A Biologically Inspired Jumping and Rolling Robot

Mobile robots for rough terrain are of interest to researchers as their range of possible uses is large, including exploration activities for inhospitable areas on Earth and on other planets and bodies in the solar system, searching in disaster sites for survivors, and performing surveillance for military applications. Nature generally achieves land movement by walking using legs, but additional modes such as climbing, jumping and rolling are all produced from legs as well. Robotics tends not to use this integrated approach and adds additional mechanisms to achieve additional movements. The spherical device described within this thesis, called Jollbot, integrated a rolling motion for faster movement over smoother terrain, with a jumping movement for rougher environments. Jollbot was developed over three prototypes. The first achieved pause-and-leap style jumps by slowly storing strain energy within the metal elements of a spherical structure using an internal mechanism to deform the sphere. A jump was produced when this stored energy was rapidly released. The second prototype achieved greater jump heights using a similar structure, and added direction control to each jump by moving its centre of gravity around the polar axis of the sphere. The final prototype successfully combined rolling (at a speed of 0.7 m/s, up 4° slopes, and over 44 mm obstacles) and jumping (0.5 m cleared height), both with direction control, using a 0.6 m spherical spring steel structure. Rolling was achieved by moving the centre of gravity outside of the sphere’s contact area with the ground. Jumping was achieved by deflecting the sphere in a similar method to the first and second prototypes, but through a larger percentage deflection. An evaluation of existing rough terrain robots is made possible through the development of a five-step scoring system that produces a single numerical performance score. The system is used to evaluate the performance of Jollbot.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Concept evaluation of Mars drilling and sampling instrument

The search for possible extinct or existing life is the goal of the exobiology investigations to be undertaken during future Mars missions. As it has been learnt from the NASA Viking, Pathfinder and Mars Exploration Rover mission, sampling of surface soil and rocks can gain only limited scientific information. In fact, possible organic signatures tend to be erased by surface processes (weathering, oxidation and exposure to UV radiation from the Sun). The challenge of the missions have mostly been getting there; only roughly one third of all Mars missions have reached their goal, either an orbit around the planet, or landing to the surface. The two Viking landers in the 1970's were the first to touch down the soil of Mars in working order and performing scientific studies there. After that there was a long gap, until 1997 the Pathfinder landed safely on the surface and released a little rover, the Sojourner. In 2004 other rovers came: the Mars Exploration Rover Spirit and a while after that, the sister rover Opportunity. These five successful landings are less than half of all attempts to land on Mars. Russia, Europe and the United States have all had their landers, but Mars is challenging. Even Mars orbit has been tough to reach by many nation's orbiters. It is then understandable that of these five successful landings, performed by National Aeronautics and Space Administration (NASA), there have not yet been very complicated mechanical deep-drilling instruments onboard. The risks to get there are great, and the risk of malfunctioning of a complicated instrument there is also high. Another reason to avoid a deep-driller from the lander payload is simply the mass constrains. A drill is a heavy piece of payload, and the mass allocations for scientific instruments are small. In the launch window of 2009, both European Space Agency (ESA) and NASA have their plans to send a rover to Mars. Both of them will include some means to analyse the subsurface material. ESA's rover, called the ExoMars rover, will carry a deep-driller onboard in its Pasteur payload. At the time of writing this thesis, an exact definition of the Pasteur drill has not yet been defined. The author of this thesis has studied the driller instruments in his past work projects and in his doctoral studies. The main focus of this thesis is to analyse the feasibility of different drill configurations to fit to the requirements of the ExoMars' Pasteur payload drill by using the information gathered from the past projects. In this thesis, the author introduces a new concept of a robotic driller, called the MASA drill. The MASA drill fulfils the needs for the drill instrument onboard the Pasteur payload. The main study in this thesis concentrates on design work of the MASA drill, as well as analysis of its operation and performance capabilities in the difficult task of drilling and sampling.reviewe

Design, modelling and control of a rotorcraft landing gear for uneven ground conditions

The ability to perform vertical take-off and landing, hovering and lateral flight provides rotorcrafts crucial advantages over other aircrafts and land vehicles for operations in remote areas. However, a major limitation of rotorcrafts is the requirement of a flat surface to land, increasing the difficulty and risk of landing operations on rough terrain or unstable surfaces. This limitation is mainly due to the use of conventional landing gear like skids or wheels. The growing use of Unmanned Aerial Vehicles (UAVs) also increases the necessity for more landing autonomy of these systems. This thesis presents the investigation into the development of an adaptive robotic landing gear for a small UAV that enhances the landing capabilities of current rotorcrafts. This landing gear consists in a legged system that is able to sense and adapt the position of its legs to the terrain conditions. This research covers the development of effective tools for the design and testing of the control system using software and hardware platforms. Mathematical models using multibody system dynamics are developed and implemented in software simulations. A hardware robot is designed and built to validate the simulation results. The system proposed in this thesis consists in a landing gear with four robotic legs that uses an Inertial Measurement Unit (IMU) to sense the body attitude, Force Sensing Resistors (FSR) to measure feet pressure and a distance sensor to detect ground approach. The actuators used are position-controlled servo motors that also provide angular position feedback. The control strategy provides position commands to coordinate the motion of all joints based on attitude and foot pressure information. It offers the advantage of being position-controlled, so it is easier to be implemented in hardware systems using low-cost components, and at the same time, the feet forcecontrol and leg design add compliance to the system. Through software simulations and laboratory experiments the system successfully landed on a 20° slope surface, substantially increasing the current slope landing limit

A play of bodies: a phenomenology of videogame experience

Videogames require robust yet flexible methods and vocabularies of critical analysis that appreciate both the textual and embodied pleasures of players. Such analysis cannot start with the player’s intentions as an autonomous user nor with the videogame as a stable object; rather, it must account for the dynamic interplay between videogame hardware, sensorial perception, and audiovisual and haptic representations. If it is to understand how a particular videogame is engaged as both textual artefact and embodied practice, such analysis must be concerned with not just what the player does with the videogame, but what the videogame does with the player. This thesis forwards a phenomenology of videogame experience to account for how the player and the videogame incorporate each other in reflexive cycles that mediate presence, attention, perception, and agency. It does not hope to understand videogames either ‘as narratives’ or ‘as games’ but as particular amalgamations of existing and nascent media and forms—it hopes to understand videogames as videogames. It explores videogame play as a convergence of eyes-on-screens, ears-at-speakers, and muscles-against-interfaces to interrogate the limits of current game studies approaches that often obscure rich commonalities between videogames and other media forms. Drawing upon phenomenology, posthumanism, and cyborg theory, and embedded in detailed and multifaceted analyses of various videogames on different platforms as played, this thesis develops nuanced understandings of how the player and the videogame come together during play to form particular modes of embodiment through which a videogame work is both interpreted and perceived

Maritime expressions:a corpus based exploration of maritime metaphors

This study uses a purpose-built corpus to explore the linguistic legacy of Britain’s maritime history found in the form of hundreds of specialised ‘Maritime Expressions’ (MEs), such as TAKEN ABACK, ANCHOR and ALOOF, that permeate modern English. Selecting just those expressions commencing with ’A’, it analyses 61 MEs in detail and describes the processes by which these technical expressions, from a highly specialised occupational discourse community, have made their way into modern English. The Maritime Text Corpus (MTC) comprises 8.8 million words, encompassing a range of text types and registers, selected to provide a cross-section of ‘maritime’ writing. It is analysed using WordSmith analytical software (Scott, 2010), with the 100 million-word British National Corpus (BNC) as a reference corpus. Using the MTC, a list of keywords of specific salience within the maritime discourse has been compiled and, using frequency data, concordances and collocations, these MEs are described in detail and their use and form in the MTC and the BNC is compared. The study examines the transformation from ME to figurative use in the general discourse, in terms of form and metaphoricity. MEs are classified according to their metaphorical strength and their transference from maritime usage into new registers and domains such as those of business, politics, sports and reportage etc. A revised model of metaphoricity is developed and a new category of figurative expression, the ‘resonator’, is proposed. Additionally, developing the work of Lakov and Johnson, Kovesces and others on Conceptual Metaphor Theory (CMT), a number of Maritime Conceptual Metaphors are identified and their cultural significance is discussed