Singularity-free path planning for the Stewart platform manipulator

This paper addresses the problem of singularity-free path planning for the six-degree-of-freedom parallel manipulator known as the Stewart platform manipulator. Unlike serial manipulators, the Stewart platform possesses singular configurations within the workspace where the manipulator is uncontrollable. An algorithm has been developed to construct continuous paths within the workspace of the manipulator by avoiding singularities and ill-conditioning. Given two end-poses of the manipulator, the algorithm finds out safe (well-conditioned) via points and plans a continuous path from the initial pose to the final one. When the two end-poses belong to different branches and no singularity-free path is possible, the algorithm indicates the impossibility of a valid path. A numerical example has also been presented as illustration of the path planning strategy.

The ultimate edge: The case for planning media for sustaining space communities

Governments and intergovernmental organisations have long recognised that space communities – the ultimate ‘settlements at the edge’ – will exist one day and have based their first plans for these on another region ‘at the edge’, the Antarctic. United States President Eisenhower proposed to the United Nations in 1960 that the principles of the Antarctic Treaty be applied to outer space and celestial bodies (State Department, n.d.). Three years later the UN adopted the Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space and in 1967 that became the Outer Space Treaty. According to the UN Office for Outer Space Affairs, ‘the Treaty was opened for signature by the three depository Governments (the Russian Federation, the United Kingdom and the United States of America) in January 1967, and it entered into force in October 1967’ (Office for Outer Space Affairs, n.d). The status of the treaty (at time of writing) was 89 signatories and 102 parties (Office for Disarmament Affairs, n.d.). Other related instruments include the Rescue Agreement, the Liability Convention, the Registration Convention and the Moon Agreement (Office for Outer Space Affairs, n.d.-a). Jumping to the present, a newsagency reported in July 2014 (Reuters, 2014) that the British Government had shortlisted eight aerodromes in its search for a potential base for the UK’s first spaceplane flights which Ministers want to happen by 2018 (UK Space Agency, 2014). The United States already has a spaceport, in New Mexico (Cokley, Rankin, Heinrich, & McAuliffe, 2013)...

An automated emergency landing system for fixed-wing aircraft: Planning and control

A number of hurdles must be overcome in order to integrate unmanned aircraft into civilian airspace for routine operations. The ability of the aircraft to land safely in an emergency is essential to reduce the risk to people, infrastructure and aircraft. To date, few field-demonstrated systems have been presented that show online re-planning and repeatability from failure to touchdown. This paper presents the development of the Guidance, Navigation and Control (GNC) component of an Automated Emergency Landing System (AELS) intended to address this gap, suited to a variety of fixed-wing aircraft. Field-tested on both a fixed-wing UAV and Cessna 172R during repeated emergency landing experiments, a trochoid-based path planner computes feasible trajectories and a simplified control system executes the required manoeuvres to guide the aircraft towards touchdown on a predefined landing site. This is achieved in zero-thrust conditions with engine forced to idle to simulate failure. During an autonomous landing, the controller uses airspeed, inertial and GPS data to track motion and maintains essential flight parameters to guarantee flyability, while the planner monitors glide ratio and re-plans to ensure approach at correct altitude. Simulations show reliability of the system in a variety of wind conditions and its repeated ability to land within the boundary of a predefined landing site. Results from field-tests for the two aircraft demonstrate the effectiveness of the proposed GNC system in live operation. Results show that the system is capable of guiding the aircraft to close proximity of a predefined keyhole in nearly 100% of cases.

Planning, development and management of sustainable cities: A commentary from the guest editors

Cities are the most dramatic manifestations of human activities on the surface of the earth. These human-dominated organisms—i.e., cities—degrade natural habitats, simplify species composition, disrupt hydrological systems, and modify energy flow and nutrient cycling. Today, these consequential impacts of human activities, originated from population increase, rapid urbanization, high private motor vehicle dependency, deregulated industrialization and mass livestock production, are increasing exponentially and causing great deal of environmental, social, and economic challenges both at global and local scales. In such a situation, establishment of sustainable cities, through sustainable urban development practices, is seen as a potential panacea to combat these challenges responsibly, effectively, and efficiently. This paper offers a critical review of the key literature on the issues relating to planning, development and management of sustainable cities, introduces the contributions from the Special Issue, and speculates on the prospective research directions to place necessary mechanisms to secure a sustainable urban future for all.

Fuzzy optimization model for water quality management of a river system - Closure

A fuzzy waste-load allocation model, FWLAM, is developed for water quality management of a river system using fuzzy multiple-objective optimization. An important feature of this model is its capability to incorporate the aspirations and conflicting objectives of the pollution control agency and dischargers. The vagueness associated with specifying the water quality criteria and fraction removal levels is modeled in a fuzzy framework. The goals related to the pollution control agency and dischargers are expressed as fuzzy sets. The membership functions of these fuzzy sets are considered to represent the variation of satisfaction levels of the pollution control agency and dischargers in attaining their respective goals. Two formulations—namely, the MAX-MIN and MAX-BIAS formulations—are proposed for FWLAM. The MAX-MIN formulation maximizes the minimum satisfaction level in the system. The MAX-BIAS formulation maximizes a bias measure, giving a solution that favors the dischargers. Maximization of the bias measure attempts to keep the satisfaction levels of the dischargers away from the minimum satisfaction level and that of the pollution control agency close to the minimum satisfaction level. Most of the conventional water quality management models use waste treatment cost curves that are uncertain and nonlinear. Unlike such models, FWLAM avoids the use of cost curves. Further, the model provides the flexibility for the pollution control agency and dischargers to specify their aspirations independently.

Population health planning and health promotion: Opportunities and challenges to improve social determinants

Complex social factors and health issues challenge equitable health outcomes for many people, in particular those living in marginalised communities. Primary health care promises solutions through population health and health promotion approaches to improve social conditions (determinants) affecting health with emphasis on change at systems levels. Yet short-term efficiency focus policy decisions without long-term planning can undermine the effectiveness of primary health care. The workshop goal is to explore opportunities and share ideas about population health planning in Primary Health Networks and other community health care settings, so as to draw out opportunities, challenges and forward thinking health planning and health promotion strategies.

Governance and regional planning outcomes: Using governance indicators to support a policy implementation approach

Regional planning faces numerous decision making uncertainties related to the complex interdependencies between urban and regional centres. Questions about how to achieve sustainable planning solutions across regions are a key uncertainty and relate to a lack of information about the actual achievement of outcomes as proposed by the objectives of a plan. Regional plan implementation and its impact on environmental, social and economic outcomes have been little explored within Australian urban and regional planning research. Despite a desire to improve the conditions across Australian regions, ambiguity persists regarding the results of regional planning efforts. Of the variables affecting regional planning, scholars argue that governance has a significant impact on achieving outcomes (see Pahl-Wostl 2009). In order to better analyse the impact of governance, we propose a set of governance indicators to examine decisions across regional planning institutions and apply this to governance models across Queensland’s regions. We contend that these governance indicators can support a more rigorous assessment of the impacts of governance models on plan implementation and outcomes. We propose that this is a way to better understand the relationship between planning and outcomes across urban and regional areas.

A critical evaluation of literature on robot path planning in dynamic environment

Robot Path Planning (RPP) in dynamic environments is a search problem based on the examination of collision-free paths in the presence of dynamic and static obstacles. Many techniques have been developed to solve this problem. Trapping in a local minima and maintaining a Real-Time performance are known as the two most important challenges that these techniques face to solve such problem. This study presents a comprehensive survey of the various techniques that have been proposed in this domain. As part of this survey, we include a classification of the approaches and identify their methods.

Smarten up! Applying market design theory to housing supply

PROBLEM Cost of delivering medium density apartments impedes supply of new and more affordable housing in established suburbs EXISTING FOCUS - Planning controls - Construction costs, esp labour - Regulation eg sustainability

A Jacobian-Based Algorithm for Planning Attitude Maneuvers Using Forward and Reverse Rotations

Algorithms for planning quasistatic attitude maneuvers based on the Jacobian of the forward kinematic mapping of fully-reversed (FR) sequences of rotations are proposed in this paper. An FR sequence of rotations is a series of finite rotations that consists of initial rotations about the axes of a body-fixed coordinate frame and subsequent rotations that undo these initial rotations. Unlike the Jacobian of conventional systems such as a robot manipulator, the Jacobian of the system manipulated through FR rotations is a null matrix at the identity, which leads to a total breakdown of the traditional Jacobian formulation. Therefore, the Jacobian algorithm is reformulated and implemented so as to synthesize an FR sequence for a desired rotational displacement. The Jacobian-based algorithm presented in this paper identifies particular six-rotation FR sequences that synthesize desired orientations. We developed the single-step and the multiple-step Jacobian methods to accomplish a given task using six-rotation FR sequences. The single-step Jacobian method identifies a specific FR sequence for a given desired orientation and the multiple-step Jacobian algorithm synthesizes physically feasible FR rotations on an optimal path. A comparison with existing algorithms verifies the fast convergence ability of the Jacobian-based algorithm. Unlike closed-form solutions to the inverse kinematics problem, the Jacobian-based algorithm determines the most efficient FR sequence that yields a desired rotational displacement through a simple and inexpensive numerical calculation. The procedure presented here is useful for those motion planning problems wherein the Jacobian is singular or null.

Effect of shoes' heel height on the energy cost during jogging

The purpose of this study is to examine the changes of energy cost during a high-heeled continuous jogging.Thirteen healthy female volunteers jointed in this study with heel height of the shoes varied from 1, 4.5 and 7 cm, respectively. Each subjects jogged on the treadmill with K4b2 portable gas analysis system. The results of this study showed that ventilnation, relative oxygen consumption and energy expenditure increased with the increase of heel height and these values shows significantly larger when the heel height reached to 7 cm. Present study suggest that wearing high heel shoes jogging could directly increase energy consumption, causing neuromuscular fatigue.

General ranked set sampling with cost considerations

Nahhas, Wolfe, and Chen (2002, Biometrics 58, 964-971) considered optimal set size for ranked set sampling (RSS) with fixed operational costs. This framework can be very useful in practice to determine whether RSS is beneficial and to obtain the optimal set size that minimizes the variance of the population estimator for a fixed total cost. In this article, we propose a scheme of general RSS in which more than one observation can be taken from each ranked set. This is shown to be more cost-effective in some cases when the cost of ranking is not so small. We demonstrate using the example in Nahhas, Wolfe, and Chen (2002, Biometrics 58, 964-971), by taking two or more observations from one set even with the optimal set size from the RSS design can be more beneficial.

Application of commercially available, low-cost, miniaturised NIR spectrometers to the assessment of the sugar content of intact fruit

Recent decreases in costs, and improvements in performance, of silicon array detectors open a range of potential applications of relevance to plant physiologists, associated with spectral analysis in the visible and short-wave near infra-red (far-red) spectrum. The performance characteristics of three commercially available ‘miniature’ spectrometers based on silicon array detectors operating in the 650–1050-nm spectral region (MMS1 from Zeiss, S2000 from Ocean Optics, and FICS from Oriel, operated with a Larry detector) were compared with respect to the application of non-invasive prediction of sugar content of fruit using near infra-red spectroscopy (NIRS). The FICS–Larry gave the best wavelength resolution; however, the narrow slit and small pixel size of the charge-coupled device detector resulted in a very low sensitivity, and this instrumentation was not considered further. Wavelength resolution was poor with the MMS1 relative to the S2000 (e.g. full width at half maximum of the 912 nm Hg peak, 13 and 2 nm for the MMS1 and S2000, respectively), but the large pixel height of the array used in the MMS1 gave it sensitivity comparable to the S2000. The signal-to-signal standard error ratio of spectra was greater by an order of magnitude with the MMS1, relative to the S2000, at both near saturation and low light levels. Calibrations were developed using reflectance spectra of filter paper soaked in range of concentrations (0–20% w/v) of sucrose, using a modified partial least squares procedure. Calibrations developed with the MMS1 were superior to those developed using the S2000 (e.g. coefficient of correlation of 0.90 and 0.62, and standard error of cross-validation of 1.9 and 5.4%, respectively), indicating the importance of high signal to noise ratio over wavelength resolution to calibration accuracy. The design of a bench top assembly using the MMS1 for the non-invasive assessment of mesocarp sugar content of (intact) melon fruit is reported in terms of light source and angle between detector and light source, and optimisation of math treatment (derivative condition and smoothing function).

Strike Hard, Strike Sure - Operation Musketeer : British Military Planning during the Suez Crisis, 1956

This study analyses British military planning and actions during the Suez Crisis in 1956. It seeks to find military reasons for the change of concepts during the planning and compares these reasons with the tactical doctrines of the time. The thesis takes extensive advantage of military documents preserved in the National Archives, London. In order to expand the understanding of the exchange of views during the planning process, the private papers of high ranking military officials have also been consulted. French military documents preserved in the Service Historique de la Defence, Paris, have provided an important point of comparison. The Suez Crisis caught the British armed forces in the middle of a transition phase. The main objective of the armed forces was to establish a credible deterrence against the Soviet Union. However, due to overseas commitments the Middle East playing a paramount role because of its economic importance the armed forces were compelled to also prepare for Limited War and the Cold War. The armed forces were not fully prepared to meet this demand. The Middle Eastern garrison was being re-organised after the withdrawal from the Canal Base and the concept for a strategic reserve was unimplemented. The tactical doctrines of the time were based on experiences from the Second World War. As a result, the British view of amphibious operations and the subsequent campaigns emphasised careful planning, mastery of the sea and the air, sufficient superiority in numbers and firepower, centralised command and extensive administrative preparations. The British military had realized that Nasser could nationalise the Suez Canal and prepared an outline plan to meet this contingency. Although the plan was nothing more than a concept, it was accepted as a basis for further planning when the Canal was nationalised at the end of July. This plan was short-lived. The nominated Task Force Commanders shifted the landing site from Port Said to Alexandria because it enabled faster expansion of the bridgehead. In addition, further operations towards Cairo the hub of Nasser s power would be easier to conduct. The operational concept can be described as being traditional and was in accordance with the amphibious warfare doctrine. This plan was completely changed at the beginning of September. Apparently, General Charles Keightley, the Commander-in-Chief, and the Chairman of the Chiefs of Staff Committee developed the idea of prolonged aerial operations. The essence of the concept was to break the Egyptian will to resist by attacking the oil facilities, the transportation system and the armed forces. This victory through air concept would be supported by carefully planned psychological operations. This concept was in accordance with the Royal Air Force doctrine, which promoted a bomber offensive against selected target categories. General Keightley s plan was accepted despite suspicions at every planning level. The Joint Planning Staff and the Task Force Commanders opposed the concept from the beginning to the end because of its unpredictability. There was no information that suggested the bombing would persuade the Egyptians to submit. This problem was worsened by the fact that British intelligence was unable to provide reliable strategic information. The Task Force Commanders, who were responsible for the tactical plans, were not able to change Keightley s mind, but the concept was expanded to include a traditional amphibious assault on Port Said due to their resistance. The bombing campaign was never tested as the Royal Air Force was denied authorisation to destroy the transportation and oil targets. The Chiefs of Staff and General Keightley were too slow to realise that the execution of the plan depended on the determination of the Prime Minister. However, poor health, a lack of American and domestic support and the indecisiveness of the military had ruined Eden s resolve. In the end, a very traditional amphibious assault, which was bound to succeed at the tactical level but fail at the strategic level, was launched against Port Said.