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

该奖项支持一种新的传感原理的研究，通过结合自然灵感的想法来估计铁磁物体的位置。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）将与物体的固有磁场一起被利用，以确定它们作为移动物体的位置。新的传感原理将使非接触式位置测量成为可能，而不需要在铁质物体上放置任何传感器或传感元件。运动的铁磁物体，如汽车、活塞、滑阀和各种机器中的各种运动部件，其磁场随物体周围位置的变化而变化。物体磁场的空间变化作为位置的函数，在几个离散的空间分离位置测量磁场，以及使用新的估计算法，可以准确估计被监测物体的位置，而无需预先校准。这项技术将广泛应用于汽车、工业和越野车辆领域。为了利用普通铁磁物体的“固有”磁场，需要解决许多技术挑战。这些问题包括未知的磁场参数、需要设计非线性观测器以及需要能够考虑状态和参数约束的估计技术。通过使用具有已知分离距离的双传感器和制定严格的非线性系统观测器设计方法来解决这些挑战。冗余传感器的使用可以实现可观测性，并且可以在不需要预先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稳定性的全局保证，计算效率高，优雅，并产生更快的收敛。对状态或参数的约束，以及由于意外磁干扰引起的瞬态误差，使用移动水平估计方法来解决，其中使用约束优化公式施加已知边界。主要项目任务包括非线性观测器设计方法的分析研究，干扰抑制技术的发展，以及约束施加技术的实现。这些将应用于自由活塞发动机，液压缸和汽车迫在眉睫的碰撞检测的位置估计。

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.