Publications

IEEE Sensors Journal

Mazumdar, Anirban; Chen, Yi; van Bloemen Waanders, Bart G.; Brooks, Carlton F.; Kuehl, Michael K.; Nemer, Martin N.

Epoxies and resins can require careful temperature sensing and control in order to monitor and prevent degradation. To sense the temperature inside a mold, it is desirable to utilize a small, wireless sensing element. In this paper, we describe a new architecture for wireless temperature sensing and closed-loop temperature control of exothermic polymers. This architecture is the first to utilize magnetic field estimates of the temperature of permanent magnets within a temperature feedback control loop. We further improve performance and applicability by demonstrating sensing performance at relevant temperatures, incorporating a cure estimator, and implementing a nonlinear temperature controller. This novel architecture enables unique experimental results featuring closed-loop control of an exothermic resin without any physical connection to the inside of the mold. In this paper, we describe each of the unique features of this approach, including magnetic field-based temperature sensing, extended Kalman filtering for cure state estimation, and nonlinear feedback control over time-varying temperature trajectories. We use experimental results to demonstrate how low-cost permanent magnets can provide wireless temperature sensing up to ∼ 90°C. In addition, we use a polymer cure-control testbed to illustrate how internal temperature sensing can provide improved temperature control over both short and long time-scales. This wireless temperature sensing and control architecture holds value for a range of manufacturing applications.

IEEE Transactions on Magnetics

Chen, Yi; Mazumdar, Anirban; Brooks, Carlton F.; van Bloemen Waanders, Bart G.; Bond, Stephen D.; Nemer, Martin N.

Vibration sensing is critical for a variety of applications from structural fatigue monitoring to understanding the modes of airplane wings. In particular, remote sensing techniques are needed for measuring the vibrations of multiple points simultaneously, assessing vibrations inside opaque metal vessels, and sensing through smoke clouds and other optically challenging environments. In this paper, we propose a method which measures high-frequency displacements remotely using changes in the magnetic field generated by permanent magnets. We leverage the unique nature of vibration tracking and use a calibrated local model technique developed specifically to improve the frequency-domain estimation accuracy. The results show that two-dimensional local models surpass the dipole model in tracking high-frequency motions. A theoretical basis for understanding the effects of electronic noise and error due to correlated variables is generated in order to predict the performance of experiments prior to implementation. Simultaneous measurements of up to three independent vibrating components are shown. The relative accuracy of the magnet-based displacement tracking with respect to the video tracking ranges from 40 to 190 μ m when the maximum displacements approach ±5 mm and when sensor-to-magnet distances vary from 25 to 36 mm. Last, vibration sensing inside an opaque metal vessel and mode shape changes due to damage on an aluminum beam are also studied using the wireless permanent-magnet vibration sensing scheme.

Mazumdar, Yi C.; Guba, Oksana G.; Mazumdar, Anirban; Brooks, Carlton F.; Roberts, Christine C.; van Bloemen Waanders, Bart G.; Nemer, Martin N.

Abstract not provided.