A Non-Linear Temperature Compensation Model for Improving the Measurement Accuracy of an Inductive Proximity Sensor and Its Application-Specific Integrated Circuit Implementation

Abstract

The non-linear characteristic of a non-contacting Inductive Proximity Sensor (IPS) with the temperature affects the computation accuracy when measuring the target distance in real time. The linear model based method for distance estimation shows a large deviation at a low temperature. Accordingly, this paper presents a non-linear measurement model, which computes the target distance accurately in real time within a wide temperature range from −55 °C to 125 °C. By revisiting the temperature effect on the IPS system, this paper considers the non-linear characteristic of the IPS measurement system due to the change of temperature. The proposed model adopts a non-linear polynomial algorithm rather than the simple linear Look-Up Table (LUT) method, which provides more accurate distance estimation compared to the previous work. The introduced model is fabricated in a 0.18 μm Complementary Metal Oxide Semiconductor (CMOS) process and packaged in a CQFN40. For the most commonly used sensing distance of 4 mm, the computed distance deviation of the Application-Specific Integrated Circuit (ASIC) chips falls within the range of [−0.2,0.2] mm. According to the test results of the ASIC chips, this non-linear temperature compensation model successfully achieves real-time and high-accuracy computation within a wide temperature range with low hardware resource consumption.

Enhancing ASIC chip performance through integrated algorithm optimization

“…In the domain of filtering, multipliers are instrumental in calculating filter coefficients. They facilitate the multiplication of filter taps with input signal samples, contributing to the weighted summation required for effective signal filtering [4]. This process enables precise control over filtering characteristics, improving the quality of processed signals.…”

Effect of Excitation Signal on Double-Coil Inductive Displacement Transducer

“…The inductive transducer is a device that uses the change in self-inductance or mutual inductance of inductance coils to realize measurement. It can measure displacement, pressure, angle, speed, flow, and other parameters [ 1 ], which are widely used in high-end manufacturing equipment [ 2 ], the automotive industry [ 3 ], agricultural machinery equipment, and construction machinery. Inductive transducers have the characteristics of high reliability, high sensitivity, and good linearity, which can achieve non-contact measurement and are suitable for working in dusty, oily, mechanical vibration, and other harsh environments [ 4 , 5 ].…”