223 research outputs found
Force Sensors for the Active Safety of Road Vehicles
No full textForce and moment measurement within road vehicles plays a break-through role in automotive engineering. Both wheel force transducers and instrumented hub carriers are considered in the paper. Both technologies have advantages and disadvantages. Active safety systems (ABS, ESP, up to full automated driving) are expected to be impacted by the measurement of forces and moments at the wheels. Friction potential evaluation and driver model development and monitoring are major field of research. Force and moment measurement technology may also be exploited for lightweight construction purposes. Promising technologies are the ones that don’t need RF data transfer, providing low latency for data transfer and are resiliency against cyber-attacks
Optimal design of a beam subject to bending: a basic application
No full textThe minimisation of both the mass and deflection of a beam in bending is addressed in the paper. To solve the minimisation problem, a multi-objective approach is adopted by imposing the Fritz John conditions for Pareto-optimality. Constraints on the maximum stress and elastic stability (buckling) of the structure are taken into account. Additional constraints are set on the beam cross section dimensions. Three different cross sections of the beam are analysed and compared, namely the hollow square, the I-shaped and the hollow rectangular cross sections. The analytical expressions of the Pareto-optimal sets are derived. As expected, the I-shaped beam exhibits the best compromise in structural performance, which is related on the particular loading considered
Experimental methods to measure the lateral characteristics of bicycle tyres–a review
No full textTyre characteristics can strongly affect bicycle dynamics. In light of this, proper test-rigs are required to accurately measure tyre parameters. The paper presents a review of the methods and devices developed for the experimental characterisation of bicycle tyres in the lateral direction. The main aspects of the known test devices are described, highlighting the respective features. The technology of test-rigs for bicycle tyre parameter measurement seems to be just beginning
Concurrent topological optimization of two bodies sharing design space: problem formulation and numerical solution
No full textTopology optimization is a widely used technique for deriving efficient structural layouts for components in many engineering fields. The optimization process deals with the definition of the optimal material distribution of single components subjected to specified loads and boundary conditions, in case made of different materials or with embedded regions corresponding to other components or actuators. In this paper, a novel topology optimization problem is proposed. The case of the concurrent topological optimization of two different components sharing a part of the design spaces is considered. The design problem represents a design situation in which more than one component has to be fitted in an enclosed space and each component has its own load carrying function. In the paper, the problem is solved by a numerical technique able to allocate the common part of the design space to each component. Inside the allocated space, the actual material distribution of the component is optimized by a standard topological optimization algorithm. Numerical examples are provided to show the potentialities of the method. A (simplified) practical design problem is also considered
Measurement data obtained by an instrumented steering wheel for driver model development
No full textThe data article presents the data acquired by an Instrumented Steering Wheel, able to measure the three force components and the three moment components applied by each of the two driver hands on an Instrumented Steering Wheel (ISW). Additionally, the ISW senses the grip forces at each hand. In order to simulate emergency manoeuvres in a safe environment, a test track with a kick plate is used. Nine different drivers pass over the kick plate six times each. The drivers need to make an action on the steering wheel to counteract the lateral disturbance and recover the straight desired path. The vehicle has been instrumented with an ISW and an inertial measuring unit. Data acquired by the two sensors have been synchronized and analysed. The force components due to mass properties of the ISW have been compensated in a proper way, to highlight the loads exerted only by the driver hands. In the present data article, the data acquired during the described kick-plate test are reported for one driver during a single test. Discussion and conclusion have been presented in [1]. Data are provided in Matlab environment. Videos are provided to show how the manoeuvre occurs. The vehicle that was used for tests was modified with respect to the corresponding production vehicle. Data refer to the specific vehicle used in the tests that does not match with any vehicle produced by Toyota
Portamozzo sensorizzato
No full textLa presente invenzione si riferisce a un portamozzo (101) comprendente: un alloggiamento centrale (103) per un mozzo (100) per una ruota di veicolo; un telaio esterno (104) atto a connettere il portamozzo (101) a una sospensione del veicolo; almeno tre razze (107) interposte tra l’alloggiamento centrale (103) e il telaio esterno (104), le almeno tre razze (107) essendo rigidamente connesse all’alloggiamento centrale (103), le almeno tre razze (107) comprendendo rispettivi elementi terminali (109) connessi al telaio esterno (104) e realizzanti rispettive cerniere sferiche traslanti per le almeno tre razze (107); il portamozzo (101) comprendendo ulteriormente almeno tre sensori (201) configurati per rilevare componenti di forze e/o momenti agenti sul mozzo (100)
A sensitivity interpolation algorithm for the concurrent optimization of bodies sharing a common design space
No full textIn this paper the problem of the concurrent topological optimization of two different bodies sharing a region of the design space is dealt with. This design problem focuses on the simultaneous optimization of two bodies (components) where not only the material distribution of each body has to be optimized but also the design space has to be divided among the two bodies. This novel optimization formulation represents a design problem in which more than one component have to be located inside a limited allowable room. Each component has its own function and load carrying requirements. In the paper a novel development solution algorithm is presented. With respect to previously published papers, the new algorithm comprises an interpolation of the density fields which allows a complete independence of the meshes of the two bodies. As the bodies can be meshed with any arbitrary mesh, this new algorithm can be applied to any real geometry. The developed algorithm is used to design a complex three dimensional system, namely a multi-component arm for a tube bending machine
Instrumented steering wheel – Accurate experimental characterisation of the forces exerted by the driver hands for future Advanced Driver Assistance Systems
No full textThe interaction between driver and vehicle is analyzed in the paper. The driver acts on the steering wheel to modify the trajectory and to control the vehicle during panic situations. The knowledge of the forces exerted by the driver at the steering wheel is useful for a better understanding of the driver steering action. The final aim is to inspire the development of haptic steering wheels for better tuning of Advanced Driver Assistance Systems (ADAS). An instrumented steering wheel has been used, which includes two six axis load cells to measure the forces and the moments exerted by the driver hands and six sensors used to measure the grip strength. Two maneuvers have been considered, a moderate speed turn and a kick plate test which simulates a panic situation with an impulsive lateral disturbance. For both of the two considered situations, some common driving behaviors have been highlighted and analyzed. The preliminary results encourage the development of haptic instrumented steering wheels, able to improve ADAS. Actually it seems possible to infer the driver steering purpose before the steering wheel is actually rotated
A study on the stress gradient reconstruction in finite elements problems with application of radial basis function networks
No full textThe recovery of the stress gradient in finite elements problems is a widely discussed topic with many applications in the design process. The stress gradient is related to the second derivative (Hessian) of the nodal displacements and numerical techniques are required for its calculation. Particular difficulties are encountered in the reconstruction of the stress gradient in the boundary regions of the domain. This is of particular concern in most applications, especially in mechanical components, where the maximum values of stresses are often located in these regions and the stress gradient has a strong influence on the fatigue life of the component. This paper presents a comparison between some already published, partially modified, recovery techniques and a different approach based on radial basis function networks. The aim of the paper is to compare the performances of the different approaches for a number of element types with particular focus on the boundary regions. Some examples of mechanical interest are considered
A Portable device for measuring the cog: Design, error analysis and calibration
No full textThe paper is devoted to the design, error estimation and calibration of a portable device for the measurement of the centre of gravity of rigid bodies. The device consists in a simple but effective implementation of the knife edge method. The design of the device including safety considerations is fully described. An error estimation approach is employed in the very early stage of the design to assess the required instrumentation accuracy and the manufacturing tolerances. A calibration of the portable device is performed by means of proper calibrated masses. After calibration, the accuracy of the device corresponds to the target accuracy defined in the a-priori error analysis. The design procedure described in the paper shows a straightforward approach for the design of devices for the measurement of the inertia properties. By such a procedure, it is possible to identify the most critical design areas and make the correct choices in the early stage of the design process. Also, a deep understanding of the measuring process can be gained allowing the definition of an effective calibration procedure
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