Micro-coil with movable core for application in an inductive displacement sensor

Velten, Th; Stefan, D.; Obermeier, Ε.

doi:10.1088/0960-1317/9/2/004

Cited by 13 publications

(3 citation statements)

References 5 publications

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“…This allows the device to be used as a length measurement or a positioning system. There are two types of inductive sensors in which the reluctance of the magnetic circuit does vary: systems with a highly permeable magnetic yoke penetrating the center of a coil and transformers with a moving yoke causing the coupling between the primary and the secondary coil center (5,6). The first type of sensors is characterized by a low sensitivity, but a great linearity (7), the second by greater output signals, but also greater non-linearity.…”

Section: Micro Position Sensormentioning

confidence: 99%

Advances in Magnetic Micro Thin-Film Transducers

Gatzen¹,

Ruffert²

2007

ECS Trans.

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Magnetic Micro Electro-mechanical Systems (Magnetic MEMS) provide transducer capabilities ranging from thin-film storage devices and micro sensors to micro actuator solutions. This paper provides an overview over magnetic thin-film devices developed at the Institute for Microtechnology at the Leibniz Universitaet Hannover`s Center for Production Technology (PZH) in Garbsen, Germany. In the area of data storage, it presents a microcoil for optical data storage. In the field of micro sensors it shows two inductive length measurement systems, an eddy current proximity sensor and a micro strain gauge for force measurements. Micro actuators built as linear positioners and as tilting platforms, as well as a new actuator principle based on the magnetic shape memory (MSM) effect conclude the paper.

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Section: Micro Position Sensormentioning

confidence: 99%

Advances in Magnetic Micro Thin-Film Transducers

Gatzen¹,

Ruffert²

2007

ECS Trans.

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“…Thus, the output voltage depends on the position of the rod. The change of solenoid inductance with the position of the core is a phenomenon that has been well researched [14]- [16]. However, its application to sense the rod position of a hydraulic cylinder is a new idea with interesting challenges.…”

Section: A Inductance Variation As Principle Of Operationmentioning

confidence: 99%

A displacement sensor for nonmetallic hydraulic cylinders

2003

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A sensor was developed to provide signals proportional to the position of the rod in a hydraulic cylinder. The sensor has a coil winding in the shell of the cylinder. The sensor operates by sensing the change in the coil impedance as the rod moves in the cylinder. This paper describes the construction of the cylinder and the sensor, and the performance evaluation of the sensor. Several different materials were placed in the rod and tested. For the cylinder tested, an aluminum core provided the highest precision, about 0.38 . The full-scale output was 19.90 over a stroke length of 193 mm. The linearity was about 1.64% of full-scale. Shielding from electromagnetic interference can improve the precision dramatically. A ferrite-cored rod assembly yielded a much greater full-scale output, 1300 , but exhibited significant hysteresis.

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“…The inductive-type proximity sensor has the characteristic of water and oil resistance, and thus can be operated in a contaminated environment [6]. Several approaches have been reported to achieve the inductive proximity sensor, such as composite materials spiral wire [7] and multi-structure spiral wire [8]. The inductive proximity sensor is suitable for detecting conductive targets, but is less sensitive to objects with low conductivity and non-magnetic materials (such as the human body) [9].…”

Section: Introductionmentioning

confidence: 99%

Development of a proximity sensor with vertically monolithic integrated inductive and capacitive sensing units

Tseng

Wang

et al. 2013

J. Micromech. Microeng.

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This study designs and implements a proximity sensor consisting of inductive and capacitive sensing units. These two sensing units are vertically monolithic integrated on a single chip using the micro-fabrication processes. In addition, low-temperature fabricated nanoporous anodic aluminum oxide (np-AAO) is employed as the dielectric layer to enhance the performance of capacitive sensing. The characteristics of the presented vertically monolithic integrated inductive and capacitive proximity sensor are as follows: (1) enlarged sensing distance of conductive objectives: capacitive sensing unit for short distance detection and inductive sensing unit for long distance detection, (2) non-conductive object can be detected by the capacitive sensing unit, (3) fringe effect capacitive sensing is enhanced by the spiral coil electrode and (4) np-AAO has good dielectric properties (the dielectric constant is 11.9 in this study) for capacitive sensing. In application, various materials (including metal, plastic and a human finger) have been successfully detected by the presented sensor. Preliminary results demonstrate that the typical fabricated proximity sensor has a sensing range of 0.5–5 mm for the metal rod. In comparison, the inductive and capacitive sensing units have the sensing ranges of 1.5–5 and 0.5–3 mm, respectively. Moreover, the non-conductive plastic rod can be detected by the capacitive sensing unit.

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Micro-coil with movable core for application in an inductive displacement sensor

Cited by 13 publications

References 5 publications

Advances in Magnetic Micro Thin-Film Transducers

Advances in Magnetic Micro Thin-Film Transducers

A displacement sensor for nonmetallic hydraulic cylinders

Development of a proximity sensor with vertically monolithic integrated inductive and capacitive sensing units

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