Real-Time and Real-Fast Performance of General-Purpose and Real-Time Operating Systems in Multithreaded Physical Simulation of Complex Mechanical Systems

Physical simulation is a valuable tool in many fields of engineering for the tasks of design, prototyping, and testing. General-purpose operating systems (GPOS) are designed for real-fast tasks, such as offline simulation of complex physical models that should finish as soon as possible. Interfacing hardware at a given rate (as in a hardware-in-the-loop test) requires instead maximizing time determinism, for which real-time operating systems (RTOS) are designed. In this paper, real-fast and real-time performance of RTOS and GPOS are compared when simulating models of high complexity with large time steps. This type of applications is usually present in the automotive industry and requires a good trade-off between real-fast and real-time performance. The performance of an RTOS and a GPOS is compared by running a tire model scalable on the number of degrees-of-freedom and parallel threads. The benchmark shows that the GPOS present better performance in real-fast runs but worse in real-time due to nonexplicit task switches and to the latency associated with interprocess communication (IPC) and task switch

Real-Time and Real-Fast Performance of General-Purpose and Real-Time Operating Systems in Multithreaded Physical Simulation of Complex Mechanical Systems

Physical simulation is a valuable tool in many fields of engineering for the tasks of design, prototyping, and testing. General-purpose operating systems (GPOS) are designed for real-fast tasks, such as offline simulation of complex physical models that should finish as soon as possible. Interfacing hardware at a given rate (as in a hardware-in-the-loop test) requires instead maximizing time determinism, for which real-time operating systems (RTOS) are designed. In this paper, real-fast and real-time performance of RTOS and GPOS are compared when simulating models of high complexity with large time steps. This type of applications is usually present in the automotive industry and requires a good trade-off between real-fast and real-time performance. The performance of an RTOS and a GPOS is compared by running a tire model scalable on the number of degrees-of-freedom and parallel threads. The benchmark shows that the GPOS present better performance in real-fast runs but worse in real-time due to nonexplicit task switches and to the latency associated with interprocess communication (IPC) and task switch

Efficient modelling methodologies for multibody simulations of vehicle dynamics

Dottorato di Ricerca in Igegneria Meccanica, Ciclo XXVII, a.a. 2014Università della Calabri

Efficient modelling methodologies for multibody simulations of vehicle dynamics

Dottorato di Ricerca in Igegneria Meccanica, Ciclo XXVII, a.a. 2014Università della Calabri

Automated independent coordinates' switching for the solution of stiff DAEs with the linearly implicit Euler method

status: publishe

Real-Time and Real-Fast Performance of General-Purpose and Real-Time Operating Systems in Multithreaded Physical Simulation of Complex Mechanical Systems

Physical simulation is a valuable tool in many fields of engineering for the tasks of design, prototyping, and testing. General-purpose operating systems (GPOS) are designed for real-fast tasks, such as offline simulation of complex physical models that should finish as soon as possible. Interfacing hardware at a given rate (as in a hardware-in-the-loop test) requires instead maximizing time determinism, for which real-time operating systems (RTOS) are designed. In this paper, real-fast and real-time performance of RTOS and GPOS are compared when simulating models of high complexity with large time steps. This type of applications is usually present in the automotive industry and requires a good trade-off between real-fast and real-time performance. The performance of an RTOS and a GPOS is compared by running a tire model scalable on the number of degrees-of-freedom and parallel threads. The benchmark shows that the GPOS present better performance in real-fast runs but worse in real-time due to nonexplicit task switches and to the latency associated with interprocess communication (IPC) and task switch

Investigating the use of reduction techniques in concept modeling for vehicle body design optimization

The use of Computer Aided Engineering (CAE) tools in the automotive industry is nowadays a confirmed approach to predict the various functional performance attributes (ride and handling, NVH, crashworthiness, etc.) and adapt the design based on the outcome of virtual simulations. In particular, reduction of the time to market has been one of the main thrusts in the automotive sector in the last years, pushing researchers to find more efficient methods to solve design problems. This paper proposes a systematic procedure to efficiently evaluate the influence of design changes on the vehicle performance. The approach is based on a detailed Multibody (MB) model of chassis and suspensions of a passenger car including its Body In White (BIW) as a flexible element. Several reduction techniques (Guyan, MacNeal, Beam and Joint concept modelling) have been adopted in order to accurately represent the BIW flexibility, thus allowing a fast investigation of its influence on different driving scenarios.status: publishe

INCLUDING FLEXIBLE REPRESENTATION OF SUSPENSION COMPONENTS IN THE CO-SIMULATION ENVIRONMENT FOR ACTIVE SYSTEMS SENSITIVITY ASSESSMENT

status: publishe

Integrating vehicle body concept modelling and flexible multi-body techniques for ride and handling simulations

This paper deals with the integration of a vehicle body concept modeling methodology, based on reduced models of beams, joints and panels, with flexible Multi-body (MB) representation of the chassis of a passenger car. The aim is to enable ride and handling simulations in the initial phases of the vehicle design process, where the availability of predictive Computer Aided Engineering (CAE) tools is a key factor to steer design choices such that a faster convergence of the vehicle development cycle towards improved products is achieved. The proposed approach is demonstrated on an industrial case study, involving a commercial passenger car, for which a detailed chassis and suspension model for MB simulations is developed in LMS Virtual. Lab Motion. A flexible concept model of the vehicle's Body In White (BIW) is created as well and included in the MB model to enable fast investigations on how ride and handling performance of the full vehicle are affected by body modifications. To demonstrate the validity of the resulting concept model, a number of standard handling manoeuvres and ride excitations are simulated by using both the flexible MB model described above and a rigid MB model of the vehicle, which is derived from the same FE model. The numerical results are compared to allow assessing the influence of body flexibility on the predicted handling and ride behaviour of the vehicle. Copyright © 2012 by ASME.status: publishe

Model Based Actuator Management for a Hydraulic Active Suspension System - Improving Comfort Performance by Advanced Control

Active suspension systems aim at increasing safety by improving vehicle ride and handling performance while ensuring superior passenger comfort. This paper addresses the influence of the actuator management on the comfort performance of a complete hydraulic active suspension system. An innovative approach, based on nonlinear Model Predictive Control, is proposed and compared to a classical approach that employs a steady-state performance map of the actuator. A simulation analysis shows how taking into account actuator dynamics improves the actuator’s force tracking performance, leading to an improvement of the overall vehicle comfort performancestatus: publishe