Design of bypass rotary vane magnetorheological damper for prosthetic knee application

Abstract

Semi-active systems using magnetorheological fluids have been realized in many novel devices such as linear dampers, rotary dampers, brakes, and so on. Rotary vane-type magnetorheological damper is one such device that uses magnetorheological fluid as a hydraulic medium and a controllable magnetorheological valve to generate variable resistance. This device, due to its limited angle motion, lends itself to a natural application for prosthetic knee joint. In this article, a bypass rotary vane-type magnetorheological damper suitable for prosthetic knee device is designed. In the proposed design, the rotary vane chamber and the bypass magnetorheological valve are connected using hydraulic cables and ports. The design of rotary cylinder is implemented based on the largest possible dimensions within the envelope of a healthy human knee, while the magnetorheological valve is designed optimally using a multi-objective genetic algorithm optimization. Off-state braking torque, induced on-state braking torque and mass of the valve are selected as three objectives. The torque and angular velocity requirements of the normal human knee are used as design limits. The optimal solution is chosen from the obtained Pareto fronts by prioritizing the objective of weight reduction of magnetorheological valve. The optimal solution is capable of producing a damping torque of 73 Nm at a design speed of 8.4 rpm and current supply of 1.9 A. Potential benefits offered by this design when compared with multi-plate magnetorheological brake are flow mode operation, large clearance gap, and fewer design components, thus reducing the manufacturing complexity.

Development of Tiny Vane-Type Magnetorheological Brake Considering Quality Function Deployment

“…To determine the magnetic flux density in the fluid gap, the number of turns of the coil wire, the yield stress ( ) and the relative permeability of MRF-132 DG need to be determined. Referring to the calculations conducted by Saini et al [ 12 ], the number of turns that can fill the coil space can be determined by Equation (20). When affected by a magnetic field, yield stress (kPa) can be calculated by the polynomial Equation (21).…”

“…In general, there are three working modes of MRF, namely, shear mode [ 8 , 9 , 10 ], flow mode [ 11 , 12 ], and squeeze mode [ 13 , 14 ]. The shear mode applies the friction principle wherein the MRF is placed in the gap between two magnetic components, one moving and the other stationery.…”

“…In contrast to linear and continuous types, vane MRB have rarely been implemented. Only a few designs were found for prosthetics [ 12 , 23 ], vehicle dampers [ 24 , 25 , 26 ], and back-drivable robotic industries [ 27 ]. None of these has been applied to AFO devices, whereas according to Rahman et al [ 28 ], MRB vanes are capable of producing greater torque when compared to other types.…”

Novel active magnetorheological knee prosthesis presents low energy consumption during ground walking

“…The semi-active prostheses, which employs controllable dampers, can dissipate energy and better adapt to various walking speeds and to various types of activities compared to passive prostheses (Hafner et al, 2007;Johansson et al, 2005). Magnetorheological (MR) fluid-based devices present reduced energy consumption, low relation between weight and output torque, fast response time and satisfactory control capacity (Leal-Junior et al, 2020;Rossa et al, 2014), and their use in semi-active prostheses has been significant (Gudmundsson et al, 2010;Herr and Wilkenfeld, 2003;Jonsdottir et al, 2009;Mousavi and Sayyaadi, 2018;Saini et al, 2020;Sayyaadi and Zareh, 2017;Xu et al, 2016). However, the aforementioned prostheses cannot mimic the active torque that is exerted by the muscles, which hinders the performance of basic movements such as going up on stairs and ramps and leaving a bench with a natural posture, thereby causing asymmetrical movements and high metabolic consumption (Geng et al, 2010;Herr and Wilkenfeld, 2003;Kapti and Yucenur, 2006).…”

Design and development of MR damper for two wheeler application and Kwok model parameters tuning for designed damper

“…This process was helpful in designing the MRD with respect to the requirements of the passenger vehicle. Saini et al 4 designed a rotary vane MR damper for prosthetic applications considering ASI 1020 steel and analysed the damper parameters to provide effective flux density in the MR fluid flow gap. Acharya et al 5 characterised a self-designed MR fluid and manufactured a monotube MRD and subsequently used Herschel-Bulkley model to mathematically represent the flow curves at different magnetic fields for the determination of dynamic yield stress.…”