Power Requirement of Active Vibration Control Systems

SUMMARY

The paper deals with the theoretical estimation of the minimal power requirement, necessary for the operation of the active vibration control system (AVCS), connected with a passive one. It is assumed this compound system is used for the vibration control purposes in the heavy vehicle driver's seats. The systems considered in the paper are of two kinds. In the first case the electro-hydraulic actuator of the AVCS is situated in series to the spring-damper combination of the seat suspension. The second system under consideration is formed by parallel connection of electro-pneumatic actuator and the spring-damper combination of the seat suspension, which is a mechanical model of a real air spring with controlled in-flow and out-flow of the air. The comparison of results for both compound systems shows markedly higher power consumption of the serial system. The theoretical results are in acceptable agreement with the experimental data.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part II: Experimental Study

From the theoretical study presented in [1], we investigate the experimental feasibility of the active seat suspension to improve ride comfort. The prototype of the reversible electromechanical actuator used in the active seat suspension is presented. First, the kinematic guide with a vertical auto-levelling system is described. Second, the electromechamical actuator and the power drive transmission are presented. It is noticed that the prototype design is achieved with a systemic approach taking into account the industrial constraints. Then, the laboratory experimental setup is described. Several tests are performed on the prototype for model validation and performance purposes. Correct force feedback control in the actuator is verified. The real performances of the active seat suspension on a prototype is investigated for different pertubation inputs. Experimental results clearly show the efficiency of the active seat suspension to improve passenger comfort and demonstrate its feasability.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part II: Experimental Study

From the theoretical study presented in [1], we investigate the experimental feasibility of the active seat suspension to improve ride comfort. The prototype of the reversible electromechanical actuator used in the active seat suspension is presented. First, the kinematic guide with a vertical auto-levelling system is described. Second, the electromechamical actuator and the power drive transmission are presented. It is noticed that the prototype design is achieved with a systemic approach taking into account the industrial constraints. Then, the laboratory experimental setup is described. Several tests are performed on the prototype for model validation and performance purposes. Correct force feedback control in the actuator is verified. The real performances of the active seat suspension on a prototype is investigated for different pertubation inputs. Experimental results clearly show the efficiency of the active seat suspension to improve passenger comfort and demonstrate its feasability.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part I: Theoretical Study

This paper provides an overview of a theoretical study of an active seat suspension. The principal objective of this study is to improve ride passenger comfort by reducing transmitted seat acceleration. The seat is represented by a non-linear two degree of freedom model. The system is linearized for small perturbations around the equilibrium. To control the dynamic of the seat suspension, an original feedback control command with a reversible electromechanical actuator is achieved. The synthesis of the regulator is realized on the linearized model of the seat suspension and the root locus method is employed. Stability and robustness characteristics have been studied. Numerical simulations in time and frequency domain show the interests of the regulator and its capability to isolate seat passenger.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part I: Theoretical Study

This paper provides an overview of a theoretical study of an active seat suspension. The principal objective of this study is to improve ride passenger comfort by reducing transmitted seat acceleration. The seat is represented by a non-linear two degree of freedom model. The system is linearized for small perturbations around the equilibrium. To control the dynamic of the seat suspension, an original feedback control command with a reversible electromechanical actuator is achieved. The synthesis of the regulator is realized on the linearized model of the seat suspension and the root locus method is employed. Stability and robustness characteristics have been studied. Numerical simulations in time and frequency domain show the interests of the regulator and its capability to isolate seat passenger.     

Actuator optimal placement studies of high-speed power bogie for active hunting stability

ABSTRACT

We put forward three actuator placements of the high-speed train power bogie to improve the train hunting stability. The active control forces act on the frame, between the frame and the motor, and on the motor by the inertial or retractable actuator, respectively, based on the feedback states of vibration velocity of the front and rear end beams. The feedback gains and the motor suspension parameters in different cases are optimised with the two objectives of system stability margin and control effort. The required actuator outputs of the three cases are compared based on the theoretical analysis with a 8 DOF bogie model. The results show that the three control cases can effectively improve the hunting stability, especially at high speed. The active control of motor lateral movement is helpful to increase the dynamic vibration absorbing function of the motor flexible suspension, and the control output is obviously smaller than the other two control cases. In addition, the influence of system delay on stability was analysed and we could use or avoid the effects of delay on the stability.     

空气弹簧座椅在冲击式压路机上的应用

针对冲击式压路机牵引主机座椅悬架系统与车的刚性连接问题,提出了应用空气弹簧座椅的设想。应用机械系统动力学软件ADAMS建立了牵引车仿真模型、减振器仿真模型及D级路面时域仿真激励信号,并加入相关约束组成整车振动仿真模型,进行振动仿真分析,结果表明：空气弹簧座椅的整车振动仿真模型可以有效地衰减人体受到的振动。     

Control system synthesis of seat suspensions used for protection of working machine operators

This paper deals with a novel approach to the control system synthesis of semi-active and active seat suspensions. An original control strategy is discussed in order to increase the effectiveness of vibration isolators used for protection of working machines operators. As an example of the proposed control system design, the suspension systems with a magneto-rheological damper and a pneumatic spring are investigated using a laboratory experimental set-up with seated humans.     

Hybrid modeling of seat-cab coupled system for truck

For the complex structure and vibration characteristics of the seat and cab system of truck, there is no reliable theoretical model for the suspensions design at present, which seriously restricts the improvement of ride comfort. In this paper, a 4 degree-of-freedom seat-cab coupled system model was presented; using the mechanism modeling method, its vibration equations were built; then, by the tested cab suspensions excitations and seat acceleration response, its parameters identification mathematical model was established. Combining the tested signals and a simulation model with the parameters identification mathematical model, a new method of hybrid modeling of seat-cab coupled system was presented. With a practical example of seat and cab system, the parameters values were identified and validated by simulation and test. The results show that the model and method proposed are correct and reliable, and lay a good foundation for the optimal design of seat suspension and cab suspensions to improve ride comfort.     

A study of locomotive driver's seat vertical suspension system with adjustable damper

This paper shows that laboratory measurements can be used for the identification of structure and parameters of commercial seat vertical suspension system model. A commonly used single-degree-of-freedom suspension model does not suffice. The system model presented is based on Zener's structure and clearly describes the dynamic properties of a vertical seat suspension with an adjustable damper. The model introduced, augmented with seat cushion dynamic model, predicts the seat vertical vibration mitigation properties under field conditions with a reasonable accuracy. Optimisation of the adjustable damper setting is performed using a two-objective function optimisation technique. This enables us to optimise not only the exerted vertical vibration acceleration but also the seat relative vertical displacement (stroke). Optimisation was facilitated for the particular suspended seat without the requirement of further field measurements. In addition, a two-parameter optimisation was performed showing possible further improvement in both objectives at the manufacturer's discretion. This study could be representative of driver's seats equipped with vertical seat suspension system using an air-spring and an adjustable damper.     

汽车主动悬架的自校正控制

主动悬系统能使车辆的乘坐舒适性和操纵稳定性同时得到改善，其中执行机构和控制算法的优劣决定了该系统的性能。     

On the Performance Capabilities of Active Automobile Suspension Systems of Limited Bandwidth

Using methods established in earlier work, calculations are carried out to reveal the influence of actuator bandwidth on the performance capabilities of a class of active suspension system for automobiles. The suspension consists of an actuator in series with a spring, the combination being in parallel with a passive damper, and the system is modelled as a single wheel station traversing a random road. The results indicate that a system with a 3 Hz bandwidth actuator and variable damping will have excellent ride performance qualities over a wide range of road roughness conditions. Since such a system can be expected to be easily adaptable to the running conditions, to provide good static and dynamic attitude control, to be capable of contributing to good steering control responses and to be inexpensive in terms of capital and energy consumption costs compared with most of the active systems which have previously been discussed, it is suggested that it is a prime candidate for further study and practical development.     

Self-powered active control applied to a truck cab suspension

A method of active vibration control using regenerated vibration energy, i.e. self-powered active control, applied to the cab suspension of a heavy duty truck. In the proposed system, an electric generator that is installed in the suspension of the chassis regenerates vibration energy and stores it in the condenser. An actuator in the cab suspension achieves active vibration control using the energy stored in the condenser. Numerical simulations and basic experiments demonstrate better isolation performance of the self-powered active vibration control system than that of a passive and a semi-active control.     

Kineto-dynamic design optimisation for vehicle-specific seat-suspension systems

Designs and analyses of seat-suspension systems are invariably performed considering effective vertical spring rate and damping properties, while neglecting important contributions due to kinematics of the widely used cross-linkage mechanism. In this study, a kineto-dynamic model of a seat-suspension is formulated to obtain relations for effective vertical suspension stiffness and damping characteristics as functions of those of the air spring and the hydraulic damper, respectively. The proposed relations are verified through simulations of the multi-body dynamic model of the cross-linkage seat-suspension in the ADAMS platform. The validity of the kineto-dynamic model is also demonstrated through comparisons of its vibration transmission response with the experimental data. The model is used to identify optimal air spring coordinates to attain nearly constant natural frequency of the suspension, irrespective of the seated body mass and seated height. A methodology is further proposed to identify optimal damping requirements for vehicle-specific suspension designs to achieve minimal seat effective amplitude transmissibility (SEAT) and vibration dose value (VDV) considering vibration spectra of different classes of earthmoving vehicles. The shock and vibration isolation performance potentials of the optimal designs are evaluated under selected vehicle vibration superimposed with shock motions. Results show that the vehicle-specific optimal designs could provide substantial reductions in the SEAT and VDV values for the vehicle classes considered.     

Energy Flow in Active Attitude Control Suspensions: A Bond Graph Analysis

Fully active ground vehicle suspensions which completely replace the passive spring and damper elements with a force generating actuator have required a significant amount of power. Alternative systems which retain compliant elements to handle high frequency isolation but include active elements to control the vehicle body attitude have been developed to reduce the power requirements. These suspensions are called “low bandwidth” or “fast load leveler” systems and they often incorporate semi-active dampers which produce high frequency controllable forces with low power requirements. Here, two contrasting attitude control systems are studied to show that actuator power can be significantly reduced if the actuator is used to vary a lever ratio instead of being used to compress the suspension spring directly. Both types of systems have been successfully implemented in prototype form. Bond graphs for idealized versions of the suspensions show clearly the significant differences in actuator power and energy requirements even though the abstract mathematical structures of the two systems are remarkably similar. Computer simulations confirm the analytical results.     

Active controller design for an electromagnetic energy-regenerative suspension

In this paper, with the parameters acquired from measured and tested data, a three-phase mathematical model is applied to the motor component of the developed electromagnetic suspension actuator. A main/inner-loop structure is used for its active control, and the constraints of the control current and energy flow states of actuator are analyzed by simplifying the inner-loop control system. Two different control modes, i.e., Consumptive Full Active (CFA) and Regenerative Semi Active (RSA) modes, which emphasize vibration control of sprung mass and vibration energy regeneration caused by road roughness, respectively, are proposed. Simulations are carried out using different road conditions, and the results demonstrate that the CFA mode can improve vehicle ride comfort by more than 30 percent, despite battery energy consumption; in RSA mode, the ride comfort can be improved by up to 10 percent with the battery charged by regenerated energy.     

Adaptive impedance control of a hydraulic suspension system using particle swarm optimisation

This paper presents a novel active control approach for a hydraulic suspension system subject to road disturbances. A novel impedance model is used as a model reference in a particular robust adaptive control which is applied for the first time to the hydraulic suspension system. A scheme is introduced for selecting the impedance parameters. The impedance model prescribes a desired behaviour of the active suspension system in a wide range of different road conditions. Moreover, performance of the control system is improved by applying a particle swarm optimisation algorithm for optimising control design parameters. Design of the control system consists of two interior loops. The inner loop is a force control of the hydraulic actuator, while the outer loop is a robust model reference adaptive control (MRAC). This type of MRAC has been applied for uncertain linear systems. As another novelty, despite nonlinearity of the hydraulic actuator, the suspension system and the force loop together are presented as an uncertain linear system to the MRAC. The proposed control method is simulated on a quarter-car model. Simulation results show effectiveness of the method.     

Actively controlled vehicle suspension with energy regeneration capabilities

The paper presents an innovative dual purpose automotive suspension topology, combining for the first time the active damping qualities with mechanical vibrations power regeneration capabilities. The new configuration consists of a linear generator as an actuator, a power processing stage based on a gyrator operating under sliding mode control and dynamics controllers. The researched design is simple and energetically efficient, enables an accurate force–velocity suspension characteristic control as well as energy regeneration control, with no practical implementation constraints imposed over the theoretical design. Active damping is based on Skyhook suspension control scheme, which enables overcoming the passive damping tradeoff between high- and low-frequency performance, improving both body isolation and the tire's road grip. The system-level design includes configuration of three system operation modes: passive, semi–active or fully active damping, all using the same electro-mechanical infrastructure, and each focusing on different objective: dynamics improvement or power regeneration. Conclusively, the innovative hybrid suspension is theoretically researched, practically designed and analysed, and proven to be feasible as well as profitable in the aspects of power regeneration, vehicle dynamics improvement and human health risks reduction.     

铰接式自卸车悬架系统动力学建模与仿真

建立了一个铰接式自卸车9自由度线性动力学模型，并用Matlab语言编写了基于Simpson算法的仿真程序，来仿真它对路面随机输入的响应，用以计算数种工况下座椅总加权加速度均方根值。仿真结果表明，所建模型能较好地吻合座椅的实际振动，不仅可以正确评估系统的平顺性性能，还可为新型铰接车辆悬架系统、橡胶弹簧的优化设计提供理论和方法支持。     

Hybrid modelling and damping collaborative optimisation of Five-suspensions for coupling driver-seat-cab system

For the complex structure and vibration characteristics of coupling driver-seat-cab system of trucks, there is no damping optimisation theory for its suspensions at present, which seriously restricts the improvement of vehicle ride comfort. Thus, in this paper, the seat suspension was regarded as ‘the fifth suspension’ of cab, the ‘Five-suspensions’ for this system was proposed. Based on this, using the mechanism modelling method, a 4 degree-of-freedom coupling driver-seat-cab system model was presented; then, by the tested cab suspensions excitation and seat acceleration response, its parameters identification mathematical model was established. Based on this, taking optimal ride comfort as target, its damping collaborative optimisation mathematical model was built. Combining the tested signals and a simulation model with the mathematical models of parameters identification and damping collaborative optimisation, a complete flow of hybrid modelling and damping collaborative optimisation of Five-suspensions was presented. With a practical example of seat and cab system, the damping parameters were optimised and validated by simulation and bench test. The results show that the model and method proposed are correct and reliable, providing a valuable reference for the design of seat suspension and cab suspensions.