volume | PIER Journals

Abstract

Magnetic angle sensors detect the angular position of a permanent magnet attached to a rotating shaft. The magnet is polarized diametrically to the rotation axis. No soft magnetic flux guides are present. The semiconductor die is placed on and orthogonal to the rotation axis. There are two kinds of systems: (i) perpendicular systems detect the field components perpendicular to the rotation axis, and (ii) axial systems detect the component parallel to the rotation axis. The former use magneto-resistive sensors or vertical Hall effect devices; the latter use Hall plates. This paper focuses on axial systems, derives their conceptual limitations, and compares them with perpendicular systems. An optimized system and optimum shapes of magnets are reported. Angle errors due to assembly tolerances of magnet and sensor versus shaft are explained. It is proven that assembly tolerances of optimized axial systems give three times larger errors than perpendicular systems.

1. Ausserlechner, U., "Inaccuracies of anisotropic magneto-resistance angle sensors due to assembly tolerances," Progress In Electromagnetics Research B, Vol. 40, 79-99, 2012.

2. Granig, W., St. Hartmann, and B. Koppl, "Performance and technology comparison of GMR versus commonly used angle sensor principles for automotive applications," SAE World Congress & Exhibition, SAE document No. 2007-01-0397, Detroit, USA, Apr. 2007.

3. Granig, W., J. Zimmer, Ch. Kolle, D. Hammerschmidt, B. Schaffer, R Borgschulze, and C. Reidl, "Integrated giant magnetic resistance based angle sensor," Proc. IEEE Sensors, 542-545, Daegu, Korea, Oct. 2006.

4. Ausserlechner, U., "Inaccuracies of giant magneto-resistive angle sensors due to assembly tolerances," IEEE Trans. Magn., Vol. 45, No. 5, 2165-2174, May 2009.
doi:10.1109/TMAG.2009.2013712

5. Ausserlechner, U., "The optimum layout for giant magneto-resistive angle sensors," IEEE Sens. J., Vol. 10, No. 10, 1571-1582, 2010.
doi:10.1109/JSEN.2010.2040732

6. Demierre, M., E. Schurig, Ch. Schott, P. A. Besse, and R. S. Popovic, "Contactless 360^o absolute angular CMOS microsystem based on vertical hall sensors," Sensors and Actuators, Vol. A116, 39-44, 2004.

7. Pascal, J., L. Hebrard, and V. Frick, "3D Hall probe integrated in 0.35 μm CMOS technology for magnetic field pulses measurements," Circuits and Systems and TAISA Conf. 2008, NEWCASTAISA 2008, 97-100, Conf. Publications, 2008.

8. Reymond, S., P. Kejik, and R. S. Popovic, "True 2D CMOS integrated hall sensor," IEEE Sensors Conf., 860-863, 2007.

9. Metz, M., A. Haberli, M. Schneider, R. Steiner, C. Maier, and H. Baltes, "Contactless angle measurement using four hall devices on single chip," Transducers'97 Int'l Conf Solid-State Sensors and Actuators, 385-388, Chicago, Jun. 16-19, 1997.

10. Gao, X. H., M. H. Jin, L. Jiang, Z. W. Xie, P. He, L. Yang, Y. W. Liu, R. Wei, H. G. Cai, H. Liu, J. Butterfass, M. Grebenstein, N. Seitz, and G. Hirzinger, "The HIT/DLR dexterous hand: Work in progress," Proc. IEEE Int'l Conf Robotics & Automation, 3164-3168, Taipei, Taiwan, Sep. 14-19, 2003.

11. Takahashi, T., Y. Nagano, and S. Kawahito, "Development of a high precision angle sensor," NTN Techn. Rev., Vol. 73, 98-103, 2005.

12. Ausserlechner, U., "Limits of offset cancellation by the principle of spinning current Hall probe," Proc. IEEE Sensors, Vol. 3, 1117-1120, 2004.

13. Ausserlechner, U., M. Motz, and M. Holliber, "Compensation of the piezo-Hall effect in integrated Hall sensors on (100)-Si," IEEE Sens. J., Vol. 7, No. 11, 1475-1482, 2007.
doi:10.1109/JSEN.2007.907039

14. Ausserlechner, U., M. Motz, and M. Holliber, "Drift of magnetic sensitivity of smart Hall sensors due to moisture absorbed by the IC-package," Proc. IEEE Sensors, Vol. 1, 455-458, 2004.

15. Engel-Herbert, R. and T. Hesjedal, "Calculation of the magnetic stray field of a uniaxial magnetic domain," J. Appl. Phys., Vol. 97, 074504-1-074504-4, 2005.

16. Ausserlechner, U., "Integrierter differentieller magnetfeldsensor,", Patent DE10314602, Mar. 31, 2003.

17. Seeger, K., Semiconductor Physics, Springer Series in Solid-State Sciences 40, 4th Edition, Eq. (4.2.35) at p. 56, Springer, Berlin, 1988.

18. Husstedt, H., U. Ausserlechner, and M. Kaltenbacher, "In-situ analysis of deformation and mechanical stress of packaged silicon dies with an array of Hall plates," IEEE Sens. J., Vol. 11, No. 11, 2993-3000, 2011.
doi:10.1109/JSEN.2011.2154326

19. Ausserlechner, U., "Concept for compensating the influences of external disturbing quantities on physical functional parameters of integrated circuits,", Patent US6906514, Jun. 14, 2005.

20. Ausserlechner, U., "Magnetic field sensor apparatus,", Patent US7474093, Jan. 6, 2009.

Dr. Udo Ausserlechner