Design methods for mobility

In this paper, an overall description of the design of a robotic hand is discussed, with particular attention to the required sensory subsystem, its integration within the mechanical structure of the hand and the required control architecture. Different solutions for the joint configuration and the structure of the tendon network adopted for the transmission system are present together with three types of sensors applied on the finger and on the actuators. The integrated design of the hand finger and the sensors is reported and the motivations leading to this particular implementation are thoroughly addressed, taking into account both the mechanical constraints and the control requirements.

Keywords: Robot control , Robotic design , Robotic hands , Sensor systems , Sensors integration

The use of UAS (Uninhabited Aerial System) in civil missions addresses quite a number of questions related to safety, security and economics, but the most critical challenge the civil UAS will face is the insertion into civil airspace. Avoiding collisions between aircrafts, expediting and maintaining an orderly flow of air traffic are very important goals for Air Traffic Management (ATM). The methodology we propose matches aeronautical science and operation research with ATM constraints and it is based on a two phases procedure: strategic and tactical. The strategic phase is based on Mixed Integer Linear Programming (MILP) and the Travelling Salesman Problem (TSP) method; it is performed off-line and gives as output a basic 3D route in order to allow the UAV to fly over N target points selected by the operator, avoiding fixed obstacles and minimizing an assigned cost function (fuel consumption, time and environmental impact). Once computed the route, the tactical phase starts, which is entirely performed on-line during flight. Civil air traffic constraints (minimum separation) are taken into account using TAR (Traffic Avoidance Resolution) module that combines a simple geometric computation with a TSP time extension model. The results coming from simulation are analyzed using Computer Graphic tools in order to easily and rapidly evaluate the performances of the proposed model. Separation between the UAV and physical obstacles, no fly-zones or other aircrafts populating the scenario, can be evaluated. Moreover, results coming from optimization such as trajectory and the associated fuel consumption, time or environmental impact of the mission are displayed. Copyright © 2009 by the authors.

The superior mobility of a military vehicle provides the combat crew with a tactical advantage through increased cross country speed. The suspension system plays a fundamental role in evaluating a vehicle mobility. A mathematical model that allows realistic simulations of vehicles operating in a wide spectrum of environmental conditions may help to lower costs and time required during their development. The paper concerns with vehicle-terrain interaction modeling, for a military tracked tank, through multi-body and block-oriented approaches. It is focused on the consequences that the suspension system has got on the comfort and on the performance. Thus through a multi-body software a realistic three dimensional model of a tracked fighting vehicle is developed. This virtual model confirms some experimental data available on its longitudinal dynamics. In order to simplify the multi-body simulations, a block-oriented approach is adopted to develop a model of the same vehicle. Some dynamic simulations are discussed in order to validate the proposed models and to compare the two different approaches. Copyright © 2009 SAE International.

Adhesively bonded multi-layer structures are frequently used, mostly in the aerospace industry, for their structural efficiency. Nondestructive evaluation of bond integrity in these types of structures, both after manufacturing and for periodic inspection during service, is extremely important. A laser-based ultrasonic technique has been evaluated for non-contact detection of disbonds in aluminum multi-layer structures. Two configurations have been used to detect disbonded areas: pitch-catch with unidirectional guided wave scan and through-transmission with bidirectional scan. Guided wave scanning was done with a laser line source and air-coupled transducer sensing at 500 kHz, 1 ;MHz, and 2 MHz. Signals showed attenuation of the main frequency component and frequency shift on disbonded areas, whereas, a regular and standard waveform is seen outside disbonds. In through-transmission the longitudinal wave at normal incidence was monitored with a 1 MHz probe. One sample showed, besides the introduced inserts, other disbonded areas. After the ultrasonic measurements the sample was cut to visually check adhesive and interfaces. The guided wave pitch-catch scan allowed fast inspection and quick indication of disbonded zones, while the through-transmission C-Scan provided better definition of defects but was slower and required access from both sides of the test part.

Keywords: Guided waves , Laser ultrasound , Multi-layer structures

This paper describes an approach to the keel design of a sailing yacht. The related software, which is fully automatic, leads to the optimal shape by modifying the surface used to define the keel planform. B-spline curves and surfaces have been used due to their ability in following complex shapes. The algorithm integrates ad hoc implemented original software with computational fluid dynamics (CFD) commercial ones. The optimisation procedure uses genetic algorithms (GAs) and a gradient-based optimiser for the refinement of the solution. A careful CAD and CFD modelling leads to a stable and efficient generalised method, which has been applied to the design of the centreboard of the 5o5 international class racing dinghy. © 2008 Elsevier Ltd. All rights reserved.

Keywords: CFD , Design optimisation , GAs , Sailing yacht

A fully mechanical infinitely variable transmission (IVT) based on the use of an oscillating inertia is described. The system includes a four-bar linkage mechanism, an epicyclic gear train and a pair of one-way clutches. The proposed IVT can be used in place of both gear-box and clutch in self-propelled vehicles. A basic model is used for a first attempt sizing of the transmission kinematic parameters. A more accurate model, achieved using Bond Graphs, is used to investigate the dynamic effect of inertias, one-way clutch compliance, and minor design changes in the kinematic parameters. Finally, simulations compare the behavior of a car fitted with a manual gear-box and the same car fitted with the proposed IVT. Copyright © 2008 by ASME.

This paper describes the design and manufacturing of the Agusta Westland flight mechanics simulator for rotorcraft design. The aims of the simulator are the design of the handling qualities of any new rotorcraft, the simulation of flight manoeuvres, including those following engine failures and tail rotor loss, the instruments panel lay-out optimisation, etc.. The simulator has no motion capability and it is equipped with a pilot seat plus one assistant seat with no command lines. The pilot's flight controls have four Moog motors for control loading of the feedback force. The simulator is driven by a home code named SIMENV that interfaces all the off the shelf software packages running in the simulation of rotorcraft flight (MATLAB®, VEGA®, VAPS®, Flightlab®). The out of the window display is provided by three video projectors on an emicylindrical screen with 6m of diameter. Two more LCD monitors, placed near the pilot's feet, give the ground view, so that the feeling of being onboard is increased and take-off and landing manoeuvres can be simulated. A cluster of 13 PCs give the computational power for real time simulation and visual generation. The simulator described in the paper is now operational and currently used to improve the factory design chain efficiency. This paper presents also some diagrams explaining the activity of simulation performed to validate this design tool. Results obtained are good and the simulator ongoing work plays an important role in the conceptual phase of AgustaWestland helicopter design process. By this, not only engineers but also the pilot can now be involved in the helicopter design from the initial phase of the activity process.

Keywords: Flight dynamics and control , Flight testing and simulation , Simulator design

Considerable progress has been made in the development of Velocity Prediction Programs (VPPs) suitable for analysis of racing yacht performance. In addition, investigations on yacht dynamics (i.e. optimal tacking procedure) are now available. While these tools will no doubt be further refined and computations speeded up, there is also a need to assess the performance of the yacht's helmsman and crew. The scope of the present study is the prediction of the performances of a yacht-crew system as a whole, by deriving numerical models for human behaviour alongside with those referred to the physics of yacht motion. The latter issue, the mechanical side of the problem, is analysed by solving yacht equations of motions in the time domain; crew inputs in terms of yacht steering and sail trim are considered. The yacht-crew system can sail a racecourse in an arbitrary wind pattern, according to strategic rules and given decision making schemata. © 2008: Royal Institution of Naval Architects.

The interest of both the academics and industrials for the UASs (Uninhabited Aerial Systems) has been significantly growing for the last ten years. Technological developments in their design are opening the way for their exploitation in a wide range of applications. Nevertheless, the expected benefits are not yet fully exploited due to the still significant number of accidents. Several researches have demonstrated that the absence of vehicle decisional capacity is among the most important causes of such accidents. One of the proposed solutions is to increase the vehicle ability to perform autonomous mission planning. In this paper a planning algorithm for UASs mission is presented. Such algorithm has been designed following an heuristic approach in order to rapidly provide a robust solution to mission planning problem in evolving scenario. Original obstacle avoidance strategies have been conceived in order to generate mission plans which are consistent with flight rules and with the vehicle performance constraints. Simulation test results show that very efficient routes are computed in a few seconds. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

A new generation of aircraft piston engines is currently being introduced on the market. These new engines come directly from the huge experience achieved in the motorcycle and automotive racing and production. However direct use of automotive power unit is not advisable, since car engines work mainly in the first quarter of the power output, while sport motorcycles are used in a very "light" way, with the engines that span several times through the entire range of power outputs and rpm. The other problem is fuel. Aircraft spark ignition engine for ultralight and light aircrafts may continue to use automotive gasoline, while diesel engines for light up to cargo aircraft should use jet(A1) and jp4. However, the large experience obtained from racing/high-performance motorcycles, racing/high-performance cars and common rail engines cannot be ignored. Thousand of hours and billion of Euros have been spent for this development and the results are interesting. This paper tries to calculate the future aircraft engine performance from the many experimental data already available on a certain type of combustion chamber or better from a well defined and experimented cylinder unit. On the other side the "lean-thinking" approach to aircraft engine design may be not applicable. The lean thinking approach tends to prefer the time-to-market to the optimization of the engine unit. With engines that will probably stay on the market for 30 years this approach is not convenient. An important optimization during the design phase is possible with modern CAD tools. Mass and cost reduction may easily reach the 30%. On the other side the "brain storming approach" is not applicable to the heavily-constrained aircraft-engine design, where it is common that inapplicable solutions and ideas seem to be the best during the initial phase even to experts. Our research team developed three different families of engines: the first family uses the cylinder unit of a well proven motorcycle engine, which comes directly from racing and was sold in tenth of thousands in the world market. These spark ignition engines have 4 up to 16 cylinders (Figg. 1, 2), with power from 150 HP to 800 HP. This type of engines have very brilliant power to weight ratios with not superlative fuel consumptions. They are conceived for ultralight aircrafts and helicopters, tilt rotor, tilt shaft and tilt motor power lift V/STOL aircrafts. The second cylinder unit comes directly from the 2 valves FIAT 1900 jtd, that is one of the best two valves turbocharged common rail diesel available on the market. These units span from 4 up to 16 cylinders with power outputs from 175 HP (Fig. 3) up to 1000 HP. They run with jp4, jp8 or jet (A1) and can be bolted directly to the original engine mount of existing light aircraft like Cessna 172/182/337 or can be used in new light aircrafts. The third one is an originally conceived twin combustion chamber diesel family with output power from 600 HP to 4000 HP (hybrid engine) originally conceived for the Hercules C130J, ATR42 or ATR72 aircrafts (Figg. 4, 5). Our hybrid engine is composed by two separate engines: the VD007 diesel and a turboshaft. Each engine moves a separate contra rotating propeller. In ordinary flight the turboshaft works as a turbocharger. In this case the rear propeller is nearly idle. During take off or emergency the turboshaft combustion chamber is activated and additional power is available. In this case pitch is given to the rear propeller that outputs additional useful thrust. All these engines use only the thermo-fluid-dynamics and a few parts of the original cylinder unit, since aircraft application need extended modifications and, in many cases, complete redesign. However on all these engines a large amount of experimental, road and reliability data are available. Their direct application in the aircraft field is a plain mistake, since automotive and motorcycle are very different, but it is not the case to discard all this data that are available for free. For this reason innovative simulation methods were used to obtain engine performance envelope, with the possibility to choose the most convenient off-design solution on a certain aircraft, depending on the use and on the requirements. It is also possible to obtain reliability data for the aircraft FADEC (Full Authority Digital Engine Control) that controls all these new units. It is important to underline that airborne FADECs should be completely different from ground borne FADECs since in the aircraft application recovery strategies are to be chosen by the well trained pilot, while in the automotive field recovery is usually applied automatically in order to preserve engine integrity. A new method for the determination of the engine performance envelope is introduced as an example on the turbo/hybrid diesel unit for the C130J; this engine is called VD007. This approach has been successfully applied on the small diesel jtd family and also to the spark ignition family. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

In order to keep or to reach a high level of competitiveness and performance of a product, it is necessary to explore all the possible solutions that allow the best compromise between costs and project requirements. By this point of view the study of alternative designs and/or materials to use, is an important aspect that can identify a new concept or way of thinking about a product. This paper presents how to make use of composite materials in the field of heavy vehicles transportation. A new semitrailer in composite material has been designed, using a methodical redesign approach and an optimisation process. The main innovation in this project is, besides the use of the Glass Fibre Reinforced Plastics (GFRPs), also a new topology of the vehicle frame; the designed semitrailer, in fact, has a monocoque structure. Copyright © 2007 Inderscience Enterprises Ltd.

Keywords: Composite material , Redesign process , Semitrailer , Structural frame

The paper deals with the developing of a virtual training system to be implemented in an aeronautic company. The strength of the training method based on the use of Virtual Reality is the high degree of interactivity that it is possible to obtain in a virtual environment. In fact, unlike the traditional methods based on classroom lessons supported by slides and videos that only allow a passive participation of the users to the training, Virtual Reality, with its immersive environments, allows the students both to visualize realistically the contents of the lesson, and to interact with the represented objects. According to that, thanks to the collaboration with Alenia, one of the most important Italian companies in the aeronautical field, we elaborated an innovative virtual training methodology, named AVIRA, specifically dedicated to the users working with composed materials. For the development of this system we started from a real case regarding a particular production process of a specific component. The considered production process is the stratification/lamination of carboresin, used for the fabrication of aeronautical components of high technological content, that is currently active at Alenia Aeronautica in Foggia. © The Eurographics Association 2007.

Recently, the problem to estimate the felt comfort associated with the vibrations on city buses has been put in evidence, with particular attention about the infrastructurevehicle interactions. The aim of this work is to evaluate the effects of the traffic calming devices on the passengers of the public transports by vibration measurements. A self-sufficient measurement system has been implemented. It links each measurement with a geographical information resulting from a Global Positioning System (GPS), and permits to obtain a map of a comfort index directly, using the Geographic Information System (GIS). The presented system is based on widely used hardware components, i.e. a laptop computer, a commercial GPS receiver and three mono-axial servo-accelerometers. A custom software has also been developed.

Keywords: Comfort index , GIS , Vibration measurements

Virtual Reality and related technologies are becoming a common practice in the design industry in general and more specifically in the automotive field. By the joined use of virtual prototyping methodologies it is possible to achieve the reduction of the time-to-market, as well as the costs deriving from the creation of physical prototypes. Ergonomics tests conducted in Virtual Reality environments can be successfully used to influence the design of products. We have set up a mixed reality environment that allows us to simulate and test postural aspects as well as various levels and modalities of users' interaction. In order to achieve a performing interaction, correct registration and visualization parameters must be carefully set for preventing possible interaction errors, such as pointing with precision to the assigned target. The paper presents a methodology for tuning stereoscopic properties of the mixed reality environments used for ergonomic tests of a car interior in order to achieve correct visualization and positioning parameters. The environment includes a virtual human controlled by an optical motion tracking system, physical objects onto which the graphic virtual environment is superimposed, and a rotatory haptic device for controlling the car on-board infotainment. interface. © The Eurographics Association 2007.

The field of computer graphics is greatly increasing its overall performance enabling consequently the implementation of most of the product design process phases into virtual environments. The deriving benefits of using virtual practices in product development have been proved intrinsically highly valuable, since they foster the reduction of time to market, process uncertainty, and the translation of most prototyping activities into the virtual environment. In this paper we present the developed platform in mixed environment for ergonomic validation. Specifically we defined a methodology for testing both aspects related to design and ergonomic validation by allowing the tester to interact visually and physically with the car dashboard control devices and related interface by the mean of a rotatory haptic device. By experimental session it has been highlighted that it is possible gathering qualitative data about the design, and finding typical occlusion problems, but also quantitative data can be collected by testing the infotainment interface and the consequent users' distraction during the device use. © Springer-Verlag Berlin Heidelberg 2007.

Keywords: Ergonomic analysis , Mixed environments , Tactons

The challenge of racing one-design yachts is to maximize the performance of the yacht within the scope allowed by the relevant regulations. Such tuning of the yacht, for a well-policed rale, should only make possible small gains. The main area of possible performance gain is in how best an individual sailor or crew can fine tune their racing strategy. The ability to model such strategic decisions requires an understanding of both the physical behaviour of the yacht and how an individual sailor makes such decisions. The present study seeks to predict the performances of a yacht-crew system as a whole by deriving numerical models for human behaviour alongside those referring to the physics of yacht motion. The former aspect, a transposition of athletes' psychology within the racing scene, is investigated by means of questionnaires submitted to skilled athletes and structured interviews with sailing coaches. The latter issue, the mechanical side of the problem, is analysed by solving yacht equations of motions in the time domain; crew inputs in terms of yacht steering and sail trim are considered. The paper presents results from simulations in which the yacht-crew system can sail a racecourse in an arbitrary wind pattern, according to strategic and tactical rules derived by common practice and following the decision making schemata obtained above.

A sailing simulator is described that takes into account human factors with respect to strategic decisions during a race. Models for yacht-crew interaction have been designed and implemented for the helmsman and the sail tailers, as well as a 'routing engine' that solves problems of a strategical and a tactical nature (e.g. navigation in windshifts, collision avoidance). One or more users can interact with the simulator, so that their behaviour and decision-making process can be recorded, analyzed and compared to that of the automatic crews. The software was implemented in MATLAB-Simulink and consists of two modules: 'Robo-Yacht', for solo and drag races, and 'Robo-Race' for fleet regattas. In the latter case, a real-time animation of the race is delivered to the user in real-time within a virtual reality environment. A series of case studies are presented that demonstrate realistic interactions between a yacht whose decisions are made by a sailor and a mini fleet of autonomous yachts.

The research presented in this paper focuses on an advanced interface in a UAV Ground Control Station whose aim is to guarantee a high level of situation awareness and a low level of workload in the control and supervision of unmanned vehicles. The interface is based on a touch screen-used to command the UAV by means of high level commands-and a 3D Virtual Display which provides a stereoscopic and augmented visualization of the complex scenario in which the vehicle operates. Good levels of situation awareness are also guaranteed by an audio feedback that informs the operator about any change in operational situation, as well as when the mission objectives have been accomplished. Test results have revealed that this interface provides the operator with good sense of presence and enhanced awareness of the mission scenario and the aircraft under his control.

Diesel piston engines are becoming popular in the aeronautical field for the high efficiency and the possibility to work with jp4 and jp8 fuels. This paper updates a secondary advantage of piston engine: the Meredith effect. An accurate tuning and design of the cooling system can add a significant additional thrust to the engine plant. This effect, well known since the beginning of WWII, is being refined in this paper. Optimization of the diffuser and the nozzle has been performed and a new radiator, with wing section tubes has been developed. As an example, this new cooling system has been applied to the VD007 hybrid turbo-diesel engine. This power plant has been designed for the C-130J airplanes. The curves of additional thrust vs. speed has been calculated along with size and shape.

A Design of Experiment (DoE) based methodology is proposed for use in optimising sailing mast structures. The method uses Finite Element Analysis to simulate mast behaviour when subject to typical design loadings. Due to the large number of possible combinations of design variables the use of a fractional factorial selection is used to determine their values for the limited number of simulations required. The analysis is based around a mast for use with the Mini Transat 6.50 class of yacht and provides a suitable challenge when compared to the typically conservative approach used in mast design. The mast structure is considered with respect to standing rigging working loads and spreaders geometry on the deformed shape of a pretensioned mast. Responses in terms of maximum value of mast camber, position of mast camber and generalized distance from optimal curves are provided, response surfaces over design variables domains are built and the most influential parameters are selected. Moreover, the present approach allowed us to provide combinations of parameters leading to optimal matching between a given target curve and the shape of a pretensioned mast. © 2006 Roval Institution of Naval Architects.