Multi-body Co-simulation Research Articles

Real-time multi-body co-simulation model of a veneer peeling lathe

ABSTRACT This paper introduces a real-time co-simulation model for the prediction of the dynamics behavior of a veneer peeling lathe machine. The real-time co-simulation model introduced is described in the framework of multi-body system dynamics. It makes use of a co-simulation procedure in which a semi-recursive multi-body approach is combined with a detailed contact description. In the employed closed-loop semi-recursive method, the constraint conditions are carried out in the system motion differential equations via the augmented Lagrangian method. A contact procedure is presented to describe the contact between the wooden log and the cutting blade and the support rollers. The results obtained by the co-simulation are compared against those experimentally measured through a peeling lathe machine in operation and an approximate finite element model of the peeling process. According to the numerical results, it is concluded that the real-time simulation model can predict dynamic performance of the complicated system of a veneer peeling lathe in real-time. Solvability of equations of motion makes the introduced model suitable to be utilized in a number of product process purposes such as marketing, training and product development projects.

A tight coupling scheme for smooth/non-smooth multibody co-simulation of a particle damper

To simulate coupled problems, composed of smooth and non-smooth particle subsystems, a tight, i.e. iterative coupling scheme is implemented. In the proposed setup, the non-smooth solver iterations are enclosed in each iteration of the smooth solver at every time step. The stability properties of the coupling scheme are tested using Dahlquist’s test equations for co-simulation methods, highlighting the higher degree of stability of the tight coupling scheme, compared to the loose, non-iterative one. Results also denote that the properties of the solvers used to analyse the subsystems play an important role in the stability of co-simulation. The performance of the proposed scheme is further assessed by two illustrative examples: a particle damper subjected to prescribed motion, and a cantilever beam, modelled using finite elements, with a particle damper mounted at the free end. The proposed numerical solutions agree well with results from reduced order models and experiments, which demonstrates that the proposed scheme can effectively handle coupled problems of multibody systems and particle dampers.

Stabilizing an Urban Semi-Autonomous Bicycle

A comprehensive and a deep analysis on how to stabilize an urban semi-autonomous bicycle was carried out. Its more relevant aspects are presented in this paper. The resulting stabilized bicycle is intended to serve as a future evolution for the current bike-share programs. This bicycle would go to meet the user autonomously, and after that it could be used by the rider in the traditional fashion. Therefore, the resulting system must be stable throughout the entire operating speed range and must be rideable by a person when used in manual mode. A study of bicycle dynamics and stability control has led the way followed throughout this investigation. Consecutively, all the examined aspects are applied to introduce a few alternatives for solving the stability problem. One of them, the Alnilam concept, is further developed to unveil its possibilities. Furthermore, it has been successfully tested in a multibody co-simulation using Adams and Simulink, thus illustrating its behavior and testing its performance. The results of this simulation are very promising and encouraging to further develop this concept.

Research on the Effects of Hydropneumatic Parameters on Tracked Vehicle Ride Safety Based on Cosimulation

Ride safety of a tracked vehicle is the key focus of this research. The factors that affect the ride safety of a vehicle are analyzed and evaluation parameters with their criteria are proposed. A multibody cosimulation approach is used to investigate the effects of hydropneumatic parameters on the ride safety and aid with design optimization and tuning of the suspension system. Based on the cosimulation environment, the vehicle multibody dynamics (MBD) model and the road model are developed using RecurDyn, which is linked to the hydropneumatic suspension model developed in Lab AMESim. Test verification of a single suspension unit is accomplished and the suspension parameters are implemented within the hydropneumatic model. Virtual tests on a G class road at different speeds are conducted. Effects of the accumulator charge pressure, damping diameter, and the track tensioning pressure on the ride safety are analyzed and quantified. This research shows that low accumulator charge pressure, improper damping diameter, and insufficient track tensioning pressure will deteriorate the ride safety. The results provide useful references for the optimal design and control of the parameters of a hydropneumatic suspension.

Validation of a squeeze-film-damper test rig by using multibody cosimulation

Squeeze-film dampers (SFD) are applied to provide damping at the outer ring of ball bearings used in jet engines. The main functions are to cap rotor oscillations and to reduce dynamic forces. A new test rig was designed to allow an orbital motion of the rotor shaft excited by two independently controllable electromagnetic shakers. In order to achieve this excitation, the two shakers are rigidly coupled together; due to this, a degree of freedom is missing in this mechanism. The precisely adjusted stiffness of the coupling elements acts as a solid joint to provide the missing DOF. The resulting shear forces acting on the opposite shaker are supported by a support structure, designed as part of the coupling elements. A multibody cosimulation and several other virtual studies are performed to verify and validate the dynamic behavior of the test rig. The SFD behavior cannot be implemented in the cosimulation by using a standard library damping element of the simulation tools because its behavior is nonlinear due to its design and functionality. It is implemented according to its valid theory, based on Reynolds equations for plain bearings. The calculation of the multibody physics takes place in MSC Adams, whereas the theory of the SFD is described and implemented as a mathematical model in MATLAB/Simu link. A both-ends-against-the-middle approach is realized and discussed.

Multi-body co-simulation of semi-active suspension systems

This paper describes the development and use of a multi-body co-simulation approach for predicting the dynamic response of a vehicle containing magnetorheological (MR) semi-active dampers. The approach is used to investigate the effects of various local and global control strategies on the load histories of suspension components for the purpose of assessing their likely impact on fatigue life. The approach adopted aims to exploit the capability of a multi-body system (MBS) code and a mathematical simulation code, by integrating the MBS vehicle models with selected semi-active damper/controller models. Various MBS vehicle models are developed of increasing complexity using MSC.visualNastran, which are linked to three local, two-state switchable, control algorithms and also two global controllers, each developed in MATLAB/Simulink. The control strategies are implemented within the vehicle model using an MR damper model derived from experimental test data. Road inputs, including both bump/pothole and random road excitation, and the tyre model are also implemented within MATLAB/Simulink. Ultimately, the aim is to develop an approach which would allow concurrent structural optimization and controller optimization to enable lighter and more durable suspension components to be produced.