Franco Giuseppe Dedini

Combined application of QFD and VA tools in the product design process

The aim of both value analysis (VA) and quality function deployment (QFD) is to reduce waste by avoiding redesign and providing optimal location of costs in general. To satisfy the consumers most important needs, the VA prioritizes the increase in the cost of the product and not the subsequent price rise. QFD aims at generating clear engineering needs from consumer requirements thus, minimizing the reprojecting cost (“cost” should read “waste”) and changes in the products. The existing common concepts between two design tools, QFD (the project tool) and VA (the product optimization tool) motivated this study. QFD establishes a link among parameters such as the consumer needs, engineering requirements and a comparative analysis of the consumer perception against that of rival companies. The VA prioritizes a rise in the aggregate value (perceived by the consumer) by optimization development and production costs. The proposed methodology is capable of integrating these two tools, integrating costs with product development (“for the consumer”) for a joint analysis. This way it is possible to establish optimum cost values for each engineering requirement. It is also possible to evaluate the cost of each product function. Furthermore, the methodology provides a tool that supports decision making in product development and projects. This work evaluates the integrated use of the QFD and VA tools. Employing a survey that was carried out which intended to reveal the young male consumers’ requirements concerning a sports bicycle.

Gear Shifting Strategies Co-simulations to Optimize Vehicle Performance and Fuel Consumption

The vehicle longitudinal dynamics is responsible for calculating the vehicle power consumption to attend a specific route, estimating, by the equations, the forces acting on the system such as aerodynamic drag, rolling resistance, climbing resistance and the driver behavior. The gear shifting strategies influence significantly in the vehicle acceleration performance and fuel consumption because it changes the powertrain inertia and the engine speed. The literature presents gear shifting strategies based on the engine power and torque. A fuel economy strategy is more difficult to determine, because it depends on a large number of factors like the engine efficiency, vehicle speed, transition ratio and required acceleration. This paper presents a study based on the US06 standard velocity profile, in which the high speeds and acceleration stretches create a situation where the vehicle performance is limited by the engine available power and by the tire-ground traction limit. Because of the many factors involved in the vehicle behavior, it was developed an algorithm to optimize the gear shifting process to choose the more adequate strategy to each stretch. The analysis were performed by co-simulation between the multibody dynamics software Adams\( ^{\rm{TM}} \) and Matlab/Simulink\( ^{\rm{TM}} \), where is defined the vehicle power demand.

Vehicle gear shifting strategy optimization with respect to performance and fuel consumption

ABSTRACT Based on the movement resistance forces, the vehicle longitudinal dynamics is related to power demand for a specific route. The vehicle gear shifting influences significantly the acceleration performance and fuel consumption because it changes the engine operation point and the powertrain inertia. This paper presents a study based on the US06 velocity profile that involves high speed and high acceleration phases, where the vehicle performance is limited by both the engine power and the tire traction limit. For improving the vehicle performance without increasing fuel consumption, a genetic algorithm (GA) technique is used.

Measurement of wheelchair contact force with a low cost bench test.

In mechanical engineering, it is well established that contact between the tire and the ground is a key parameter in characterizing the dynamic behavior of vehicles and an important factor in design control. Therefore, it is an important part of dynamic simulation models for vehicles, including wheelchairs. This work presents a bench test designed to experimentally monitor and measure the forces transmitted to the ground by a moving wheel. The test bench is composed of a table and a track with a fixed wheel structure and powertrain system. The table is an integrated structure that measures the longitudinal and lateral forces produced by tire contact. This table allows characterization of the tire and tests the tire under varying loads at different slip and camber angles. Additionally, the test bench can also be used to evaluate other tires, such as caster tires. The performances of the new device are illustrated, and the results show the differences between tires, which are related to the dynamic behaviors of wheelchair model. Finally, preliminary experiments performed using the test bench have shown that it is able to monitor and measure the forces generated by the contact between the tire and the ground.

A study of battery power for a different electric vehicle propulsion system

This paper presents a simulation of an electric vehicle propulsion system. The simulation assumes BLDC motors combined with a proportional-integral controller and batteries. Regarding the longitudinal dynamics of electric vehicles (EV), models of different components and configurations are introduced and simulated. The simulations show the potential of each configuration according to the battery size. Thus, the objective is to find the best configuration (batteries size and propulsion system setup), keeping the original drivability. Six different configurations will be analyzed using the standard Brazilian urban driving cycle NBR6601. A rule-based method is used in the power management strategy that indicates the batteries states. This information aids the decision on the correct specification of the battery for each simulated configuration according to some restrictions.

Biomechanical model for the determination of forces on upper-extremity members during standard wheelchair propulsion

New technologies and new configurations have brought great improvements to wheelchair development. These developments create problems for wheelchair users concerned with the choice of the best wheelchair for their specific needs, skills and capabilities. Handicapped people, who exclusively depend on the manual wheelchair for locomotion, face great difficulties because they have constant pain in their upper-extremity members, mainly in the shoulder, elbow and wrist. Manual propulsion can be considered a cyclical effort, thus the pains are symptoms of injuries from repetitive efforts. The problem becomes worse when the user has to overcome architectural obstacles, because it significantly increases the required propulsion force. The aim of this paper is to determine the dynamical efforts over the upper-extremity members during the manual wheelchair propulsion using Newton-Euler and Jourdain equations, and inverse dynamic techniques. The dynamical efforts consider the forces and moments over upper-extremity joints during the propulsion movement. As a result, it is possible to establish a system of equations and thus evaluate the efforts over the joints. Another result is the possibility to simulate the system using the anthropometric values of real subjects aiming at making it easier to choose the best wheelchair, considering his/her physical and anthropometric characteristics. Besides, the study of the propulsion patterns (different patterns of propulsion lead to different biomechanics) allows physical training aimed at improving the propulsion efficiency.

Modeling a Hands-Free Controlled Power Wheelchair

This paper will present a study of the dynamics of the contact between the tire of a wheelchair and the ground. The model of the contact between road and tire has been implemented using a mathematical concept in a 2D multibody program, creating a laboratory. With this laboratory, it is possible to see the behavior of the wheelchair with different input sources. In this work the input is taken care of by a program called HaWCoS which allows the user to control a wheelchair without the need to use the hands. The results make it possible to develop new products for people with special needs and to develop better control systems by taking the dynamic behavior of wheelchairs into consideration.

Simulation of the scenario of the biaxial wheel fatigue test

Abstract This paper presents a new approach to the virtualization of the scenario of the biaxial wheel fatigue test. This test is the state-of-art and the standard requirement for the validation of vehicle wheels. During this test, tire and wheel specimens run inside an inner drum while standardized vertical and horizontal loads are applied. Thus, the scenario of this test can be modeled in three levels: the multibody dynamics of the test facility, the wheel/tire/inner drum contact, and the analysis of the flexible wheel. In the proposed virtualization, the multibody dynamics of the test facility was implemented in MSC.ADAMS. The wheel/tire/inner drum contact was simulated by means of CDTire; as it works parallel to MSC.ADAMS, one single co-simulation could perform the tire dynamics and the test facility dynamics. Finally, the wheel strains were calculated by an ABAQUS simulation, which received the tire/wheel load data from the simulation in MSC.ADAMS and CDTire. A physical test facility and a physical wheel specimen were instrumented, allowing the comparison between acquired and simulated data. The use of this specialized software is a novelty in the virtualization of the scenario of this test; furthermore a high detailed simulation is required for the further development of such already well established test procedure.

Gear shifting multi-objective optimization to improve vehicle performance, fuel consumption, and engine emissions

ABSTRACT In the present work, the Adaptive-Weight Genetic Algorithm was employed in order to determine the gear shifting strategies that allow an automobile to work in the best compromise among fuel consumption, engine emissions, and vehicle performance. For the assessment of each of the three objective functions, a simulation model based on engine data and on the well-established equations of the longitudinal dynamics was developed. The driving cycle chosen for the calculations was the FTP-75, which takes into account both cold and hot starts, meaning that the transient operation during the warm-up of the catalyst is also considered.

Study of Different Electric Vehicle Propulsion System Configurations

This paper presents a study of an electric vehicle (EV) with two different drive systems and three available electric motors (EMs) configurations. The EMs are BLDC (Brushless Direct Current) motors combined with a proportional-integral controller (PI). The vehicle power demand is divided between the drive systems through rules based vehicle power management control (PMC) that aims to reduce the lithium-ion battery discharges during the Brazilian urban driving cycle NBR6601. The results indicate the potential of each simulated configuration and the combination drive system/EM in which present the lower battery discharge. Each EV configuration is compared and the best configuration is defined.