The minimum phase property is an important notion in systems and control theory: In this paper, a characterization of the minimum phase property of nonlinear control systems in terms of a dissipation inequality is der...
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ISBN:
(纸本)9783540707004
The minimum phase property is an important notion in systems and control theory: In this paper, a characterization of the minimum phase property of nonlinear control systems in terms of a dissipation inequality is derived. It is shown that this dissipation inequality is equivalent to the classical definition of the minimum phase property in the sense of Byrnes and Isidori, if the control system is affine in the input and the so-called input-output normal form exists.
This chapter presents an overview on the modeling and model-based control of autonomous helicopters. Firstly it introduces some of the platforms and control architectures that has been developed in the last 15 years. ...
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ISBN:
(纸本)9783540707004
This chapter presents an overview on the modeling and model-based control of autonomous helicopters. Firstly it introduces some of the platforms and control architectures that has been developed in the last 15 years. Later, the Chapter considers the modeling of the helicopter and the identification techniques. Then, it overviews different linear and non-linear model-based control approaches. This section also includes experiments on the control of the helicopter vertical motion that illustrate the presented techniques and point out the interest of nonlinear analysis methods to study the dynamic behavior of the helicopter. Finally, the Chapter presents open research lines coming from two challenging applications: the autonomous landing in oscillating platforms and the lifting and transporting of a single load with several helicopters.
We investigate the benefits of employing a suitable risk-based metric to determine in real-time the high level actions that an agile sensor should execute during a mission. Faced with a barrage of competing goals, a s...
ISBN:
(纸本)9783540743545
We investigate the benefits of employing a suitable risk-based metric to determine in real-time the high level actions that an agile sensor should execute during a mission. Faced with a barrage of competing goals, a sensor resource manager must optimize system performance while simultaneously meeting all requirements. Numerous authors advocate the use of information-theoretic measures for driving sensor tasking algorithms, wherein the relative value of different sensing actions is calculated in terms of the expected gain in information. In this chapter, motivated by the sensor resource allocation problem in missile defense, we deviate from the information-based trend and propose an approach for determining sensor tasking decisions based on risk, or expected loss of defended assets. We present results of a missile defense simulation that illustrate the advantages of our risk-based objective function over its information-theoretic and rule-based counterparts.
This chapter discusses problems dealing with cooperative control of multiple agents moving in a region. An appropriate search strategy for the whole system can be embodied: hierarchical, coordinated, or cooperative. G...
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ISBN:
(纸本)9783540743545
This chapter discusses problems dealing with cooperative control of multiple agents moving in a region. An appropriate search strategy for the whole system can be embodied: hierarchical, coordinated, or cooperative. Geometrical and computational aspects of many-target search problems axe considered. Nonlinear and bilinear processes of search for moving objects are proposed. Search problems of ecological danger objects and detection of biological and chemical agents using multi-spectral information are also considered. Multiagent coordination problems are studied in detail. This problem is addressed for a class of targets for which control Lyapunov functions can be derived. We describe such a multiagent system by a hierarchical structure, which can be simplified using a fiber bundle. Then, using geometrical techniques, we study controllability, observability, and optimality problems. In addition, we also consider a cooperative problem when the agents motions must satisfy a separation constraint throughout the encounter to be conflict-free. A classification of maneuvers based on different commutative diagrams is introduced using their fiber bundle representation. In the case of two agents, these optimality conditions allow us to construct optimal maneuvers geometrically.
We model the immune dynamics between T cells and cancer cells in leukemia patients after a bone-marrow (or a stem-cell) transplant. We use a system of nine delay differential equations that incorporate time delays and...
ISBN:
(纸本)9783540719878
We model the immune dynamics between T cells and cancer cells in leukemia patients after a bone-marrow (or a stem-cell) transplant. We use a system of nine delay differential equations that incorporate time delays and account for the progression of cells through different stages. This model is an extension of our earlier model [3]. We conduct a sensitivity analysis of the model parameters with respect to the minimum cancer concentration attained during the first remission and the time until the first relapse. In addition, we examine the effects of varying the initial host cell concentration and the cancer cell concentration on the likelihood of a successful transplant. We observe that higher initial concentrations of general host blood cells increase the chance of success. Such higher initial concentrations can be obtained, e.g., by reducing the amount of chemotherapy that is administered prior to the transplant, a procedure known as a mini-transplant. Our results suggest that mini-transplants may be advantageous over full transplants. We identify the regions of the parameters for which mini-transplants are advantageous using statistical tools.
We consider a combinatorial motion planning problem (CMP) that naturally arises in many applications involving unmanned aerial vehicles (UAVs) with fuel and motion constraints. The motion constraint we consider is the...
ISBN:
(纸本)9783540743545
We consider a combinatorial motion planning problem (CMP) that naturally arises in many applications involving unmanned aerial vehicles (UAVs) with fuel and motion constraints. The motion constraint we consider is the inability of a vehicle to turn at an arbitrary yaw rate. The CMP is a generalization of a single Travelling Salesman Problem and is NP-Hard. In this paper, we exploit the combinatorial structure of the problem and provide heuristics with computational results to address the same.
We present an overview of our results on stabilizing scheduled output feedback Model Predictive control (MPC) algorithm for constrained nonlinear systems based on our previous publications [19, 20]. Scheduled MPC prov...
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ISBN:
(纸本)9783540726982
We present an overview of our results on stabilizing scheduled output feedback Model Predictive control (MPC) algorithm for constrained nonlinear systems based on our previous publications [19, 20]. Scheduled MPC provides an important alternative to conventional nonlinear MPC formulations and this paper addresses the issues involved in its implementation and analysis, within the context of the NMPC05 workshop. The basic formulation involves the design of a set of local output feedback predictive controllers with their estimated regions of stability covering the desired operating region, and implement them as a single scheduled output feedback MPC which on-line switches between the set of local controllers and achieves nonlinear transitions with guaranteed stability. This algorithm provides a general framework for scheduled output feedback MPC design.
The importance of the obstacle avoidance problem is stressed in [4]. Computation of reachability sets for the obstacle avoidance problem is addressed, for continuous-time systems in [4, 5] and for discrete-time system...
The objective of the TARGET VISITATION PROBLEM is to determine a path for an unmanned aerial vehicle that begins at a point of origin and needs to visit several targets before returning to its starting point. An optim...
ISBN:
(纸本)9783540743545
The objective of the TARGET VISITATION PROBLEM is to determine a path for an unmanned aerial vehicle that begins at a point of origin and needs to visit several targets before returning to its starting point. An optimal visitation sequence is one which minimizes the total distance traveled and maximizes the utility of the visitation order. This utility measure is defined for each pair of targets and represents the relative value of visiting a particular target before another. In this chapter, we present the results of a preliminary study investigating the effectiveness of a genetic algorithm for the TARGET VISITATION PROBLEM. The encoding scheme is based on random keys. Numerical results are presented for a set of randomly generated test problems and compared with the optimal solutions as computed by a commercial integer programming package.
In the literature, e.g. [10], one can find the so-called basic UAV mission target assignment in which m UAVs each with a capacity limit q visit n targets in a cooperative manner (and return to their departure points) ...
ISBN:
(纸本)9783540743545
In the literature, e.g. [10], one can find the so-called basic UAV mission target assignment in which m UAVs each with a capacity limit q visit n targets in a cooperative manner (and return to their departure points) such that the cost incurred by each UAV's travel is minimized. In [10], we proposed a mixed integer linear program (MILP) formulation which exactly solves the problem, as well as four alternative MILP formulations which are computationally less intensive (and therefore suited for real-time purposes) yet yield a theoretically guaranteed sub-optimal solution. In this chapter, we further consider timing constraints imposed on some p of the targets, so-called prime targets. This consideration is often required for scenarios in which prime targets must be visited in a pre-defined time interval, and mathematically results in the addition of several integer linear constraints to the previous MILP formulation making the problem computationally intractable. We propose a novel procedure of adding these cumbersome timing constraints to the previous MILP formulation, in order to avoid increasing too much computational cost under practically valid assumptions. We first show that the proposed procedure still guarantees the previously claimed theoretical solution quality associated with the basic mission. We then show through extensive numerical simulations that under certain conditions, our algorithms return solutions which are still computationally manageable.
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