Semi-active Control Method Research Articles

Design of semi-active suspension control method based on an enhanced inverse model for nonlinear magnetorheological dampers

Design of semi-active suspension control method based on an enhanced inverse model for nonlinear magnetorheological dampers

Semi-active control implementation in aircraft landing gear systems using hardware-in-the-loop test bench

In small-sized aircraft landing gear systems, magnetorheological (MR) dampers offer an innovative approach to adjusting damping levels under wide range of operating situations in order to achieve competing control objectives such as ride comfort, suspension travel, and energy consumption. Also, MR dampers have nonlinear dynamics and exhibit hysteresis. In this context, this paper aims to present a Hardware-In-the-Loop (HIL) technique for the implementation of backstepping control and linear quadratic regulator (LQR) control. Experimental results highlight that, compared to passive suspension (Passive Off), backstepping control and LQR control approaches reduce the fuselage vertical acceleration by 29.13% and 24.95%, respectively. Moreover, the ISO 2631 standard was adopted to evaluate ride comfort. LQR control can able to minimize the fuselage roll acceleration under a random road profile. Also, LQR control provides the highest performance in terms of fuselage roll acceleration, achieving a 6.2% improvement with lower energy consumption. By utilizing HIL, semi-active control methods can be tested and developed without the need for the aircraft, while keeping the characteristics that the physical aircraft would bring.

Study on the effect of semi-active control method matching for truck cab and seat suspension on driver comfort

This paper proposes a novel solution for addressing the challenges of whole-body vibrations in the heavy truck industry. Despite the substantial growth in this industry, excessive fatigue, back pain, neck pain, and other illnesses caused by rough and bumpy roads remain a major concern for truck drivers. To mitigate these issues, this study develops a comprehensive vibration reduction system based on a near-zero stiffness seat suspension system and a semi-active ON-OFF damping control system for the cab and seat. The study also evaluates the sensitivity of seat and cab suspension to vibration comfort by developing a nonlinear vibration system mathematical model. Simulation analysis results demonstrate that the proposed system can significantly reduce whole-body vibration experienced by the driver, potentially enhancing driver comfort and reducing the risk of illness and injury. However, further experimental validation and optimization are needed to fully evaluate the system's effectiveness and feasibility in practice.

Enhanced Semi-active piezoelectric vibration control method with shunt circuit by energy dissipations switching

Piezoelectric vibration control holds the advantages of lightweight and anti-electromagnetic interference, and has broad application prospects in fields such as aerospace and mechanical engineering. A semi-active control method based on a piezoelectric smart cantilever beam with a passive shunt circuit is proposed for vibration control. The contribution is that the proposed semi-active control method is used to achieve energy dissipations switching by changing the piezoelectric electrical boundary conditions. The open-circuit state of piezoelectric materials corresponds to higher stiffness and dissipation of elastic potential energy, while the short-circuit state is accompanied by lower stiffness and dissipation of electrical energy. Firstly, the stiffness difference of different electrical boundary conditions of the piezoelectric materials is derived and its effect on the vibration characteristics is analyzed. Then, the proposed passive shunt circuit for the vibration control principle is analyzed, and the modeling of the piezoelectric smart cantilever beam with the passive shunt circuit is developed. Finally, a prototype is manufactured and the measurement system is constructed. The correctness and the feasibility of the semi-active vibration control method are verified by experiments, and the logarithmic damping coefficient is 0.8919. The superiority of the proposed shunt circuit is demonstrated experimentally with the comparison groups including depolarized comparison group and the common shunt circuits.

GA-LQR for vehicle semi-active suspension with BiLSTM inverse model of magnetic rheological damper

This paper proposes a magnetic rheological (MR) semi-active control method based on bidirectional long short-term memory (BiLSTM) neural network, linear quadratic regulator (LQR) control algorithm, and genetic algorithm (GA). The LQR algorithm with GA optimizing the weight coefficients generates the expected damping force. Due to the nonlinear hysteresis characteristics of the magnetic rheological damper (MRD) and the fact that its input and output have certain time dependence, an inverse model of MRD is established by BiLSTM. The control current is predicted by BiLSTM and then the current is input to the MRD to obtain the damping force that is infinitely close to the expected damping force. The damping force is then applied to the suspension system to form a complete closed-loop feedback control, which realizes the damping effect and generates a real-time control. The simulation results show that the MRD inverse model can accurately predict the required control current, and the GA-optimized LQR control algorithm has a good suppression effect on the vertical vehicle acceleration, dynamic tire load, and suspension dynamic stroke.

Semi-Active Vibration Control of Seat Suspension Equipped with a Variable Equivalent Inertance-Variable Damping Device

The seat suspension has a significant influence on riding comfort in many practical applications, such as heavy duty vehicles, military vehicles, and high-speed crafts. This paper proposes a seat suspension equipped with a variable equivalent inertance-variable damping (VEI–VD) device and a novel semi-active vibration control strategy. The VEI–VD device can control its equivalent inertance and damping by controlling two external resistors in its electric circuit. Especially, the VEI part of the device can store and release vibration energy via the inside flywheel, which enables the seat suspension to have a four-quadrant controllable capability in the available force–velocity diagram, similar to an active system. First, the dynamic model of the VEI–VD device is built, and a prototype is developed and tested to identify the model parameters and verify its characteristics. Then, a semi-active vibration control method is proposed for the VEI–VD seat suspension. The control method uses a sliding mode controller to acquire the desired control force for reducing vibration; then, according to the desired force and system states, the VEI–VD device is tuned by a force-tracking scheme to generate a real force. In the numerical validation, the vibration transmissibility of VEI–VD seat suspension around its natural frequency is tested with different states. The effectiveness of force-tracking control strategies for different types of suspensions is verified. In the random excitation test, the root means square acceleration of the VEI–VD seat is reduced by 30.72% compared with a passive seat. The VEI–VD seat suspension shows great potential in applications.

Semi-active control of buildings using different control algorithms considering SSI

In current work, a comprehensive study on control algorithms with the presence of soil-structure interaction (SSI) effects is presented. Algorithms used in this study are Clipped-Optimal Control (COC), Lyapunov, Bang-Bang and Fuzzy with two Passive-On (P-On) and Passive-Off (P-Off) cases. Furthermore, characteristics of soil including four cases of fixed base, dense, medium and soft soil are investigated. In order to evaluate the efficiency of these algorithms in determining the appropriate voltage of the Magneto-rheological Damper (MR) and the corresponding control force, a 5-story linear shear building under 21 ground motions is selected. Earthquake records used in this paper contain 3 sets of 7 ground motions including far-fault and near fault records with fling step and forward directivity. Important effects such as nonlinear behavior of MR damper, actuator dynamics and damper saturation are also considered in this study. Mean and standard deviation of structural responses for the 3 sets of presented records show that the reduction in structural responses increases with reducing the stiffness of the base of the structure. Moreover, COC and Bang-Bang algorithms presented better performances than the other considered control algorithms and provide a robust method for semi-active control of structures equipped with MR dampers.

Optimal Semi-Active Control for a Hybrid Wind-Wave Energy System on Motion Reduction

Integration of wave energy converters and floating wind turbine can potentially reduce the levelized cost of energy. The coupling effects between the wave energy converters and the foundation, however, could amplify the foundation motion so that both the efficiency and the fatigue life of wind turbine would be degraded. In this study, wave energy converters are designed as a controlled suspension system for a novel hybrid wind-wave energy system, and an optimal semi-active control method having predictive ability is proposed for reducing the foundation motion. In the controller design, the physical constraints and the passivity of the wave energy converters are also taken into consideration. A full numerical model taking account of aero-hydro-servo-mooring coupled dynamics is proposed for a comprehensive analysis of the controller under various environmental conditions. Numerical results show that the foundation motion can be reduced by 16% even in very rough sea states with the help of the controller.

A Review Paper on Comparative Analysis on RCC Structure with Energy Dissipation Device and Composite Structure

Abstract: In recent years considerable attention has been paid to research and development of structural vibration control devices with particular emphasis on mitigation of wind and seismic response of buildings. Many vibration-control measures like passive, active, semi-active and hybrid vibration control methods have been developed. Base isolation is a passive vibration control system. The isolator partially reflects and partially absorbs input seismic energy before it gets transmitted to the superstructure. Lead rubber bearing isolators are placed between the superstructure and foundation, which reduces the horizontal stiffness of the system. It thereby increases the time period of the structure and decreases the spectral acceleration of the structure. The superstructure acts like a rigid body, thus inter storey drift is reduced. This study is concerned with the effects of various vertical irregularities on the seismic response of a structure and controls this response using base isolation. The objective of the study is to carry out response spectrum analysis. The predominant lateral loads acting upon building structures are earthquake and wind induced forces. If wind load is much greaterthan earthquake load, the lateral force resisting system required to tackle wind loading may be enough to resist the smaller earthquake load. In this situation, a seismic base isolator will not bring any benefit to the building system. Furthermore, if time period of a building without isolator is greater, incorporation of isolator will not bring much difference to the building behavior with respect to seismic load. Additionally, for buildings with lowerstructural time periods, incorporation of an isolator will greatly alter the seismic behavior

A novel preview control for MLD models and its neural network approximation for real‐time implementation: Application to semi‐active vibration control of a vehicle suspension

Advances in image processing technology have made it possible to measure the surface shape of the road ahead while driving. A new semi-active suspension control method considering the forward road surface shape is proposed. A vehicle model equipped with a semi-active suspension can be expressed as an mixed logical dynamical model. When the shape of the road ahead can be measured, the information on future disturbances is available before the vehicle undergoes. In this paper, the finite time optimization problem for the mixed logical dynamical model is formulated to consider the future disturbances as a mixed integer quadratic programming problem in the same way as the conventional control problem without future disturbance. However, the mixed integer quadratic programming problem is hard to obtain the control action within the control cycle period required in the real-time vibration control with general computers for vehicles. In this paper, the reduction of the computational load is achieved by constructing an approximation function of the designed controller. A neural network is adopted for the approximation. The performance evaluation of the proposed method is evaluated by simulations. In the simulation study, the proposed method achieves better ride comfort with the equivalent suspension stroke compared to the traditional methods.

Implementation of semi-active suspension control methods in a full car model and a comparative study in terms of ride comfort and road holding

Semi-active suspension systems are becoming increasingly common in the automotive industry due to their low energy consumption and cost advantages. A significant milestone in semi-active suspension control is the emergence of the skyhook control method. Then, the active driven damper method was introduced to bring the semi-active control closer to the optimum limit of the system. Later, power driven damper was introduced to reduce the jerk of the active driven damper and skyhook. The active and power-driven damper are mixed with skyhook control to be optimal throughout the entire frequency range. However, the methods mentioned above have been developed using the quarter car model, and no comparative studies have been found on the full car model effectiveness and the application of the methods, realistically. In this study, the above methods, which have been used in the literature, frequently, were compared first, on the quarter car model to reveal the system response characteristics. Then, a curved regular grid road profile and a high-fidelity full car model were used to compare the centralised skyhook continuous and four quarter car approaches.

Development of a Novel Seat Suspension Based on the Cubic Stewart Parallel Mechanism and Magnetorheological Fluid Damper

To alleviate the impact and vibrations to a driver in multiple directions during the driving of non-road vehicles, the authors of this paper proposed a multi-degree-of-freedom (MDOF) seat damping suspension that was based on the cubic Stewart mechanism and magnetorheological fluid (MRF) damper. A kinematics analysis of the cubic Stewart mechanism was carried out. The relative motion velocity of each leg of the Stewart mechanism was calculated from the center velocity of the upper and lower platforms, according to a reverse kinematics equation. Furthermore, forward and inverse dynamic models of the MRF damper were established, which laid the foundation for semi-active control of the seat suspension. Finally, a semi-active control method for multidimensional damping based on the optimized fuzzy skyhook control method was proposed. The research results showed that using this method could simultaneously improve the vibration damping performance of a seat suspension in the vertical, horizontal, and roll directions.

Self-sensing method for semi-active structural identification by removing piecewise bias from piezoelectric voltage

Structural system identification (SSI) that uses many actuators and sensors will be more accessible as a sensing technology if the number of these devices decreases. Recently, a semi-active SSI using a piezoelectric transducer and a unique semi-active input generation circuit was proposed. The semi-active SSI outperforms conventional SSIs with low energy consumption. If the semi-active input and its vibration response are estimated from the voltage generated by a piezoelectric transducer, some sensors will become redundant. Conventional self-sensing methods estimate structural vibrations without using vibration sensors. The semi-active SSI in combination with the self-sensing method will be more accessible than current technologies from the perspectives of a lower energy consumption and fewer number of devices. However, the following two problems exist: (1) A semi-active input generation circuit cannot introduce conventional hardware-based self-sensing methods with additional electric circuits because the electrical components in the additional circuits degrade the performance of the piezoelectric transducer. (2) Software-based self-sensing methods, such as the Kalman filter, cannot be used in system identification scenarios because the electromechanical parameters and models are unknown. To overcome these drawbacks, a novel software-based self-sensing method that does not require electromechanical models is proposed in this paper, and the effectiveness of the proposed method is thoroughly investigated using both simulations and experiments. The identification performance of the proposed method using the estimated input and output is the same as that using directly measured data. The proposed method can especially contribute to the predictive maintenance of structures in isolated environments. • A self-sensing method for piezoelectric semi-active control is proposed. • The elongation and inflow charge of the transducer is estimated from the piezoelectric voltage. • The proposed self-sensing method does not use additional circuits. • The structural system identification is implemented using estimated data.

A semi-active control method for magnetorheological dampers to suppress the milling vibration of thin-walled workpieces

Thin-walled workpieces are widely used in the aerospace field, and milling is the main processing method of such components. However, thin-walled workpieces are prone to vibrate during milling because of their weak stiffness, and the vibrations significantly affect the processing quality. Therefore, it is important to develop a novel milling vibration suppression method for thin-walled parts. The present work focused on the milling vibration control of a thin-walled workpiece using a semi-active magnetorheological (MR) damper. The forward dynamic model and inverse control model of the MR damper were first established, and its actuating position on the workpiece was then determined by modal analysis. The dynamic model of the MR damper at this position was built based on the proposed dynamic parameter acquisition method and used in the following semi-active control algorithm design. The effectiveness of this algorithm was verified by MATLAB/Simulink simulations. Finally, six groups of milling experiments were carried out using the non-damper, the rigid rod, the damper applied with 1-, 2-, and 3-A currents, and the semi-active control damper to validate the practical effect of the proposed algorithm. It was found that the designed semi-active control MR damper outperformed the constant-current control dampers or the rigid rod. In comparison to the non-damper experiment, the root mean square (RMS) values of milling forces in x- and y-directions decreased by 45.12% and 48.58%, respectively, and surface roughness decreased by 40.22%.

Semi-active control of crankshaft skyhook based on magnetorheological torsional damper

The purpose of this study was to solve the problem that the damping of rubber or silicone oil torsional dampers used in crankshafts is not adjustable and cannot effectively control torsional vibration at different resonant frequencies. Based on the controlled rheological properties of magnetorheological (MR) smart materials, this study designed a new type of variable damping MR torsional damper (MRTD) and proposed a semi-active control method to effectively control the torsional vibration of the crankshaft under multiple harmonic resonances. First, a mechanical model of the MRTD and a lumped parametric mass model of the crankshaft system were developed, and the resonance frequency harmonic range of the crankshaft system operation was determined by the torsional vibration characteristics analysis. Then a semi-active skyhook control method for the MRTD was proposed, and a joint control simulation analysis was performed using Amesim and Matlab software. The torsional vibration control effects of the crankshaft system with no damper, MRTD with different damping coefficients, and MRTD with skyhook control under acceleration and uniform speed conditions were comprehensively investigated. The simulation results indicated that the skyhook damping control significantly reduced the torsional vibration amplitude under both acceleration and uniform speed conditions, verifying the effectiveness of the skyhook-based control strategy for MRTD.

Semi-active piezoelectric structural damping adjustment and enhancement by synchronized switching on energy injection technique

Synchronized switch damping (SSD) principle and derived techniques are a classical semi-active vibration control method based on piezoelectric elements. This paper presents a novel energy injection based SSD technique which has better effect of vibration reduction but with simpler implementation of electronic circuitry. The proposed circuit is composed of a flyback transformer, an ordinary low voltage source and two kinds of synchronized switches. Through controlling the synchronized switches, the electrical energy is extracted from the voltage source to the transformer, and then injected to the piezoelectric elements, increasing the piezoelectric voltage as needed. Moreover, this injection energy can be easily adjusted by changing the duty cycle of the corresponding switch control signal. The operation principle of this technique is introduced, the analytical expression of vibration attenuations is also derived for a typical electromechanical model. Finally, theoretical predictions confirmed by experimental results show that the proposed SSD technique provides an adaptive structural damping and enhances the effect of vibration attenuation.

Vibration control of semi-active suspension by the neural network that learned the optimal preview control of MLD model

Advances in image processing technology have made it possible to measure the surface shape of the road ahead while driving. We propose a new semi-active suspension control method that considers the forward road surface shape. A vehicle model equipped with a semi-active suspension can be expressed as an MLD (Mixed Logical Dynamical) model. When the shape of the road ahead can be measured accurately, that the information on the future disturbances is available before the vehicle undergoes. In this paper, we formulate the finite time optimization problem of the MLD model in consideration of the future disturbances as a MIQP (Mixed Integer Quadratic Programming) problem in the same way as the conventional optimal control problem without future disturbance. The solution to the MIQP problem can be obtained by a commonly available solver software. However, because the MIQP problem is classified as NP-hard, it is hard to obtain the control action within the control cycle period required by the vibration control problem with general computers for vehicles. In this paper, we achieve this reduction in computational load by constructing an approximation function for the designed controller. A multilayer neural network is adopted for the approximation. The performance evaluation of the proposed control method was evaluated by a simulation. In the simulation study, the proposed method was able to achieve better ride comfort with the equivalent suspension stroke compared to the traditional MLD predictive control and the Skyhook approximation methods. Moreover, the proposed method enables to generate the control signal within the control cycle period.

Cloud-based adaptive semi-active suspension control for improving driving comfort and road holding

The improvement of driving comfort and vehicle stability performance is essential for the vehicles, which can be actualized by adaptive semi-active suspension control. Cloud computing allows several features for autonomous vehicles. Implementing the adaptive suspension control using historical road data gathered in the cloud database is one of these features. This paper deals with the adaptive semi-active suspension control from the perspective of a Vehicle-to-Cloud-to-Vehicle integration. Measured and historical performance(vertical acceleration and tire deformation) and velocity data in different locations and road irregularities from other vehicles have been stored in the cloud database and used to design the dedicated scheduling variable. The novelty of this paper is developing the adaptive semi-active suspension control method with different scheduling parameter design approaches based on cloud application for the road adaptation capabilities of the suspension system. The control architecture is founded on the Linear Parameter-Varying framework, where the scheduling variable allows the trade-off between driving comfort and vehicle stability. The real data simulation demonstrates the operation of the introduced method in the TruckSim simulation environment and Matlab/Simulink. The results show that both vehicle stability and driving comfort has been improved.

Semi-active vibration control of structural systems with a variable inerter

We propose a design method of semi-active vibration control systems using a variable inerter for structural systems subject to seismic disturbances. The inerter is a vibration control device generating resistance force proportional to the relative acceleration between both ends. In the variable inerter, the inertia mass of the inerter can be changed by a command signal in realtime. The mathematical model of the variable inerter is defined considering the dynamic delay of the inertia mass change subject to the command signal. For the dynamic model of a structural system with the variable inerter, we propose a semi-active control law based on a reference active control system. The reference active control system is a virtual system showing the ideal control performance. In the proposed semi-active control law, the variable inertia mass is changed by considering a predicted control output, the predicted error between the control output of the semi-active and reference active control systems, and the predicted reaction force of the inerter. The characteristic of the reference active control is optimized so that the control performance of the resulting semi-active control system is close to that of the best control systems among the passive off (without control), passive on (maximum inertia mass), and reference active control systems. A simulation study shows the effectiveness of the proposed semi-active control method.

Optimal Allocation and Control of Magnetorheological Dampers for Enhancing Seismic Performance of the Adjacent Structures Using Whale Optimization Algorithm

The control strategy for protecting adjacent structures from earthquake excitations is gaining increasing significance. In this study, to improve the seismic performance, a semiactive control strategy using magnetorheological (MR) dampers to couple the adjacent structures is proposed. In this control strategy, to fully exploit the performance of MR dampers, the allocation (including the locations and the number) and fuzzy logic controller (FLC) system of MR dampers are simultaneously optimally designed by whale optimization algorithm (WOA) with a special encoding scheme. Simulation results verify that WOA provides competitive performance compared with the other three metaheuristic algorithms in terms of solution quality and robustness. Compared with other semiactive control methods including on-off, linear quadratic regulator-clipped voltage law, and WOA-FLC (optimal allocation is not considered) methods, by using much less MR dampers, the proposed control strategy can exhibit more excellent overall performance in terms of reducing the seismic responses and mitigating pounding.