Magnetorheological Fluid Clutch Research Articles

A Study on Power Transmission Control for Applying MR Fluid Multi-Plate Clutch to Automobile Power Distribution Device

The aim of this study is to design and manufacture a multi-plate clutch system that uses magnetorheological (MR) fluid control to allow for a variable power transmission ratio in power distribution systems. MR fluid is a smart material that enables presenting a solution to the shocks and power loss that occur due to mechanical problems in power distribution systems. As such, the longitudinal and lateral dynamic properties of 4WD (four-wheel drive) vehicles were examined and analyzed to develop an algorithm to control the front/rear power distribution according to the road surface state and driving conditions. To verify the algorithm, the CarSim vehicle dynamics simulation program was adopted to perform experiments to understand the vehicle’s dynamic performance improvements and turning stability via a HILS (Hardware in the Loop) system. In this study, an MR fluid, multi-plate clutch was used that combines a dry clutch and a wet clutch using the characteristics of the MR fluid. Such a clutch was designed to enable continuous and smooth torque transmission by utilizing the strengths of each of the dry and wet clutches. The CarSim vehicle dynamics program was used to conduct the experiments, which were conducted by linking to the manufactured MR fluid clutch experimental device. The experiments investigated the dynamic performance based on the power distribution ratio by performing longitudinal flat, inclined driving and lateral DLC (double lane change) driving. In summary, this study found that it is possible to perform power transmission by applying a current to an MR fluid and forming a magnetic field to change the flow properties of the fluid to control the torque transmission ratio that occurs in an MR fluid clutch.

Experimental measurement of a multi-pole magnetorheological fluid clutch under air cooling.

Thermal characteristics have a profound effect on the allowable slip power and torque transmission stability of magnetorheological (MR) fluid devices. This paper investigates the thermal properties of a multi-pole MR clutch under different heat dissipation methods. First, the structure of the clutch is described, and heat generation and heat dissipation of the designed clutch are studied theoretically. Then, a numerical model is established, and several simulations are conducted on steady-state and transient temperatures under various operation conditions. After that, a temperature testing platform for the MR clutch is built, and several temperature experiments are carried out. The results show that the allowable steady-state slip power of the clutch under natural air cooling is about 147W. Under forced air cooling, the allowable steady-state slip powers are 1.295, 1.555, and 1.790 kW, respectively, when the wind speeds are 3.5, 7.0, and 10.5m/s. Furthermore, it turned out that the transmission torque of the MR clutch decreases with the increase in temperature. The experimental and simulated values of temperature are in good agreement in terms of numerical values and trends, indicating that the established temperature field simulation model can better reflect the temperature characteristics of the actual operation of the proposed multi-pole MR clutch. This research achievement can provide support for research on heat dissipation technology for MR devices with multiple excitation sources.

Development and evaluation of a magnetorheological fluid-based clutch with hybrid excitation

This article presents the development and control of a hybrid excitation magnetorheological (MR) fluid clutch with improved magnetic cores. The clutch adopts a hybrid excitation design with coils and permanent magnets. To obtain an increased torque, an improved magnetic core shape of the permanent magnet is adopted in the clutch. Furthermore, simulation is used to test the magnetic field in the fluid gaps. Then, a prototype is manufactured, and a test bed is built. Experiments prove that the designed hybrid excitation MR clutch has an improved torque. In order to achieve accurate torque output, a genetic algorithm (GA) optimized fuzzy proportional-integral-differential (PID) controller is presented and compared with the other two controllers, and the effectiveness is verified by simulations and experiments. It turns out that the proposed GA optimized fuzzy PID controller is effective in improving the torque tracking accuracy and can be used for torque control of MR clutches.

Erratum: A low-power magnetorheological fluid clutch utilizing electropermanent magnet arrays

An erratum on: A low-power magnetorheological fluid clutch utilizing electropermanent magnet arrays. Bira N, Dhagat P and Davidson JR (2022), Front. Mater. 9:1039004. doi: 10.3389/fmats.2022.1039004Figure/Table LegendDue to a production error, there was a mistake in the legend for Figure 11 as published. The legend for Figure 11 was accidentally removed during typesetting. The correct legend appears below. The publisher apologizes for this mistake. The original version of this article has been updated.

Improvement of Haptic Interface for Teleoperation Endoscopic Surgery Simulators Using Magnetorheological Fluid Devices

A magnetorheological (MR) fluid is a composite material comprising ferromagnetic particles, medium oils, and several types of additives. We developed an MR fluid clutch for haptics (H-MRC) and installed it in a haptic interface that simulates teleoperation endoscopic surgery (ES). To enhance its operability, we redesigned the H-MRC to reduce its weight and improve its control system. We reduced the weight of the H-MRC and haptic gripper by 77.0 g and 137.0 g, respectively. To evaluate the influence of the improvement and force feedback functions on remote operation skills, we conducted pick-and-place tests with a remotely controlled system. In the tests, we subjectively evaluated the NASA-TLX and quantitatively evaluated the success rate of the task. The results of the subjective assessment showed significant reductions in mental stress during the teleoperation task. In addition, the results of the quantitative evaluation showed that the force feedback function was effective against the teleoperation skills of the operators.

Optimal Control for a Modified Bouc-Wen Model in a Magnetorheological Fluid Master Robot

Magnetorheological fluid (MRF) clutch is a kind of passive actuator with advantages, like fast response and low inertia. However, due to the complex natural property, it is difficult to model such devices accurately, and this leads to degraded performance. In this letter, a steady-state model and transient model are combined to describe the MRF clutch. In the steady-state part, hysteresis phenomenon is accurately depicted by a modified Bouc-Wen model and a polynomial. In the transient part, a 1st-order system is applied to express the dynamic response. Model predictive control (MPC) is applied to enhances the response time and alleviate resulting hysteresis distortion of the clutch. Two experiments were implemented to verify the effectiveness of the design. The first reveals the high precision and response speed of the clutch, based on the proposed model and MPC. It shows that the average model error and settling time are improved to be less than 1 Nmm and 20 ms respectively. The second confirms the effectiveness of MPC in alleviating hysteresis distortion, and the minor errors prove the accuracy of proposed model even with multi-frequency commands. Thus, the proposed model and MPC are adequate for promoting the model accuracy and response time of the MRF clutch based force feedback devices.

Investigation of the torque transmission time constant of a multi-disc magnetorheological clutch in the case of ramp function excitation

In this work the torque transmission time constant of a multi-disc magnetorheological (MR) fluid clutch is presented. The self-built clutch contains six layers of MR fluid and it is excited by an external electromagnetic coil. The transmitted torque is measured by a torque sensor using a self-developed LabVIEW software. Torque transmission is measured using ramp excitation with different slopes. The time constant of the clutch is derived from the time delay of the torque response. Our measurements showed the time constants as a hyperbolic function of the slope of the ramp excitation.

A novel magneto-rheological fluid dual-clutch design for two-speed transmission of electric vehicles

The dual-clutch transmission (DCT) in electric vehicles can significantly decrease the torque interruption and improve the shifting comfort. The magneto-rheological fluid (MRF) is a kind of intelligent material commonly used for torque transmission devices with high control accuracy and fast response, e.g. MRF clutch. This paper proposes a novel MRF dual-clutch (MRFDC) design for the two-speed transmission of EVs combining the DCT and MRF clutch advantages. The MRFDC is composed of an internal clutch and an external clutch. The two clutches with the same input shaft and different output shaft can shift between two gears by controlling the input current through the coils in the two clutches. The relationship between the input current and the magnetic flux density is obtained by the finite element analysis of the magnetic field under different input current. Theoretical analysis is carried out to estimate the output torque of MRFDC according to the geometric dimensions of MRFDC structure and rheological properties of MRF. The Herschel-Bulkley model is applied to describe the MRF behaviour because the shear rate of MRF is relatively high. The output torque model is built considering the magnetic flux density. Therefore, the relationship between the transmissible torque and applied input current is determined. Finally, the MRFDC model is experimentally verified on the testbed; besides, the transmissible torque tests and response time tests for internal and external MRF clutches are carried out, respectively. The test results agree with the simulation results, and the differences are within 2 N m. It is suggested that the MRFDC can be applied in EVs to improve vehicle performance.

A study of factors affecting torque transmission in permanent magnet-based magnetorheological fluid clutch

In this article, the study of several factors affecting the torque transmission capability of a permanent magnet-based, drum-type magnetorheological fluid (MRF) clutch is presented. These factors are: number of magnetic poles in the magnet assembly, material of the clutch, MRF layer thickness, and relative rotational velocity between the input and output stages of the clutch. For this purpose, a special single-MRF layer clutch was designed and fabricated, one which allows the convenient assembly and disassembly to reduce preparation time for testing. The average transmitted torque of this clutch under several combinations of the aforementioned factors was recorded and analyzed. Additionally, several magnetostatic simulations of the clutch were carried out, and both the magnetic flux density and transmittable torque calculated from the results of these simulation were compared against experimental measurements. It was found that magnet assemblies with lower number of magnetic poles resulted in higher torque outputs, however, the effectiveness of the utilized torque variation mechanism was reduced due to magnetic saturation of the components of the clutch. The material of the clutch was found to have a significant effect at low relative rotational velocities, resulting in a nonlinear relationship between transmitted torque and relative angular velocity. This nonlinear effect was more significant when aluminum was used in the components which interact directly with the MR fluid whereas the use of ferromagnetic components reduced this effect. Finally, the thickness of the MRF layer was found to have a significant effect on the transmitted torque of the MRF clutch, although not according to what magnetostatic simulations predict.

Twin-driven actuator with multi-layered disc magnetorheological fluid clutches for haptics

Magnetorheological fluids are composite materials made of ferromagnetic particles, medium oils, and several types of additives. We have developed actuation systems for the fine haptic control of master–slave robots. In this study, we proposed a new structure of a magnetorheological fluid–based actuator suitable for haptic devices. For the basic structure of the actuator, we proposed a twin-driven magnetorheological fluid actuator using two multi-layered disc-type magnetorheological fluid clutches for haptics. We conducted performance measures for the magnetorheological fluid clutches for haptics with three commercially available magnetorheological fluids (i.e. 122EG, 132DG, and 140CG from Lord Corp.). The experimental results show that 132DG is a better material for force control. Then, we proposed two types of twin-driven magnetorheological fluid actuators (i.e. link type and belt type) and compared their performance. The results show that the averages of the time constant are 19.1 and 16.1 ms for the link type and belt type, respectively. Furthermore, the averages of torque error are 0.033 and 0.068 N m for the link type and belt type, respectively. However, the belt-type twin-driven magnetorheological fluid actuator is better if a large range of motion is required, while the link-type twin-driven magnetorheological fluid actuator is better if accurate torque control is required.

Magnetohydrodynamics modelling of a permanent magnets activated MRF clutch–brake

Chattering due to vibrations on the machine tool shaft and control of the transmitted torque are both a concern in precision machining. Hence, a magnetorheological fluid clutch–brake, also acting as a rotary damper could be a promising solution. Permanent magnets are used to mechanically activate the clutch thus offering simplicity and reliability in operation. The viscosity of the magnetorheological fluid changes with the action of the magnetic field thus allowing to tune the transmitted torque. Moreover, the fluid adds damping in the system. In this paper, a computational magnetohydrodynamics model has been realized in order to numerically investigate and visualize the torque transmission under different rotational velocities when submitted to magnetic flux. The model was validated with experimental data from the literature. Results showed that because the permanent magnets have a limited flux intensity, the torque transmission is only efficient at lower rotational velocities.

Development of a novel high-speed actuation mechanism using a magneto-rheological fluid clutch and its application to a fluid control valve

In many dynamic systems, such as vehicles, engine air and fuel control systems, fluid power systems, industrial robotics, and testing machines, high-speed actuators are necessary to achieve efficient system operation and high bandwidth performance. This article introduces a new actuation mechanism to enable high-speed actuation. The premise for this actuation mechanism is to momentarily couple a moving component (kinetic energy source) with translational components, which is enabled by a coupling/clutch system. The kinetic energy source (flywheel, electric motor, pump or motor shaft, etc.) is intermittently clutched and declutched to produce linear motion. This article presents such an energy coupler actuator using a magneto-rheological fluid clutch, initially focused on an application for high-speed valve actuation. A multi-physics coupled model was developed to evaluate the proposed energy coupler actuator performance. Simulations were conducted to optimize the energy coupler actuator design parameters. A prototype of the magneto-rheological fluid energy coupler actuator based on the optimal design solution was fabricated and experimentally tested, which achieved 1.6-mm stroke in 4.7 ms.

Rendering viscosity using a four degrees of freedom wearable force feedback device with pneumatic artificial muscles and magnetorheological fluid clutches

Rendering viscosity using a four degrees of freedom wearable force feedback device with pneumatic artificial muscles and magnetorheological fluid clutches

Development of a Passive Magnetorheological Fluid Clutch With Field-Blocking Mechanism

This paper introduces a new torque variation mechanism for a magnetorheological fluid (MRF) clutch which uses permanent magnets. Previous prototypes of this clutch changed the position of the permanent magnets in and out of the clutch to vary the transmitted torque. The new design uses a field-blocking mechanism, a steel cylinder which covers the magnets, to vary the transmitted torque. The steel cylinder moves in and out the clutch, covering the magnets, and thus alter the intensity of the magnetic field the MRF experiences. Magnetostatic simulations of the magnetic field behavior inside the clutch and fluid dynamic simulations were carried out with the objective of finding the torque transmission capability. A mathematical model was also used for this purpose, where the magnetostatic simulation results were used to estimate the transmitted torque at several clutch configurations. Finally, several experimental measurements were carried out to determine the real behavior of the clutch and compare and verify the simulations and mathematical model results.

Development of a Wearable 4-DOF Force Feedback Device Using Pneumatic Artificial Muscles and Magnetorheological Fluid Clutches and Experiment of Rendering Elastic Force

Development of a Wearable 4-DOF Force Feedback Device Using Pneumatic Artificial Muscles and Magnetorheological Fluid Clutches and Experiment of Rendering Elastic Force

A Controllable Engine Cooling Pump Based on a Magnetorheological Fluid Clutch

A Controllable Engine Cooling Pump Based on a Magnetorheological Fluid Clutch

Steady-State Heat-Flow Coupling Field of a High-Power Magnetorheological Fluid Clutch Utilizing Liquid Cooling

Compared with traditional speed regulation (SR) approaches like variable frequency and hydraulic coupling, magnetorheological clutch (MRC) provides a more superior solution for high-efficiency energy saving SR. However, recent developments have demonstrated that severe heating is an outstanding challenge for MRC, especially in high-power applications. Among commonly used cooling methods, liquid cooling offers a viable alternative for the problem. Aiming at pre-evaluating the cooling efficiency of a liquid-cooled MRC in high-power situations, this study introduces a heat-flow coupling simulation method. In this paper, theoretical basis for the simulation is presented first, which is followed by an illustration of the heat-flow coupling simulation. This paper details the simulation model establishment, finite element meshing (FEM), boundary conditions, and simulation parameters. After the simulations, the results concerning the steady flow field of the internal coolant, along with the steady-state temperature fields of MRC, magnetorheological (MR) fluids and the coolant are presented and discussed. Finally, several heating tests of an MRC prototype under various operation conditions are performed and the results verify the correctness and rationality of the simulation.

Design and Manufacturing Aspects of Magneto-rheological Fluid (MRF) Clutch

This paper describes a research work concerned with design method and manufacturing details of a Magneto-rheological Fluid (MRF) Clutch which has a multi-layered disks and micro-size (1 micro meters) gaps of MR fluid for automotive applications. Magneto-rheological Fluid devices are finding a wide variety of applications to meet the new market demand. An MR fluid will be in a free-flowing liquid state in the absence of magnetic field, but under a strong magnetic field its viscosity can be increased by more than two orders of magnitude in a very short time (milliseconds) and it exhibits solid-like characteristics. Various devices working with MR fluids include Clutches, Brakes, Hydraulic valves, dampers, robotic arms. The micro-size gap works for the reduction of magnetic resistance, amount of power supply and size of the total system. The controllability of MR fluids provides an adjustable torque transmission and slippage for the applications. Three-dimensional solid modelling is performed for clutch design and manufactured. The benefits with using MRF are fast response, simple interface between electrical power input and mechanical power output and of course the excellent controllability of the fluid. MRF clutches are known as good Torque transmitting devices.

Geometry optimization of a magnetorheological clutch operated by coils

Magnetorheological fluids are smart materials responsive to magnetic field, widely applied in dampers and shock absorbers but also in clutches and brakes. The magnetorheological fluid gap shape is a very important topic in the design of clutches, since it directly influences the transmissible torque and the power loss. In this paper, an approach to magnetorheological fluid clutch design based on optimization is proposed and tested on four different layouts. Starting from a given available volume, two magnetorheological fluid gap shapes, namely single cylinder and multi-disc, and two coils positions, i.e. internal or external, were considered. A lumped parameter model was developed to analytically compute the magnetic flux along the clutch magnetic circuit and to calculate the transmissible torque of the clutch. The optimal geometry of the clutch for maximum transmissible torque, in terms of number and dimensions of the coil sectors, was determined for each shape and coil configuration and the results were validated by finite element models.

Comparison of Affecting Factors on the Shear Stress Output of Cylinder-Typed MRF Clutch

With the purpose of studying the main influence on the cylinder-typed magneto-rheological fluid (MRF) clutch, the relationship between the output of shear stress and its affecting factors is presented in this paper; through theoretical derivation from the Bingham Model and the cylinder-typed shear model, the stress born by the MRF in the clutch is analysed, and the affecting factors on the clutch is also simulated and verified through experiments. The study shows that as the magnetic field strengthens, the shear stress of the cylinder-typed MRF clutch grows linearly, with proportionality constant at 0.162; the increase of shear rate, relevant to the magnetic field strength, makes little difference to the torque output, with proportionality constant at 0.00026B. The results indicate that mechanical-electrical integration of clutch devices can be achieved through the control of magnetic field output of the electromagnet.