Communicating simulated emotional states of robots by expressive movements

This research focuses on the non-verbal communication of non-android robots by comparing the results produced by three different emotional models: Russell’s circumplex model of affect, Tellegen-Watson-Clark model and PAD scale. The relationship between the motion of the robot and the perceived emotion is developed. The motion parameters such as velocity and acceleration are changed systematically to observe the change in the perception of affect. The embodiment is programmed to adopt the smooth human motion profile of the robot in contrast to the traditional trapezoidal velocity profile. From the results produced it can be concluded that the emotions perceived by the user is the same on all three scales, validating the reliability of all the three emotional scale models and also of the emotions perceived by the user. Moreover the selected motion parameters of velocity and acceleration are linked with the change of perceived emotions

Benchmark footbridge for vibration serviceability assessment under the vertical component of pedestrian load

This is the author accepted manuscript. The final version is available from American Society of Civil Engineers via the DOI in this recordData availability: the electronic format of the data used is available at www.warwick.ac.uk/go/civileng/crg/structures/publications/dataVibration serviceability criteria are governing the design and determining the cost of modern, slender footbridges. Efficient and reliable evaluation of dynamic performance of these structures usually requires a detailed insight into the structural behavior under human-induced dynamic loading. Design procedures are becoming ever more sophisticated and versatile, and for their successful use, a thorough verification on a range of structures is required. The verification is currently hampered by a lack of experimental data that are presented in the form directly usable in the verification process. This study presents a comprehensive experimental data set acquired on a box-girder footbridge that is lively in the vertical direction. The data are acquired under normal operating conditions and are presented using a range of descriptors suitable for easy extraction of desired information. This will allow researchers and designers to use this bridge as a benchmark structure for vibration serviceability checks under the vertical component of the pedestrian loading. In addition, capabilities of a sophisticated force model (developed for walking over rigid surfaces) to predict vibrations on this lively bridge are investigated. It was found that there are discrepancies between computed and measured responses. These differences most likely are a consequence of the pedestrian-structure interaction on this lively bridge. The interaction was then quantified in the form of pedestrian contribution to the overall damping of the human-structure system. © 2012 American Society of Civil Engineers.Engineering and Physical Sciences Research Council (EPSRC

Modelling pedestrian interaction with perceptibly vibrating footbridges

This is the final version. Available on open access from the publisher via the link in this recordTo evaluate the vibration serviceability of footbridge structures most structural engineers use pedestrian force models that are defined for walking on rigid surfaces. This approach is no longer applicable for slender, light-weight and low-frequency structures that are prone to perceptible vibrations under walking excitation. To overcome this issue, it is necessary to understand the pedestrian walking locomotion and how the locomotion process interacts with the vibrating structure. This paper compares three approaches for modelling pedestrian walking over lively structures, and it critically evaluates their suitability for modelling the feedback mechanism between the structure and the pedestrian. The models are evaluated with respect to their capability to reproduce human-like motion as well as to replicate the vibration patterns observed on lively bridges. It has been shown that models used in biomechanics are good candidates for applications in the structural engineering context. © Faculty of Mechanical Engineering, Belgrade.Engineering and Physical Sciences Research Council (EPSRC)University of Warwic

Measuring Ground Reaction Force and Quantifying Variability in Jumping and Bobbing Actions

This is the final version. Available on open access from American Society of Civil Engineers via the DOI in this recordData Availability: Electronic format of the data collected in this research can be downloaded free of charge from the University of Warwick webpage http://wrap.warwick.ac.uk/80470/.This paper investigates variability in bobbing and jumping actions, including variations within a population of eight test subjects (intersubject variability) and variability on a cycle-by-cycle basis for each individual (intrasubject variability). A motion-capture system and a force plate were employed to characterize the peak ground reaction force, frequency of the activity, range of body movement, and dynamic loading factors for at least first three harmonics. In addition, contact ratios were also measured for jumping activity. It is confirmed that most parameters are frequency dependent and vary significantly between individuals. Moreover, the study provides a rare insight into intrasubject variations, revealing that it is more difficult to perform bobbing in a consistent way. The paper demonstrates that the vibration response of a structure is sensitive to cycle-by-cycle variations in the forcing parameters, with highest sensitivity to variations in the activity frequency. In addition, this paper investigates whether accurate monitoring of the ground reaction force is possible by recording the kinematics of a single point on the human body. It is concluded that monitoring the C7th vertebrae at the base of the neck is appropriate for recording frequency content of up to 4 Hz for bobbing and 5 Hz for jumping. The results from this study are expected to contribute to the development of stochastic models of human actions on assembly structures. The proposed simplified measurements of the forcing function have potential to be used for monitoring groups and crowds of people on structures that host sports and music events and characterizing human-structure and human-human interaction effects.Engineering and Physical Sciences Research Council (EPSRC

Quantification of dynamic excitation potential of pedestrian population crossing footbridges

This is the final version. Available on open access from Hindawi via the DOI in this recordDue to their slenderness, many modern footbridges may vibrate significantly under pedestrian traffic. Consequently, the vibration serviceability of these structures under human-induced dynamic loading is becoming their governing design criterion. Many current vibration serviceability design guidelines, concerned with prediction of the vibration in the vertical direction, estimate a single response level that corresponds to an "average" person crossing the bridge with the step frequency that matches a footbridge natural frequency. However, different pedestrians have different dynamic excitation potential, and therefore could generate significantly different vibration response of the bridge structure. This paper aims to quantify this potential by estimating the range of structural vibrations (in the vertical direction) that could be induced by different individuals and the probability of occurrence of any particular vibration level. This is done by introducing the inter- and intra-subject variability in the walking force modelling. The former term refers to inability of a pedestrian to induce an exactly the same force with each step while the latter refers to different forces (in terms of their magnitude, frequency and crossing speed) induced by different people. Both types of variability are modelled using the appropriate probability density functions. The probability distributions were then implemented into a framework procedure for vibration response prediction under a single person excitation. Instead of a single response value obtained using currently available design guidelines, this new framework yields a range of possible acceleration responses induced by different people and a distribution function for these responses. The acceleration ranges estimated are then compared with experimental data from two real-life footbridges. The substantial differences in the dynamic response induced by different people are obtained in both the numerical and the experimental results presented. These results therefore confirm huge variability in different people's dynamic potential to excite the structure. The proposed approach for quantifying this variability could be used as a sound basis for development of new probability-based vibration serviceability assessment procedures for pedestrian bridges. © 2011 - IOS Press and the authors. All rights reserved.Engineering and Physical Sciences Research Council (EPSRC

Experimental characterisation of walking locomotion on rigid level surfaces using motion capture system

This is the final version. Available on open access from Elsevier via the DOI in this recordLow-frequency structures, such as footbridges and long-span floors, are often sensitive to variations in dynamic loading induced by pedestrians. As a result, the design of these structures using traditional deterministic approaches is being replaced by stochastic load models that can accommodate different styles of walking. To inform development and facilitate wider implementation of the new stochastic approaches, a database of experimental data characterising both inter- and intra-subject variability of gait parameters is required. This study aims to contribute to the development of such a database by providing a set of data for walking over rigid level surfaces.The motion capture system Vicon was used for simultaneous monitoring of the kinematic and kinetic gait parameters. Ten test subjects walking at 13 different speeds participated in the experimental programme. Novel experimental data on pacing rate, step length, step width, angular positions of the legs and the trunk, and the force amplitude were collected and statistically characterised. The acquired data are suitable for calibration of the bipedal pedestrian models intended for civil engineering applications.Engineering and Physical Sciences Research Council (EPSRC)University of Warwic

Influence of Low-Frequency Vertical Vibration on Walking Locomotion

This is the final version. Available on open access license from American Society of Civil Engineers via the DOI in this recordData Availability: Electronic format of the data collected in this research can be downloaded freely from the University of Warwick webpages http://wrap.warwick.ac.uk/79038/.Walking locomotion has been a subject of studies in diverse research fields, such as computer, medical, and sport sciences, biomechanics, and robotics, resulting in improved understanding of underlying body motion and gait efficiency and pathology (when present). Only recently, a detailed understanding of kinematics and kinetics of the walking locomotion has become an important requirement in structural engineering applications due to an increasing sensitivity of modern, lightweight, low-frequency, and lightly damped footbridges to pedestrian-induced dynamic excitation. To facilitate development, calibration and verification of pedestrian models requires experimental characterization of walking gait parameters and understanding whether and how these parameters are influenced by the structural vibration. This study investigates whether low-frequency vibrations in the vertical direction affect seven walking locomotion parameters: pacing frequency, step length, step width, angle of attack, end-of-step angle, trunk angle, and amplitude of the first forcing harmonic. Three participants took part in a testing program consisting of walking on a treadmill placed on both stationary and vibrating supporting surfaces. The collected data suggest that an increasing level of vibration results in an increase in step-by-step variability for the majority of parameters. Furthermore, the existence of the self-excited force, previously observed only in numerical simulations of walking on pre-excited bridge decks, was confirmed. In addition, the deck vibration tended to have a beneficial effect of reducing the net force induced into the structure when walking at a pacing rate close to the vibration frequency. Finally, it was found that the vibration level perceptible by a pedestrian is one to two orders of magnitude larger than that typical of a standing person, and that the sensitivity to vibration decreases as the speed of walking increases.Engineering and Physical Sciences Research Council (EPSRC

Frequency response function-based explicit framework for dynamic identification in human-structure systems

This is the final version. Available on open access from Elsevier via the DOI in this recordData accessibility: The data are self-contained in the paper.The aim of this paper is to propose a novel theoretical framework for dynamic identification in a structure occupied by a single human. The framework enables the prediction of the dynamics of the human-structure system from the known properties of the individual system components, the identification of human body dynamics from the known dynamics of the empty structure and the human-structure system and the identification of the properties of the structure from the known dynamics of the human and the human-structure system. The novelty of the proposed framework is the provision of closed-form solutions in terms of frequency response functions obtained by curve fitting measured data. The advantages of the framework over existing methods are that there is neither need for nonlinear optimisation nor need for spatial/modal models of the empty structure and the human-structure system. In addition, the second-order perturbation method is employed to quantify the effect of uncertainties in human body dynamics on the dynamic identification of the empty structure and the human-structure system. The explicit formulation makes the method computationally efficient and straightforward to use. A series of numerical examples and experiments are provided to illustrate the working of the method.Engineering and Physical Sciences Research Council (EPSRC

HIV/AIDS and the teaching and learning of anatomy

A research paper on the teaching of HIV/AIDS to medical students using "virtual, computer aided anatomy" instead of real cadavers at the Zimbabwe Medical Teaching Hospital.Anatomy, a word derived from the Greek words “ava” (across) and “tomin” (section), is the study of the composition of the body by cutting and separating its structures one from the other in order to examine their shapes, relations and connections to one another. Therefore, most lecturers involved in medical education will agree that dissection of human cadavers is the best method of teaching and learning anatomy. This method allows one to personally dissect the cadaver. During this process, one sees, touches and handles anatomical structures. This experience leads to a better understanding and long term remembrance of the subject. In addition to this, the observations made on several cadavers enable the student and the teacher to appreciate the presence of variations of the human structure; an experience which assists medical practitioners in physical diagnosis

Programming of 3-Axis Hybrid Kinematics CNC Machine for Rapid Prototyping Using Subtractive and Additive Processes

The paper presents the programming and program verification on a 3-axis hybrid kinematics CNC machine for rapid prototyping using subtractive and additive processes. The original hybrid (parallel-serial) 3-axis O-X glide mechanism developed to build a rapid prototyping machine and multifunctional machine tools is presented. The paper analyzes the available programming software, which can be one of the standard CAD/CAM systems or a specialized CAM system, for subtractive processes, i.e. desktop milling. For the additive processes, the software for generating G code based on the STL file as well as the possibility of simulating the machine when working is considered. To verify the program, the simulation of material removal for subtractive processes as well as the simulation of material addition for additive processes were considered. The paper presents the prototype of a hybrid kinematics CNC machine and some of the results of testing with an open control system based on the LinuxCNC