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1.
The steering torque of automobile EPS steering system is significant for driving steering control and good driving feel. Servo motor control and external interference moment are the core factors affecting EPS steering system. With the advancement of automotive technology, the requirements of EPS control technology have been gradually improved, and the driving and handling of vehicles at high speed have become the key issues. For the current EPS steering system at high speed vibration and steering feel, active disturbance rejection EPS torque control method is proposed, EPS variable mode controller was developed. The control of the variable mode is verified by experiment and the vibration torque from the road is controlled, determine the control frequency of 30 KHz, the amount of current fluctuation is the smallest. The ADRC (active disturbance rejection controller) technology is used to suppress the interference of the road surface, finally, the validity of active immunity is verified by bench test. Steering wheel vibration torque can be reduced by an average of 28.5% to 33.3%.  相似文献   

2.
The problem of positioning of actuators and sensors on smart materials has been a point of interest in recent years. This is due to the fact that in many practical applications there are limitations in space, weight, etc. of the smart structures, which make the problem of positioning more complex. In addition, it is required that the actuators/sensors have the best possible performance. The development of smart structures technology in recent years has provided numerous opportunities for vibration control applications. The use of piezoelectric ceramics or polymers has shown great promise in the development of this technology. The employment of piezoelectric material as actuators in vibration control is beneficial because these actuators only excite the elastic modes of the structures without exciting the rigid-body modes. This is important since very often only elastic motions of the structures are needed to be controlled. The purpose of this paper is to introduce a novel approach developed for optimizing the location of piezoelectric actuators for vibration suppression of flexible structures. A flexible fin with bonded piezoelectric actuators is considered in this study. The frequency response function (FRF) of the system is then recorded and maximization of the FRF peaks is considered as the objective function of the optimization algorithm to find the optimal placement of the piezoelectric actuators on the smart fin. Three multi-layer perceptron neural networks are employed to perform surface fitting to the discrete data generated by the finite element method (FEM). Invasive weed optimization (IWO), a novel numerical stochastic optimization algorithm, is then employed to maximize the weighted summation of FRF peaks. Results indicate an accurate surface fitting for the FRF peak data and an optimal placement of the piezoelectric actuators for vibration suppression is achieved.  相似文献   

3.
This paper addresses the agile attitude maneuver of flexible spacecraft using control moment gyros without modal information. Here, piezoelectric actuators are employed to actively suppress the vibration of flexible appendages. Both the dynamics and the proposed controller are globally developed on the Special Orthogonal Group SO(3), avoiding ambiguities and singularities associated with other attitude representations. More specifically, an observer is first designed to estimate the modal information of vibration. A robust control law is developed by synthesizing a proportional-derivative (PD) controller, an adaptive sliding mode controller, and an active vibration-suppression controller, which use the information of the estimated structural modes. The stability of the closed-loop system is proved using Lyapunov stability theory. Finally, numerical examples are performed to show the effectiveness of the proposed method.  相似文献   

4.
This paper considers vibration control of a single mass flexible rotor on damped flexible supports with active feedback control. Both proportional and derivative feedback control are utilized. Free vibrations and unbalance response of the rotor-control system are determined. The effect of proportional control is to increase the critical speed of rotating machinery while the effect of derivative control is to reduce the amplitude of vibration. Generally larger ratios of support stiffness to shaft stiffness require larger values of control parameters to produce given amplitudes of vibration.  相似文献   

5.
Semi-active systems are those in which a passive, dissipative element (damper, friction clutch, fluid orifice) is modulated, via low power inputs, to enhance the performance of its associated dynamic system. This type of control is inherently nonlinear, thus forcing the closed-loop response of the total system to be determined numerically using a digital computer. Although, strictly speaking, the frequency response for nonlinear systems does not exist, it is typical to simulate semi-active systems with sinusoidal input and present results as frequency transmissibilities. This paper uses energy dissipation per cycle to determine an approximate frequency response of semi-active systems requiring only a calculator for numerical analysis.  相似文献   

6.
The inerter has garnered much attention in the past two decades owing to its unique mechanical characteristics. As a substitution of the capacitance element based on the electrical-mechanical analogy, the inerter has outstanding advantages. Extensive investigations have been conducted for the development of inerter-based vibration isolation system. This paper provides a retrospective perspective and an update on the inerter's progress for vibration isolation in different fields. The advantages of inerter compared with mass element are analyzed and revealed. Some existing reviews and highly-cited papers are summarized to outline the inerter development progress. Thereafter, the inerter is reviewed in detail from the perspective of network analogy and synthesis, mechanical domain, and power flow transmission. The devices improvement and control approach are summarized. Finally, the significance of inerter research, the challenge in current studies, and promising inerter application fields are presented and discussed. This paper is closed by conclusions, which highlight the necessity of inerter research, current challenges, and future research directions.  相似文献   

7.
This paper investigates an application of a ball-screw inerter for mitigation of impact loadings. The problem of impact absorption is to provide a minimum reaction force that optimally decelerates and eventually stops an impacting object within the available absorber stroke. It significantly differs from vibration mitigation problems which are typical application of inerters. The paper demonstrates that the optimum absorption can be achieved by fully passive means. For known values of the object mass and inerter parameters, the obtained solution is independent of the impact velocity. The optimum passive absorption is achieved by employing a variable thread lead. As a result, two force components emerge, the typical inertance-related force and a damping-like term, and sum up to provide the optimum constant deceleration force. This result is relatively unique: conventional absorbers do not provide a constant force even with complex active control systems. Finally, an optimization problem is formulated to reduce the influence of process uncertainties (range of possible mass values, unknown friction). The results are verified and analyzed in a numerical example.  相似文献   

8.
A vibration control strategy is addressed for the three-dimensional vibration suppression of an Euler-Bernoulli beam (EBB) subject to asymmetric output constraints in this paper. A special piecewise barrier Lyapunov function candidate is provided to prevent the asymmetric output constraint violation, and a model-based boundary control (MBC) is developed subsequently to ensure the coupled vibration reduction. Moreover, considering the parameter uncertainties, an adaptive law is designed to estimate the uncertain parameter and to update the vibration controller. The main challenge of this work is to consider the asymmetric output constraint in a nonlinear and coupled infinite-dimensional system. Finally, numerical simulations are made to present the system performance under the proposed vibration controllers which maintain the output being restrained in the predefined scope.  相似文献   

9.
Recent research in the field of vehicle electrification has indicated that synchronous machines, which include the permanent magnet synchronous machine (PMSM) and the externally excited synchronous machine (EESM), represent a viable solution for electric propulsion. A challenging problem for synchronous machines drives employed in automotive applications is to obtain accurate mathematical models which can deal with parametric variation and which are suitable for real-time simulations and synthesis of control laws. The goal of this paper is to provide a mathematical modeling framework for synchronous machines that can answer to this challenging problem. To this end, using the rotor reference frame, the mathematical models of PMSMs and EESMs are constructed taking into account also the parametric variation due to magnetic saturation and temperature variation. Then, a complex state-space bilinear model for both EESM and PMSM with parametric variation due to magnetic saturation and temperature are developed. Considering the parametric variation as a polytopic bounded disturbance, it is then shown how to split the bilinear complex model in two PWA variable parameter state-space models suitable for a cascade control structure. Based on the developed models, a dynamic unified simulator was constructed in Matlab®/Simulink®. Measurement data obtained in a real test-bench system were used to verify the accuracy of the simulator. The discrete-time simulator was then integrated in an industrial hardware-in-the-loop test bench for real-time evaluation of a current control scheme in EESM drives.  相似文献   

10.
This paper addresses the issue of the active vibration control of the transverse modes in a flexible elastic systems. The control is implemented by discrete sets of piezoelectric actuators that apply the optimal forces. The performance index is a time-dependent quadratic functional of state variables and their time derivatives, and control forces which are determined by minimizing the objective functional subject to a penalty term on the control functions. A combination of Galerkin and variational approaches are employed to determine the control forces in the time domain explicitly in terms of coupled amplitudes and velocities. The effectiveness of the proposed method is demonstrated by applying it to a physical problem controlled by piezoelectric patch actuators.  相似文献   

11.
Sampled-data control for time-delay systems   总被引：1，自引：0，他引：1  
The sampled-data systems are hybrid ones involving continuous time and discrete time signals, which makes the traditional analysis and synthesis methodologies of time-delay systems unable to be directly used in the cases of hybrid systems with time-delay. The primary disadvantages of current design techniques of sampled-data control are their inabilities to deal effectively with time-delay and the model uncertainty. In this paper, we generalized the analysis methodology of time-delay systems to that of the hybrid systems with time-delay and uncertainty, which developed a design procedure of sampled-data control for time-delay systems. Asymptotic stability of the time-delay hybrid systems was developed. The time-delay dependent robust sampled-data control for the time-varying delay of an uncertain linear system was then discussed. The results were described as linear matrix inequalities, which can be solved using newly released LMITool.  相似文献   

12.
The paper presents an explicit two-step calibration procedure for tuned inerter based vibration absorbers on flexible structures. It makes use of a local approximate representation of the structural response to the device force, in which the contribution of the non-resonant modes is represented approximately around the resonance frequency by a background flexibility and a background inertia term. The calibration procedure then consists of two steps. The first step calibrates an equivalent vibration absorber including the background terms, and the second step subsequently evaluates the parameters of the actual device by extracting the background flexibility and inertia parameters. The first step represents the classic idealized single degree of freedom representation of the structure, whereas the second step leads to an increase of stiffness, inertia and damping parameters of the actual device due to background flexibility of the structure. The procedure is illustrated in detail for three inerter based vibration absorbers: parallel coupling of damper and stiffness, parallel coupling of damper and inerter, and finally a device with two dampers in parallel with stiffness and inerter elements, respectively. Explicit expressions for the calibration are obtained for each device, and it is demonstrated that the procedure leads to a balanced plateau of amplification around the resonance frequency of the magnitude assumed as the basis for the device parameter calibration.  相似文献   

13.
王兰  张胜利 《科教文汇》2021,(13):46-47
该文深入分析了翻转课堂与网络教学的异同,虽然都有网络视频教学,但是二者的应用场景和教学模式是完全不同的。网络教学是对传统课堂教学的补充手段,适用于没有条件实现线下教学的场景。而翻转课堂是对传统课堂的升级,翻转指的是课内课外教学内容的转换。学生课外自学传统课堂上传授的内容,而在教师的指导下,课堂时间可以用于完成更复杂的知识的实践和应用。随着时代和科技的发展,这两种教学方式必将得到更广泛的应用。  相似文献   

14.
In this paper, a novel semi-active variable admittance (VA) concept is proposed, and a seat suspension prototype with a magnetorheological fluid damper based rotary VA device is designed, manufactured, and experimentally validated. The conventional inerter with a single flywheel has a constant inertance, which can effectively improve the suspension performance by being integrated into a mechanical network with springs and dampers. The proposed rotary VA device comprises a gear reducer, two flywheels and a variable damping (VD) device which is used to connect the two flywheels. With carefully designing, the rotary VA device is compacted and is similar with a VD device in size. The rotary VA device is installed in the centre of a seat suspension's scissors structure to form a VA seat suspension. According to the test results, the equivalent inertance of the seat suspension can vary from 11.3 Kg–76.6 Kg with a 3 Hz frequency and 5 mm amplitude sinusoidal movement by changing the current from 0 A–1 A. By analysing the system characteristics, a hybrid controller with two acceleration feedbacks is proposed. Thereafter, the seat suspension and controller are validated in experiments by comparing the performance with a conventional passive seat suspension. The random vibration test shows the excellent performance of the proposed seat suspension; the frequency weighted root mean square acceleration of the seat is reduced by 43.6%, which indicates a great improvement of the ride comfort. The VA device shows great prospect in the suspension application.  相似文献   

15.
There exist mixed deadzone-saturation input nonlinearities and output constraint in the practical implementation environment for flexible mechanical systems, and they have crucial influences on the performance of flexible systems. In this paper, two class of flexible structures are investigated and analyzed by designing the active boundary vibration control with auxiliary systems. Based on the infinite dimensional dynamic model of flexible mechanical systems, the barrier logarithmic terms are brought into the Lyapunov function and boundary vibration control laws for maintaining the output signals within the constrained region. Besides, the auxiliary terms are designed in the control laws to compensate for mixed nonlinear inputs which integrate the deadzone and saturation characteristics. With the simulation results, the theoretical analysis for the flexible mechanical systems is verified to be correct and the designed control laws are effective.  相似文献   

16.
从锅炉受热面管道振动的原因出发,提出加装抗振隔板是消除振动最有效的方法,并给出抗振隔板选取方法及其结构和安装方法,最后给出抗振隔板及悬吊所用材料的选取。  相似文献   

17.
Suppression of the vibration caused by environmental loads in marine risers is critical to prevent irreparable damages. This paper addresses this issue by proposing a novel boundary control for a flexible riser connected to a vessel at its top. In this regard, initially, a sliding mode observer (SMO)-based disturbance estimator is constructed to estimate the uncertainty of the vessel's dynamics. Next, using backstepping, a suitable virtual control along with the respective error dynamics are derived. A fractional-order error surface is defined to achieve Mittag-Leffler convergence for the control error variable. A second-order sliding mode (SOSM) control law is used to stabilize this error surface. The boundedness and ultimate boundedness of the riser's deflection under the proposed boundary control is shown by Lyapunov analysis. Comparative simulations demonstrate the robust vibration suppression performance of the proposed controller.  相似文献   

18.
A robust fault-tolerant control scheme for distributed actuated electric vehicles is proposed to maintain vehicle stability suffering actuator faults while considering the driver personality differences. The proposed scheme integrates the cooperative game and terminal sliding mode control into the framework of the feedback linearization method (FLM). Firstly, the nonlinearities of the driver-vehicle system are treated by the knowledge of Lie derivative, and then a set of controllable virtual subsystems is obtained through diffeomorphism. To achieve multi-objective cooperation, the interaction framework of virtual subsystems is modeled based on cooperative game theory, which provides a basic feedback control scheme (BFCS). Finally, a terminal sliding mode technology-based active compensation control scheme is integrated into BFCS to handle the systemic disturbances caused by actuator faults. An implementation of hardware-in-the-loop verifies that the stability of the vehicle under the control of the developed approach can be guaranteed for different drivers and different fault types.  相似文献   

19.
Two different control approaches for suppressing DC-link voltage unbalance in Three-Level Neutral-Point Clamped Converters (NPCs) are presented in this paper. They both guarantee DC-link voltage equalization over any NPC operating conditions, i.e. when the NPC feeds or is supplied by the main AC grid at different active and/or reactive power rates. The proposed control approaches consist of either a hysteresis or a proportional regulator, each of which synthesizes the most suitable control action based on the actual DC-link voltage unbalance. Particularly, two different PWM techniques have been developed in order to achieve DC-link voltage equalization successfully, preserving NPC voltage and current waveforms at the same time. The performances achievable by means of both the proposed control approaches have been compared to each other through an extensive simulation study in order to highlight their most important advantages and drawbacks, as well as their effectiveness over any operating conditions. Particularly, both control approaches are validated in the Matlab-Simulink environment referring to DC-link voltage equalization of an NPC that represents the point of common coupling between a DC microgrid and the main AC grid.  相似文献   

20.
We report the Laser Induced Forward Transfer (LIFT) of antibodies from a liquid donor film onto paper receivers for application as point-of-care diagnostic sensors. To minimise the loss of functionality of the active biomolecules during transfer, a dynamic release layer was employed to shield the biomaterial from direct exposure to the pulsed laser source. Cellulose paper was chosen as the ideal receiver because of its inherent bio-compatibility, liquid transport properties, wide availability and low cost, all of which make it an efficient and suitable platform for point-of-care diagnostic sensors. Both enzyme-tagged and untagged IgG antibodies were LIFT-printed and their functionality was confirmed via a colorimetric enzyme-linked immunosorbent assay. Localisation of the printed antibodies was exhibited, which can allow the creation of complex 2-d patterns such as QR codes or letters for use in a final working device. Finally, a calibration curve was determined that related the intensity of the colour obtained to the concentration of active antibodies to enable quantitative assessment of the device performance. The motivation for this work was to implement a laser-based procedure for manufacturing low-cost, point-of-care diagnostic devices on paper.  相似文献   

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