Magnetorheological fluid in prostheses: A state-of-the-art review

Abstract

Magnetorheological fluids (MRF) are intelligent materials that can vary their yield stress in response to an applied magnetic field. This characteristic, combined with active and multifunctional control, allows the development of actuators with fast response time, low energy consumption, long service life, and reduced dimensions and weights. Various studies have been conducted to improve MR dampers in prosthetic applications, including knees, ankle-foot, hands, and sockets. Here, we present a critical review of the progress of MRFs in the prosthetic field. In addition, research in prostheses’ design, optimization, and control of magnetorheological actuators is investigated, along with MRF modeling, mode of operation, type of MR actuator, classification, and working principle of MRF-based devices. Although MRFs are considered promising materials for designing novel prosthetic devices, this review shows that applications have been predominantly focused on lower limb prostheses. We conclude by discussing possible future applications and challenges that must be faced to enable and improve commercial applications based on MRF technology.

Magnetorheological Fluid-Based Haptic Feedback Damper

“…We took the magnetic field strength dataset in the ordinate range of 0 mm to 20 mm at the central axis of the NdFeB magnet and plotted the magnetic field strength and distance curve, as shown in Figure 8. According to the value of the exported dataset, the magnetic field strength of 139.747 kA/m at z was 3.155 mm, and the yield stress of magnetorheological fluid was 88.779 kPa, which was found by substituting Equation (19), and the damping force F was obtained by substituting Equation ( 18):…”

“…However, although research on magnetorheological fluids (MRFs) has achieved certain results, applying them to dampers still encounters many challenges and difficulties, such as the difficulty of precise control of the magnetic field applied to the MRFs, the influence of the MRF viscosity on the overall temperature, and the difficulty of decreasing the fabrication cost [19]. For this reason, this study explored the application of magnetorheological fluids in the field of dampers using a keyboard as an example.…”

Magnetic Characterization of MR Fluid by Means of Neural Networks

“…Another important application of MR is the biomedical one, with the use of prosthetic devices suitable for improving the movement of the knees in limb amputees in whom a prosthesis has been applied. Because of their high precision and control speed (the time of response is less than 10 milliseconds), these fluids allow us to obtain exceptional results concerning the fluidity and spontaneity of movement articulation [11,12]. MR fluids are composed of water and mineral, synthetic or silicone oils mixed with 10-40% of dispersed iron powder with a size of 0.1-10 µm.…”

Multi-condition adaptive detail characterization model of magnetorheological dampers and experimental verification

“…As a type of semi-active damper, the MRD can regulate the damping characteristics by adjusting excitation current [1][2][3], possessing advantages such as fast response speed, a wide adjustable range of damping force, and low power consumption [4][5][6][7]. It has a promising prospect in the field of vibration control and has been widely applied in fields such as vehicle suspension [8][9][10][11], human exoskeletons [12][13][14], buildings [15][16][17] and bridges [18][19][20].…”