Sinusoidal Displacement Input Research Articles

Modelling and simulation of MR damper characterization and uncertainty assessment in marine engine vibration isolation with FLPID control

ABSTRACT This paper meticulously examines the magneto-rheological (MR) damper to exploring its application in a semi-active isolator system. The MR damper’s distinctive capability to regulate damping force through an externally applied magnetic field is investigated via extensive experimental testing. Sinusoidal displacement inputs with varying electromagnet currents reveal a direct correlation between higher current levels and augmented MR damper forces. Validation of the experimental results is achieved through the Viscous Plus Dahl Model, showcasing its accuracy in capturing the damper’s hysteresis behavior. The study extends its scope to practical implementation by integrating the MR damper into a marine diesel engine system. A fuzzy logic-based self-tuning PID controller collaborates with the MR damper to establish a semi-active vibration isolator. The integrated model, encompassing primary and secondary masses, the engine, and the isolator with passive and semi-active systems, is rigorously analyzed. Experimental validation and theoretical simulations, aligned with data gathered from experiments, affirm the model’s fidelity in representing the MR damper. Simulation outcomes underscore the significant enhancement in vibration reduction characteristics of the semi-active isolator system compared to its passive counterpart, particularly evident in the improved performance of the 1200 kg engine under diverse operating conditions.

Experimental and analytical modelling on a novel self-centering viscous damper

Self-centering (SC) supplemental dampers offer a feasible approach to realize low-damage structures. A novel self-centering viscous damper (SCVD) that incorporates an SC part and a viscous damper (VD) part in parallel, and then series with a length adjustable (LA) part. The working mechanism and hysteretic model were both analyzed for the SCVDs. Dynamic reversed sinusoidal displacement inputs were used in experimental proof-of-concept validation studies. Each component was examined separately to describe and distinguish their distinct contributions to the whole device. Individual results in summing are consistent with hybrid device outcomes for the same input. The SCVDs showed excellent self-centering capability with satisfactory energy dissipation. A maximum equivalent viscous damping ratio (EVDR) of 99.37% was observed. A theoretical model and a numerical model were built and examined for the proposed SCVDs. The inevitable gaps from installation have a noticeable effect on the VD part and the SCVD, especially for small strokes. Except for small strokes, comparisons of test findings and analytical models reveal similar hysteretic reactions, for which the coefficients of determination are greater than 0.9, thereby validating the performance of the theoretical and analytical models to simulate the behavior of the tested SCVDs. In comparison to existing SCVDs, the suggested SCVDs have a more controllable SC ability, length adjustability, and energy dissipation capacity based on the demands of the designers. Furthermore, five distinct lateral resisting components were used in nonlinear response history analysis to compare the seismic and resilient performance amongst the moment resisting frame (MRF), buckling restrained brace (BRB), SC, VD and SCVD systems. Finally, the addition of SCVDs and VD parts can both be effective in controlling the maximum and residual story drift ratios on average. Overall, our findings provide innovative, simple implementable choices for developing low-damage structures.

A wave energy harvester based on coaxial mechanical motion rectifier and variable inertia flywheel

The wave energy harvester has been employed to power marine devices. For the wave energy harvester based on mechanical motion rectifier, the output power and efficiency are limited due to low inertia-damping ratio and perpendicular motion transformation. A coaxial mechanical motion rectifier with the function of increasing transmission ratio is designed based on a planetary gear train and four one-way clutches, and the input and output shafts are arranged coaxially. A variable inertia flywheel is incorporated in the wave energy harvester to extend the overrunning phase by slowing down the velocity attenuation of the generator. The wheel in variable inertia flywheel is reduced to four cantilever sliders to decrease the starting torque. The dynamics model of the wave energy harvester considering the meshing and overrunning phases is investigated due to the introduction of variable inertia flywheel. The input force and output voltage are simulated with sinusoidal displacement input after obtaining the angular velocity of generator with variable inertia flywheel. A maximum efficiency of 51.54% and average output power of 1.17 W on Instron machine are achieved, while a maximum output power of 3.35 W in ocean tests is obtained. The experiments verify that the design of coaxial mechanical motion rectifier and variable inertia flywheel is beneficial to improving the output power and efficiency.

Evaluation of a commercial MR damper for application in semi-active suspension

As the rheology of a magneto-rheological (MR) fluid can be controlled by an externally applied magnetic field, the damping force generated by a MR damper can be controlled by varying the current supplied to an electromagnet inside the damper. This paper presents the experimental evaluation of such a MR damper RD-8040-1 by Lord Corporation, USA, and its application in a semi-active suspension. The experiments were carried out in damping force testing machine. Sinusoidal displacement input was given to the test damper. The set of experiments were repeated for different levels of current (0–1.5 A in steps of 0.25 A) supplied to the MR damper. Plots of force versus displacement for each frequency of excitation and plots of maximum force versus frequency of excitation show that higher values of current lead to elevated values of MR damper forces. This increase in MR damper load with current supplied is studied and analyzed to develop a mathematical model of the MR damper under investigation. The nonlinear softening hysteretic behavior of the MR damper is simulated by using genetic algorithm provided in the optimization toolbox of MATLAB. Calculations on energy dissipation and equivalent damping coefficient of the MR damper show that the same damper can make the suspension system behave as an underdamped system, critically damped system or overdamped system depending on the value of current supplied to it. The application of this MR damper for heavy vehicle driver’s seat suspension is explored with the help of MATLAB simulations.

Single-Actuator-Based Three-DoF Planar Manipulation via a Viscoelastic and Nonparallel Hybrid Joint Mechanism

This paper proposes a dexterous nonprehensile manipulation using the vibration of a plate, in which a three-degree-of-freedom (DoF) motion of a part is controlled based on a single actuator. First, a manipulator whose end effector is a flat plate is introduced. The manipulator employs a hybrid joint mechanism with a viscoelasticity and a nonparallel axis layout. The characteristic of the mechanism is that the shape, orientation, and size of the vibrational orbit of the plate vary based on the sinusoidal displacement input to the actuator. Subsequently, the trajectories of multiple point masses on the plate are analyzed to understand the approximated three-DoF motion of a part. The simulation results reveal that the whirlpool-like characteristics of the trajectory map, which aid in the rotational and translational motions of the part, can be managed by the input frequency, offset angle, and amplitude of the sinusoidal displacement input. Based on the trajectory maps, nine primitives for manipulating the part are designed. Finally, the proposed manipulation scheme is experimentally validated using a prototype. After confirming the nine primitives in the experiment, applications to one-DoF, two-DoF, and three-DoF parts feeding tasks are demonstrated.

Design of energy harvester using rotating motion rectifier and its application on bicycle

The energy harvester has been employed to transform mechanical vibration into electrical power in the field of road transportation. An electromagnetic energy harvester for bicycle application to recycle low-frequency vibration is proposed. The input of up-down motion is transformed into bidirectional rotation by the transmission part, and then translated into unidirectional rotation by the rotating motion rectifier. The rectifier outputs rotation to the generator, and the electrical energy generated can be stored in super capacity at the charging mode or light up the LED at the discharging mode. Lab experiments are conducted to test the proposed harvester on Instron servo-hydraulic machine. A power of 0.491 W and a total efficiency of 52.8% are achieved with sinusoidal displacement inputs from 1.0 Hz to 2.5 Hz and external resistors from 50 Ω to 200 Ω. Field tests of applying the harvester onto the bicycle are carried out and a power of 0.313 W is obtained when riding through the speed bump. Above tests demonstrate potential applications of the harvester in self-powered devices.

Omnidirectional Nonprehensile Manipulation Using Only One Actuator

This paper presents a novel nonprehensile manipulation method that uses the vibration of a plate, where the two degrees of freedom of a part on the plate are controlled by only one actuator. First, a manipulator whose end effector is a flat plate is introduced. By employing an underactuated joint mechanism, the shape and orientation of the vibrational orbit of the plate vary according to frequency and offset angle of the sinusoidal displacement input to an actuator. Then, simulation analyses reveal that the manipulator can omnidirectionally induce translational velocity to the part on the plate. There exists an orthogonality between the effects of the frequency and offset angle on the velocity map of the part. Based on this characteristic, a visual feedback control for manipulating the part is designed. Finally, the proposed method is validated via experiments using a prototype manipulator. A target-trajectory tracking task and a four-way part-feeding task are demonstrated.

Spectral Analysis and Experimental Validation of a Low-Damage Hybrid Dissipater

Supplemental dissipation plays a vital role in reducing structural damage, repair costs, and downtime due to earthquakes. A hybrid dissipation mechanism has been developed to offer repeatable and consistent energy dissipation, while maintaining significant re-centring capability. This dissipation device consists of a viscous damper (VD) and a friction ring-spring (RS) combining rate-dependent dissipative behaviour of the viscous device with rate-independent dissipation and re-centring from the ring-spring. This approach, ensures simultaneous displacement reduction and increased self-centring potential. Spectral analysis of a single-degree-of-freedom structure has been carried out to outline the efficacy of the device and delineate the impact and contribution of each component to the overall device behaviour. A prototype hybrid device is tested comprising a viscous damper with silicone fluid and a ring-spring with peak design force of 26kN. These components are connected in a parallel configuration through a fixed outer shell and a moving coupled shaft. Experimental proof-of-concept testing for the hybrid device and single ring-spring includes sinusoidal displacement inputs with amplitude of 25 and 30 mm, loading frequencies of [0.25-1.75] Hz, and ring-spring pre-load of 21 and 34%. The overall device has a peak response force of 32kN at input velocities of ~200 mm/s. At this speed, ~20kN comes from the ring spring and ~12kN from the viscous damper. Further tests on the single viscous device are conducted using silicone oils with viscosities of 100, 500, and 1000 cSt and peak input velocities of [50-300] mm/s to evaluate the impact of viscosity on the damping force. These experimental tests are used to delineate the function of the individual components of the device and assess the behaviour of the hybrid combination, in comparison to the predicted analytical behaviour.

Design and Experimental Validation of a Re-centring Viscous Dissipater

The design and experimental validation of a passive, hybrid self-centring supplemental damper for low-damage structures is presented. The device combines rate-dependent dissipation of a viscous damper with the rate-independent dissipation and re-centring restoring force of a ring-spring in a parallel fashion. Experimental proof-of-concept validation tests use sinusoidal displacement inputs consisting of [25, 30]mm amplitudes and [0.25–1.75]Hz frequencies, for two levels of ring-spring pre-load equal to 21% and 34% of the design force. Each component is tested individually to characterise and delineate their specific contributions to the overall device. The ring-spring has a design force capacity of 26kN and a return stiffness ratio of 34% that remain independent of the velocity input. The viscous device input velocities of [50–330]mm/s provide velocity dependent dissipative forces with a maximum of 22kN at the maximum input velocity. Individual results in summation match the hybrid device results for the same input, indicating no loss of efficiency in the hybrid device load transfer. Overall, these results offer a range of new, easily implemented options for energy dissipation in developing low-damage structures, which can also provide necessary re-centring capability within the same package. The overall method is readily generalised for a wide range of hybrid device force capacities and design requirements.

Damping properties and energy evaluation of a regenerative shock absorber

This paper presents dynamics analysis of a regenerative shock absorber using a linkage mechanism as motion transmission developed from a valid kinematics analysis. The main objective of this study is to obtain force and energy regeneration properties, which is followed by regeneration efficiency. Physical based models are adopted from the structural design and mathematical models are derived in order to conduct numerical investigations. Parameters are determined by estimation and measurement, while sinusoidal displacement input and its derivations are used to study system behaviors. In fixed amplitude and frequency, the total damping force is explored in time, displacement and velocity response, while regenerative power is compared to mechanical power in time domain for gaining efficiency. The result shows that asymmetry occurs in force–velocity curve which is influenced by mass inertias of epicyclic gears. In different amplitudes and frequencies, the damping nature, harvested power and efficiency are studied and linked with regard to the proportion of mechanical and electrical force. The result indicates that the electrical force has much contributed in low range of amplitudes and frequency, which is followed by energy harvesting and regeneration efficiency.

Modeling and experimental study of a linear power generator for road energy harvesting

There are a large number of vehicles running on the road, and the shape of the road surface varies accordingly. Thus, this kinetic energy can be harvested to power electrical equipment along the road, and this energy harvesting technology has good environmental adaptability because it will not be affected by the sun, wind, or other natural environmental factors. A permanent magnet linear generator is designed and tested for road kinetic energy harvesting. The generator is described by a single degree of freedom system model with mass-spring-damping. The system response is analysed on the basis of the system model. The mover's vibration response is modeled over two stages according to the vehicle's wheel load. The power generation process is simulated and calculated according to the aforementioned models. The magnetic force and magnetic field are calculated by use of the finite element method; because of the non-linear magnetic force, the output electromotive force (EMF) is subject to frequency multiplication under conditions of sinusoidal displacement input. A prototype is manufactured and embedded in the road for experimental research purposes. The test result shows that the maximum peak-to-peak value of the output EMF and average power are up to 484.18 V and 255.1 W, respectively, as a car passes over the generator at a speed 20 km/h. Moreover, the time-domain and amplitude-frequency characteristics agree well with those calculated. It is demonstrated that the proposed model is able to describe the road power generator.

Damping Force and Energy Regeneration Characteristics of the Regenerative Pendulum Vibration Absorber

This paper presents the characteristics of damping force and energy regeneration of a pendulum. The damping force analysis includes force-displacement and force velocity loops when the pendulum, attached in a cart, is subjected with sinusoidal displacement input. The energy regeneration analysis includes the voltage, the current and the power generated by a generator. The main objectives of this paper are to obtain the mathematical models and to characterize both force and energy regeneration based on the inputs. The results show that the amplitudes and the frequencies at low level are most likely basic damper behavior. Moreover, the energy regeneration increases as well as the amplitude and the frequency.

Kinematics Analysis of a Leg Mechanism as a Motion Converter

This paper presents kinematics analysis of a leg mechanism for converting linear motion into rotary motion to be used as a Regenerative Shock Absorber (RSA). The kinematics analysis determines the positions, the velocities and the accelerations when a leg mechanism is subjected to a linearly reciprocating motion. The main objectives of this paper are to obtain valid mathematical models and to figure out the ability of the mechanism converting motion. The work carried out in this paper includes deriving and analyzing mathematical model using analytical kinematics. A numerical simulation is used to show the response of the mathematical models. The validation is performed by comparing the result from kinematic simulation software and numerical simulation of the mathematical models. The performance of a leg mechanism is evaluated under sinusoidal displacement input for typical amplitudes and frequencies. The validation results show that the proposed mathematical models are generally valid. Moreover, the mechanism can convert 0.04 m of linear motion into 116.84° of rotation motion.

Observations of MR Fluid Clumping Behaviour in a Squeeze-Mode Damper

Abstract The study summarises the results of quasistatic experimental tests of an MR squeeze-mode damper prototype (MRSQD) performed at the MTS testing machine. Of particular interests was the influence of MR fluid clumping behaviour in the MRSQD working gap on the force output of the device. The MRSQD tests were assessed by measuring the damping force output at prescribed sinusoidal displacement inputs and at various (fixed) voltage levels resulting in the respective average current levels in the control coil. The influence of piston position offset on the damping force was also investigated. The collected data were shown in the form of damping force time histories and damping force-piston displacements loops and discussed with respect to MR fluid clumping behaviour.

3106 定常振動と減衰の係数励振を利用したインパルス応答の低減(OS3-4 振動,騒音,乗り心地の制御,OS3 交通・物流システムの制御,オーガナイズド・セッション)

This paper proposes a new control method of a transient response by a variable damper when a single-degree-of-freedom vibration isolation system with a stationary displacement input receives an impact input. In our previous study, we confirmed that resonance arises not only at the natural frequency but also at other frequencies by the parametric excitation of damping and the base input. In this paper, we use the excitation froce that can be generated by the sinusoidal displacement input and the damping parametric excitation as the control force for the impulse response reduction. We show the effectiveness of the proposed control method by numerical simulation.

Electrorheological damper analysis using an Eyring-plastic model

This paper presents experimental and theoretical analysis of an electrorheological (ER)damper. To describe practical damper characteristics of force versus velocity and forceversus displacement response to sinusoidal displacement inputs, an Eyring model isproposed. On the basis of an Eyring rheological model, an Eyring-plastic model isconstructed by combination of simple nonlinear functions. Therefore, the Eyring-plasticmodel has the advantage of simple design and formulation, even though it is in the form ofa nonlinear function. In addition, the Eyring-plastic model can capture practical damperresponses quite well, particularly in both the pre-yield and the post-yield states. AnER damper is configured and its damping force under various electric fields andexcitation frequencies is experimentally tested. On the basis of the damper responsetested, the Eyring-plastic model is constructed and its validation is proved bycomparing the predicted damper results with the experimental data for forceversus sinusoidal velocity and force versus sinusoidal displacement responses.