A New SSUKF Observer for Sliding Mode Force Tracking H∞ Control of Electrohydraulic Active Suspension

Compared to passive and semi‐active suspensions, active suspensions have the capacity to overcome the tradeoff design of vehicle ride comfort and handling performance. In this paper, a new control system with modified spherical simplex UKF (SSUKF) observer and sliding mode force tracker is proposed for electrohydraulic active suspensions. The estimated states obtained from the SSUKF observer are used to derive the mode energy of body motion and design the target demanded forces for suspension actuators. A sliding mode controller is presented to drive electrohydraulic actuators to track the demanded forces. Based on a robust H∞ control method, a new control strategy depending on body mode energy is proposed to restrict body motion. The performance comparisons between passive and active suspensions under three typical excitations are presented, and the obtained results indicate that the proposed control system can significantly depress body motion and decrease the mode energy to improve ride comfort and also effectively enhance the road hold abilities.     

Fault diagnosis for a class of active suspension systems with dynamic actuators’ faults

In this paper, a new fault diagnosis and fault-tolerant control method for a class of active suspension systems with actuator faults is proposed. The considered actuators have uncertain dynamic characteristics, which are the electromagnetic actuators made up with a motor control system and a ball screw transmission mechanism. To detect such suspension system actuator faults, dynamic fault diagnosis observers are designed for the actuators to estimate the possible faults. The actuators are analyzed to first and second order dynamic models, respectively, whose output can be measured but the rate is non-measurable. Then, the fault diagnosis method is developed for these two kinds of models to obtain the fault information. Using the fault estimation and adaptive control technique, a robust fault-tolerant controller is constructed to guarantee the performance of the rail vehicles in the faulty case. Finally, using the parameters of a practical suspension system, a simulation study is conducted to show the effectiveness of the proposed method.     

汽车主动悬挂控制的研究现状和未来挑战

主动悬挂系统能提高车辆的乘坐舒适性和操纵性,得到了广泛的研究和重视.掌握悬挂控制的研究现状,可以更好地研究和利用主动悬挂技术.本文立足现有文献,依照不同的控制策略,从七个方面阐述了主动悬挂控制的研究现状,总结出了尚需解决的非线性悬挂建模、悬挂集成控制、控制系统性能评估等六个基本问题.文章最后分析了鲁棒控制、自适应控制、智能控制在车辆悬挂控制中的局限性及出现的挑战性课题,提出了车辆主动悬挂技术的发展方向.     

Self-sensing actuators with passive damping for adaptive vibration control of hard disk drives

A push–pull piezoelectrically actuated devices have been developed for higher bandwidth servo systems as microactuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only and therefore a dual-stage servo system using enhanced active–passive hybrid micro piezoelectric actuators is proposed to improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. In this paper, three different configurations of self-sensing actuators (SSAs) incorporating an adaptive mechanism for vibration control of suspensions in dual-stage hard disk drives (HDDs) are investigated. In the piezo-based SSA configuration, the signal sensed due to mechanical deformation is mixed with the control input signal, which would be corrupted due to the variation of the piezoelectric capacitance when a fixed bridge circuit is used. In this study, a self-tuning adaptive compensation is used to combine with the SSA technique to extract the true sensing signal for the vibration control of suspensions in HDDs. An assembled suspension with piezoelectric microactuators is tested to demonstrate the vibration suppression performance of this adaptive structure under an external shock disturbance such as hammer excitation. The experimental results show that the target vibration modes have been suppressed effectively with using the adaptive positive position feedback controller for the enhanced SSAs with passive damping in HDDs.     

一类非线性激励器系统的鲁棒自适应跟踪

考虑一类具有非线性激励器不确定系统的鲁棒跟踪问题，其不确定性是部分已知的。所构造的鲁棒自适应控制方案能确保系统的跟踪误差终极一致有界．与已有文献结果相比．未知参数估计的自适应律和控制器是连续的，从而使得所提出的设计方案在实际控制问题中易实现。且与具有线性激励器的系统一样具有较强的鲁棒性．最后通过数值算例进一步说明了该设计方案是有效的。     

基于模糊神经网络的二自由度主动悬架滑模控制系统设计

主动悬架滑模控制系统受到行驶路面影响,车体震动加速度功率谱密度与实际密度不一致,导致系统控制效果不佳,提出基于模糊神经网络的二自由度主动悬架滑模控制系统设计;基于二自由度硬件结构,在主动悬架液压伺服系统中安装蓄能器,减小空间内存;采用磁流变阻尼器,调整电流大小控制阻尼;设计自适应减振座椅悬架并计算阻尼值,实现了主动悬架的控制;考虑路面不规则度,构建二自由度主动悬架滑模控制模型,依据牛顿定律计算悬架弹性元件受力;采用模糊控制规则校正控制误差,采用模糊神经网络设计主动悬架滑膜控制方案,经迭代处理得到满足优化要求的解,实现滑膜控制;由试验结果可知,车体震动加速度功率谱密度与实际密度一致,从最初的0 ms^(-2)到最终的1.5 ms^(-2),具有良好控制效果,确保乘车的舒适性。     

Adaptive backstepping output feedback control of DC motor actuator with friction and load uncertainty compensation

In this paper, we present an output feedback backstepping controller for mechatronic actuators with dynamic adaptive parameters for friction and load compensation. The targeted application is angular position control of automotive mechatronic valves, which possess nonlinear dynamics due to friction. The proposed controller requires only position measurement. The velocity, current, and friction dynamics are obtained by estimation and observation. The adaptive control law compensates the variations in friction behavior and load torque variation, which are common in real life applications. Lyapunov analysis has been used to show the asymptotic convergence of the closed‐loop system to zero. Simulation and laboratory experimental results illustrate the effectiveness and robustness of the controller. Further experiments on an engine test bench demonstrate the applicability of this controller in commercial engines, as well as its effectiveness as compared with conventional PI controllers.Copyright © 2014 John Wiley & Sons, Ltd.     

A class of active LQG optimal actuators

Active and passive vehicle suspensions viewed as control actuators are discussed using the notion of passivity developed in network theory. For the specific example of a two-degree-of-freedom linear model of a vehicle, it is shown that for the given quadratic performance index, only active optimal suspension realizations are possible.     

Fault-tolerant actuators and drives—Structures, fault detection principles and applications

As fault detection and fault diagnosis methods are more and more finding their way into modern industrial mechatronic products, it is now time to take the next step. Based on the research efforts for fault detection and diagnosis, a status report has been prepared for research on fault management, i.e. automatic reactions of the system to continue operation after the detection of faults. These reactions may employ hardware redundancy (i.e. switching from a faulty actuator to another, intact one) or analytical redundancy (i.e. switching from a faulty sensor to a “model sensor” or “soft sensor”).A total fault-tolerance concept must encompass all components of a system, i.e. the actuators and drives, the process itself, the sensors as well as the controller and communication. In many cases, a degradation of functions has to be accepted after a fault has appeared. Concentrating on some widespread actuation principles, the paper will focus on electric drives and hydraulic actuators.First, a review is given on fault-tolerance principles and general structural considerations, e.g. hot-standby and cold-standby, focusing on the scheme of an overall fault-tolerant control system. Then, fault statistics for existing actuators and drives will be presented. These fault statistics give hints on the parts of the actuators which are most susceptible to faults. Different designs of fault-tolerant actuators and drives, which have been realized as laboratory prototypes or even on an industrial scale, shall be presented and evaluated with respect to their capabilities of withstanding faults. Finally, an outlook for fault-tolerant mechatronic systems will be given.     

Dual-stage servo systems and vibration compensation in computer hard disk drives

This paper discusses two mechatronic innovations in magnetic hard disk drive servo systems, which may have to be deployed in the near future, in order to sustain the continuing 60% annual increase in storage density of these devices. The first is the use of high bandwidth dual-stage actuator servo systems to improve the precision and track-following capability of the read/write head positioning control system. The second is the instrumentation of disk drive suspensions with vibration sensing strain gages, in order to enhance airflow-induced suspension vibration suppression in hard disk drives.     

Mechatronic developments for railway vehicles of the future

Railway vehicles have principally been designed by mechanical engineers since railways began in the early 1800s, i.e. before electronics and feedback control were invented. Today however they contain substantial amounts of electronic and computer control, in particular the traction systems, which have been converted entirely. However electronic control can also be applied to the vehicle suspension and guidance functions, which can provide large improvements in performance. More significantly, incorporation of sensors, controllers and actuators into the design process from the start can enable vehicle designers to take advantage of different mechanical configurations which are not possible with a purely mechanical approach—in other words the true spirit of mechatronics. The paper reviews the concepts, the current state-of-the-art and opportunities for mechatronic developments for railways for the future.     

Targeted processing for real-time embedded mechatronic systems

This paper describes the architecture and design framework for a multiprocessor system on chip (SoC) solution that is being developed for adaptive, high-performance, embedded real-time control applications. Most of the design-to-implementation stages are automated by software tools avoiding most of the error-prone programming tasks and hardware-related issues. Therefore, the work presented here minimises the interdisciplinary design efforts typical to mechatronic systems design, allowing control engineers to focus mainly on the control laws development. The performance achieved by the proposed architecture allows for a straightforward addressing of implementation requirements for a variety of embedded applications, including micro-electromechanical systems.     

Robust fault-tolerant controller design for linear time-invariant systems with actuator failures: an indirect adaptive method

In this paper, indirect adaptive state feedback control schemes are developed to solve the robust faulttolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. A more general and practical model of actuator faults is presented. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the lower and upper bounds of actuator-stuck faults and perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive robust state feed-back controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that the robust adaptive closed-loop systems can be ensured to be asymptotically stable under the influence of actuator faults and bounded perturbations. An example is provided to further illustrate the fault compensation effectiveness.     

Trends in hydraulic actuators and components in legged and tough robots: a review

Abstract

Hydraulics is an old technology which is being applied in many applications including large machinery, heavy industries, and early robotics. The traditional features of hydraulics that possess a high power to weight ratio compared to other power transmission system make it suitable to work in a tough and robust environment. However, the trend of hydraulic system has decreased since the introduction and mass usage of the powerful brushless motor and rare earth magnetic motor in industrial sector since the 1980s. Recently, hydraulic systems have shown incremental demand where the innovation of hydraulic actuators and components was actively conducted aimed at compactness, lightweight with higher energy-efficiency, clean and friendly features for many applications in both mobile and industrial hydraulics. This review shows the hydraulic trends in tough robotics applications which focus on legged robots such as humanoid, search and rescue robot and large machinery. New innovations of hydraulic components such as actuators, pump, and other accessories and trends are discussed for future hydraulics in tough robotics applications.     

Robust fault-tolerant controller design for linear time-invariant systems with actuator failures: an indirect adaptive method

In this paper, indirect adaptive state feedback control schemes are developed to solve the robust faulttolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. A more general and practical model of actuator faults is presented. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the lower and upper bounds of actuator-stuck faults and perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive robust state feed-back controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that the robust adaptive closed-loop systems can be ensured to be asymptotically stable under the influence of actuator faults and bounded perturbations. An example is provided to further illustrate the fault compensation effectiveness.     

Mechatronic solutions for high-speed railway vehicles

This paper presents recent developments in the study of active steering for railway wheels. It demonstrates the potential benefits from this form of active control and studies what could be achieved when modern control techniques are used on the vehicles via mechatronic components. The study is based on a mechanically simplified vehicle and active control strategies for three wheelset/wheel-pair configurations are studied, which are solid axle wheelset, independently rotating wheelset and directly steered wheel pairs. Various mechatronic vehicle configurations are discussed and different control schemes are presented. Two key performance requirements, i.e. the curving performance of the wheelset and ride quality of the vehicle, are assessed for all proposed schemes. Finally, actuation requirement is also investigated.     

Linear and non-linear skyhook damping control laws for active railway suspensions

This paper presents and compares different control strategies for applying “skyhook” damping control laws in active suspension systems for railway vehicles. It first examines a number of linear approaches for filtering the absolute velocity signal in order to optimise the trade-off between the random and deterministic track input requirements, and then what can be achieved using non-linear methods based upon Kalman-filters is explored. The principles that are developed are general and can be applied to both vertical and lateral secondary suspensions, although the paper concentrates upon the vertical direction and quantifies the performance achievable for a particular combination of track characteristics.     

Avoiding defects in manufacturing processes: A review for automated CFRP production

Linear robots, numerically controlled machines and articulated robots are some of the major components in automation. In various applications, these single systems are linked together to become advanced mechatronic systems since they can realize special and general tasks. Unfortunately, the degree of automation in carbon fiber reinforced plastic (CFRP) manufacturing is currently rather low. A lot of research still needs to be done in order to achieve the knowledge necessary to gain a consistent, robust and reliable production chain for CFRP. The most decisive criterion in automation is the tradeoff between speed in production and the attainable layup accuracy. One aspect that affects accuracy is vibration caused by rapid movement and interaction forces. In the case of advanced mechatronic systems, the effect of the dynamic coupling is one key factor in accuracy. Over the last few decades, the field of active vibration suppression has made use of its excellent capability to improve the accuracy of machines. Therefore, the paper presents a comprehensive review of active vibration suppression technology for the improvement of precision in manufacturing. The work is mainly focused on, but not limited to, the production of components made of CFRP. The paper concludes with a discussion of promising approaches to identify a trend for future work.     

Advanced model predictive control framework for autonomous intelligent mechatronic systems: A tutorial overview and perspectives

This paper presents a review on the development and application of model predictive control (MPC) for autonomous intelligent mechatronic systems (AIMS). Starting from the conceptual analysis of “mechatronics”, we analyze the characteristics and control system design requirements of AIMS. In order to fulfill the design requirements, we propose to develop a unified MPC framework for AIMS. The main MPC schemes, covering MPC basics, robust MPC, distributed MPC, Lyapunov-based MPC, event-based MPC, network-based MPC, switched MPC, fast MPC, are reviewed with an attempt to document some of the key achievements in the past decades. Furthermore, we provide the review and analysis of MPC applications to three types of mechatronic systems, including unmanned aerial vehicles (UAVs), autonomous marine vehicles (AMVs), and autonomous ground robots (AGRs). Some promising research directions and concluding remarks are presented.     

磁悬浮刚性转子系统振动机理分析与动力学建模

磁悬浮惯性执行机构采用磁轴承支承,可通过主动控制实现极微振动,但磁悬浮惯性执行机构仍存在频谱分量丰富的振动.首先在转子动静不平衡和Sensor Runout振动机理分析的基础上,重点分析了Magnet Runout产生振动机理;然后,建立包含多振动源的系统动力学建模,并将整个动力学模型分解为平动和转动子系统,分析表明转子动静不平衡、Sensor Runout和Magnet Runout是通过不同的途径产生振动,不仅产生同频振动还包含倍频振动;最后,提出磁悬浮刚性转子系统主动振动控制的要求,为以后的主动振动控制研究奠定基础.