Semi-active System Research Articles

Analysis Comparison of PSMEID With Preview for Controlling Shock Vibration of UAV’s Landing Gear System

Semi-active dampers reduce the effects of shock vibrations because they can operate at specific vibration frequencies at a lower cost than more complex active dampers. PSMEID is one of the alternative methods developed in the semi-active damping system. PSMEID has been developed by adapting it by adding a PSMEID active time prediction system when an impact occurs. This research attempts to compare two types of PSMEID with active time prediction, where the position of each model offered has a different PSMEID mass position when applied to the landing gear damper of an Unmanned Aerial Vehicle (UAV). This comparison aims to give the user a choice among these optimal models suitable for use in multiple conditions. When simulated using the same parameter values, the PSMEID placed on the unsprung mass can reduce acceleration amplitude by up to 6.6 percent when the landing gear is dropped at 0.15 meters from the ground. The model that places the PSMEID on the sprung mass can help reduce the velocity amplitude up to 8.8 percent when dropped at a height of 0.05 meters, and the spring constant value of the PSMEID (KPS) is 1600 N/m. All these simulations show that the PSMEID should be activated just before the landing gear hits the runway surface (TB < TL).

Research on the sensing properties and vibration reduction performance of self-sensing self-tuning magnetic fluid damper

Abstract The semi-active control damping system has gained popularity due to its quick response time and versatility. However, external sensors are susceptible to environmental interference, affecting system reliability and increasing complexity and maintenance costs, restricting their use. To address this, a self-sensing self-tuning magnetic fluid damper (SSMFD) is proposed. The vibration-measuring induction coil is wound on the damper to sense the magnetic fluid vibration information in real time, and the vibration signal is communicated to the self-tuning control circuit. The control circuit calculates and determines the dominant frequency of structural vibration, then outputs the relevant current signal to set the damper’s natural frequency to track the excitation frequency, resulting in self-tuning vibration reduction. First, the self-sensing unit’s output induced electromotive force model is created, followed by an expression of the damper’s natural frequency, indicating that the self-sensing unit can achieve self-tuning vibration reduction by tracking the excitation frequency. The multi-field coupling simulation model of the magnetic fluid damper is generated, and the induction coil coupling mode and damper excitation angle are defined to obtain the maximum induced voltage. Finally, an experimental platform was developed to assess the damper’s self-sensing and self-tuning vibration reduction performance. The experimental results show that the proposed SSMFD performs well, making it a feasible solution for achieving self-sensing and self-tuning vibration reduction.

Performance Verification and Evaluation of Semi-Active Actuator System Using Quarter Car Lab Simulation with RLDA Data

This study outlines a methodology for determining the durability specifications of electronically controlled dampers by examining performance degradation observed on actual driving roads. It identifies areas of performance decline and the primary causes affecting major actuator dampers. Traditionally, the durability performance of automobile parts has been assessed by calculating damage based on load profiles. However, analyzing actual road conditions is essential because the control commands of electronically controlled suspension systems change in real time according to load conditions. Simulations based on Road Load Data Acquisition (RLDA) use statistically independent representative road surfaces to assess damper deterioration performance. Following this analysis, a rig test of the damper is performed to establish the durability specifications for damper actuator products. The primary form of performance degradation observed was a change in the tensile damping force, which was more substantial than the degradation observed on the compression side. Oil leakage and cavitation were identified as significant influencing factors from a Failure Mode and Effects Analysis (FMEA) perspective. The study concludes that additional design research is necessary, focusing on damper oil and leakage, while also considering the control algorithm’s effects in designing electronically controlled dampers.

Design and experimental study of a semi-active shear-mode vibration absorber using magnetorheological elastomer

This paper presents the design process of a magnetorheological elastomer (MRE) absorber with a shear symmetric structure based on detailed simulation and experiments. First, the MRE materials and dimensional parameters of the MRE absorber are determined, and magnetic field simulation is performed to analyze the magnetic induction performance in the working area. Then, a dynamic simulation model is constructed to analyze the frequency response characteristics of a semi-active vibration system. Finally, a vibration experimental platform is built to test the response performance of the shear-mode MRE absorber. The experimental results showed that the stiffness of the MRE absorber can be effectively adjusted by current. When the applied current changes from 0.5 to 2 A, a vibration reduction frequency band of 8.91 to 14.19 Hz will be formed. The closer the natural frequency in this frequency band is to the external excitation frequency, the better the vibration reduction effect, which verifies the effectiveness of semi-active vibration control for the primary system. These results validate the rationality and feasibility of the semi-active MRE absorber, providing a good reference for the design of MRE absorbers.

Comparison of passive and semi-active piezoelectric transducer damping of cantilever oscillation

The aim of this work is the analysis of passive and semi-active damping methods on the model woven beam with a piezoelectric (PZ) layer. The mathematical model of the PZ layer on cantilever beam is derived. For modeling, real product parameters of PZ layer are used, and through simulation find the optimal values to dampen it. The resistive-inductance passive model, and State-Switch Damping SSD semi-active model are used in this work. The models are processed in the MATLAB Simulink environment and the results of the behavior of the models compared to each other. The program involving passive and semi-active systems, where analyze the behavior of the model for different parameters and the damping capabilities of individual methods are compared. The simulation results show the effectiveness of the semi-active system in comparison with the passive systems, also it shows the passive method is not so effective at low frequency as it in high frequency, and the semi-active method is not optimal for high frequency vibration.

Exploring the Learning Curve of Dental Implant Placement Using a Task-Autonomous Robotic System Among Young Dentists From Different Specialties-A Pilot Module Study.

The learning curve effect of dynamic computer-assisted implant surgery (D-CAIS) was observed among inexperienced novice surgeons. The learning curves can provide valuable information for novice surgeons and valid comparisons between new and conventional techniques. Recently, robotic computer-assisted implant surgery (R-CAIS) has shown promise as a novel dental implant surgical technique for both partially and edentulous patients. However, its learning curve remains unknown. The aim of this study was to explore the learning curve of dental implant placement surgery with a task-autonomous robotic system among young dentists with different specialties. Four young dentists (mean age: 25.3 ± 1.5 years at the beginning of their first attempt) with equal representation of males and females and with different specialties participated in this study. None of the participants had prior experience in R-CAIS. Each operator placed eight implants over eight attempts using a semi-active task-autonomous robotic system. Among the eight implants, four were straight lateral incisor implants, and four were 30°-tilted premolar implants. The implants were placed in each dental quadrant of the maxillary and mandibular jaw modules. The operation time was recorded. Coronal, apical, and angular deviations between the planned and actual sites of implant placement were measured by merging preoperative and postoperative cone-beam computed tomography (CBCT) scans. The data were analyzed with repeated-measures ANOVA (α = 0.05). The mean time for implant placement was associated with the number of attempts (p < 0.01). The time taken for the second attempt was significantly shorter than that of the first attempt (33.26 vs. 30.47 min; p < 0.001) then it plateaued. Three-dimensional (3D) angular (p = 0.31), coronal deviation (p = 0.26), and apical deviation (p = 0.06) did not differ significantly among attempts. The mean values and standard deviations of 3D coronal deviation, 3D apical deviation, and 3D angular deviation were 0.71 ± 0.31 mm, 0.72 ± 0.30 mm, and 0.94 ± 0.58°, respectively. Neither the position of the jaw (p > 0.59) nor the tilt angle of the implant (straight or 30°-tilted, p > 0.85) was related to implant placement accuracy. Dentists quickly learned the basic workflow of R-CAIS and thus facilitated the clinicians in the mastery of implant placement on edentulous jaw modules, leading to a comparable operating speed and high precision. Moreover, the accuracy of placement of straight and tilted implants in both the maxilla and mandible with R-CAIS was satisfactory.

Smart Rumble Strip System to Prevent Over-Height Vehicle Collisions.

Collisions of over-height vehicles with low clearance bridges is commonly encountered worldwide. They have caused damage to bridge structures, interruption to traffic, injuries or even fatalities to road users. To mitigate such risks, passive systems that involve warning gantries, flashing lights and illuminated signage are commonly installed. Semi-active systems using laser- or infrared-based detection systems in conjunction with visual warnings have been implemented. Nevertheless, some drivers ignore these visual warnings and collisions continue to occur. This paper presents a novel concept for a collision prevention system, which makes use of a series of sensor-activated, motorized rumble strips. These rumble strips span across a certain distance ahead of a low clearance bridge. When an over-height vehicle is detected, a mechanism is triggered which elevates the rumble strips. The noise and vibrations produce a vigorous alert to the offending driver. They also increase effective friction of the road surface, thus assisting to slow down the vehicle and shorten the stopping distance. The strips will be lowered after a certain time has elapsed, thus minimizing their effects on other vehicles. This article presents a conceptual framework and quantifies the vibration and noise caused by rumble strips in road tests. Road tests indicated that the vibration level typically exceeded 1 g and noise level reached approximately 90 dB in the cabin of a 3.5-ton truck. Fabrication of a proof-of-concept mechanized rumble strip model was presented and verified in an outdoor environment. The circuitry and mechanical design, and requirements in actual implementation, are discussed. The proposed event-triggered rumble strip system could significantly mitigate over-height vehicle collisions that cause major disruptions and injuries worldwide. Further works, including a comprehensive road test involving various types of vehicles, are envisaged.

Virtual prototype modeling and fuzzy control of the heave compensation system for a 500-ton deep-sea mining vessel

The unexpected heave motion of vessels generated by waves has always threatened the safe operation of mining vessels. The heave compensation system is a critical equipment for offshore cranes to ensure the safety and stability of the deep-sea mining vessel operation. Unfortunately, the nominal load of the mining vessel transporting minerals has become increasingly large, which has led to the dynamic performance of the heave compensation decline and a significant increase in energy consumption. To solve these problems, a semiactive heave compensation system and fuzzy logic-based controller are proposed in this paper. First, an active-passive hybrid heave compensation system is designed to reduce energy consumption greatly. The virtual prototype models of the proposed heave compensation system in a 500-ton deep-sea mining vessel are also built. Then, an adaptive tuning PID controller is developed based on the Transfer function of the heave compensation system and Mamdani-type fuzzy logic. Virtual prototype simulation results of AMESim-Simulink joint simulation illustrate that the accuracy of compensation for the four or six sea states reaches more than 90% with the proposed method and the power of the active compensation system is about 21% of the total power. Finally, the experimental results are included to demonstrate the effectiveness of the proposed semiactive heave compensation system.

Adverse events related to robotic-assisted knee arthroplasty: a cross-sectional study from the MAUDE database.

Robotic-assisted surgical technique has been clinically available for decades, yet real-world adverse events (AEs) and complications associated with primary knee arthroplasty remain unclear. In March 2023, we searched the FDA website and extracted AEs related to robotic assisted knee arthroplasty (RAKA) from the MAUDE database over the past 10 years. The "Brand Name" function queried major robotic platforms, including active and semi-active systems. The overall incidence of AEs was estimated based on annual surgical volume from the current American Joint Replacement Registry (AJRR). Two authors independently collected data on event date, event type, device problem, and patient problem. Of 839 eligible reports, device malfunction comprised mechanical failure (343/839, 40.88%) and software failure (261/839, 31.11%). For surgical complications, inappropriate bone resection (115/839, 13.71%) was most frequent, followed by bone/soft tissue damage (83/839, 9.89%). Notably, over-resection exceeding 2mm (88/839, 10.49%), joint infection (25/839, 2.98%), and aseptic loosening (1/839, 0.12%) were major complications. Only two track pins related AEs were found. Moreover, the distribution of these AEs differed substantially between robot manufacturers. According to the AEs volume and AJRR data, the overall incidences of AEs related to RAKAs were calculated with 0.83% (839/100,892) between November 2010 and March 2023. Our analysis shows that while reported AEs might be increasing for RAKAs, the overall rate remains relatively low. Reassuringly, device malfunction was the most commonly AEs observed, with a minor impact on postoperative outcomes. Furthermore, our data provide a benchmark for patients, surgeons, and manufacturers to evaluate RAKA performance, though continued improvement in reducing serious AEs incidence is warranted.

Passivity-Based Control for Transient Power Sharing and State of Charge Restoration in a Semi-Active Supercapacitor-Battery System

Passivity-Based Control for Transient Power Sharing and State of Charge Restoration in a Semi-Active Supercapacitor-Battery System

Regenerative Braking Conscious Rule-Based Energy Management Strategy for Semi-Active Hybrid Energy Storage Systems for Electric Vehicles

Hybrid Energy Storage Systems (HESS) function as a solution to extend the lifespan of battery packs by maintaining a low charge/discharge rate. The integration of HESS in electric vehicles (EVs) is facilitated by supercapacitors (SC), known for their safe operation even under harsh conditions. The widely adopted rule-based power follower energy management strategy (EMS) is employed to control and restrict battery discharge within a defined range with SC support. Additionally, it charges the SC to accommodate regenerative energy, but it often neglects exploring the SC voltage set reference. This study investigates the SC voltage reference point and introduces a method to generate the reference point by equating the SC energy with the available kinetic energy in the moving vehicle. The proposed method was simulated and compared against the benchmark method using a portion of the medium segment Worldwide Harmonized Light Vehicles Test Procedure (WLTP) driving cycle. The results demonstrate a more stable discharge power for the battery bank, accompanied by improvements in battery voltage stability. The root mean square (RMS) battery current values were found to be 43.68 A and 42.92 A for the benchmarked and proposed methods, respectively, indicating a slight improvement of about 1%. Furthermore, the proposed method reduces the voltage deviation from 2.73% to about 2.57%, showcasing an additional positive outcome. These findings suggest that dynamically adjusting the SC voltage based on kinetic energy can enhance battery life and stability in EVs, offering a promising direction for future research and development of EMS.

Semiactive Car-Seat System for Rear-End Collisions

This study proposes and simulates a smart system that can be used in production car seats to decrease whiplash risk in rear-end crashes. A sliding seat incorporating a semiactively controlled magnetorheological (MR) damper model positioned under the seat-pan is simulated with a validated biofidelic human body model. Since this is the first study that demonstrates a computer controlled anti-whiplash car seat system to the best of the authors’ knowledge, a benchmark analysis is carried out to compare the proposed semiactive seat with a state-of-the-art passive anti-whiplash car seat using 23 different crash pulses, including the moderate and high severity crash pulses within the European New Car Assessment Program (EuroNCAP) whiplash risk assessment framework. The proposed semiactive design outperforms the passive seat design by further reducing the values of the critical EuroNCAP whiplash criteria, such as NIC and Nkm, together with the loads acting on the upper neck. The semiactive seat lowers the upper-neck shear force by an amount of 4 kg and 7 kg while lessening the NIC by 10% and 21% and Nkm by 9% and 56% for the EuroNCAP crash pulses, having a delta-V of 16 km/h and 24 km/h, respectively. The findings presented in this paper can aid in the design of car seats to further mitigate whiplash risk in rear-end crashes.

Event-triggered semi-active TLCD for ground motion-induced vibration control

One potential drawback of tuned liquid column dampers (TLCDs) is their relatively low control efficiency during the initial stage of structural vibration caused by external excitations. This is because satisfactory control effects can only be achieved when the liquid inside TLCD is fully oscillating, which is not the case during the initial stage. To solve this problem, in this study, an event-triggered semi-active technique is creatively proposed to improve the vibration reduction efficiency of TLCDs during the initial stage. The fundamental idea of the proposed approach is to provide an initial displacement to the liquid column via baffles, and then release the constraints on the initial liquid displacement at an appropriate time to achieve the rapid activation of TLCDs. A strategy from the standpoint of phase difference between liquid column motion and structural motion is proposed to determine the triggering conditions (i.e. when to release the constraints). The effectiveness of the proposed semi-active system is examined under both harmonic and stochastic excitations. The results show that the proposed strategy successfully improves the vibration suppression performance of TLCDs in the early stage of structural vibration.

Development of a semi-active MR inerter for seismic protection of civil structures

Civil engineering structures are susceptible to collapsing when exposed to severe vibrations. Therefore, it is essential to protect them from undesirable vibrations triggered by natural calamities like earthquakes or strong winds. This paper proposes an innovative semi-active Magnetorheological (MR) inerter system with a compact structure for seismic protection. The inerter system consists of four rubber bearings and the semi-active MR inerter. The inertance of the semi-active MR inerter can be switched according to different working scenarios. This unique operating principle enhances the adaptability of the system. To assess the performance of the proposed inerter system, a scaled three-storey building was constructed following scaling laws. Four scaled earthquake signals with different dominant frequencies were used as ground motion excitations. An inertance switch controller based on short-time Fourier transformation (STFT) methodology was built to determine the desired inertance of the inerter. Both the simulation and experimental results indicated that the proposed semi-active MR inerter system provides superior vibration mitigation capacity over the passive inerter systems. Specifically, the employment of the semi-active MR inerter effectively reduces the acceleration responses of the structures under different seismic excitations.

Optimal Layout of Suspension System Employing Mechatronic Inerter for Comfort Enhancement Based on Structure-Immittance Approach

&lt;div&gt;The usage of the inerter and its studies has greatly developed in recent years as it offers better performance compared to passive systems and has lower cost and power consumption than active and semi-active systems. This article focuses on studying a half-vehicle model to obtain the optimal layout of the mechatronic inerter, spring, and damper suspension system (ISD) for comfort enhancement with the aid of the structure-immittance approach, ensuring structural simplicity.&lt;/div&gt; &lt;div&gt;The mechatronic inerter, which consists of a single capacitance, resistance, and inductance, is added to a half-vehicle model composed of an inerter, spring, and damper. All possible layouts are studied to achieve the optimal design layout. Evaluation criteria such as the performance index, system peak-to-peak value, and settling time are utilized to assess body acceleration, thereby improving passenger comfort. Furthermore, the system’s impact on dynamic tire load and suspension working space under diverse road conditions is analyzed. Theoretical analyses conducted using MATLAB/Simulink demonstrate that the novel mechatronic ISD layout significantly enhances body acceleration performance compared to conventional passive systems, switchable hydraulic ISD systems, and fuzzy logic-controlled three-setting switchable dampers.&lt;/div&gt;

Enhanced ship engine vibration reduction using magnetorheological dampers and Adaptive Neuro-Fuzzy Control System

ABSTRACT In this paper, an innovative approach is proposed to mitigate ship engine vibrations by integrating a semi-active control system with magnetorheological (MR) dampers and an Adaptive Neuro-Fuzzy Control System (ANFIS). The ANFIS controller adjusts MR damper damping force to effectively adapt to engine vibrations. A comprehensive mathematical model simulates the complex dynamics of the ship engine vibration system, validated with real-world data. The model incorporates engine vibration measurements and MR damper properties to train the ANFIS controller. Compared to passive control systems, the proposed semi-active system reduces torsional vibrations by 22.606% and longitudinal vibrations by 29.840%. The ANFIS controller dynamically adjusts damping force in response to engine conditions, ensuring optimal performance. This system effectively mitigates ship engine vibrations, improving overall ship performance and passenger comfort. Consistency between modeling and experimental results confirms the system's viability and efficacy.

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.

Pseudo-Active Actuators With Positive-Negative Dampings

Although semi-active actuators have the advantages of low power consumption, simple structure, and high reliability, their output force and excitation are always in the same direction, and they can only achieve mechanical properties in the first and third quadrants of the force-velocity diagram. Thence, the performance of semi-active actuator-based systems is incomparable to that of active actuator-based systems. Inspired by the concept of “four-quadrant operation” of active actuators such as motors, this paper proposes the configuration and principle of a pseudo-active actuator with four-quadrant controllability performance. The proposed pseudo-active actuator consists of two secondary semi-active damping actuators and a mechanical compensation mechanism, which can conditionally achieve the characteristics of arbitrary adjustment within the four quadrants of the force-velocity diagrams. Through the mechanical compensation mechanism, the output force of the first semi-active actuator is the same as the excitation direction, and the output force of the second semi-active actuator is opposite to the excitation. Tuning the inputs of the two semi-active actuators allows real-time and continuous control of the mechanical outputs of the pseudo-active actuators in the four-quadrant diagram. Based on the structural principle of the pseudo-active actuator, the mechanical properties of the pseudo-active actuator are analyzed. An experimental test bench is established to verify the controllable mechanical properties of the pseudo-active actuator prototype.

A novel semi-active control of an integrated chassis and seat quasi-zero stiffness suspension system for off-road vehicles

This article introduces an innovative semi-active suspension system for off-road vehicles, incorporating a quasi-zero stiffness suspension to enhance driver comfort. The system includes a central pneumatic spring, double-acting pneumatic linear actuators for adjustable stiffness, and magnetorheological dampers for controlled damping. Using Lyapunov stability theory, a static output feedback control law is designed to address uncertainties in road profiles, driver body parameters, and actuator saturation, relying on measured variables as feedback. Performance constraints focus on driver head acceleration, suspension displacement, and dynamic tire load. The control law problem is converted into a convex optimization problem with linear matrix inequalities. The new semi-active QZSS system is theoretically tested via Matlab simulations and validated through hardware-in-the-loop testing. Comparative analysis between passive QZSS and the new semi-active QZSS on different roads, and vehicle speeds closely aligns with simulation results, with minor disparities attributable to network discrepancies and signal interruptions. Impressively, the semi-active QZSS system reduces driver head vertical acceleration between 26.53 and 35.0% compared to passive air QZSS, showing potential for significantly improving ride comfort, reducing vibration transfer, and enhancing driver wellbeing with minimal energy requirement.

Model of a Radar Semi-Active Homing System for a Guided Missile

Model of a Radar Semi-Active Homing System for a Guided Missile