Search Results (189)

Severe longitudinal vibrations and abnormal tension fluctuations in hoisting ropes pose significant threats to the safe and stable operation of mine hoisting systems. To address these issues, this paper proposes a semi-active vibration-suppression strategy combining a magnetorheological damper (MRD) with output-feedback adaptive sliding-mode control (ASMC). A dynamic model of the MRD-equipped hoisting system is developed using Hamilton’s principle. The nonlinear hysteresis of the MRD is described by a simplified extended hyperbolic tangent function model (SEHTFM), and an inverse model converts the desired control force into a feasible real-time current command. Using only displacement and velocity measurements at the conveyance–rope connection, the ASMC compensates for matched uncertainties, including boundary excitation, modeling and truncation errors, and force-realization errors. Numerical simulations compare an optimized passive viscous damper benchmark, SMC–MRD, and ASMC–MRD responses under varying payloads, accelerations, and hoisting speeds. During constant-speed operation, ASMC–MRD achieves peak reduction rates of 82.8% in dynamic displacement and 77.6% in dynamic tension relative to the optimized passive benchmark. The results demonstrate accurate force realization with small bounded tracking errors and improved robustness under variable operating conditions. Full article

This study investigates physics-informed and data-driven hybrid modeling strategies for an automotive-grade electrohydraulic (EH) semi-active damper system. Although deep sequence learning architectures such as Long Short-Term Memory (LSTM) networks and Transformers can provide high predictive accuracy, purely data-driven approaches may struggle to preserve physical consistency and maintain robustness under unseen operating conditions. These limitations become more pronounced for EH dampers, whose hysteretic characteristics exhibit highly nonlinear and non-proportional variations under different current and frequency excitations, unlike the more scalable behavior commonly observed in magnetorheological (MR) dampers. To address these challenges, two physics-informed integration strategies are investigated. The first strategy combines physical and data-driven models through parallel loss-function synthesis. The second strategy introduces a learnable physics layer (PINN-Hybrid), in which the coefficients of the extended hyperbolic tangent formulation are adaptively learned within the neural network architecture. In this framework, the physical model acts as a structural regularization mechanism that guides the learning process while preserving the flexibility of data-driven sequence modeling. The proposed models are evaluated under abrupt valve-control operating conditions. Comparative results indicate that the proposed physics-informed architectures improve hysteresis continuity, physical plausibility, and robustness compared with purely data-driven approaches, particularly in low-velocity and transition regions. The proposed framework therefore demonstrates the potential of physics-informed learning strategies for reliable real-time modeling of nonlinear automotive EH damper systems. Full article

To improve the energy capture efficiency of wave energy converters (WECs), various control strategies based on adjustable power take-off (PTO) systems have been developed. However, such approaches often impose stringent requirements on PTO structural design and generator performance. To address this issue, this paper proposes a novel variable-stiffness point-absorber wave energy converter (VSPAWEC). In the proposed system, a stiffness regulator (SR) composed of a magnetorheological damper (MRD) and a spring mechanism is introduced as a frequency-tuning device, enabling stiffness compensation of the point absorber within a certain operating range. Based on the SR mechanism, a frequency-tracking resonance control strategy is further developed. Specifically, a sliding mode control algorithm is employed to regulate the MRD in real time, allowing the piston rod to track a reference position signal generated from the known dominant wave frequency. In this way, the spring force applied to the buoy can be adjusted adaptively, so that resonance between the buoy and the incident waves can be achieved. Finally, numerical simulations are conducted to evaluate the variable-stiffness characteristics of the proposed VSPAWEC and to verify the effectiveness of the developed frequency-tracking control strategy. The results demonstrate the feasibility of the proposed concept for resonance tuning and wave energy capture enhancement. Full article

Magnetorheological (MR) dampers enable semi-active control in prosthetic knees by providing rapidly adjustable resistance with low mechanical complexity. This paper evaluates three torque level control methodologies for a transfemoral prosthetic leg incorporating an MR damper: a model-based feedforward strategy, an adaptive inverse-dynamics controller, and a robust inverse-dynamics controller. A Lagrange-based planar leg model with explicit force-to-torque mapping is formulated, and a reference knee trajectory is estimated from measurable gait variables using a cubic polynomial model whose order is selected through least-squares RMSE analysis. Each controller is assessed using knee-angle tracking accuracy and control effort to capture the practical trade-off between motion quality and energy demand. Results demonstrated that the adaptive inverse-dynamics controller has the smallest tracking error but requires the highest effort, whereas the robust inverse-dynamics approach realizes approximately the same tracking performance with reduced effort, thereby suggesting the best accuracy–effort compromise in the present work. Results, likewise, examined actuator feasibility by considering the MR damper as the primary dissipative element and the DC motor as a supplemental active actuator required when damping alone cannot satisfy the commanded knee torque. Full article

To address the coupled challenges of tire dynamic load regulation and ride comfort improvement in hydrogen-powered heavy-duty trucks (HPHDTs) under non-stationary road excitations, this study evaluates a magnetorheological (MR) damper-based semi-active front suspension system. A vehicle–road coupled dynamic simulation model was developed in MATLAB/Simulink (R2025b) using a Class C road profile, and three representative driving conditions, namely acceleration, deceleration, and constant-speed driving, were considered. Four control strategies, namely, interval type-2 (IT2) fuzzy control, type-1 (T1) fuzzy control, skyhook control, and PID control, were comparatively investigated. The results indicate that deceleration is the most critical operating condition, resulting in more severe tire–road interactions and poorer ride comfort than the other scenarios. Among the evaluated strategies, IT2 fuzzy control provides the best overall performance. Compared with the passive suspension, it reduces the front-wheel RMS dynamic load by 63.39% and improves ride comfort by 64.67% under deceleration. The T1 fuzzy and PID controllers provide moderate improvements, whereas skyhook control exhibits relatively limited effectiveness. These findings demonstrate that combining MR dampers with IT2 fuzzy control provides a feasible and robust approach for improving road friendliness, ride quality, and operational stability in advanced heavy-duty vehicle suspension design. Full article

Accurate modeling of smart composite dampers is crucial for simulation and model-based control. This study focuses on the constitutive modeling of a novel damper that synergistically combines an Entangled Metallic Wire Mesh (EMWM) with a magnetorheological (MR) fluid. Unlike traditional MR dampers, the interaction between the field-responsive MR fluid and the rate-sensitive, deformable EMWM matrix introduces strong coupled current–frequency dependence. To capture this essential characteristic, a control-oriented, bivariate (current–frequency) hysteresis model is formulated, wherein all parameters are explicit, continuous functions of both the control current (I) and excitation frequency (f). A systematic two-step identification method is employed to derive these functions from dynamic tests. A key finding is that the identified damping exponent (α) consistently exceeds unity across the tested operational range. This quantitatively indicates a transition from viscous-dominated to inertial-flow-dominated dissipation within the EMWM matrix, a distinctive mechanism attributed to non-Darcian flow in its porous structure. The fully parameterized model demonstrates high fidelity (R² > 0.99) within the characterized low-frequency, small-amplitude regime and shows reliable predictive capability for interpolated conditions. The presented model serves as a ready-to-use constitutive tool for the simulation and design of low-frequency vibration isolation systems utilizing EMWM-MR composites, and the revealed inertial flow mechanism provides fundamental insight for the development of next-generation adaptive dampers. Full article

Magnetorheological (MR) semi-active suspensions offer clear advantages in improving ride comfort and handling stability, yet their engineering applications are often hindered by strong nonlinear hysteresis of the damper, the randomness of road excitations, and the reliance on manual tuning of controller parameters. To address these issues, this paper proposes an integrated framework of “experimental modeling–semi-active implementation–adaptive control.” First, characteristic tests of the MR damper are conducted, based on which a current-dependent Bouc–Wen forward model is established. Tianji’s Horse Racing Optimization (THRO) is then employed for parameter identification to reproduce the hysteresis behavior accurately. Second, a back propagation (BP) neural network-based inverse current model is developed to achieve rapid mapping from “desired damping force” to “driving current,” enabling semi-active actuation. Furthermore, a radial basis function (RBF) neural network is embedded into the active disturbance rejection control (ADRC) structure to estimate the system Jacobian online and to tune key extended state observer (ESO) gains in real time, forming the proposed RBF-ADRC strategy and thereby enhancing disturbance observation and compensation capability. Simulation results under pulse-road and Class-C random-road excitations show that, compared with the passive suspension, the proposed method reduces the root mean square error values of sprung-mass acceleration, suspension dynamic deflection, and tire dynamic load by 25.14%, 18.71%, and 11.61%, respectively, while also outperforming skyhook control and fixed-gain ADRC. Frequency-domain results further show stronger attenuation in the low-frequency band relevant to body vibration. Under pulse excitation, RBF-ADRC yields smaller peak and trough body accelerations and faster post-impact recovery. Under ±30% sprung-mass variations, it achieves the best worst-case and fluctuation-range robustness among the compared strategies and remains close to offline retuning. These results demonstrate that the proposed method improves both control performance and robustness while reducing the need for repeated manual calibration. Full article

This study analyzes the hydrodynamic characteristics of a short magnetorheological squeeze film damper, with emphasis on the fluid microstructure responsible for generating damping forces. The magnetorheological fluid contains non-Brownian spherical particles suspended in a non-magnetic Newtonian fluid. When exposed to a magnetic field, these particles form chain-like structures that restrict fluid motion. In this context, the Mason number characterizes the fluid microstructure and establishes the ratio of viscous to magnetic forces. The mathematical model for solving the flow field, which depends on the continuity and momentum laws, the Bingham rheological model, and boundary conditions at the interfaces, is solved analytically. The Reynolds equation determines the fluid pressure distribution and follows the Sommerfeld boundary condition. Mass imbalance induces chaotic rotor motion, resulting in lateral vibrations. As the journal squeezes the fluid, positive pressure develops, generating damping forces that dissipate vibration energy. The results in this research show that the Mason number significantly affects fluid pressure, which increases as magnetostatic forces exceed viscous forces. This increase in pressure produces damping forces that reduce rotor displacement. Additionally, both radial and tangential forces increase with particle volume fraction, in contrast to classical Newtonian behavior. These findings are relevant to the handling of magnetorheological fluids in vibration control mechanisms. Full article

When it comes to active or semi-active suspension, one of many design challenges is the ability to dynamically change the damping rate of a shock absorber. Two fundamental means of accomplishing variable damping are by changing the restriction imposed on the fluid or changing the viscosity of the fluid. One way to change the restriction imposed on the fluid is by using a valve controlled by a solenoid. As more current flows through the solenoid a plunger gets pulled into the center of the coil, which acts against a mechanical spring that pushes it to a default state. There are specific kinds of fluids, such as ferrofluids or magnetorheological fluids, that change their viscosity in the presence of magnetic fields. This paper aims to guide the reader through the design of an electromagnetic damper, how to derive theoretical performance criteria from a semi-active suspension system, and design optimization considerations. The design will test three different coil specifications, including size, wire size, location, applied voltage, and amperage. The experimental evaluation was conducted as a qualitative proof-of-concept to verify the presence of field-dependent viscosity and damping behavior under low-frequency manual excitation. Quantitative performance assessment was performed using analytical and numerical modeling to determine whether the proposed design satisfies semi-active suspension damping requirements. Full article

Magnetorheological (MR) dampers exhibit significant hysteretic nonlinearities, particularly under dynamic operating conditions, where accurately modeling the complex coupling between magnetic flux density and excitation current remains challenging. To overcome the limitations of the conventional static Jiles–Atherton (JA) model in capturing dynamic hysteresis responses, a dynamic JA model incorporating multiple loss mechanisms (LS-DJAM) is proposed for MR dampers. Building on loss separation theory, the model integrates eddy current and excess loss mechanisms to more accurately represent the dynamic hysteresis behavior of MR dampers. By coupling the Bingham mechanical model, a magneto-mechanical constitutive relation for MR dampers is established. Furthermore, to enhance the accuracy of LS-DJAM parameter identification, a hybrid particle swarm optimization–genetic algorithm (PSO–GA) is developed. Genetic operators are embedded within the PSO framework to strengthen the global search capability and mitigate premature convergence, thereby enabling efficient LS-DJAM parameter identification. The proposed LS-DJAM, identified via the PSO–GA, significantly enhances the modeling of MR damper output forces. PSO–GA parameter estimation improves accuracy by over 60%, and the LS-DJAM reduces the maximum modeling error by 87.5% compared with the conventional JA model. It accurately captures the dynamic hysteresis characteristics of MR dampers, providing a robust theoretical basis and practical framework for high-performance control and engineering optimization. Full article

This paper presents a virtual reference-based preview semi-active suspension system using a Magneto-Rheological (MR) damper to improve ride comfort when traversing bumps. The algorithm is designed to track the virtual reference profile of the vehicle’s corner by introducing a Model Predictive Control (MPC) method while considering the passivity of the MR damper. The proposed MPC is formulated to rely solely on estimable variables from an Inertial Measurement Unit (IMU) and vertical accelerometer. To support implementation on an Electronic Control Unit (ECU), the suspension state estimator employs a simple band-limited filtering structure. The proposed method is evaluated in simulation and achieves performance comparable to a controller that has accurate prior knowledge of the road profile. In addition, simulation results demonstrate that the proposed approach exhibits low sensitivity to sensor noise and bump perception uncertainty, making it well suited for real-world vehicle applications. Full article

During takeoff and landing, aircraft operate in a variety of situations, posing significant challenges to landing gear systems. Passive hydraulic–pneumatic dampers are commonly used in conventional landing gear to absorb impact energy and reduce vibration. However, due to their fixed damping characteristics and inability to adjust to changing operating conditions, these passive systems have several limitations. Recent research has focused on creating intelligent landing gear systems with magnetic dampers (MR) to overcome these limitations. By changing the magnetic field acting on the MR fluid, MR dampers provide semi-active control of the landing gear dynamics and adjust the damping force in real time. This flexibility reduces structural load during landing, increases riding comfort, and improves energy absorption efficiency. This study examines the current state of MR damper application for aircraft landing gear. The review categorizes current control techniques and highlights the structural integration of MR dampers in landing gear assemblies. Purpose: The magnetorheological (MR) damper has become a promising semiactive system to replace the conventional passive damper in aircraft landing gear. However, the mechanical structure and control strategy of the MR damper must be designed to be suitable for aircraft landing gear applications. Methods: Researchers have explored the potential structure designed, the mathematical model of the MR landing gear system, and the control algorithm that was developed for aircraft landing gear applications. Results: According to the mathematical model of the MR damper, three types of models, which are pseudo-static models, parametric models, and unparameterized models, are detailed with their application. Based on these mathematical models, many control algorithms were studied, from classical control, such as PID and skyhook control, to modern control, such as intelligent control and SMC control. Full article

A magnetorheological (MR) damper is an intelligent semi-active control device characterized by its output damping force and adjustable coefficient that vary in response to changes in the internal magnetic field. This study proposes a multiphysics coupling model that takes into account the electromotive force within the magnetorheological fluid, which is related to both the magnetic field intensity and shear stress. The Bingham–Papanastasiou constitutive model was employed to accurately represent the dynamic performance during the simulation of magnetorheological dampers, thereby overcoming its discontinuity. The investigation delves into the unique responses elicited by single-coil and three-coil configurations under identical excitation conditions. Through theoretical and magnetohydrodynamic analyses, the nonlinear rheological behavior of the MR fluid is elucidated. The study also scrutinizes the effects of various internal structural parameters on the mechanical characteristics of the MR damper using the results of simulations. An assessment of parameter sensitivity on the damper’s output was carried out, and the response surface methodology was subsequently utilized to derive a surrogate model expression. Ultimately, an optimized design was obtained, achieving a balance between output damping force and adjustable coefficient. This method lays the groundwork for the mathematical modeling and simulation analysis of multi-coil magnetorheological dampers. Full article

This paper introduces a novel Magnetorheological (MR) damper integrated with a ball-screw mechanism (SMRB damper) that is designed to unify translational and rotational motions for enhanced automotive suspension performance. While shear-mode rotary MR dampers offer excellent responsiveness and stability, prior designs face persistent issues such as high off-state torque, structural complexity, or limited damping force. The proposed damper aims to overcome these limitations. Its design and operating principle are presented, followed by the development of a mathematical model based on the Bingham-plastic formulation and finite element analysis. To maximize damping capability, the key structural parameters are optimized using an Adaptive Particle Swarm Optimization (APSO) algorithm. Finally, a prototype is fabricated based on the optimized results, and experimental tests validate its performance against simulation predictions, demonstrating its improved potential for vibration control applications. Full article

During the launch phase of a carrier rocket, the spacecraft carried by the rocket will be subjected to strong vibrations from the rocket body. Therefore, based on the special working conditions during the rocket launch phase, a passive-tuned magnetorheological (PT-MR) damper using the magnetorheological (MR) composite was proposed, which achieves stable and efficient operational performance using permanent magnets (PMs). Firstly, the influence of squeeze mode on the performances of the MR composite was analyzed for different vibration conditions. Then, by analyzing the squeeze strengthening effect of the MR composite and the influence of non-uniform radial gap size on the damping force, the mechanical model of the proposed damper was derived. Furthermore, the damper prototype was fabricated and its mechanical properties were tested, and the test results showed that the proposed damper can generate a damping force exceeding 800 N. Finally, the vibration isolation effectiveness of the proposed damper was verified from a system perspective by building the simulation model of whole-spacecraft vibration isolation. Full article