Mathematical Model for Absolute Magnetic Measuring Systems in Industrial Applications

• Published in: Journal of physics. Conference series 2015-09, Vol.633 (1), p.12080
• Main Authors: Fügenschuh, Armin, Fügenschuh, Marzena, Ludszuweit, Marina, Mojsic, Aleksandar, Sokó, Joanna
• Format: Article
• Language: English
• Subjects: Hall effect; Industrial applications; Measurement methods; Physics; Position measurement; Robustness (mathematics); Sensor arrays; Stability
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/633/1/012080

Scales for measuring systems are either based on incremental or absolute measuring methods. Incremental scales need to initialize a measurement cycle at a reference point. From there, the position is computed by counting increments of a periodic graduation. Absolute methods do not need reference points, since the position can be read directly from the scale. The positions on the complete scales are encoded using two incremental tracks with different graduation. We present a new method for absolute measuring using only one track for position encoding up to micrometre range. Instead of the common perpendicular magnetic areas, we use a pattern of trapezoidal magnetic areas, to store more complex information. For positioning, we use the magnetic field where every position is characterized by a set of values measured by a hall sensor array. We implement a method for reconstruction of absolute positions from the set of unique measured values. We compare two patterns with respect to uniqueness, accuracy, stability and robustness of positioning. We discuss how stability and robustness are influenced by different errors during the measurement in real applications and how those errors can be compensated.