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Stability problems associated with robot control with obstacle avoidance are analyzed.Obstacle avoidance algorithms based on potential function are revised to accomplish stable re-design. A stability proof using Lyapunov theory and passivity theory is provided for the re-designed obstacle avoidance algorithm. The paper presents a modification of potential functions for obstacle avoidance aiming to
Control of robotic systems subject to friction phenomena is an important issue since growing demands on accuracy require elimination of friction disturbances. If several modelse.g., friction model, rigid-body dynamicsare required to describe the behavior with high precision, each model requires the knowledge of numerous parameters (perhaps time-varying) as well as an increased number of signals an
To facilitate model-based control of combustion timing and work output in Homogeneous Charge Compression Ignition (HCCI) engines, a cycle-resolved model of HCCI incorporating cylinder wall temperature dynamics is presented. Heat transfer between the in-cylinder charge and the cylinder walls is important for explaining HCCI cycle-to-cycle behaviour but is rarely included in control-oriented models.
Due to the possibility of increased efficiency and reduced emissions, Homogeneous Charge Compression Ignition (HCCI) is a promising alternative to conventional internal combustion engines. Ignition timing in HCCI is highly sensitive to operating conditions and lacks direct actuation, making it a challenging subject for closed-loop control. This paper presents results on model-based control of igni
The paper suggests conditions for presence of quadratic Lyapunov functions for nonlinear observer based feedback systems with an input nonlinearity in the feedback path. Provided that the system using state feedback satisfies the circle criterion (i.e., when all states can be measured), we show that stability of the extended system with output feedback control from a (full state) Luenberger-type o
We study the extension of the class of linear time-invariant open-loop systems that may be transformed into SPR systems introducing a reduced-order observer. It is shown that for open-loop stable systems a cascaded observer achieves the result. For open-loop unstable systems observer-based feedback is required to succeed. In general, any stabilizable and observable system may be transformed into a
This paper addresses the problem of velocity reconstruction of robotic systems with rigid-body dynamics subject to friction. The aim of this paper is to estimate the velocities in the joint of a robot as well as the friction interacting with these velocities. Confronted with friction phenomena interacting with velocity dynamics, we have developed a non-linear observer, partly model-based for estim
In light of the changing circumstances for teaching, teachers’ views on organizational communication processes were explored. Empirically, this paper is based on five semi-structured focus groups, each interviewed on two occasions. In total, 44 primary and lower secondary-school teachers working in one municipality in Sweden participated. The interviews were framed by a pre-survey concerning demog
The Xiamaling Formation in the North China Block contains a well-preserved 1400 Ma sedimentary sequence with a low degree of thermal maturity. Previous studies have confirmed the dynamic and complex nature of this evolving marine setting, including the existence of an oxygen-minimum zone, using multi-proxy approaches, including iron speciation, trace metal dynamics, and organic geochemistry. Here,
The paper suggests conditions for presence of quadratic Lyapunov functions for nonlinear observer based feedback systems with an 'input nonlinearity' in the feedback path. Provided that the system using state feedback satisfies the Circle Criterion (i.e., when all states can be measured), we show that the extended system with only output feedback control from a (full state) Luenberger-type observe
We consider a tracking problem for mechanical systems. It is assumed that feedback controller is designed neglecting some disturbances, which could be approximately modeled by a dynamic LuGre friction model. We are interested to derive an additive observer-based compensator to annihilate or reduce the influence of such a disturbance. We exploit a recently suggested approach for observer design for
In this work, we present implementation and experiment of the theory of dynamic force sensing for robotic manipulators. Since the inertial forces are undesirable forces to be measured in the robot manipulation, it is processed, using sensor fusion techniques, the force sensor signal in order to extract the contact force exerted by the robot. We propose a complete formulation and implementation of
The theory for motion planning and feedback stabilization of periodic orbits has regained a large interest during the last couple of years, with applications in, for instance, biped locomotion. The analysis of zero-dynamics after partial feedback linearization has been one means. More recently, the introduction of virtual holonomic constraints has offered also the design tools for these type of sy
Within the world of professional wrestling, the blurred boundaries of the live event and physical nature of the sport intersect with the dramatized storytelling of this entertainment experience. As such, this chapter considers how audiences and fans interact with professional performers to co-produce the cultural practices of professional wrestling. The author uses ethnographic research at live pr
This paper presents a new control strategy for an underactuated two-link robot, called the Pendubot. The goal is to create stable oscillations of the outer link of the pendubot, which is not directly actuated. We exploit a recently proposed feedback control design strategy, based on motion planning via virtual holonomic constraints. This strategy is shown to be useful for design of regulators for
Under hösten 2017 och våren 2018 genomförde innovationsenheten PART – Preventivt arbete tillsammans– och Institutionen för service management och tjänstevetenskap vid Lunds universitet ett utvecklingsarbete,med syftet att ta fram en modell för att öka kunskapen om resursanvändning i barnavårdsutredningar. Måletmed den framtagna modellen är att göra det möjligt att kartlägga arbetsuppgifter och tid
Har den egyptiska revolutionen nått sin slutstation eller kommer de närmaste dagarna att erbjuda överraskande nya vägar framåt?
