A capacitive angular sensor with flexible digitated electrodes

Abstract

Purpose – This paper aims to present a prototype of a capacitive angular-position sensor which exploits advantages of flexible/printed electronics. The novelty of the sensor is that the capacitor structure is placed at the circumference of the rotor and stator, that it posses two channels (capacitor structures) electrically shifted for p/4 and that the rotor is common for both channels. The electrodes of the sensing capacitor are digitated, providing a triangular transfer function. Design/methodology/approach – This sensor prototype consists of two flexible inkjet-printed silver electrodes forming a cylindrical capacitor structure. One of them is wrapped around the stator and another is wrapped around the rotor part of a simple mechanical platform used to precisely adjust the angular displacement. Findings – The capacitance as a function of angular position was measured using an inductance capacitance impedance (LCZ) Meter, and results are presented for a full-turn measurement range. The experimental results are compared with analytical ones and very good agreement has been achieved. Originality/value – The proposed capacitive sensor structure can be used as an absolute or an incremental encoder with different resolutions, and it can be applied in automotive industry or robotics.

The Boom in 3D-Printed Sensor Technology

“…The sensor’s mechanical construction consists of five components, namely, a stator, a rotor, a shaft, ball bearings and a lid (Figure 8B,C). Figure 8D shows the mounted foils and the final sensor structure [23]. The measured capacitance as a function of the angular position for both channels is depicted in Figure 8E.…”

Nonlinear Error Compensation of Capacitive Angular Encoders Based on Improved Particle Swarm Optimization Support Vector Machines

“…and R is a real number in the range [5], [10]; V k+1 ij is the velocity at which the particle iterates (k + 1) times; and V max ij is the maximum velocity of the particle.…”

“…Rotary encoders applied to measure the angular position and speed have been broadly utilized in industrial automation control systems [1]- [4]. They are expected to achieve high precision, high resolution and high reliability in harsh environments [5]- [7]. There are many types of encoders, such as, electromagnetic, inductive, capacitive, optical types.…”

Periodic Nonlinear Error Analysis and Compensation of a Single-Excited Petal-Shaped Capacitive Encoder to Achieve High-Accuracy Measurement

“…Rotary encoders are widely used to provide positional feedback information and achieve precise control [1,2,3,4,5]. The encoders are classified as optical, magnetic, inductive, and capacitive according to their measurement principle.…”

“…Optical and magnetic encoders are dominant in the market as they can achieve high precision, but they tend to be relatively expensive and bulky [2,6,7,8,9,10]. Currently, capacitive encoders have been gaining interest owing to their simplified design, potential for further miniaturization, insensitivity to magnetic field variation, long lifespan, low cost, and high measurement accuracy [5,10,11,12].…”