Transformer position sensor for a pneumatic cylinder

A novel transformer-based sensor for a pneumatic cylinder enables measurements of the piston position to be made through a thick conductive cylinder. Unlike existing industrial solutions, which are mainly based on a moving magnet, our sensors do not require modifications to the parts inside the cylinder

A Study on the Sensor-Embedded Hydraulic Cylinder for Offshore Application and Position Tuning Control of Multiple Cylinders

In this paper, an idea to comprise a sensor-embedded hydraulic cylinder for offshore applications was suggested. The idea not only includes a scale processing method of piston rod using ceramic plasma coating by Ti-ceramic and Al-ceramic, but also includes a remote detecting method using two sets of optical sensors and optical fibers. And it includes exclusive developing methods of circuit elements for the embedded sensor amplifier. Based on the methods mentioned above, a practical sensor-embedded hydraulic cylinder was developed and several experiments were executed in order to verifying the effectiveness of the suggested method. There are two main advantages of the developed sensor-embedded hydraulic cylinder. One is that the embedded sensor can detect the piston rod strokes without time delay because light is used as a detecting medium, and it can be adapted to detect instantaneous high speed strokes of piston rod owing to the surge pressure of hydraulic oil. The other advantage is that the embedded sensor is robust against vibrations and shocks during operations, by installing only optical fiber head on the cylinder. In this paper, a position tuning control method was also discussed, in order to control the positions of multiple cylinders for high power and high precision hydraulic control systems. The discussed method is to comprise a tuning controller based on CPU in view of digital hardware and software. To verify the effectiveness of the discussed method, computer simulations were executed by using two different mathematical models as hydraulic cylinder models. According to the simulation results, the discussed tuning control method was turned out to generate differential tuning control signals accurately. It is expected that the discussed method will be used more effectively than the conventional mechanical tuning control methods in view of accuracy and price burden. A further study will be concentrated on experiments to analyze the control performance quantitatively for a practical system which is combined the suggested sensor-embedded hydraulic cylinders with the discussed position tuning controller.목차 Abstract 제 1 장 서론 = 1 제 2 장 해수용 센서내장형 유압실린더 = 3 2.1 해수용 센서내장형 유압실린더 개발의 필요성 = 3 2.2 해수용 센서내장형 유압실린더의 구성 = 4 2.2.1 센서내장형 유압실린더의 구성요소 = 4 2.2.2 내장형 센서를 이용한 스트로크 검출 원리 = 6 2.3 내장형 센서를 위한 해수용 피스톤 로드의 처리 = 7 2.4 양방향 스트로크 검출을 위한 광파이버헤드의 설치방법 = 9 제 3 장 내장형 센서 전용앰프의 설계와 각 요소의 기능 = 11 3.1 내장형 센서앰프의 전체구성 = 11 3.2 내장형 센서앰프 각 요소의 설계와 기능 = 12 3.2.1 발/수광 센서 전용의 아날로그 회로 = 12 3.2.2 출력 안？ㅐ？ 위한 자동 게인 조정회로 = 14 3.2.3 트리거 및 외부감도조정 회로 = 15 3.2.4 업/다운 카운터 회로 = 16 3.3 80C196KC 중심의 데이터 처리 = 17 제 4 장 다중 실린더 위치동조 제어의 구현 = 21 4.1 위치동조 제어의 필요성 = 21 4.2 동조제어기의 구현 방법 = 22 4.3 동조제어기의 전체 구성 = 22 제 5 장 실험 및 시뮬레이션 = 24 5.1 내장형 센서앰프 동작 실험 = 24 5.1.1 증분방식 스트로크 측정의 가능성 = 24 5.1.2 양방향 스트로크 측정의 가능성 = 25 5.1.3 출력위상 안정을 위한 자동 게인 조정 가능성 = 26 5.1.4 외부 트리거 레벨조정과 감도조정의 가능성 = 27 5.2 해수용 센서 내장형 실린더의 스트로크 검출 실험 = 29 5.2.1 스트로크 검출의 선형성 및 정확도 실험 = 29 5.2.2 스트로크 검출의 반복 정밀도 실험 = 30 5.3 두개의 유압실린더 위치동조 제어를 위한 시뮬레이션 = 32 5.3.1 2개의 유압실린더 수학모델 = 32 5.3.2 퍼지 PID제어기의 구조 및 응답특성 = 34 5.3.3 위치동조 제어기의 구현 = 39 5.3.4 시뮬레이션 결과 = 40 제 6 장 결론 = 48 참고 문헌 = 4

Robuste Lokalisierung magnetischer Quellen mithilfe integrierter 3D-Hall-Sensor-Anordnungen

Magnetfeldsensoren erlauben die indirekte, berührungslose Bestimmung der Position bewegter Objekte und finden daher millionenfach Anwendung im Industrie- und Automobilbereich. Positionsmesssysteme in diesen Anwendungsbereichen haben die Aufgabe einen linearen Weg oder den Winkel der Rotationsbewegung eines Permanentmagneten zu erfassen. In Labor-Anwendungen wurde bereits gezeigt, dass das Feld magnetischer Quellen genutzt werden kann alle sechs mechanischen Freiheitsgrade zu bestimmen. Unter schwierigen Umgebungsbedingungen sind Auswertungen mit nur einem einzigen Freiheitsgrad jedoch alternativlos. Gründe hierfür sind der rechentechnische Aufwand komplexer Auswertealgorithmen, aber auch zu erwartende magnetische und temperaturbedingte Störungen. Zudem gibt es kaum Anhaltspunkte für die Auslegung magnetfeldbasierter Positionsmesssysteme, was den Einsatz erschwert. Ziel dieser Arbeit ist es daher, Methoden zu erarbeiten, die es ermöglichen die Vorteile integrierter Magnetfeldsensoren auch für schwierige Umgebungen nutzbar zu machen, und somit die Möglichkeiten der Technologie auszuschöpfen. Kompakte Hall-Sensor-Anordnungen, die am Fraunhofer Institut für Integrierte Schaltungen (IIS) entwickelt wurden, dienen als Ausgangspunkt. Sie ermöglichen es, den Magnetfeldvektor einer magnetischen Quelle an mehreren Stellen und auf engstem Raum zu messen. Um daraus die Position zu ermitteln, und somit das inverse Problem der Magnetostatik zu lösen, wird in dieser Arbeit ein analytisches Modell eines beispielhaften Messsystems entwickelt und verschiedene numerische Lösungsverfahren evaluiert. Das Unscented Kalman-Filter zeigt sich im Hinblick auf die Anforderungen industrieller Anwendungen als besonders geeignet. Von der stochastischen Modellierung des Systems ausgehend, werden Methoden und Richtlinien zum Entwurf magnetfeldbasierter Positionsmesssysteme abgeleitet und ein Verfahren vorgestellt, das es ermöglicht Permanentmagneten zu charakterisieren, und somit die Eigenschaften der Lokalisierung zu verbessern. Algorithmische Anpassungen des Unscented-Kalman-Filters, deren Wirksamkeit anhand von Messungen und Simulationen belegt wird, reduzieren die Empfindlichkeit gegenüber Störungen in schwierigen Umgebungen.Magnetic sensors allow indirect, non-contact localization of moving objects and thus are used millions of times in industrial and automotive applications. Such position measurement systems have the task of determining the linear displacement or rotation of a permanent magnet. Laboratory applications already showed that the field of magnetic sources can be used to determine up to six mechanical degrees of freedom. Nevertheless, under harsh environmental conditions, evaluations with a single degree of freedom are without alternative. The reasons for this lie in the computational effort of complex localization algorithms, but also in the expected magnetic and temperature dependent distortions. Furthermore, there are hardly any guidelines for the design of magnet field based position measurement systems which complicates the use. Therefore, it is the objective of this work to provide methods that allow exploiting the technical capabilities of magnetic field sensors even in harsh environments. Compact Hall-Sensors arrangements that were developed at the Fraunhofer Institute for Integrated Circuits (IIS) are used, that allow the measurement of the magnetic field vector of a magnetic source. To measure the position, and thus solve the underlying inverse magnetostatic problem, an analytical model of an exemplary application is derived and different numerical approaches are investigated. The Unscented Kalman Filter turns out to meet the requirements of industrial applications. Starting from a stochastic system model, methods and guidelines for the design of magnet field based position sensing systems are derived and a method for the characterization of permanent magnets is proposed which improves the properties of the localization. Algorithmic modifications reduce the susceptibility to typical distortions in harsh environments. The methods are evaluated based on measurements and simulations