Search results for " Control"
showing 10 items of 7691 documents
A Hybrid Control Strategy for Quadratic Boost Converters with Inductor Currents Estimation
2020
International audience; This paper deals with a control strategy for a DC-DC quadratic boost converter. In particular, a hybrid control scheme is proposed to encompass a control law and an observer for the estimation of the system states, based only on the measurements of the input and output voltages. Differently from classical control methods, where the controller is designed from a small-signal model, here the real model of the system is examined without considering the average values of the discrete variables. Using hybrid dynamical system theory, asymptotic stability of a neighborhood of the equilibrium point is established, ensuring practical stability of the origin, which contains es…
Non-linear active disturbance rejection control for upper limb rehabilitation exoskeleton
2020
Trajectory tracking in upper limb rehabilitation exercises is utilized for repeatability of joint movement to improve the patient’s recovery in the early stages of rehabilitation. In this article, non-linear active disturbance rejection control as a combination of non-linear extended-state observer and non-linear state error feedback is used for the sinusoidal trajectory tracking control of the two-link model of an upper limb rehabilitation exoskeleton. The two links represent movements like flexion/extension for both the shoulder joint and the elbow joint in the sagittal plane. The Euler–Lagrange method was employed to acquire a dynamic model of an upper limb rehabilitation exoskeleton. T…
Dissipativity-Based Small-Gain Theorems for Stochastic Network Systems
2016
In this paper, some small-gain theorems are proposed for stochastic network systems which describe large-scale systems with interconnections, uncertainties and random disturbances. By the aid of conditional dissipativity and showing times of stochastic interval, small-gain conditions proposed for the deterministic case are extended to the stochastic case. When some design parameters are tunable in practice, we invaginate a simpler method to verify small-gain condition by selecting one subsystem as a monitor. Compared with the existing results, the existence-and-uniqueness of solution and ultimate uniform boundedness of input are removed from requirements of input-to-state stability and smal…
Hard material small-batch industrial machining robot
2018
Abstract Hard materials can be cost effectively machined with standard industrial robots by enhancing current state-of-the-art technologies. It is demonstrated that even hard metals with specific robotics-optimised novel hard-metal tools can be machined by standard industrial robots with an improved position-control approach and enhanced compliance-control functions. It also shows that the novel strategies to compensate for elastic robot errors, based on models and advanced control, as well as the utilisation of new affordable sensors and human-machine interfaces, can considerably improve the robot performance and applicability of robots in machining tasks. In conjunction with the developme…
Challenges influencing the safety of migrant workers in the construction industry: A qualitative study in Italy, Spain, and the UK
2021
Abstract The construction industry is notoriously high risk for accidents, injuries, and deaths, particularly for non-national or migrant workers, who comprise a significant proportion of the workforce. This paper presents an international, qualitative study focused on exploring the challenges which influence the safety of migrant construction workers in Italy, Spain, and the UK. Based on a comprehensive review of the literature, we formulated two research questions about the challenges relating to safety that migrant workers face and the challenges to safety training effectively improving migrant workers’ safety behaviours. We present our template analysis of semi-structured interviews and…
A systematic review of human behaviour in and around floodwater
2020
Abstract Flooding can have a major impact on people's safety and livelihood. Understanding people's flood-related behaviours may assist in the development of more effective strategies aimed at lessening the impact of floods including mortality and morbidity. This systematic review examined peer-reviewed literature published from January-1989 to April-2019 on human behaviour in and around floodwater to identify behaviour patterns as well as protective and risk factors. We extracted three main themes from a thematic analysis of included studies (N = 54): activities and risk-taking behaviours (n = 24); loss reduction, knowledge, and warnings (n = 37); and diet and hygiene (n = 4). This review …
Survey of Cyber Threats in Air Traffic Control and Aircraft Communications Systems
2018
Air traffic control systems based on the ADS-B standard have been widely adopted in civil aviation to the point that they are now considered the de facto standard. ADS-B provides major benefits to airports and airlines by increasing the safety of air traffic management and control and allowing more flights to travel near busy airports. However, the ADS-B technology lacks sufficient security measures. The ADS-B system is vulnerable and exposed to cyberattacks. We survey the potential known threats and attacks against ADS-B and assess the potential cybersecurity threats to air traffic management and control. The widespread use of ADS-B and the lack of security features in it, i.e., all the AD…
The impact on disaster governance of the intersection of environmental hazards, border conflict and disaster responses in Ladakh, India
2018
Abstract The Indian border region of Ladakh, in Jammu and Kashmir State, has a sensitive Himalayan ecosystem and has experienced natural hazards and disasters of varying scales over the decades. Ladakh is also situated on a fault-line of multiple tensions, including ongoing border disagreements and intermittent conflict with China and Pakistan. The Indian army has thus become a permanent fixture in the region. This paper examines the implications of the intersection of these environmental and security factors for disaster governance in the region. Using Social Domains theory, the paper argues first, that a hazard-centred paradigm of ‘universal’ disaster science emerges from the colonial per…
Sustainable growth and environmental catastrophes
2017
Abstract In the standard AK growth model we introduce the threat of an ecological catastrophe and study the consequences for the economic variables in the long-run. We extend the basic framework by considering two environmental externalities: the first one is local and gives account of the marginal damage from emissions flow; the second one is aggregate, or global, and relates to the extreme damage which may happen if the accumulated stock of pollutants is on the threshold of a worldwide catastrophe. In this context dominated by market failures, we focus on the socially optimal solution and the search of conditions for sustainability. We identify the efficient balanced growth path, which ma…
Self-validating bundles for flexible data access control
2016
Modern cloud-based services offer free or low-cost content sharing with significant advantages for the users but also new issues in privacy and security. To protect sensitive contents (i.e., copyrighted, top secret, and personal data) from the unauthorized access, sophisticated access management systems or/and decryption schemes have been proposed, generally based on trusted applications at client side. These applications work also as access controllers, verifying specific permissions and restrictions accessing user’s resources. We propose secure bundles (S-bundles), which encapsulate a behavioral model (provided as bytecode) to define versatile stand-alone access controllers and encoding/d…