Abstract: Human-centered design is based on the satisfaction of the user needs mainly related to performances, interaction, usability, accessibility, and visibility issues. However, the quality of the interaction process is hidden and usually difficult to detect. The paper proposes a multi-disciplinary assessment tool for the evaluation of the human-machine interaction, based on the collection of physiological data and anthropometrical performance data. Such a method can be used both within on-field tests and virtual simulations, supporting the spread of digital approaches in industry. The methodology allows objectifying how users interact with machine or interface items, thanks to the collection of the users’ performance during task execution, the digitalization of collected data, and the evaluation of users’ physical and mental workload. Such a system has been applied to an industrial case study focusing on agricultural machinery driving and control to support the system re-design in terms of interface features, commands’ location and grouping, and positioning of additional devices.

Keywords: Digital factory | Ergonomics | Human factors | Human-centered design | Human-machine interaction

Abstract: Although the so-called Industry 4.0 trend is promoting the increasing automation of processes in the factories of the future, manual activities still play an extremely important role within the factory and human factors greatly affect the process performance. However, the analysis of human-machine interaction and the prediction of human performance in industry are difficult but crucial to have an optimized design of workspaces and interfaces, reducing time and cost of implementation, and avoiding late design changes. This research adopts a multimodal human-centered approach for the analysis of human-machine interaction, and proposes a multimodal experimental set-up for the evaluation of the workers' experience to support the design of industrial workstations. The set-up combines virtual mockups, interaction with both physical and virtual objects, and monitoring sensors to track users and analyze their actions and reactions. It allows creating a multimodal environment able to deepen the interaction between humans and systems or interfaces, to support design activities. Indeed, it has been demonstrated that the analysis of the reactions of the users involved, allows to evaluate the quality of the interaction, identify the critical issues, define corrective actions, and propose guidelines for system design or redesign [1]. The paper describes the application of the proposed set-up on two industrial case studies and reports the main results.

Keywords: Digital Manufacturing | Human Factors | Human-Centered Design | Industry 4.0 | Virtual Reality

Abstract: Analysis of human-related aspects is fundamental to guarantee workers’ wellbeing, which directly limits errors and risks during task execution, increases productivity, and reduces cost [1]. In this context, virtual prototypes and Digital Human Models (DHMs) can be used to simulate and optimize human performances in advance, before the creation of the real machine, plant or facility. The research defines a human-centred methodology and advanced Virtual Reality (VR) technologies to support the design of ergonomic workstations. The methodology considers both physical and cognitive ergonomics and defines a proper set of metrics to assess human factors. The advanced virtual immersive environment creates highly realistic and interactive simulations where human performance can be anticipated and assessed from the early design stages. Experimentation is carried out on an industrial case study in pipe industry.

Keywords: Digital Human Model | Ergonomics | Human-Centred Design | Sustainable Manufacturing | Virtual Reality

Abstract: In this paper, an engineering method for the power flow assessment of a position-controlled servo-mechanism is outlined. The considered system is composed of a permanent magnet synchronous motor coupled to a standard power converter, and directly connected to a slider crank mechanism. After the accurate description of a consistent power flow model, a sequential identification technique is discussed, which allows to determine the dynamic parameters of linkage, electric motor and electronic driver by means of non-invasive experimental measures. The proposed model allows to accurately predict the major sources of power loss within the system.

Keywords: Design of Experiments | Power flow assessment | Servo-actuated mechanism | Virtual prototyping

Abstract: At the current state-of-the-art, Robotic Deburring (RD) has been successfully adopted in many industrial applications, but it still needs improvements in terms offinal quality. In fact, the effectiveness of a RD process is highly influenced by the limited accuracyof the robot motions and by the unpredictable variety of burr size/shape. Tool compliance partially solves the problem, although dedicated engineering design tools are strictly needed, in order to identify those optimized parameters and RD strategies that allow achieving the best quality and cost-effectiveness. In this context, the present paper proposes a CAD-based Virtual Prototype (VP) of a pneumatic compliant spindle, suitable to assess the process efficiency in different case scenarios. The proposed VP is created by integrating a 3D multi-body model of the spindle mechanical structure with the behavioural model of the process forces, as adapted from previous literature. Numerical simulations are provided, concerning the prediction of both cutting forces and surface finishing accuracy.

Keywords: CAD-based tools | Compliant spindle | Robotic deburring | Virtual Prototyping

Abstract: The selection of conceptual design alternatives is crucial in product development. This is due both to the fact that an iterative process is required to solve the problem and that communication among design team members should be optimized. In addition, several design constraints need to be respected. Although the literature offers several alternative selection methods, to date, only very few are currently being used in industry. A comparison of the various approaches would improve the knowledge transfer between design research and practice, helping practitioners to approach these decision support tools more effectively. This paper proposes a structured comparison of two decision support methods, namely the Fuzzy-Analytic Hierarchy Process and Pugh’s Controlled Convergence. From the literature debate regarding selection methods, four relevant criteria are identified: computational effort, suitability for the early design stages, suitability for group decision making, and ease of application. Finally a sensitivity analysis is proposed to test the robustness of each method. An industrial case study is described regarding an innovative and low-cost solution to increase the duration of heel tips in women’s shoes. The selection of conceptual design alternatives of the heel tip presents complex challenges because of the extremely difficult geometric constraints and demanding design criteria.

Keywords: Concept selection | Engineering design methods | Fuzzy-analytic hierarchy process | Pugh’s controlled convergence

Abstract: Reconfigurable manufacturing systems (RMS) are considered the future of manufacturing, being able to overcome both dedicated (DMS) and flexible manufacturing systems (FMS). In fact, they provide significant cost and time reductions in the launch of new products, and in the integration of new manufacturing processes into existing systems. The goals of RMS design are the extension of the production variety, the adaption to rapid changes in the market demand, and the minimization of the investment costs. Despite the interest of many authors, the debate on RMS is still open due to the lack of practical applications. This work is a review of the state-of-The-art on the design of cellular RMS, compared to DMS, by means of optimization. The problem addressed belongs to the NP-Hard family of combinatorial problem. The focus is on non-exact meta-heuristic and artificial intelligence methods, since these have been proven to be effective and robust in solving complex manufacturing design problems. A wide investigation on the most recurrent techniques in DMS and RMS literature is performed at first. A critical analysis over these techniques is given in the end. © 2014 Springer-Verlag London.

Keywords: Artificial intelligence | Cellular manufacturing systems | Industrial design | Meta-heuristics | Optimization | Reconfigurable manufacturing systems

Abstract: Large displacement compliant joints can substitute traditional kinematic pairs in robotic articulated structures for increasing ease-of-assembly, robustness, and safety. Nonetheless, besides their limited motion capabilities, compliant joints might be subjected to undesired spatial deformations which can deteriorate the system stability and performance whenever a low number of control inputs is available. In all these cases, it is convenient to select/design joint morphologies which enable a selectively compliant behavior, i.e., a low stiffness along a single desired direction. Within this context, this paper outlines an engineering method for quantifying the joint's selective compliance by means of local and global performance indices. The approach is validated by comparing two beam-like flexures whose analytic solution is known from the literature. Finally, two joint morphologies, previously employed in the fabrication of robotic/prosthetic hands, are critically compared on the basis of the proposed criteria. © 1996-2012 IEEE.

Keywords: Design criteria | large displacement compliant joints | performance evaluation

Abstract: Changeability accomplishes the engineering design of competitive sustainable manufacturing systems, considered as industrial products characterized by inherent life cycle. Main drivers for changeability are manufacturing system reconfigurability and hybridization. A Hybrid Reconfigurable System (H-RS) is characterized by the coexistence and cooperation of industrial robots and skilled human workers to perform complex tasks within a common reconfigurable production environment. H-RSs rise use-productivity along their total system life cycle, fostering the evaluation and implementation of feasible and innovative technologies, and increasing the utilization ratio and the multiple use-or re-use-of resources. The paper proposes an engineering method which aims at enhancing changeability in H-RSs through the application of a multi level reconfigurability approach within a digital environment. The method includes the advanced design and modeling of digital devices which embed mechanics, electronics, control logic and software code. Advanced models are exploited to analyze the system performance in the system domain of changes and to realize an effective human training. An industrial case study describes the application of the method to the design of a hybrid reconfigurable workcell for manufacturing and assembly of top class car chassis. © 2012 Springer-Verlag.

Keywords: Automotive | Changeability | Digital environment | Hybrid Reconfigurable System

Abstract: Engineering changeability-oriented and cost-driven approaches are needed by enterprises to design and optimize manufacturing and assembly systems for the demanding production requirements of the present industrial scenario. The integrated design of Reconfigurable Systems addresses tailored flexibility through modularity, integrability of resources, product and process customization, and system convertibility and diagnosability. The cooperation of robot and humans in hybrid environments offers a good trade-off between changeability, high quality and low costs, by exploiting the human dexterity and cognitive proactivity, together with robotic accuracy and performances. Virtual prototyping methods and digital manufacturing solutions are now mature and effective enough to play a strategic role within the hybrid reconfigurable system (H-RS) design and optimization process. The present research work proposes an engineering method to design and optimize H-RSs, by using virtual prototyping and digital manufacturing as a strategic support for the analysis and synthesis of the technical solutions, especially those related to human-robot cooperation. An industrial case study on a hybrid reconfigurable assembly system of a top class car aluminum chassis is finally presented. © 2011 Springer-Verlag.

Keywords: Automotive industry | Digital manufacturing | Hybrid reconfigurable system | Virtual prototyping

Abstract: Adaptive manufacturing systems achieve intelligence and adaptation capabilities through the close interaction between mechanics, electronics, control and software engineering. Mechatronic design of intelligent manufacturing behaviours is of paramount importance for the final performances of complex systems and requires deep integration between mechanical and control engineering. Virtual Commissioning environments offer engineers new opportunities for the design of complex intelligent behaviours and for the enhancement of the performance of adaptive manufacturing systems. This paper discloses a systematic design method focused on interdisciplinary behavioural simulations: Virtual Commissioning tools are used to virtually explore new solution spaces for an effective mechatronic optimization. The results, achieved by applying the method in reengineering a module of an automotive sensor manufacturing line, are finally presented. © 2009 Springer-Verlag.

Keywords: Computer aided engineering | Mechatronic design | Virtual commissioning

Abstract: This paper presents a global optimization method able to find gear profile modifications that minimize vibrations. A non linear dynamic model is used to study the vibrational behavior; the dynamic model is validated using data available in literature. The optimization method takes into account the influence of torque levels both on the static and the dynamic response. Therefore, two different objective functions are considered; the first one is based on static analysis and the second one is based on the dynamic behavior of a lumped mass system. The procedure can find the optimal profile modification that reduce the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random-Simplex optimization algorithm is developed; the optimum reliability is also estimated using a Monte Carlo simulation. The approach shows good performances both for the computational efficiency and the reliability of results. Copyright © 2007 by ASME.

Abstract: In the present paper we are concerned with vibration problems in gears mesh. A 2D model is developed, which is able to create the teeth profile for the contact profile and the tooth fillet for a very large classes of 2D gears. A single degree of freedom model is developed using lumped masses. The stiffness of the gears is calculated using the finite element code (MSC MARC) from different meshing position of two identical gears, using contact elements for the teeth interaction. This approach allows to evaluate accurately the variable global stiffness, which depends on the gear position, materials and teeth geometry. The variable stiffness gives rise to a parametric excitation, which is periodic; therefore it gives rise to a Mathieu type instability. A Fourier series of the variable stiffness is obtained from the numerical data evaluated with the FEM model. The dynamic model is analyzed by means of direct simulations and continuation techniques; the latter one are able to follow periodic responses and detect instabilities and dynamic bifurcations.

Abstract: Direct type [1] Tire Monitoring Systems supervise tire internal inflating pressure. The authors previously proved that Tire Monitoring must be focused on the tire (i.e.: vehicle) dynamic behaviour [2]: the real aim of the supervising action. In this case, even the external absolute pressure must be taken into account. NHTSA studies showed improper warnings must be avoided in order to keep the driver confidence with the system; internal temperature decrease is the Tire Monitoring Systems' main cause of improper warnings. A new approach for optimal Tire Monitoring Systems temperature compensation related to external environmental temperature, able to avoid improper warnings, will be presented. Copyright © 2004 SAE International.

Abstract: The problem of gear noise in vehicles has been intensively studied in the past; however, recently the interest about this problem grew because of great restrictions in the laws regarding noise level and the increase of international competition. One of the most important vibration and noise sources is transmission error that excites the gearbox as a dynamic system, the gearbox surfaces, and connected components; the external box radiates noise. However, the current understanding of gear vibration remains incomplete, even though there is general agreement about the nature of the phenomenon. Vibrations are due to several sources: torsion resonance, impulsive or cyclic fluctuations in drive torque, gear mesh transmission error, local component vibration responses and fluctuations in the output torque demand. The concept of a vibrating system made of two gears is generally modeled through two wheels linked by the teeth mesh stiffness. In its simplest form, this model can simulate the classical linear resonance, i.e. the resonant frequency of the system. However, more complex phenomena such as parametric instabilities can be an important source of noise. In the present paper vibration problems in the gears of an industrial vehicle are investigated through the use of perturbation technique. A suitable software has been developed to generate the gear profiles in order to evaluate global mesh stiffness using finite element analysis. Copyright © 2004 by ASME.

Abstract: Monitoring tires working conditions has proved to be very important for best aircraft ground performances. Thus, to prevent safety risks it is necessary to recognize all the parameters really affecting tires dynamic behaviour and study a proper supervising strategy, able to guarantee an easy and effective security action. It will be proved that measuring tire internal gas pressure (even with internal temperature compensation, then measuring the total internal gas mass) it is not possible to monitor accurately the tire dynamic behaviour. In this paper a new approach to design a new generation of tires monitoring system will be presented. Copyright © 2003 SAE International.

Abstract: Hip joint simulators were developed for predicting, by attempting to duplicate in vitro physiological loads and motion, the wear rate that total hip replacements are likely to show in vivo. From a theoretical point of view, loading and motion cycles of hip joints could be closely reproduced by three rotation actuators and three force actuators. However existing devices have been designed assuming that some of these degrees of freedom are negligible, in order to reduce the complexity of the equipment. The present study singles out some preliminary indications on the design choices regarding the spatial configuration of loading and motion actuators. The aim is to define theoretically a simplified simulator but still able to apply the most physiologically realistic loading cycle to the specimen.

Keywords: Biomechanics | Hip joint simulator | Wear

Abstract: The outcome of a nonlinear finite element stress analysis of ceramic heads for artificial hip joints is presented. The analysis mainly covers the influence of taper friction, support conditions and trunnion modulus of elasticity on the hoop stress distribution at the surface of the head bore. The paper quantifies how much the maximum tensile stress decreases with increasing frictional coefficient, with stiffening of the support and with stiffening of the trunnion material. An appreciable rise of the maximum tensile upon unloading of the head is also shown for the case of cup support. The computational results are found in close correspondence with photoelastic measurements of taper pressures and encourage the use, for preliminary design purposes, of an approximate theoretical model retrieved from the literature. © 1995 by ASME.

Abstract: The reduction of fractures by means of an Ilizarov's fixator is obtained by successively shortening or lengthening the rods. This entails that all reduction operations of the fracture stumps be performed with a series of empirical attempts, requiring great experience and manual dexterity in the surgeon. Moreover this process involves a long exposure of both physician and patient to potentially harmful radiation due to the continuous checking of the intermediate positions on the X-ray image intensifier. In order to overcome these limits a new device has been conceived, based on the application of three stepper-motors on three rods. Its basic principle is functionally very similar to Ilizarov's prototype. The relative motions between the two frames are carried out by controlling the three actuators with a computer, which processes the number of required steps on the basis of an algorithm, starting from a few inputs supplied by the surgeon. This article illustrates the functional kinematic study necessary for the complete automation of the reduction process. Also considered is the complex problem of the reduction trajectory definition, intended as a sequence of configurations of partial correction, obtained by formalizing in geometrical terms the empirical criteria followed by the orthopaedic surgeon in reducing fractures. Such a sequence is intended to be a suggestion for the surgeon who can visualize and possibly interact with the system to determine a trajectory harmless for the soft tissues surrounding the bone. © 1994.

Keywords: external fixator | fracture reduction | Kinematic analysis | robotics

Abstract: An axisymmetric, mechanical analysis of conical press-fit ceramic heads is performed. The head strength and its fracture modes are assessed experimentally. The stress field is examined by finite element, strain gauge and photoelastic methods. An alternative head design, characterized by a cylindrical engagement with the stem, is analysed with the same techniques and its merits are explored. © 1990, Institution of Mechanical Engineers. All rights reserved.

Abstract: A method is described for measuring the rotating shaft surface temperature in a full circular bearing. The experimental measurements related to a journal bearing with a unitary length/diameter ratio, are reported. Contrary to the commonly held assumption, the shaft surf ace temperature is found to remain not quite constant, but to fluctuate during the journal revolution; the value of the temperature in the revolution appears to be maximum about the minimum film thickness. Typical surface temperature distribution scope traces, circumferential variation amplitudes of the surface temperature and increases in the mean revolution value of the journal surface temperature with respect to that of the inlet lubricant oil, are plotted versus shaft speed, lubricant viscosity and bearing load. The journal speed and lubricant viscosity appear to significantly affect the rotating shaft surface temperature as well as its fluctuation in the revolution; the effect of the bearing load is less influential. © 1988 by ASME.

Abstract: The dynamic stiffness and damping characteristics of externally pressurized porous thrust bearings were experimentally found by measuring the response to a sinusoidal excitation with constant-amplitude acceleration. (from authors abstract)

Abstract: A theoretical analysis of an externally pressurized porous gas thrust bearing is carried out using a mathematical model with lumped parameters, which can also pick out possible assembly errors. Experimental results are presented, confriming the effectiveness of the method. © 1978.