Active vibration control of flexible bodied railway vehicles via smart structures

Future railway vehicles are going to be designed lighter in order to achieve higher speed. Suppressing the flexible modes becomes a crucial issue for improving the ride quality of the light-weight high speed railway vehicles. The concept of smart structure brings structural damping to flexible structures by integrating smart actuators and sensors onto the structure. Smart structure eliminates the need for extensive heavy mechanical actuation systems and achieves higher performance levels through their functionality for suppressing the flexible modes. Active secondary suspension is the effective conventional approach for vibration control of the railway vehicle to improve the ride quality. But its ability in suppressing the flexible modes is limited. So it is motivated to combine active structural damping for suppressing the flexible modes and the vibration control through active secondary suspension which has an effect on both rigid and flexible modes. The side-view model of the flexible-bodied railway vehicle integrated with piezoelectric actuators and sensors is derived. The procedure for selection of placement configurations of the piezoelectric actuators and sensors using structural norms is presented. Initial control studies show that the flexibility of the vehicle body will cause a considerable degradation in ride quality if it is neglected in the design model. Centralized and decentralized control strategies with various control approaches (e.g. modal control with skyhook damping, LQG/H2 control, H_infinity control and model predictive control (MPC))are applied for the combined control of active structural damping and active suspension control. The active structural damping effectively suppresses the flexible modes as a complement to the work of the active suspension control

Combining active structural damping and active suspension control in flexible bodied railway vehicles

There is a desire to design lightweight railway vehicle bodies for future high speed trains. Previously, suppression of structural vibration of the flexible lightweight vehicle body was attempted via use of active suspensions (conventional actuators) or by structural damping via piezoelectric actuators, with the aim being to improve the ride quality. In a railway vehicle the typical active suspension setup comprises front and rear suspension conventional actuators, while adding more macro-actuator elements to minimise structural vibrations can substantially impact vehicle weight and location considerations. In this paper, we show that piezoelectric actuator control can provide complementary action to active suspensions. Decentralized control is adopted for combined active structural damping and active suspension design via Linear Quadratic Gaussian (LQG) method and modal control with skyhook damping respectively. The side-view model of a flexible-bodied railway vehicle integrated with piezoelectric actuators and appropriate sensor outputs is derived and the placement of the piezoelectric actuators and sensors is addressed via structural norms. It is shown that vibrations of both the flexible modes and rigid modes are suppressed effectively. This suggests that with the combined approach, control by both piezoelectric actuators and suspension actuators could be used in a more efficient way to address vibrations in light railway vehicle bodies

Model predictive control based on mixed H2/H∞ control approach for active vibration control of railway vehicles

This paper investigates the application of Model Predictive Control (MPC) technology based on mixed H2/H1 control approach for active suspension control of a railway vehicle, the aim being to improve the ride quality of the railway vehicle. Comparisons are made with more conventional control approaches, and the applicability of the linear matrix inequality approach is illustrated via the railway vehicle example

Combined active suspension and structural damping control for suppression of flexible bodied railway vehicle vibration

The design trend for future high speed trains is envisaged to be lightweight, rising the cost of structural vibration due to the extra exibility. In this context, studies have looked into suppression of such vibrations via use of either (conventional actuators) active suspensions or by structural damping via piezoelectric actuators. The addition of extra macro-actuators will highly impact vehicle weight and is subject to location constraints, while the use of only piezo-actuators normally does not reach the required force levels for appropriate suppression. However, piezo-actuators provide appropriate complementary action with conventional active suspension. In this paper, we present a decentralized control scheme for suppressing the vertical vibration of the vehicle body, combining active structural damping via frequency- weighted H2 control and active suspension control using skyhook damping via structured H1 synthesis. A vertical side-view model of a exible-bodied railway vehicle is used for the control study, with the con_guration of piezoelectric actuators and sensors determined via structural norms. Stability robustness of the controller is analysed with respect to parametric and dynamic uncertainties using _ analysis techniques. Results illustrate the e_ectiveness of the proposed control scheme for both exible and rigid modes while guaranteeing robustness to model uncertaint

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

The use of novel mechanical devices for enhancing the performance of railway vehicles

Following successful implementation of inerters for passive mechanical control in racing cars, this research studies potential innovative solutions for railway vehicle suspensions by bringing the inerter concept to the design of mechatronic systems. The inerter is a kinetic energy storage device which reacts to relative accelerations; together with springs and dampers, it can implement a range of mechanical networks distinguished by their frequency characteristics. This thesis investigates advantages of inerter-based novel devices to simplify the design of active solutions. Most of the research work is devoted to the enhancement of vertical ride quality; integrated active-plus-novel-passive solutions are proposed for the secondary suspensions. These are defined by different active control strategies and passive configurations including inerters. By optimisation of the suspension parameters, a synergy between passive and active configurations is demonstrated for a range of ride quality conditions. The evidence of cooperative work is found in the reduction of the required active forces and suspension travelling. This reveals a potential for reducing the actuator size. Benefits on power requirements and actuator dynamic compensation were also identified. One of the strategies features a nonlinear control law proposed here to compensate for 'sky-hook' damping effects on suspension deflection; this, together with inerter-based devices attains up to 50% in active force reduction for a setting providing 30% of ride quality enhancement. The study is developed from both, an analytical and an engineering perspective. Validation of the results with a more sophisticated model is performed. The lateral stability problem was briefly considered towards the end of the investigation. A potential use of inerter-based devices to replace the static yaw stiffness by dynamic characteristics was identified. This leads to a synergy with 'absolute stiffness', an active stability solution for controlling the wheelset 'hunting' problem, for reducing the creep forces developed during curve negotiation

Improvement of semi-active control suspensions based on gain-scheduling control

This study presents the development of a non-linear control strategy for a semi-active suspension controller using a gain-scheduling structure controller. The aim of the study is to overcome the constraints of conventional control strategies and improve semi-active suspension to achieve performance close to that of full active control. Various control strategies have been investigated to improve the performance of semi-active vibration control systems. A wide range of semi-active control strategies have also been experimentally tested by researchers in the attempt to enhance the performance of semi-active suspension systems. However, the findings published in the literature indicate that there appears to be a ceiling to performance improvements with the control strategies that have been proposed to date, which is about the half of what could be achieved with full active control. The main constraint for semi-active devices such as Magnetorheological (MR) dampers is that they are only capable of providing active control forces by dissipating energy, in their active mode, and they switch to work as simple passive dampers, the passive mode, when energy injection is demanded by the associated control laws. The split in durations of time between the active and passive modes for the conventional semi-active control strategies is around 50:50. This study will focus on the development of a novel semi-active control strategy that aims to extend the duration of the active mode and hence reduce the duration of the passive mode for semi-active suspensions by using a gain-scheduling control structure that dynamically changes the control force demanded by the operating conditions. The proposed control method is applied to both vertical and lateral suspensions of a railway vehicle in this study and the improvements in ride quality are evaluated with several different track data. For the purpose of performance comparison, a semi-active controller based on skyhook damping control integrated with MR dampers and also a vehicle with passive suspensions are used as the benchmark, and are used as a reference case for assessment of the proposed design. Numerical simulations are carried out to assess the performance of the proposed gain-scheduling controller. The simulation results obtained illustrate the performance improvement of the proposed control strategy over conventional semi-active control approaches, where the ride quality of the new controller is shown to be significantly improved and comparable with that of full active control. Potentially, this kind of adaptive capability with variable control approaches can be used to deliver the level of the performance that is currently only possible with fully active suspension without incurring the associated high costs and power consumption

Multibody dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: Formulations and Numerical Methods, Efficient Methods and Real-Time Applications, Flexible Multibody Dynamics, Contact Dynamics and Constraints, Multiphysics and Coupled Problems, Control and Optimization, Software Development and Computer Technology, Aerospace and Maritime Applications, Biomechanics, Railroad Vehicle Dynamics, Road Vehicle Dynamics, Robotics, Benchmark Problems. The conference is organized by the Department of Mechanical Engineering of the Universitat Politècnica de Catalunya (UPC) in Barcelona. The organizers would like to thank the authors for submitting their contributions, the keynote lecturers for accepting the invitation and for the quality of their talks, the awards and scientific committees for their support to the organization of the conference, and finally the topic organizers for reviewing all extended abstracts and selecting the awards nominees.Postprint (published version