Aerial Collision Research Articles

A Quadrotor With a Passively Reconfigurable Airframe for Hybrid Terrestrial Locomotion

Despite efforts to circumvent and alleviate the impact of a mid-flight collision, it remains extremely challenging to safeguard a multirotor vehicle when it operates in cluttered environments. In this work, we introduce a flying robot with the ability to roll through a gap narrower than its diameter to prevent a possible aerial collision entirely. The novelty of the proposed design lies in a simple passive mechanism that redirects the propelling thrust for the terrestrial operation without the need for extra actuators. As a result, the robot remains compact and lightweight. Furthermore, to overcome the underactuation associated with the passive structure, the transitions between flight and rolling are accomplished with a highly dynamic maneuver. In the experimental demonstration, the robot seamlessly switched between the aerial and terrestrial locomotion to safely negotiate a 10-cm opening.

A Time-Efficient Method to Avoid Collisions for Collision Cones: An Implementation for UAVs Navigating in Dynamic Environments

This paper presents a methodology that can be used to avoid collisions of aerial drones. Even though there are many collision avoidance methods available in literature, collision cone is a proven method that can be used to predict a collision beforehand. In this research, we propose an algorithm to avoid a collision in a time-efficient manner for collision cone based aerial collision avoidance approaches. Furthermore, the paper has considered all possible scenarios including heading change, speed change and combined heading and speed change, to avoid a collision. The heading-based method was mathematically proven to be the most time-efficient method out of the three. The proposed heading-based method was compared with other work presented in the literature and validated with both simulations and experiments. A Matrice 600 Pro hexacopter is used for the collision avoidance experiments.

VIDEO ANALYSIS OF CONTACT TECHNIQUE DURING HEAD COLLISIONS IN RUGBY UNION

BackgroundRugby union is characterised by frequent and dynamic collisions. Players typically aim to avoid direct contact to the head due to its potential for serious head injury. However, head collisions...

Resilin microjoints: a smart design strategy to avoid failure in dragonfly wings.

Dragonflies are fast and manoeuvrable fliers and this ability is reflected in their unique wing morphology. Due to the specific lightweight structure, with the crossing veins joined by rubber-like resilin patches, wings possess strong deformability but can resist high forces and large deformations during aerial collisions. The computational results demonstrate the strong influence of resilin-containing vein joints on the stress distribution within the wing. The presence of flexible resilin in the contact region of the veins prevents excessive bending of the cross veins and significantly reduces the stress concentration in the joint.

Video analysis of concussion injury mechanism in under-18 rugby

BackgroundUnderstanding the mechanism of injury is necessary for the development of effective injury prevention strategies. Video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which...

Contact technique and concussions in the South African under-18 Coca-Cola Craven Week Rugby tournament

In rugby union, understanding the techniques and events leading to concussions is important because of the nature of the injury and the severity and potential long-term consequences, particularly in junior players. Proper contact technique is a prerequisite for successful participation in rugby and is a major factor associated with injury. However, the execution of proper contact technique and its relationship to injury has yet to be studied in matches. Therefore, the aim of this study was to compare contact techniques leading to concussion with a representative sample of similarly matched non-injury (NI) contact events. Injury surveillance was conducted at the 2011–2013 under-18 Craven Week Rugby tournaments. Video footage of 10 concussive events (5 tackle, 4 ruck and 1 aerial collision) and 83 NI events were identified (19 tackle, 61 ruck and 3 aerial collisions). Thereafter, each phase of play was analysed using standardised technical proficiency criteria. Overall score for ruck proficiency in concussive events was 5.67 (out of a total of 15) vs. 6.98 for NI events (n = 54) (effect size = 0.52, small). Overall average score for tackler proficiency was 7.25 (n = 4) and 6.67 (n = 15) for injury and NI tackles, respectively (out of 16) (effect size = 0.19, trivial). This is the first study to compare concussion injury contact technique to a player-matched sample of NI contact techniques. Certain individual technical criteria had an effect towards an NI outcome, and others had an effect towards a concussive event, highlighting that failure to execute certain techniques may substantially increase the opportunity for concussion.

The mating system of a bee fly (Diptera: Bombyliidae). II. Factors affecting male territorial and mating success

Males of an undescribed bombyliidfly (Comptosia sp.)occupy traditional territories on a Southeast Queensland hilltop, to which females come solely for the purpose of mating. Territorial fights between males involve aerial collisions during which modified spines on the wing margins produce scars on the bodies of opponents. Territory owners and mating males are not different in size or age from the remainder of the male population. Although residency is related to fighting success, the strength of the effect is ambiguous. Consequently, our data do not appear to fit predictions from game theoretical models for fighting protocol. Hilltop males lacked the extensive population variation typically found in territorial species, and thus, the presumed advantages of traits such as large size may be suppressed. Hilltop males were larger than males at a nonhilltop, resource-based mating site and the possibility of alternative mating tactics is discussed.

Prescribing of Thyroxine

<h3>Background</h3> Understanding the mechanism of injury is necessary for the development of effective injury prevention strategies. Video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which can be used to formulate these strategies. Therefore, we conducted a video analysis of the mechanism of concussion injury in junior-level rugby union and compared it with a representative and matched non-injury sample. <h3>Methods</h3> Injury reports for 18 concussion events were collected from the 2011 to 2013 under-18 Craven Week tournaments. Also, video footage was recorded for all 3 years. On the basis of the injury events, a representative ‘control’ sample of matched non-injury events in the same players was identified. The video footage, which had been recorded at each tournament, was then retrospectively analysed and coded. 10 injury events (5 tackle, 4 ruck, 1 aerial collision) and 83 non-injury events were analysed. <h3>Results</h3> All concussions were a result of contact with an opponent and 60% of players were unaware of the impending contact. For the measurement of <i>head position on contact</i>, 43% had a ‘down’ position, 29% the ‘up and forward’ and 29% the ‘away’ position (n=7). The speed of the injured tackler was observed as ‘slow’ in 60% of injurious tackles (n=5). In 3 of the 4 rucks in which injury occurred (75%), the concussed player was acting defensively either in the capacity of ‘support’ (n=2) or as the ‘jackal’ (n=1). <h3>Conclusions</h3> Training interventions aimed at improving peripheral vision, strengthening of the cervical muscles, targeted conditioning programmes to reduce the effects of fatigue, and emphasising safe and effective playing techniques have the potential to reduce the risk of sustaining a concussion injury.

International Civil Aviation Organization

The 30th session of the Council of the International Civil Aviation Organization (ICAO) took place in Montreal from January 28 to April 18, 1957. In its consideration of the problems of air navigation, the Council, upon a recommendation of the Third Air Navigation Conference as endorsed by the Air Navigation Commission, approved the establishment of an Airworthiness Committee and noted the proposal of the Air Navigation Commission for its work program. The Council also agreed that the Air Navigation Commission should on its own authority take action on the provisional AMC's (Acceptable Means of Compliance) prepared by the Airworthiness Committee. A report by the Air Navigation Commission on signals to be used when an aircraft has infringed on restricted airspace was endorsed by the Council, which decided that a paper on the legal aspects of the question should be prepared as soon as practicable. In accordance with a resolution of the tenth session of the Assembly, the Council approved the establishment of a panel of statistical experts nominated by the following countries: Australia, Canada, Egypt, France, Italy, Lebanon, the Netherlands, New Zealand, Pakistan, Spain, the United Kingdom, and the United States. In the legal field, the Council accepted the invitation of the Japanese government to hold the eleventh session of the Legal Committee in Tokyo in September 1957 and referred a report by the Air Transport Committee on the economic aspects of the liability limits on the proposed Convention on Aerial Collisions to the Legal Committee.

International Civil Aviation Organization

The Subcommittee on Aerial Collisions, established by the Legal Committee of the International Civil Aviation Organization at its ninth session, met in Paris from January 12 to 22, 1954, with Mr. Andre Garnault (France) as chairman. A draft convention on aerial collisions, prepared at the meeting for consideration by the Legal Committee at its tenth session, reviewed the entire question of the liability of an operator or carrier in the case of aerial collision.