The design principle of internal model control (IMC) focuses on developing a feedforward controller which also acts in the feedback loop to attenuate disturbances. This paper uses ideas developed in the theory of flat...
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The design principle of internal model control (IMC) focuses on developing a feedforward controller which also acts in the feedback loop to attenuate disturbances. This paper uses ideas developed in the theory of flat systems for the design of feedforward controllers and adapts them to IMC control. By extending this idea, a method for output feedback control of nonlinear flat systems is presented. It shows the interesting result that the classical design procedure for IMC controllers and the new flatness-based approach end up with identical results for linear systems
Metabolic or cell signalling pathways are examples of biochemical networks exhibiting possible complex dynamics in the form of steady-state multiplicity, sustained oscillations or even deterministic chaos. The origin ...
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Metabolic or cell signalling pathways are examples of biochemical networks exhibiting possible complex dynamics in the form of steady-state multiplicity, sustained oscillations or even deterministic chaos. The origin of these nonlinear phenomena is not always well understood, nor it can be systematically predicted beyond a case by case basis. Despite considerable progress in dynamic aspects, efforts are still needed to develop efficient and robust methods of stabilization and control of reaction networks. In this work, we combine concepts and tools from irreversible thermodynamics and systems theory to explore the underlying dynamic properties of a general class of chemical and biochemical networks. Lyapunov and passivity based methods are given for the systematic design of globally stabilizing feedback controllers in both the concentration space and a novel minimal description of the kinetic networks dynamics: the reaction space.
In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust controls are prop...
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In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust controls are proposed based on a simplified dynamic model, the defined reference signals and the mixed tracking errors. The proposed control strategies guarantee that the system motion converges to the desired manifold with prescribed performance. Constraint force control is developed, which does not utilize force feedback control but is based on the passivity of hybrid joint. Experiment results validate not only the states of the system asymptotically converge to the desired trajectory but also the constraint force asymptotically converges to the desired force
Smith predictor is very sensitive to uncertain system with variable time-delay. Using dual-locus diagram method, we first analyse the essence of Smith predictor's sensitivity and present a proposition to illustrat...
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Smith predictor is very sensitive to uncertain system with variable time-delay. Using dual-locus diagram method, we first analyse the essence of Smith predictor's sensitivity and present a proposition to illustrate the system stability criteria with relation to system gain and time-delay variation. Then a new modified Smith predictor is proposed to compensate the variable time-delay system with uncertain model for set-point tracking. After that, we discuss the system internal stability and give two-degree freedom controller self-adaptive to eliminate the impact of system uncertainty with varying time-delay. Examples show the improved performance compared to previous modified Smith predictor structures
Integrated virtual reality with intelligent tutoring system, a multi-agent architecture was proposed for intelligent virtual training system (IVTS) for mine safety training. In order to make sure IVTS agent's task...
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Integrated virtual reality with intelligent tutoring system, a multi-agent architecture was proposed for intelligent virtual training system (IVTS) for mine safety training. In order to make sure IVTS agent's task plans reliable and adaptive, a Petri nets-based declarative method was applied to model the virtual training task planning knowledge, which was represented as task planning knowledge Petri nets (TP-PNets), and an algorithm was implemented to construct TP-PNets. Then, hierarchy colored Petri nets (HCPN) was used to model multi-agent task planning behaviors for IVTS, and simulation and message sequence chart was used to analyze and verify the agent task planning HCPN model
On-orbital services of space robot are playing more and more important roles in the space operation. Nearly all space operation can not possibly avoid to contact the target. The contact and impact do not possibly avoi...
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On-orbital services of space robot are playing more and more important roles in the space operation. Nearly all space operation can not possibly avoid to contact the target. The contact and impact do not possibly avoid when the space robot captures the object. The impulse caused by impact is bad to the space robot and object. This paper derives the impact dynamic equations according to the dynamic model of space robot system and the object. We propose a genetic algorithm (GA) based on approach to search the optimal configuration of space robot at capturing moment in order to minimize or avoid the impact. An illustrative example has verified that the proposed method has satisfactory performance and real significance for reducing the impact.
A typical servicing operation in space mainly includes three phases: capturing the target, berthing and docking the target, and repairing the target. The attitude of a satellite usually changes after the capturing, be...
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A typical servicing operation in space mainly includes three phases: capturing the target, berthing and docking the target, and repairing the target. The attitude of a satellite usually changes after the capturing, because the control system is turned off during this phase for safety reasons. In this paper, a method is proposed to achieve the berthing of the target and reorientating the satellite attitude at the same time, both by involving manipulator motion only. Firstly, the constraints on the manipulator and the objective function are defined according to the planning problem. Then the joint trajectory is parameterized by sinusoidal function, whose argument is the polynomial. Finally, genetic algorithm is used to search for the global optimal resolution of the parameters. When the parameters are found, each joint trajectory can be determined. This planned trajectory is smooth and more applicable for the control of the free-floating robotic system. Our proposed method is verified by simulation
The random surface error, tracking error, position error and shadow of receiver of parabolic dish concentrators are analysed by using the ray tracing and the Monte-Carlo method. Several examples are given. The analysi...
A generic two degree of freedom controller introduced for linear plants is extended for nonlinear processes. The nonlinear controller consists of two parts: the first depending on the design parameters and the invaria...
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A generic two degree of freedom controller introduced for linear plants is extended for nonlinear processes. The nonlinear controller consists of two parts: the first depending on the design parameters and the invariant part of the process, the second only on the model of the plant. A simple iterative controller refinement scheme is constructed. The efficiency of this scheme is presented by simulation examples.
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