Modeling Backscattering Behavior of Vulnerable Road Users Based on High-Resolution Radar Measurements

Bei der Weiterentwicklung der Technologie des autonomen Fahrens (AD) ist die Beschaffung zuverlässiger dreidimensionaler Umgebungsinformationen eine unverzichtbare Aufgabe, um ein sicheres Fahren zu ermöglichen. Diese Herausforderung kann durch den Einsatz von Fahrzeugradaren zusammen mit optischen Sensoren, z. B. Kameras oder Lidars, bewältigt werden, sei es in der Simulation oder in konventionellen Tests auf der Straße. Das Betriebsverhalten von Fahrzeugradaren kann in einer Over-the-Air (OTA) Vehicle-in-the-Loop (ViL) Umgebung genau bewertet werden. Für eine umfassende experimentelle Verifizierung der Fahrzeugradare muss jedoch die Umgebung, insbesondere die gefährdeten Verkehrsteilnehmer (VRUs), möglichst realistisch modelliert werden. Moderne Radarsensoren sind in der Lage, hochaufgelöste Erkennungsinformationen von komplexen Verkehrszielen zu liefern, um diese zu verfolgen. Diese hochauflösenden Erkennungsdaten, die die reflektierten Signale von den Streupunkten (SPs) der VRUs enthalten, können zur Erzeugung von Rückstreumodelle genutzt werden. Darüber hinaus kann ein realistischeres Rückstreumodell der VRUs, insbesondere von Menschen als Fußgänger oder Radfahrer, durch die Modellierung der Bewegung ihrer Extremitäten in Verkehrsszenarien erreicht werden. Die Voraussetzung für die Erstellung eines solchen detaillierten Modells in verschiedenen Situationen sind der Radarquerschnitt (RCS) und die Doppler-Signaturen, die sich aus den menschlichen Extremitäten in einer bewegten Situation ergeben. Diese Daten können durch die gesammelten Radardaten aus hochauflösenden RCS-Messungen im Radial- und Winkelbereich gewonnen werden, was durch die Analyse der Range-Doppler-Spezifikation der menschlichen Extremitäten in verschiedenen Bewegungen möglich ist. Die entwickelten realistischen Radarmodelle können bei der Wellenausbreitung im Radarkanal, bei der Zielerkennung und -klassifizierung sowie bei Datentrainingsalgorithmen zur Validierung und Verifizierung der Kfz-Radarfunktionen eingesetzt werden. Anschließend kann mit dieser Bewertung die Sicherheit von fortschrittlichen Fahrerassistenzsystemen (ADAS) beurteilt werden. Daher wird in dieser Arbeit ein hochauflösendes RCS-Messverfahren vorgeschlagen, um die relevanten SPs verschiedener VRUs mit hoher radialer und winkelmäßiger Auflösung zu bestimmen. Eine Gruppe unterschiedliche VRUs wird in statischen Situationen gemessen, und die notwendigen Signalverarbeitungsschritte, um die relevanten SPs mit den entsprechenden RCS-Werten zu extrahieren, werden im Detail beschrieben. Während der Analyse der gemessenen Daten wird ein Algorithmus entwickelt, um die physischen Größen der gemessenen Testpersonen aus dem extrahierten Rückstreumodell zu schätzen und sie anhand ihrer Größe und Statur zu klassifizieren. Zusätzlich wird ein Dummy-Mensch vermessen, der eine vergleichbare Größe wie die vermessenen Probanden hat. Das extrahierte Rückstreuverhalten einer beispielhaften VRU-Gruppe wird für ihre verschiedenen Typen ausgewertet, um die Übereinstimmung zwischen virtuellen Validierungen und der Realität aufzuzeigen und den Genauigkeitsgrad der Modelle sicherzustellen. In einem weiteren Schritt wird diese hochauflösende RCS-Messtechnik mit der Motion Capture Technologie kombiniert, um die Reflektivität der SPs von den menschlichen Körperregionen in verschiedenen Bewegungen zu erfassen und die Radarsignaturen der menschlichen Extremitäten genau zu schätzen. Spezielle Signalverarbeitungsschritte werden eingesetzt, um die Radarsignaturen aus den Messergebnissen des sich bewegenden Menschen zu extrahieren. Diese nachbearbeiteten Daten ermöglichen es der Technik, die zeitlich variierenden SPs an den Extremitäten des menschlichen Körpers mit den entsprechenden RCS-Werten und Dopplersignaturen einzuführen. Das extrahierte Rückstreumodell der VRUs enthält eine Vielzahl von SPs. Daher wird ein Clustering-Algorithmus entwickelt, um die Berechnungskomplexität bei Radarkanalsimulationen durch die Einführung einiger virtueller Streuzentren (SCs) zu minimieren. Jedes entwickelte virtuelle SCs hat seine eigene spezifische Streueigenschaft

Designing Tactile Interfaces for Abstract Interpersonal Communication, Pedestrian Navigation and Motorcyclists Navigation

The tactile medium of communication with users is appropriate for displaying information in situations where auditory and visual mediums are saturated. There are situations where a subject's ability to receive information through either of these channels is severely restricted by the environment they are in or through any physical impairments that the subject may have. In this project, we have focused on two groups of users who need sustained visual and auditory focus in their task: Soldiers on the battle field and motorcyclists. Soldiers on the battle field use their visual and auditory capabilities to maintain awareness of their environment to guard themselves from enemy assault. One of the major challenges to coordination in a hazardous environment is maintaining communication between team members while mitigating cognitive load. Compromise in communication between team members may result in mistakes that can adversely affect the outcome of a mission. We have built two vibrotactile displays, Tactor I and Tactor II, each with nine actuators arranged in a three-by-three matrix with differing contact areas that can represent a total of 511 shapes. We used two dimensions of tactile medium, shapes and waveforms, to represent verb phrases and evaluated ability of users to perceive verb phrases the tactile code. We evaluated the effectiveness of communicating verb phrases while the users were performing two tasks simultaneously. The results showed that performing additional visual task did not affect the accuracy or the time taken to perceive tactile codes. Another challenge in coordinating Soldiers on a battle field is navigating them to respective assembly areas. We have developed HaptiGo, a lightweight haptic vest that provides pedestrians both navigational intelligence and obstacle detection capabilities. HaptiGo consists of optimally-placed vibro-tactile sensors that utilize natural and small form factor interaction cues, thus emulating the sensation of being passively guided towards the intended direction. We evaluated HaptiGo and found that it was able to successfully navigate users with timely alerts of incoming obstacles without increasing cognitive load, thereby increasing their environmental awareness. Additionally, we show that users are able to respond to directional information without training. The needs of motorcyclists are di erent from those of Soldiers. Motorcyclists' need to maintain visual and auditory situational awareness at all times is crucial since they are highly exposed on the road. Route guidance systems, such as the Garmin, have been well tested on automobilists, but remain much less safe for use by motorcyclists. Audio/visual routing systems decrease motorcyclists' situational awareness and vehicle control, and thus increase the chances of an accident. To enable motorcyclists to take advantage of route guidance while maintaining situational awareness, we created HaptiMoto, a wearable haptic route guidance system. HaptiMoto uses tactile signals to encode the distance and direction of approaching turns, thus avoiding interference with audio/visual awareness. Evaluations show that HaptiMoto is intuitive for motorcyclists, and a safer alternative to existing solutions

ATV Dynamics and Pediatric Rider Safety

It has been observed through numerous academic and governmental agency studies that pediatric all-terrain vehicle ridership carries significant risk of injury and death. While no doubt valuable to safety, the post-hoc approach employed in these studies does little to explain the why and how behind the risk factors. Furthermore, there has been no prolonged, widespread, organized, and concerted effort to reconstruct and catalog the details and causes of the large (20,000+) number of ATV-related injuries that occur each year as has been done for road-based motor vehicle accidents. This dissertation takes the opposite approach from a meta-analysis and instead examines the injury risk factors through a two-pronged, a priori, physics-based approach. Specifically, this dissertation study sought to: 1) experimentally determine whether age is an effective metric for assessing proper rider fit on an ATV, and 2) demonstrate experimentally and analytically how the combined dynamics of the ATV and riders can contribute to vehicular instability. These two studies were conducted using instrumented human subjects and ATVs and measured in a biodynamics laboratory. The key finding from the rider versus ATV size study was:1) contrary to publicly circulated engine size and age-based fit guidelines, age is not an effective metric for assessing rider fit on ATVs; instead, stature is the more reliable measure. The key findings from the rollover propensity study were: 2a) the combination of common terrain and throttle input can easily lead to a rearwards rollover, with or without additional riders sitting behind the ATV driver, and 2b) the minimum turning radius before initiating a sideways rollover can be easily be exceeded when ATVs are driven on commonly-encountered terrain and at surprisingly low speeds. The results of this dissertation study thus provide new evidence for mitigating two root causes of ATV injury by informing better parental guidance: first, clearly revealing that stature and not age is the key metric for who fits on what ATV model, and second, revealing the ease with which backward and sideways rollovers can occur

Representative testing of personal protection equipment

The purpose of the work reported within this thesis was to design and implement a series of tests which better replicate the impact conditions experienced during a game, and allow for quantitative measurements of performance of various items of personal protection equipment (PPE). The sports of cricket and taekwondo were used as case studies. The aim was to improve on existing testing protocols making them more representative of real life, an approach that has not been previously attempted in the literature and so required design of multiple items of novel equipment. A representative cricket impact test was developed utilizing a ball canon firing a cricket ball mass at an equivalent bowling velocity of 31 m/s (70 mph) and a novel, freely suspended force acquisition system with embedded accelerometers from which the transmitted force values could be derived. Throughout the testing secondary variables of coefficient of restitution (COR), deformation and contact time were measured from high speed video footage to give further insight into the impact mechanics of the three tested leg guards. Contact times were in the range of 3 ms - 4 ms, COR between 0.38 - 0.50 and deformation between 45 mm - 52 mm. These results were compared against other benchmark tests to establish how close the representative test was to an actual human related ball-pad impact and to estimate human tolerance levels to impact. A rig to mimic a human on human kicking impact in taekwondo was designed to measure performance of the piece of body protection equipment used in training and competition, commonly referred to as a hogu. Primarily a mechanical simulator was designed to replicate the speed and mass of a human leg impacting during a roundhouse kick. A force acquisition system was manufactured, capable of integrating with the kicking robot functioning, with a human torso sized and shaped anvil, using a similar accelerometer based system of force measurement as that introduced in the cricket testing. This test was then used to measure performance levels of nine off-the-shelf hogus and protective training pads. Using transmitted peak force and time to peak force (TTPF) as indicators of protection, these values were found to range from between 0.5 kN 7.5 kN and 9 ms - 23 ms across the pads indicating a major difference in the protection provided

Simulation of Vehicle-Pedestrian Interaction

The literature on vehicle crash reconstruction provides a number of empirical or classical theoretical models for the distance pedestrians are thrown in impacts with various types of vehicles and impact speeds. The aim of this research was to compare the predictions offered by computer simulation to those obtained using the empirical and classical theoretical models traditionally utilised in vehicle-pedestrian accident reconstruction. Particular attention was paid to the pedestrian throw distance versus vehicle impact speed relationship and the determination of pedestrian injury patterns and associated severity. It was discovered that computer simulation offered improved pedestrian kinematic prediction in comparison to traditional vehicle-pedestrian accident reconstruction techniques. The superior kinematic prediction was found to result in a more reliable pedestrian throw distance versus vehicle impact speed relationship, particularly in regard to varying vehicle and pedestrian parameters such as shape, size and orientation. The pedestrian injury prediction capability of computer simulation was found to be very good for head and lower extremity injury determination. Such injury prediction capabilities were noted to be useful in providing additional correlation of vehicle impact speed predictions, whether these predictions were made using computer simulation, traditional vehicle-pedestrian accident reconstruction methods or a combination of both. A generalised approach to the use of computer simulation for the reconstruction of vehicle-pedestrian accidents was also offered. It is hoped that this approach is developed and improved by other researchers so that over time guidelines for a standardised approach to the simulation of vehicle-pedestrian accidents might evolve. Thoracic injury prediction, particularly for frontal impacts, was found to be less than ideal. It is suspected that the relatively poor thoracic biofidelity stems from the development of pedestrian mathematical models from occupant mathematical models, which were in turn developed from cadaver and dummy tests. It is hoped that future research will result in improved thoracic biofidelity in human mathematical models

The development of ergonomics design criteria for powered human movement systems

This research developed from a concept for a powered exoskeletal system for manipulating a person's posture to provide them with physical sensations as though taking part in an activity in which they otherwise would not be able to participate. The aim for this research was to develop a set of criteria relating to this physical manipulation, which could be used, in conjunction with visual and audio stimuli, to govern the design of a commercial personal entertainment simulator for use by members of the public. Investigations revealed that there is currently no existing system comparable to this proposed simulator. Therefore, various fields were researched, including robotics, physiotherapy, virtual reality, haptics and existing simulators; with a view to combining elements of these fields for the development of a manipulation system appropriate to public entertainment use. A survey was conducted on members of the public to investigate their experiences of sports, theme park rides and virtual reality; their personalities; and their opinions of the proposed simulator. This survey indicated that the likely users of such a system would be sensation-seeking, physically active people. The activities which generated the most interest were those which were hazardous, difficult, or required long distance travel. To be consistent with these findings, practical trials were undertaken using the sport of skiing as the context for conducting practical investigations into postural manipulation. Existing and original studies of the movements involved in skiing revealed the complexity of this activity, and the variety of techniques employed by different skiers. These findings, combined with the survey data and earlier investigations, led to the development of a versatile prototype system which could accommodate this variability and impose customised skiing movements on volunteers. Volunteer trials using this prototype demonstrated that members of the public were willing to have their postures controlled by external forces, and although some participants were apprehensive at first, they all reported the experience to be enjoyable. Tests with different applied movements showed that users were comfortable with manipulations at speeds and accelerations up to and exceeding those employed in skiing for real. The principal criteria concluded from these trials were that it is possible to safely and comfortably manipulate human postures through external technology, and that this external control can be used to provide an enjoyable and exhilarating entertainment experience.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Advances in Mechanical Systems Dynamics 2020

The fundamentals of mechanical system dynamics were established before the beginning of the industrial era. The 18th century was a very important time for science and was characterized by the development of classical mechanics. This development progressed in the 19th century, and new, important applications related to industrialization were found and studied. The development of computers in the 20th century revolutionized mechanical system dynamics owing to the development of numerical simulation. We are now in the presence of the fourth industrial revolution. Mechanical systems are increasingly integrated with electrical, fluidic, and electronic systems, and the industrial environment has become characterized by the cyber-physical systems of industry 4.0. Within this framework, the status-of-the-art has become represented by integrated mechanical systems and supported by accurate dynamic models able to predict their dynamic behavior. Therefore, mechanical systems dynamics will play a central role in forthcoming years. This Special Issue aims to disseminate the latest research findings and ideas in the field of mechanical systems dynamics, with particular emphasis on novel trends and applications

Minimally Invasive Expeditionary Surgical Care Using Human-Inspired Robots

This technical report serves as an updated collection of subject matter experts on surgical care using human-inspired robotics for human exploration. It is a summary of the Blue Sky Meeting, organized by the Florida Institute for Human and Machine Cognition (IHMC), Pensacola, Florida, and held on October 2-3, 2018. It contains an executive summary, the final report, all of the presentation materials, and an updated reference list