Design methods for mobility

A bursting number of achievements in the autonomous vehicle industry have been obtained during the past decades. Various systems have been developed to make automated driving possible. Due to the algorithm used in the autonomous vehicle system, the performance of the vehicle differs from one to another. However, very few studies have given insight into the influence caused by implementing different algorithms from a human factors point of view. Two systems based on two algorithms with different characteristics are utilized to generate the two driving styles of the autonomous vehicle, which are implemented into a driving simulator in order to create the autonomous driving experience. User's skin conductance (SC) data, which enables the evaluation of user's cognitive workload and mental stress were recorded and analyzed. Subjective measures were applied by filling out Swedish occupational fatigue inventory (SOFI-20) to get a user self-reporting perspective view of their behavior changes along with the experiments. The results showed that human's states were affected by the driving styles of different autonomous systems, especially in the period of speed variation. By analyzing users' self-assessment data, a correlation was observed between the user “Sleepiness” and the driving style of the autonomous vehicle. These results would be meaningful for the future development of the autonomous vehicle systems, in terms of balancing the performance of the vehicle and user's experience.

Keywords: Autonomous vehicle , Driving style , Human behavior

mHealth technology, by using habitual devices, i.e., smartphones, improves prevention, diagnosis, treatment, monitoring, and management of health. Monitoring heart profile during intense sports activities allows to diagnose pathologies, not identifiable with the traditional Holter approach and, therefore, it can help preventing possible injuries. On the other hand, denoising and extracting features from electrocardiographic (ECG) signal acquired during physical activity is a challenging task due to motion artifacts and measurement noise. In this paper, we propose a solution enabling a complete analysis of ECG signal through the implementation of a robust denoising algorithm, which has been characterized on synthetic signals and then has been tested on real traces acquired with a low-cost smartphone-based device during motorbike and car races.

Keywords: Compressive sensing (CS) , denoising , electrocardiographic (ECG) , mHealth , motion artifacts , races , wearable

The paper presents a feasibility study for a prototype motorbike (bike in short) with an alternative front suspension. Novel features include the adjustability of steering axis inclination, front trail, and anti-dive effect i.e. the main parameters affecting rider feedback and perception as well as motorcycle behaviour. Although being based on the well-known double-wishbone layout, the system can be adjusted to replicate the geometry of a conventional fork as a baseline for experimental testing. Unlike similar concepts that can be found in literature the kinematics can be modified by means of straightforward adjustments that do not require complex disassembly. Independent adjustability is provided for each parameter. These innovative features enable a back-to-back comparison between significantly different settings, in order to explore a wide range of characteristics in terms of dynamic response, handling properties and rider's perception with a single vehicle. The project is aimed at fostering knowledge on motorcycle dynamics within the research group and especially on rider feedback and subjective perception, somehow a neglected topic in current literature. It was undertaken under the form of a student educational project in mechanical engineering and named "F.A.B." (Fully Adjustable Bike). The paper is mainly focused on front suspension kinematics; chassis design and related structural aspects are outlined as well.

This work builds on some of the current industry techniques used in racing to evaluate vertical dynamics performance and propose a new methodology to evaluate vehicle performance. The proposed method creates a quantitative numerical index from the classic tyre vertical load variation frequency response function with some novelties that cover all peculiarities of high downforce race cars. In this method the aerodynamic forces are included as non-linear functions vs ride height and it is shown that they affect system stiffness and damping. As a result, the system response changes as a function of vehicle longitudinal speed. The importance of non-linear suspension rates in this kind of vehicle is also highlighted. The proposed index can also be customized for a certain vehicle speed range. A Formula 3 racecar model has been used as an application example.

This paper presents a preliminary investigation on the workflow that allows to replicate object by using 3D laser scanner and a desktop fused filament fabrication 3D printer. Pitfalls and limitations of those technologies will be pointed out in order to find the bottleneck of the workflow, paying specific attention to what concerns the digital workflow from the acquisition to the generation of the g-code. The findings and conclusions are drawn from a case study that has been carried out using the minimum amount of human intervention, especially during the digital post-processing of the data. The objects under investigation is a broken car door handle. Firstly, it has been digitalized using a 3D laser scanner properly calibrated and set. The accuracy, precision and resolution of the measurement tool have been recorded and the as-is acquired data has been checked against topological errors. The as-is acquired model has been compared with the original geometry. The 3d polygonal mesh has been prepared for being printed: the material, machine and process parameters have been chosen. A simulation of the deposition process to estimate warps and deviation from the nominal geometry was carried out. Finally, the object has been additively manufactured using a desktop Fused Filament Fabrication machine: the printed object has been again compared with the original geometry.

An airbag system is designed to reduce the accident outcome on the car occupants. The airbags deployment against manikins is severely tested according to international regulations. The accident scenarios with Out of Position (OP) occupants are critical since they can be hardly expected during design. The airbag deployment in these scenarios can be improved by developing adaptive strategies, provided that the Airbag Control Unit must be aware of the actual occupant position. The present research investigates a sensor system to monitor the occupants in an interactive Human-Car system. The driver position is monitored by pressure sensors, while an accelerometer enables to compensate for acceleration and noise. Real driving experiments in dynamic conditions are reported. The results prove that three OP conditions are effectively identified.

Keywords: Driver monitoring , Driving experiment , Intelligent vehicle , Out of position , Safety system

Future intelligent vehicles will be capable to monitor driver distraction while autonomous driving. However, in case of system fault, the intelligent vehicle must also manage an adaptive strategy for the Airbag Control Unit, since the airbag deployment against an Out of Position occupant can be additionally harmful. Thus, the present research work investigates a possibility to monitor the driver position as a robust information to an intelligent vehicle. A seat is sensorized with a map of pressure sensors. The system layout and setup are discussed in details. Signal processing strategy and real driving experiments are reported.

Keywords: Car seat , Driving experiment , Intelligent sensor , Intelligent vehicle , Pressure sensor , Safety system

Robot programming usually consists of four steps: (1) task planning; (2) task sequencing; (3) path planning and (4) motion planning. Task (2) and (3-4) are strongly coupled. For example, the optimal robot path, which is function of the robot kinematics, relies on the pre-defined schedule of tasks, whose sequencing is computed based on the assumption that the travelling 'cost' from one task to the next is only driven by the Euclidean distance in Cartesian space. Current methods tends to decouple the problem and sequentially compute the task sequencing in the T-space, and then compute the robot path by solving the inverse kinematics in the C-space. However, those approaches suffer the capability to reach a global optimum. This paper aims at developing a novel approach which integrates some of the key computational requirements of the path planning in the early stage of the task sequencing. Multi-attribute objectives are introduced to take into account: robot pose and reachability, data quality, obstacles avoidance, overall cycle time. The paper introduces a novel multi-attribute approach to find the optimized task sequencing via candidate poses solving inverse kinematics in the T-space. This is based on the core idea to combine T-space and C-space. The proposed solution has been tested on a vision-based inspection robot system with application to automotive body assembly systems. Results could however impact a wider area, from navigation systems, game and graph theory, to autonomous driving systems.

Keywords: Multi-attribute Optimization , Robot vision system , Robotic task sequencing , TSPN

Human-centred design is based on the satisfaction of the user needs mainly related to performances, interaction, comfort, usability, accessibility, and visibility issues. However, the “real” user experience (UX) is hidden and usually difficult to detect. The paper proposes a multimodal system based on the collection of physiological and anthropometrical performance data on field and within a mixed prototyping set-up. The mixed environment makes users interact with virtual and digital items and users' performance to be capture and digitalized, simulating human-machine interaction, while physiological and anthropometrical data collection allows to objectify the users' physical and mental workload during task execution. Such a system has been applied to an industrial case study focusing on agricultural machinery driving and control to support the definition of a new cabin and its control board, in terms of seat features, commands' positioning and grouping, and positioning of additional devices.

Keywords: Ergonomics , Human-centred design , Human-machine interaction , Mixed prototyping , User experience

Armrest in tractors is like a control dashboard for trains or airplanes; it is fundamental for managing and properly setting the machine. For this reason, there is the need to adjust it for each operator's size and application. Nowadays, armrests are usually very big and intrusive, because they are full of controls and sometimes they are not really comfortable for each user size and need. Furthermore, agricultural equipment is often used under difficult conditions: steep terrain and extreme weather conditions require products able to guarantee total safety and maximum comfort, minimizing the risk of human error caused by excessive fatigue. The aim of the project is to create an “ergonomic - compact armrest”, focused on the users' need, with the application of Ergonomics and Human Machine Interface (HMI) principles, shifting the focus from how a machine works to how a task is performed. For designing the “ergonomic - compact armrest” a new system based on the collection of “real” users biomechanical performance within a virtual lab was adopted. In this virtual environment, it was possible to test many different configurations of controls, checking which controls are mostly used, and measure the comfort index and mental work load for each configuration. On this basis, a “digital twin” of the user was created, consisting in a set of scalable virtual manikins that can interact with virtual items, and a comfort index was defined as an objective and reliable measure to evaluate workload during any task execution. Thanks to this new methodology, the “ergonomic - compact armrest” is 30% smaller than the previous one, but at the same time it accommodates in comfort the 95% of the population size, keeping on board only frequent controls positioned in ergonomic way. The results of this study could be used for other tractors controls layout design, so that human comfort can be improved and any task can be felt as natural as possible, encouraging good posture and safe behaviours, and reducing cost of prototypes and time to market.

Current designs of ground based, wind energy extraction systems have limitations of wind instability and high cost of installations. The efficiency of these systems is optimal for a nominal speed and decrease sharply for higher or lower winds. This paper introduces large air rotors at high altitude for powerful and relatively stable air stream out of ground effect. This first part deals with an existing helicopter that is transformed to an autogiro for power generation. The helicopter is linked to the ground with a cable that connects the airborne generator to the ground power grid. In our case the air rotor system flies at an altitude of about 4 km that is statistically the best compromise between power available and altitude. Two versions of the helicopter are considered: electrical (motors-generators) and hybrid (turboshafts + generators). In the electrical version, the electric motors power the helicopter that climbs up the required altitude and lift the cables. At this point, the motors are switched to generator-mode and the helicopter keeps altitude as an autogiro and generates energy. The hybrid solution adds the generator(s) to the helicopter. The hybrid-helicopter climbs with the turboshafts and then trip-off the engines to work as an autogiro-generator. We used is the largest available helicopter: the CH47 Chinook. This choice is because it is economically convenient to use the largest wind generator possible. Both fully electric and hybrid solutions proved to be technically feasible. However, the pure electric solution requires a huge amount of power from the power grid (7 MW), therefore has relatively high installation costs. For this reason, the hybrid solution is more practical. The average power produced is more than 0.8 MW. Unfortunately, the cost per kWh is two order of magnitude higher than the carbon produced one. Therefore, this solution is convenient only when you have problems to take the fuel or the grid to the place where energy is needed. Helicopter/autogiro stability and control systems enable to change altitude and to deal with emergencies. This airborne system provides the following main advantages: power production capacity higher than conventional ground-based small rotor designs; the installation is environmentally friendly also for the propeller noise.

Keywords: Airborne wind turbine , Autogiro , Electric power generation , Green energy , Hybrid helicopter

High altitude, airborne, wind-energy extraction-systems have the advantage of larger wind stability and higher power production. The efficiency of these systems is optimal because the nominal speed can be searched by varying altitude. Several airborne generators can be grouped in restricted airspace regions near consumer sites. This second part of the paper deals with the design of the simplest and cheapest autogiro for power generation. A single rotor autogiro with a minimal airframe was conceptually designed for this purpose. The power generated is 800 kW at 13,600ft (4.15 km) as in the first part of this paper. The rotor of a known helicopter, the CH-53E Super stallion, was used for the design. Generalpurpose equations for helicopters were adapted to evaluate the weight of the system. As in the first part of this paper, the airborne system is tethered to bring the power to the national electric grid. The altitude of 13,600ft (4.15 km) is statistically the best compromise between power available and tether length. On autogiro-generator deployment, the reversible electric generator works as a motor and the autogiro becomes a helicopter. This helicopter hold the tether and climbs up the required altitude. In this phase, the tether supplies the power from the national grid. Once the helicopter reaches an altitude slightly higher than the desired one, the power is turned off and the helicopter begins the autorotation. The electric motor becomes a generator. The autogiro begins to work with the rotor inclined. The control system inclines the autogiro to the required angle of attack into the incoming wind. In this configuration, the rotor produces electric power and provides the necessary lift to the airborne generator. In this configuration, the generator outputs 0.8 MW with a wind velocity of 54 knots (100 km/h). Unfortunately, the cost per kWh is one order of magnitude higher than the carbon produced one. This solution is more convenient than the one of the previous paper in which the cost was an order of magnitude higher. Still, it is not competitive with traditional energy production.

Keywords: Airborne wind turbine , Autogiro , Electric power generation , Green energy , High altitude

The paper examines the effect of the recent VR technologies on consumers behaviour providing guidelines to design a rich and immersive environment that is able to deliver high-impact and memorable experience and engage audiences and potential consumers anytime and anywhere. In order to study the impact, firstly, the paper has identified and described the technological characteristics of VR in terms of the ability of the VR devices to surround the user and the nature of simulation and the consumer engagement expressed through varying levels of cognitive, affective and behavioural manifestations. Then, a VR environment with technological characteristics of interactivity, hypertextuality, virtuality (presence of virtual elements), modality, location specificity, mobility and connectivity has been designed. VR environment shows a virtual supermarket in the form of 360 degree video able to create highly immersive sensory experiences that promote the subjective presence of consumers and impress their senses, touch their hearts, and stimulate their minds. The results obtained show that applying virtual technology to marketing activities allows marketers to identify and respond to opportunities through new technologies which are faster, more effective, and lower cost and to become more responsive to consumers' needs providing virtual experience where they want it, how they want it and when they want it.

Keywords: Computer-mediated environments , Consumer behaviour , Human–computer interaction , Virtual markets

In the past few years, a new generation of additive manufacturing (AM) techniques has rapidly become available due to the expiration of some AM patents which allowed significant cost reductions. This article explores some available techniques fostering products innovation in experimental laboratories for the development of naval propulsion, where high costs represent an important limitation for both basic research and industrial testing, by identifying significant knowledge and variables and by providing reliable and accurate data to support designers and researchers. The propeller INSEAN E779a case study was taken into account and fabricated by direct metal laser sintering in AlSi10Mg aluminium alloy and by fused deposition modeling in acrylonitrile–butadiene–styrene, and UltraT polymeric materials. The study of printing parameters, flexural tests, differential scanning calorimetry and thermogravimetric analysis, allowed to optimize the printing process conditions. A reverse engineering system, Faro-CAM2, and the iterative closest point algorithm of the geomagic control software were used to analyse deviations from the printed propeller and the CAD nominal model. The atomic force microscopy test allowed to assess the morphological features and surface roughness of printed propellers. Towing Tank tests were carried out and the hydrodynamic performance comparison was analysed in terms of torque and drag. The results of this study show differences between the benchmark and AM propellers, as a function of the advance coefficient J, the morphological characteristics and the materials. However this study also shows a substantial adequacy of AM propellers in most studies carried out in Towing Tank.

Keywords: Additive manufacturing (AM) , Marine propeller , Reverse engineering (RE)

In this work is exploited the possibility to use Electronic Speckle Pattern Interferometry (ESPI) for the characterization of different tyres with particular attention to the tyres shoulder section. Tyres characterization is of fundamental importance for vehicle dynamics modelling, since they are the main responsible of vehicles dynamical behaviour and thanks to their ability to deform, they allow to drive a vehicle generating the appropriate interaction forces at the interface with the road. Their behaviour is a consequence to their very complex structure. Two different racing tyres, one for car and other for motorcycle, have been considered. The investigation has been focused at the aim to evaluate and measure the section's components in order to get accurate information about the different layers along through the tyres shoulder section. Here we demonstrate that the different layers (rubber, nylon, steel) can be easily highlighted and identified by mean of the ESPI that, thanks to its high sensitivity, is capable to estimate the different out of plane displacement of the different layers that respond in a different way (i.e. with a different deformation) to a thermal stimulus highlighting the layers themselves. Moreover, we introduce a de-noising step in the reconstruction process: In particular we enhance the wrapped phase information by using a suitable algorithm called SPADEDH. It is important to note that the assessment about the different layers along the section is a very difficult task to obtain by visual inspection or classical microscopy. In fact, the condition of the cutted surface, or rather the strong inhomogeneity and the roughness make impossible to obtain good images especially in the shoulder area.

Keywords: Holography , Non-destructive testing , Speckle , Tyre characterization

The increasing interest about eco-sustainable materials in the industrial production (automotive, civil construction, packaging), has led to the increase of the research works dealing with biocomposites. However, until now the most attention has been devoted to the development of short fiber biocomposites for non-structural applications, whereas only a few works have considered high performance biocomposites for structural applications. Consequently, the development of structural biocomposites from robust natural fibers, as sisal fibers, is a result expected from the scientific community, but not yet achieved. In order to give a contribution to the implementation of high performance biocomposites constituted by a green matrix reinforced by sisal fibers, the present work proposes a manufacturing process that allows to obtain good quality unidirectional biocomposites with fiber volume fraction up to 70%. In detail, it uses unidirectional “stitched” fabrics, properly obtained in laboratory from optimized fibers, and a curing under a proper pressure cycle. The comparison with independent data reported in literature, has evidenced how the proposed biocomposites exhibit mechanical properties higher than most of biocomposites described in literature, so that they can advantageously substitute not only materials as steel, aluminum and glass fiber reinforced plastics, but also other biocomposites reinforced by more expensive fibers.

Keywords: Biocomposites , Ecofriendly matrixes , Natural fibers , Sisal fibers

In this study, a new method to compare rebuilt surfaces of hulls of sailing yachts is presented. In particular, the considered rebuilt surfaces are created through classic reverse engineering approaches. The new method has been developed by means of Grasshopper, a free generative algorithms editor that can be used as plugin of Rhinoceros, one of the most widespread free-form modelling software. In particular, two different algorithms have been developed: the first one allows controlling the quality of the rebuilt surfaces, the second one, instead, allows to measure the deviations between the original CAD Model and the rebuilt surface of the hull. A case study related to the hull of a small sailing yacht is also presented. The obtained results have demonstrated the efficiency of the new proposed low-cost method.

Keywords: CAD Model , CAE tools , Close range photogrammetry , Generative algorithms , Low-cost reverse engineering analysis , Sailing yacht

This paper discusses the mechanical architecture of Elloboat, an unmanned Tracked Vehicle (TV) for launching and beaching of watercrafts and small boats (up to a length of 3.5 meters). The mechanical architecture of Elloboat comprises a central saddle connected to two lateral tracks by parallelogram linkages, which may be driven by linear or rotary actuators to lift/lower the payload. The TV is able to pick the boat form a support, to travel along the beach and to perform launching while almost completely submerged. On the contrary, during beaching, the boat is relieved from the water and then transported to storage. The Elloboat mechanical architecture is redundantly constrained and actuated. In the following, after a detailed description of the device, the TV kinematic and static behaviours according to different actuation schemes are discussed on the basis of a mobility analysis and then by multibody simulations, with rigid and flexible models of joints.

Keywords: beaching , launching , multibody simulation , small boat , tracked vehicle , watercraft

Advanced driver assistance systems (ADASs) allow information provision through visual, auditory, and haptic signals to achieve multidimensional goals of mobility. However, processing information from ADAS requires operating expenses of mental workload that drivers incur from their limited attentional resources. The change in driving condition can modulate drivers' workload and potentially impair drivers' interaction with ADAS. This paper shows how the measure of cardiac activity (heart rate and the indexes of autonomic nervous system (ANS)) could discriminate the influence of different driving conditions on drivers' workload associated with attentional resources engaged while driving with ADAS. Fourteen drivers performed a car-following task with visual ADAS in a simulated driving. Drivers' workload was manipulated in two driving conditions: one in monotonous condition (constant speed) and another in more active condition (variable speed). Results showed that drivers' workload was similarly affected, but the amount of attentional resources allocation was slightly distinct between both conditions. The analysis of main effect of time demonstrated that drivers' workload increased over time without the alterations in autonomic indexes regardless of driving condition. However, the main effect of driving condition produced a higher level of sympathetic activation on variable speed driving compared to driving with constant speed. Variable speed driving requires more adjustment of steering wheel movement (SWM) to maintain lane-keeping performance, which led to higher level of task involvement and increased task engagement. The proposed measures appear promising to help designing new adaptive working modalities for ADAS on the account of variation in driving condition.

Eco-driving assistance devices are being introduced to reduce CO2 emissions, but the overall changes in the user behavior have not been sufficiently explored. While in-vehicle driver advanced systems are designed to support a single driving task (e.g. reducing emissions), they also imply the adoption of a different driving behavior and different driving attitudes in order to be efficient. Adopting for the first time a new driving style could affect driver's acceptance and undermine new technologies' efficacy. Purpose of the present research is to measure and evaluate the user's responses to first-time use of eco-driving assisting technology. Driver's performances in a virtual simulator were compared between experimental and a control group. The actual driving parameters and CO2 emissions were recorded and compared to the optimal eco-driving style calculated by CarMaker software. The cognitive costs of the new driving style were measured by changes in the modulation of autonomic nervous system and NASA-TLX workload scale. Acceptance of the assisted driving style and general eco-friendly attitudes were analyzed by self-reported measures. Results show that being exposed for the first time to eco-driving technology produces a reduction of cumulate fuel consumption only due to speed reduction, and not to changes in the driving style parameters, as recommended by the assisting software. Overall CO2 emissions of eco-driving group were not different from the control group. Rather, the first time use of the eco-driving assistance increases perceived fatigue and the physiological cardiac autonomic balance related to increased workload over time. These difficulties show that eco-driving style cannot be simply adopted by following the assistance device indications. It seems rather a process, which requires specific support during in the first driving-interaction with eco-driving technology. The design of assistance device that aims to change the driving style, could benefit from the measurement of the user's workload to avoid primacy effect that potentially undermine technology efficacy in supporting user-sustainable behaviors.

Keywords: Acceptance , Assistance technologies , CO2 emissions , Human-machine interaction , Pro-environmental behavior , Workload