The time-optimal control problem of a three-wheeled omni-directional mobile robot is addressed in this paper. Different from usual cases, in which the Pontryagin's Minimum Principle (PMP) is used, an iterative pro...
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ISBN:
(纸本)9780780395138
The time-optimal control problem of a three-wheeled omni-directional mobile robot is addressed in this paper. Different from usual cases, in which the Pontryagin's Minimum Principle (PMP) is used, an iterative procedure is proposed to transform the time-optimal problem into a nonlinear programming (NLP) one. In the NLP problem, the count of control steps is fixed initially and the sampling period is treated as a variable in the optimization process. The optimization object is to minimize the sampling period such that it is below a specific minimum value, which is set in advance, considering the accuracy of discretization. To generate initial feasible solutions of the formulated NLP problem, genetic algorithms (GAs) are adopted. Since different initial feasible solutions can be generated, the optimization process can be started from different points to find the optimal solution. In this manner, one can find a time-optimal movement of the omni-directional mobile robot between two configurations. To show the feasibility of the proposed method, simulation results are included for illustration.
In this paper, a hybrid optimization technique, in which immune genetic algorithm is combined with interior point method, is proposed for solving the dynamic reactive power optimization problem. The switching time lim...
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ISBN:
(纸本)9781424401109
In this paper, a hybrid optimization technique, in which immune genetic algorithm is combined with interior point method, is proposed for solving the dynamic reactive power optimization problem. The switching time limits of shunt capacitors and transformer tap ratios, which make the problem to be dynamic, are only related with discrete variables. In the proposed hybrid method, the immune genetic algorithm deals with the discrete variables, such as the adjustment schedules of shunt capacitors or transformer tap ratios;interior point method deals with the continuous variables, such as the voltage/reactive profiles of generators. An improved encoding scheme of the immune genetic algorithm is also introduced so that the time-related dynamic constraints of discrete variables can be satisfied automatically. The proposed method has been applied to IEEE 14 bus system over a 24-hour period to demonstrate its effectiveness.
Typically, control system design leads to a higher-order nonlinear function of the system's state variables. As a result, it is very hard to find a satisfactory mathematical solution. On the other hand, considerin...
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ISBN:
(纸本)3540465421
Typically, control system design leads to a higher-order nonlinear function of the system's state variables. As a result, it is very hard to find a satisfactory mathematical solution. On the other hand, considering a microcontroller based implementation, another difficulty is to program it to carry out the desired control algorithm. This paper presents the application of linear genetic programming in the automatic synthesis of a microcontroller assembly program, which performs an optimized control of a water bath plant. The synthesis starts from the plant's mathematical modeling and supplies directly a assembly code for the microcontroller platform. When comparing the control performance of the synthesized program with that of a neuro-fuzzy based controller, the synthesized program proved to perform slightingly better.
This paper presents design optimization of a class of special purpose transformers used in direct-arc melting furnace, adopting Genetic Algorithm (GA). The operation and performance characteristics of a furnace transf...
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ISBN:
(纸本)9781424402731
This paper presents design optimization of a class of special purpose transformers used in direct-arc melting furnace, adopting Genetic Algorithm (GA). The operation and performance characteristics of a furnace transformer connected to a large direct arc furnace formed the basis for realizing the rating of the transformer. The nonlinear mathematical model of the transformer is based on the core geometry available from manufacturer's published data. In order to verify the effectiveness of GA method, an example is considered. The results show the potential for implementation of GA as an efficient search technique for design optimization of transformers. A discussion on the variation of GA parameters while minimizing the single and multi-objective functions satisfying the performance constraints concludes the paper.
We consider the problem of optimal cooperative three-dimensional conflict resolution involving multiple Unmanned Air Vehicles (UAVs) using numerical trajectory optimization methods. The conflict problem is posed as an...
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ISBN:
(纸本)1424402093
We consider the problem of optimal cooperative three-dimensional conflict resolution involving multiple Unmanned Air Vehicles (UAVs) using numerical trajectory optimization methods. The conflict problem is posed as an optimal control problem of finding trajectories that minimize a certain objective function while maintaining the safe separation between each UAV pair. We assume the origin and destination of the UAV are known and consider UAV models with simplified linear kinematics. The main objective of this report is to present two different approaches to the solution of the problem. In the first approach, the optimal control is converted to a finite dimensional nonlinear Program (NLP) by using collocation on finite elements and by reformulating the disjunctions involved in modeling the protected zones by using continuous variables. In the second approach the optimal control is converted to a finite dimensional Mixed Integer Linear Program (MILP) using Euler discretization and reformulating the disjunctions involved with the protected zones by using binary variables and Big-M techniques. Based on results of extensive random simulations, we compare time complexity and optimality of the solutions obtained with the MILP approach and the NLP approach. NLPs are essential to enforce flyability constraints on more detailed UAV models. Moreover, any nonlinear extensions to the problem cannot be dealt with by MILP solvers. The main objective of this paper is to open the route to the use of MILP solutions (based on simple linear UAV models) in order to initialize NLP solvers which allow the use of dynamic UAV models at any desired level of detail.
Based on the classical limit theorems of upper and lower bounds, the numerical procedures developed at Newcastle utilise finite elements and non-linear programming and has proven to be both effective and efficient in ...
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ISBN:
(纸本)0415408229
Based on the classical limit theorems of upper and lower bounds, the numerical procedures developed at Newcastle utilise finite elements and non-linear programming and has proven to be both effective and efficient in solving many geotechnical stability problems. The bounding techniques have yet to be applied to the seismic stability of geotechnical structures. In this paper, both seismic bearing capacity of footings located near slopes and seismic earth pressures on retaining walls will be examined.
We propose a solution method for a water-network optimization problem using a nonconvex continuous NLP relaxation and an MINLP search. We report successful computational experience using available MINLP software on pr...
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ISBN:
(纸本)3540388753
We propose a solution method for a water-network optimization problem using a nonconvex continuous NLP relaxation and an MINLP search. We report successful computational experience using available MINLP software on problems from the literature and on difficult real-world instances.
Flexible A.C. transmission systems (FACTS) are being used more in large power systems for their significance in manipulating line power flows. Traditional state estimation methods without integrating FACTS devices wil...
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ISBN:
(纸本)9780780395251
Flexible A.C. transmission systems (FACTS) are being used more in large power systems for their significance in manipulating line power flows. Traditional state estimation methods without integrating FACTS devices will not be suitable for power systems embedded with FACTS. In this paper the state estimation of power systems in presence of FACTS devices is presented. Hopfield neural network is simulated as an optimization tool to solve the power system state estimation problem.
The problem of choosing an optimal signal set for non-Gaussian detection was reduced to a smooth inequality-constrained mini-max nonlinear programming problem by Gockenbach and Kearsley. Here, we consider the applicat...
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The problem of choosing an optimal signal set for non-Gaussian detection was reduced to a smooth inequality-constrained mini-max nonlinear programming problem by Gockenbach and Kearsley. Here, we consider the application of several optimization algorithms, both global and local, to this problem. The most promising results are obtained when special-purpose sequential quadratic programming algorithms are embedded into stochastic global algorithms.
Most facilities employ a variety of devices such as multiple switch mode power supplies, motors, fans, and other nonlinear loads. One of the adverse effects of multiple nonlinear loads is harmonic distortion. Harmonic...
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ISBN:
(纸本)9781424404926
Most facilities employ a variety of devices such as multiple switch mode power supplies, motors, fans, and other nonlinear loads. One of the adverse effects of multiple nonlinear loads is harmonic distortion. Harmonic currents in particular are receiving more attention as a critical power quality concern. In this paper, reactance one-port compensator is designed for current harmonic mitigation. The problem is formulated as a nonlinear programming (NLP) problem and the optimal parameters of the filter are determined using Particle Swarm Optimization.
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