Sensors and Sensing Devices Utilizing Electrorheological Fluids and Magnetorheological Materials-A Review

Abstract

This paper comprehensively reviews sensors and sensing devices developed or/and proposed so far utilizing two smart materials: electrorheological fluids (ERFs) and magnetorheological materials (MRMs) whose rheological characteristics such as stiffness and damping can be controlled by external stimuli; an electrical voltage for ERFs and a magnetic field for MRMs, respectively. In this review article, the MRMs are classified into magnetorheological fluids (MRF), magnetorheological elastomers (MRE) and magnetorheological plastomers (MRP). To easily understand the history of sensing research using these two smart materials, the order of this review article is organized in a chronological manner of ERF sensors, MRF sensors, MRE sensors and MRP sensors. Among many sensors fabricated from each smart material, one or two sensors or sensing devices are adopted to discuss the sensing configuration, working principle and specifications such as accuracy and sensitivity. Some sensors adopted in this article include force sensors, tactile devices, strain sensors, wearable bending sensors, magnetometers, display devices and flux measurement sensors. After briefly describing what has been reviewed in a conclusion, several challenging future works, which should be undertaken for the practical applications of sensors or/and sensing devices, are discussed in terms of response time and new technologies integrating with artificial intelligence neural networks in which several parameters affecting the sensor signals can be precisely and optimally tuned. It is sure that this review article is very helpful to potential readers who are interested in creative sensors using not only the proposed smart materials but also different types of smart materials such as shape memory alloys and active polymers.

Keywords: electrorheological fluid; flux measurement sensor; force sensor; magnetorheological materials; sensors; strain sensor; tactile sensor.

Figure 1

The tactile sensor array with three regions; (a) impedance (log scale) as a function of force (log scale) applied normally to the electrode surface. Textured silicone: 60 durometers, 100 grit size. (b) Graphic correlating curve shapes to probe indentation (2 mm probe shown). Reproduced with permission from [Nicholas Wettels], [Advanced Robotics]; published by [Taylor & Francis Group] (2008) [44].

Figure 2

The fundamental logic-gate operation with a giant electro-rheological fluid [45].

Figure 3

Schematic and working principle of a cylindrical ER device in which a user presses upon the membrane surface; (a) form factor of the ERF-based haptic device (cross-section view of the working principle of the cylindrical haptic actuator), (b) pre-press, (c) mid-press. Reproduced with permission from [Ping Sheng], [Annual review of fluid mechanics]; published by [Annual Review], (2011) [52].

Figure 4

Diagram of a self-sensing behavior with fuzzy mapping for identification of MR dampers [59]. Reproduced with permission from [Dinh Quang Truong], [Sensors and Actuators A: physical]; published by [Elsevier], (2010).

Figure 5

Configuration of the flux measurement sensor; (a) configuration of the MRF-VR system, (b) photograph of the measurement system in magnetic field calibration unit [60,61]. Reproduced with permission from [Suresh Kaluvan], [International Journal of Mechanical Systems Engineering]; published by [Graphy Publications], (2015), (b) Reproduced with permission from [Suresh Kaluvan], [Sensors and Actuators A: Physical]; published by [Elsevier], (2016).

Figure 6

Schematic representation of the dynamic motion measurement system using a MRF [62].

Figure 7

Tactile force sensor and sensing spectrum; (a) schematic of MRP sample, (b) force spectrum of MRP tactile device [66,67].

Figure 8

Dynamic sensor mimicking human organs; (a) fabricated sensor sample, (b) the microstructure inside of the sensor—the shape of the MRF chains extending from the MRE [69].

Figure 9

Dynamic motion tactile sensing device; (a) schematic of dynamic shape by the input magnetic field, (b) the field-dependent dynamic motion results in 0.5 Hz of excitation [69].

Figure 10

Schematic design of the MRE force sensor [74]. Reproduced with permission from [Weihua Li], [International Conterence on Advanced Intelligent Mechatronics]; published by [IEEE], (2009).

Figure 11

Schematic configuration and working principle of the magnetometer based on a MRE; (a) schematic diagram of magnetic sensor, (b) the sensor’s cross section indicating the direction of the magnetic field H, (c) circuit diagram of the Wheatstone bridge [76].

Figure 12

Schematic configuration the MRE force sensor [81]. Reproduced with permission from [Amir Hooshiar], [Materials Science and Engineering C]; published by [Elsevier], (2009).

Figure 13

Working principle of the inductive sensor with flat coils [82]. (a) high inductance with a small deformation of the MRE skin, (b) low inductance with a large deformation of the MRE skin. Reproduced with permission from [Hongbo Wang], [International Conference on Soft Robotics (RoboSoft)]; published by [IEEE], (2009).

Figure 14

Schematic design and operating principle of the MRE force sensor [84].

Figure 15

Schematic design of a three-axes inductive tactile sensor; (a) top view of MRE sensor (b) exploded view of MRE sensor [85]. Reproduced with permission from [Muhammad A. Khalid], [IEEE Sensors Journal]; published by [IEEE], (2022).

Figure 16

Schematic design of the MRP force sensor [92]. Reproduced with permission from [Norhiwani Mohd Hapipi], [Sensors]; published by [MDPI], (2021).