In comparison with prior control-allocation software, this program offers approximately equal accuracy but much greater computational efficiency. In addition, this program offers flexibility, robustness to actuation failures, and a capability for selective enforcement of control requirements. The computational efficiency of this program makes it suitable for such complex, real-time applications as controlling redundant aircraft actuators or redundant spacecraft thrusters. The program is written in the C language for execution in a UNIX operating system.
This program was written by Gurkirpal Singh of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free online at www.techbriefs.com/tsp under the Software category.
This software used in this innovation is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (818) 393-2827. Refer to NPO-40592.
This Brief includes a Technical Support Package (TSP).
Quadratic Programming for Allocating Control Effort
(reference NPO-40592) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA, specifically focused on "Quadratic Programming for Allocating Control Effort" (NPO-40592). It serves as a comprehensive resource for understanding the Control Allocation Problem (CAP) in six degrees of freedom (6-DOF) control applications, which is critical in aerospace and robotic systems where multiple actuators are used to achieve desired motion and control.
The document is structured into several key sections. It begins with an introduction that outlines the significance of the CAP and its relevance in various applications. The second section delves into the specifics of the CAP, discussing the challenges associated with distributing control efforts among redundant actuators while ensuring optimal performance and adherence to constraints.
A major focus of the document is the solution to the CAP, which is presented in a geometric context. This section includes a detailed algorithm designed to efficiently allocate control efforts, along with an analysis of the computational complexity involved in implementing the solution. The algorithm is particularly noteworthy as it integrates different types of force actuators, such as Pulse Width Modulation (PWM) and Pneumatic Artificial Muscles (PAM), into a unified framework, enhancing its applicability across various systems.
The document also provides examples that illustrate the practical application of the proposed methodologies, showcasing how the algorithm can be utilized in real-world scenarios. These examples serve to clarify the theoretical concepts and demonstrate the effectiveness of the approach in solving complex control allocation problems.
In summary, this Technical Support Package not only presents a robust framework for addressing the CAP but also emphasizes the importance of optimal control in systems with redundant actuators. It highlights NASA's commitment to advancing aerospace technology and making these innovations accessible for broader technological, scientific, and commercial applications. The document concludes with references and an appendix, providing additional resources for further exploration of the topic.
Overall, this document is a valuable resource for researchers and practitioners in the field of control systems, offering insights into advanced methodologies for control effort allocation and the potential for future developments in aerospace technology.
