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

Axiomatic design of customizable automotive suspension systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2007.Includes bibliographical references (p. 195-201).The design of existing suspension systems typically involves a compromise solution for the conflicting requirements of comfort and handling. For instance, cars need a soft suspension for better comfort, whereas a stiff suspension leads to better handling. Cars need high ground clearance on rough terrain, whereas a low center of gravity (CG) height is desired for swift cornering and dynamic stability at high speeds. It is advantageous to have low damping for low force transmission to vehicle frame, whereas high damping is desired for fast decay of oscillations. To eliminate these trade-offs, a novel design for a customizable automotive suspension system with independent control of stiffness, damping and ride-height is proposed in this thesis. This system is capable of providing the desired performance depending on user preference, vehicle speed, road conditions and maneuvering inputs. The design, fabrication and control of the customizable suspension prototype are discussed. The application of variable stiffness and variable ride-height suspension system to achieve improved vehicle dynamics is studied. Application to control of vehicle dynamics parameters required bandwidth and power input beyond the capability of the first prototype.(cont.) To eliminate the bandwidth restrictions of the prototype, a variable-stiffness pneumatic suspension system capable of instantaneous stiffness change with essentially no power input and no ride-height change, is developed. This is done by supporting the vehicle on air springs and connecting each air spring volume to multiple auxiliary volumes through On-Off valves. By adequately choosing N unequal auxiliary volumes, this system can achieve 2N stiffness settings. This suspension has been incorporated in a car suspension. The design, fabrication, and testing of the suspension system are reported in this thesis. A detailed frequency-domain model for the air-spring with auxiliary volumes is developed. Based on this modeling and testing, the performance limits and practical applicability of this system are discussed. The proposed variable stiffness isolator is capable of instantaneous stiffness change with no power input and no dimension change; moreover the isolator is inexpensive, robust and light. As a result, it is readily applicable to several other vibration isolation applications with conflicting stiffness requirements (such as a precision motion stages) or time-varying stiffness requirements (such as prosthetic limbs) and these applications are discussed.by Hrishikesh V. Deo.Ph.D

Design of Cab Suspensions and Semi-Active Seat Damping Control Strategies for Tractor Semi-Trailers

This thesis uses a high fidelity vertical plane ride model of the tractor semi-trailer to study the effect of different cab design configurations and semi-active seat damper control strategies on the driver’s ride comfort. The secondary suspensions of a tractor have been an area of particular interest because of the considerable ride comfort improvements they provide. A gap exists in the current engineering domain of an easily configurable high fidelity low computational cost simulation tool to analyze the ride of a tractor semi-trailer. A 15 degree of freedom model of the tractor semi-trailer was used to develop a simulation tool in the Matlab/Simulink environment. The simulation tool developed was verified against TruckSim. The contributions of the different modes of vibration to the ride comfort were analyzed. It is shown in this work that the ride at the driver’s seat can be significantly improved by relocating the cab mounts near the nodes of the 1st mode of bending of the tractor frame and by employing a full cab suspension. The developed simulation tool was used to quantify the improvements in the driver ride comfort. To develop seat isolation systems, the truck seat was modeled as a base excited 1 d.o.f. system. It is shown in this work that two optimal solutions exist depending on the spatial characteristics of the base excitation. One of the optimal solutions can be physically realized in the form of a passive spring and a passive damper in parallel. The other optimal solution can be approximated by a passive spring and a continuously variable damper in parallel. A fuzzy logic based switch mechanism was developed to switch between two realizations of the optimal solutions. A recursive least square estimator was developed to estimate the seat load and the stiffness of the spring using the same signals as the controller thus allowing universal application of the seat damper controller. The resultant controller is shown to provide the best ride comfort over various types of road surfaces. A model predictive controller for the seat damper was also developed for this work. A novel method was developed to model the bounds on the seat suspension stroke as hard constraints of the optimization problem. An efficient scheme was developed to include the frequency weighted acceleration in the performance index of the optimization problem. It is shown in this work that the MPC based seat damper controller provides better ride comfort in some specific scenarios. This work contributes towards the furthering the knowledge-base of the issues encompassing the ride quality of a tractor semi-trailer. The efficacy of the developed tractor semi-trailer ride simulation tool as a design and analysis tool is presented in this work

Design methodology of a complex CKC mechanical joint with a representation energetic tool multi-Bond graph: application to the helicopter

Due to the operation of the rotor, the helicopter is subject to important vibration levels affecting namely the fatigue of the mechanical parts and the passenger comfort. Suspensions between the main gear box (MGB) and the fuselage help to filter theses problematic vibrations. Their design can be difficult since the filtering should be efficient for different types of external forces (pumping force and roll/pitch torque) which may appear during the flight. As passive solutions classically show their limits, intelligent active solutions are proposed so that the filtering can be adjusted according to the vibration sources. Such studies still suffer from a lack of tools and methods, firstly, necessary to the design of complex mechanical systems (due to their multi-phase multi-physics multi-interaction characteristic, ...) and secondly, to develop of an intelligent joint. The main objective of this chapter is to provide a methodology for designing and analyzing an intelligent joint using an energetic representation approach: the multibond graph (MBG). This method is applied here to a complex mechanical system with closed kinematic chains (CKC) which is the joint between the main gear box (MGB) and the aircraft structure of a helicopter. Firstly, the MBG method is analyzed. Secondly, after a brief state of art of the MGB-Fuselage joint, developments focus on the 2D and 3D modeling of the MGB-Fuselage joint with a MBG approach. The 20-sim software is used to conduct the simulation of bond graph. Finally, the MBG models results are presented, illustrating the potential of the MBG tool to predict the dynamic of a complex CKC mechanical system.Chaire de la fondation d'entreprises EAD

Investigation of all-wheel-drive off-road vehicle dynamics augmented by visco-lock devices

A peculiarity of AWD off-road vehicles is that their behaviour depends not only on the total power, provided by the engine, but also on its distribution among the drive axles/wheels. In turn, this distribution is largely regulated by the drivetrain layout and its torque distribution devices. At the output of the drivetrain system, the torque is constrained by the interaction between the wheels and the soft soil. For off-road automotive applications, the design of drivetrain systems has usually been largely dominated by the mobility requirements. With the growing demand to have a multipurpose on/off road vehicle with improved manoeuvrability over deformable soil, particularly at higher speed, the challenges confronting vehicle designers have become more complex. The thesis presents a novel integrated numerical approach to assess the dynamic behaviour of all-wheel-drive vehicles whilst operating over deformable soil terrain. [Continues.

2009 Formula SAE Race Car

Design and fabrication of the 2009 Formula Society of Automotive Engineers (SAE) race car focuses on developing a simple, lightweight and easily operated vehicle. Compliance with SAE rules is compulsory and governs a significant portion of the objectives. Aspects of ergonomics, safety, ease of manufacture, and reliability are incorporated into the design specifications. Analyses are conducted on all major components to optimize strength and rigidity, improve vehicle performance, and to reduce complexity and manufacturing costs

Dynamical systems : mechatronics and life sciences

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science