the development of a fully automated robotic endoscopic steering system has been an active area of research for more than a decade. this paper aims at proposing a hardware-efficient iterative thresholding strategy to ...
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ISBN:
(纸本)9781509035496
the development of a fully automated robotic endoscopic steering system has been an active area of research for more than a decade. this paper aims at proposing a hardware-efficient iterative thresholding strategy to locate the lumen region in captured endoscopic images in order to enhance traditional endoscopes with certain degree of autonomy and intelligence. the proposed method is characterized by a definite requirement on the number of iterations of thresholding in order to detect the lumen region. the proposed algorithm has been demonstrated to be robust against varying characteristics using real endoscopic sample images. the reduction in the number of operations required by the proposed method can be up to 71% compared to a previously reported method. FPGA synthesis results of the proposed approach confirm its viability for real-time realization.
In this paper, leader-following consensus of the discrete-time heterogenous multi-agent system with bounded communication delays is studied. the heterogeneous multi-agent system is composed of first-order and second-o...
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ISBN:
(纸本)9781509035496
In this paper, leader-following consensus of the discrete-time heterogenous multi-agent system with bounded communication delays is studied. the heterogeneous multi-agent system is composed of first-order and second-order integrator agents. By applying the graph theory and the algebra theory, sufficient consensus criteria are obtained to guarantee that each agent can track the leader. Despite there exist bounded time delays among agents, consensus can also be realised under fixed and switching topologies. Event-triggered control laws are designed to reduce the frequency of individual actuation updating. Numerical examples are provided to demonstrate the effectiveness of the theoretical results.
the SAGITTA Demonstrator is a novel UAV with a digital flight control system being developed by the Institute of Flight System Dynamics of the Technical University of Munich. this paper presents the implementation of ...
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ISBN:
(纸本)9781509035496
the SAGITTA Demonstrator is a novel UAV with a digital flight control system being developed by the Institute of Flight System Dynamics of the Technical University of Munich. this paper presents the implementation of an automatic take-off algorithm as a system automation module of the auto flight system. Based on a phase-breakdown of take-off, the implementation features a state machine that covers the procedure of the maneuver and the transition conditions from one phase to another. through this state machine, the automatic take-off algorithm enables controller modules of the auto flight system and provides corresponding commands for the conduct of take-off. the design of the automatic take-off algorithm focuses on maximizing safety and robustness against uncertainties and disturbances. Presented simulation results prove the concept of the algorithm as well as its robustness to simulated reality effects.
Robust model predictive control of discrete non-linear systems with bounded time-varying delay and persistent disturbances is investigated in this paper. the T-S fuzzy systems are utilized to represent nonlinear syste...
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ISBN:
(纸本)9781509035496
Robust model predictive control of discrete non-linear systems with bounded time-varying delay and persistent disturbances is investigated in this paper. the T-S fuzzy systems are utilized to represent nonlinear systems. A Razumikhin-type Lyapunov function is adopted for time-delay systems due to its advantage in reducing the complexity especially for systems with large delays and disturbances. the robust positive invariance set theory for systems subjected to time-varying delay and disturbances is analyzed. In addition, the input-to-state stability is realized due to persistent disturbances. the controller synthesis conditions are derived by solving a sequence of matrix inequalities. Simulation on a continuous stirred-tank reactor (CSTR) is illustrated to verify the effectiveness of the proposed method.
A key problem in event-triggered control of multi-agent systems is to design triggering conditions. We first give an overview of existing triggering conditions used in the literature. However, not all existing trigger...
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ISBN:
(纸本)9781509035496
A key problem in event-triggered control of multi-agent systems is to design triggering conditions. We first give an overview of existing triggering conditions used in the literature. However, not all existing triggering conditions can both relax continuous communication between neighboring agents and admit a positive lower bound of inter-event times. then, we propose two new triggering conditions based on edge information rather than neighbor information, and show that Zeno behavior is ruled out by using a time-dependent threshold and a periodic event detector, respectively. Moreover, we list some open problems which are worththe effort to launch future investigations.
this paper presents a novel multicomputer type with a unique structure. this structure allows decoupling angular motion from translational motion along one of the body axes, and by that, five of the body degrees of fr...
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ISBN:
(纸本)9781509035496
this paper presents a novel multicomputer type with a unique structure. this structure allows decoupling angular motion from translational motion along one of the body axes, and by that, five of the body degrees of freedom (DoF) can be controlled independently. the proposed aerial vehicle is a hexacopter with six propellers, such that four propellers are attached to the vehicle body and the other two attached to a seesaw. the seesaw is free to rotate around a single axis that is fixed in the body frame. Compared to a standard hexacopter, this unique design improves the maneuverability of the aerial vehicle, without the price of additional actuators. As opposed to tilting-rotor aerial-vehicle, in the proposed design all actuators generate lift. the paper describes the dynamical model of the novel vehicle and suggests a nonlinear controller to track desired trajectories along five of its DoF. the performances of the design are demonstrated numerically.
this paper proposes a place cell model allowing place recognition in the context of robot autonomous navigation. the robustness of this approach lies in the fact that even if one or several patterns characterizing the...
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ISBN:
(纸本)9781509035496
this paper proposes a place cell model allowing place recognition in the context of robot autonomous navigation. the robustness of this approach lies in the fact that even if one or several patterns characterizing the place are removed or not visible anymore, a place can still be recognized. the recognition process in this work is improved with respect to the state-of-the-art place cells approach. Additionally, the interconnection of the modules is made such that the robot is able to learn new places as it navigates and interacts withthe environment to get to its final destination. Experimental results validate the advantage of the incremental learning allowing the robot to cope with any unforeseen changes and thus adapting itself to the environment.
the linear time invariant (LTI) observer-based discrete-time sliding-mode control problem is considered for a robust tracking of higher-order dynamic delay-time systems. Here, Luenberger observer is used for estimatio...
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ISBN:
(纸本)9781509035496
the linear time invariant (LTI) observer-based discrete-time sliding-mode control problem is considered for a robust tracking of higher-order dynamic delay-time systems. Here, Luenberger observer is used for estimation of system states as all states are not available for measurement. Sliding surface is selected based on output feedback and observer states to realize the sliding-mode control. Observer and controller parameters are tabulated by pole placement strategy. the performance of proposed control is improved with dual tuning parameter in terms of settling time and control effort. Finally, non-oscillatory, oscillatory, integrating, and non-minimum phase systems with delay-time examples are implemented with numerical simulations to demonstrate the validity of the proposed control method.
In this study, a variable viscoelastic joint system with a clutch for a human assistance was proposed. the variable viscoelastic joint system comprised antagonized artificial muscles and magneto-rheological fluid brak...
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ISBN:
(纸本)9781509035496
In this study, a variable viscoelastic joint system with a clutch for a human assistance was proposed. the variable viscoelastic joint system comprised antagonized artificial muscles and magneto-rheological fluid brake (MR-brake). this system enabled the human assisting device such as exoskeletons to retain structural softness when compared withthe existing devices driven by motor and reduction gear, which could only achieve superficial softness. In addition, a clutch system that provided high back-drivability to the wearer by structurally separating the device from the wearer was proposed. As an initial step in designing the human assisting device, a prototype withthe proposed variable viscoelastic joint system for knee assistance is developed. Also, its control method were developed. Furthermore, experiments were conducted to confirm the influence of the proposed viscoelastic joint system on the wearer and the effectiveness of the clutch system.
this paper studies state-based optimal supervisors for non-terminating discrete event systems (DESs) modeled by weighted automata. An optimal supervisor controls the DES to avoid system halts and maximizes the worst-c...
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ISBN:
(纸本)9781509035496
this paper studies state-based optimal supervisors for non-terminating discrete event systems (DESs) modeled by weighted automata. An optimal supervisor controls the DES to avoid system halts and maximizes the worst-case limit-average weight of the generated infinite sequences. A state-based supervisor controls the DES depending only on its current state, and required only polynomial space of memory in the number of states and events of the DES. An s-minimally restrictive optimal (s-optimal) supervisor is a state-based optimal supervisor whose enabled set of sequences is as large as possible. We propose an algorithm to compute an s-optimal supervisor if it exists. Moreover, we consider the control costs for enabling controllable events. We derive conditions for assigning the control costs in such a way that the optimal supervisor for the DES withthe control costs is also optimal for the DES without the control costs.
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