Spatially Separated Redundant Magnetic Sensors and Nonlinear Observers for Enhanced Position Estimation

该奖项支持通过结合自然启发的想法来估计铁磁物体位置的新型传感原理的研究。将利用用于增强感官知觉的相同传感器的空间分离（例如动物和人类的双眼和双耳）沿着物体的固有磁场来确定它们作为移动物体的位置。新的传感原理将实现非接触式位置测量，而无需在含铁物体上放置任何传感器或传感组件。运动的铁磁物体，例如汽车、活塞、滑阀和各种机器中的各种运动部件，具有作为物体周围位置的函数而变化的磁场。 作为位置的函数的对象的磁场的空间变化、在几个离散的空间分离的位置处的磁场的测量以及新颖的估计算法的使用产生了对被监测对象的位置的准确估计，而不需要预校准。该技术将在汽车、工业和越野车领域有广泛的应用。为了利用普通铁磁物体的“固有”磁场，需要解决一些技术挑战。 这些包括未知的磁场参数，需要设计非线性观测器和需要估计技术，可以考虑对状态和参数的约束。 这些挑战是通过使用双传感器与它们之间的一个已知的分离距离，并制定严格的非线性系统的观测器设计方法。 冗余传感器的使用使得能够实现可观测性，并且使得能够在不需要预校准的情况下估计参数和状态。非线性观测器的设计提供了全局稳定性的保证，计算效率高，优雅，并产生更快的收敛。 状态或参数的约束，以及由于意外的磁干扰的瞬态误差，解决了使用滚动时域估计方法，其中已知的边界施加使用约束优化配方。 主要项目任务包括非线性观测器设计方法的分析研究，抗干扰技术的发展，以及约束施加技术的实施。这些将被应用于位置估计的自由活塞发动机，液压缸，和汽车即将发生的碰撞检测。

This award supports the investigation of a novel sensing principle for estimation of positions of ferromagnetic objects through a combination of nature-inspired ideas. The spatial separation of identical sensors for enhanced sensory perception (e.g. dual eyes and ears in animals and humans) will be exploited along with the inherent magnetic fields of objects for determining their position as moving objects. The new sensing principle will enable non-contact measurement of position without requiring the placement of any sensors or sensing components on the ferrous object. Moving ferromagnetic objects such as cars, pistons, spool valves and a large variety of moving components in various machines have magnetic fields which vary as a function of the position around the object. The spatial variation of an object's magnetic field as a function of position, the measurement of magnetic field at a few discrete spatially separated locations and the use of novel estimation algorithms yield accurate estimation of the position of the monitored objects, with no pre-calibration required. This technology would have extensive applications in automotive, industrial and off-road vehicle domains.In order to exploit the "inherent" magnetic fields of common ferromagnetic objects, a number of technical challenges need to be addressed. These include unknown magnetic field parameters, the need to design nonlinear observers and the need for estimation techniques that can account for constraints on states and parameters. These challenges are addressed by using dual sensors with a known separation distance between them and by formulating rigorous observer design methods for nonlinear systems. The use of redundant sensors enables observability and enables estimation of both parameters and states without requiring pre-calibration. The design of nonlinear observers provides global guarantees of stability, is computationally efficient, elegant, and yields faster convergence. Constraints on states or parameters, and transient errors due to unexpected magnetic disturbances, are addressed using a moving horizon estimation method in which known bounds are imposed using a constrained optimization formulation. Major project tasks include analytical study of nonlinear observer design methods, development of disturbance rejection techniques, and implementation of constraint imposition techniques. These will be applied for position estimation for a free-piston engine, a hydraulic cylinder, and an automotive imminent collision detection.