Robust Nonlinear Control: Feedback Passivation and Input Saturation Techniques

9972045Lin非线性反馈设计提供了利用真正的非线性效应的潜力，例如，使用小控制来诱导大效应。本建议的目的是开发理论上合理的，实际上有用的基于无源性的低增益和低增益和高增益控制方法，用于设计反馈控制器，实现全局渐近稳定性，对建模不确定性的性能鲁棒性，和干扰衰减，为一大类非线性系统，不能充分控制现有的方法。在我们的理论发展的一个独特的线程将是系统使用的小控制和反馈钝化，其重点是如何利用固有的主导非线性的动态系统的反馈设计，而不是设计控制器通过取消非线性通过反馈线性化。反馈控制的目的是全局稳定或调节系统，并且以鲁棒的方式这样做，也就是说，以对系统中的各种扰动和结构不确定性不敏感的方式。一个统一的、基于无源性的鲁棒非线性控制理论将有助于我们设计高性能非线性控制器的能力，这些控制器能够衰减干扰并跟踪期望的轨迹，而不像传统的现代控制理论那样依赖于系统模型或模型参数的精确描述以及干扰信号的显式描述。（例如机器人、电刺激肌肉、旋转机器、感应电动机、电力系统、航空航天器、飞行器、导弹等）具有在反馈设计中不可忽略的本质上固有的非线性特性。更重要的是，控制系统，利用其真正的非线性可能会实现更好的性能比那些不。 由于大多数工程系统涉及高度非线性的执行器，传感器和过程元件，积极研究的目标是将非线性系统转换为线性系统，其中定义良好的线性控制技术是容易适用的。这种方法具有严重的局限性，例如，高能量致动器的要求和缺乏鲁棒性的参数变化和干扰的这种计划。因此，这些技术在解决现实世界的问题方面相对较少成功。 本提案中的研究计划解决了反馈设计中的需求，并提出了解决一些我们认为对非线性控制理论的发展和应用至关重要的最重要问题的方法。所提出的研究的主要成果将是新的，系统的设计方法，控制非线性动态系统，这是在现有的文献中没有。这一建议的意义在于，它确定了阻碍非线性控制理论的发展和应用的主要障碍，但也描绘了固有的非线性系统的控制的具体问题，并提出了理论创新和实际可行的方法来解决这些问题。一些重要和具有挑战性的开放问题将得到解决。从长远来看，它将为未来对若干理论和实践问题的研究提供洞察力和推动力。人们相信，采用系统方法进行低能耗控制的好处将得到更广泛的重视，特别是在工业中（例如制造业、航空航天业、电力和生物医学工程）在此基础上，提出了一种新的非线性控制方法，该方法可以应用于具有执行器饱和的非线性控制中，并有望在其它领域得到更广泛的应用。工程比传统的控制理论，由于其显着的特点和现实的假设包括。

9972045LinNonlinear feedback designs offer the potential to take advantage of genuinely nonlinear effects, for instance, to induce large effects using small controls. The objective of this proposal is to develop theoretically-sound, practically-useful passivity-based low-gain and low-and-high gain control methods for designing feedback controllers that achieve global asymptotic stability, performance robustness against modeling uncertainty, and disturbance attenuation, for a large class of nonlinear systems which cannot be adequately controlled by existing methods. A unique thread in our theoretical development would be the systematic use of small controls and feedback passivation, which focus on ways to exploit the inherently dominant nonlinearities of the dynamic system in the feedback design, rather than to design controllers by canceling the nonlinearities via feedback linearization. The purpose of a feedback control is to stabilize or regulate the system globally and do so in a robust fashion, that is, in a manner that is not sensitive to various perturbations and structural uncertainties in the system. A unified, passivity-based theory of robust nonlinear control would contribute to our ability to design high performance nonlinear controllers capable of attenuating disturbances and tracking desired trajectories, without relying as much on an accurate description of the system model or model parameters and on explicit descriptions of the disturbance signals as does conventional modern control theory.Many dynamic systems of practical importance (e.g. robotics, electrically stimulated muscles, rotating machines, induction motors, power systems, aerospace vehicles, aircraft, missiles and so on) have essentially inherent nonlinear characteristics that cannot be ignored in feedback design. More importantly, control systems that exploit their genuine nonlinearities are likely to achieve better performance than those that do not. Because most engineering systems involve highly nonlinear actuators, sensors and process elements, a goal of active research is to transform a nonlinear system into a linear system for which well-defined linear control techniques are readily applicable. This approach has serious limitations, e.g. the requirement of high energy actuators and the lack of robustness of such schemes to parameter variations and disturbances. Consequently, these techniques have had relatively little successful in solving real-world problems. The research plan in this proposal addresses the needs called for in feedback design, and it proposes approaches to tackle some of the most important issues that we believe are critical to the advancement and application of nonlinear control theory. The main outcome of the proposed research will be new, systematic design methodologies for the control of nonlinear dynamic systems, which are not available in the existing literature. The significance of this proposal is that it identifies the main barriers that hamper the advance and application of nonlinear control theory, but also delineates concrete problems for the control of inherently nonlinear systems, and suggests theoretically innovative and practically feasible methods to resolve them. A number of important and challenging open problems will be solved. In the long term, it will provide insight and thrust for future investigations into several theoretical and practical issues. It is believed that the benefits to a systematic approach towards using low energy control will be becoming more widely appreciated, particularly in industries (e.g. manufacturing, aerospace, power and biomedical engineering) where many applications of nonlinear control with actuator saturation can be found. It is also expected that the nonlinear control schemes to be developed in this program will find much broader applications in other branches of engineering than traditional control theory, due to their significant features and the inclusion of realistic assumptions.