Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 5 Articles
We present an improved method for determining the search direction in the BFGS algorithm. Our approach uses the equal inner\nproduct decomposition method for positive-definite matrices. The decomposition of an approximated Hessian matrix expresses a\ncorrection formula that is independent fromthe exact line search. This decomposed matrix is used to compute the search direction\nin a new BFGS algorithm....
Using the uncertain conversion capacity between the expressions of quantitative and qualitative concept in the cloud model, an\nenergy management strategy based on cloud model is developed for parallel hybrid vehicles (PHVs). By the driver input and the\nstate of charge (SOC) of the energy storage, a set of rules are developed to effectively determine the torque split between the internal\ncombustion engine (ICE) and the electric motor. An analysis of the simulation results is conducted using ADVISOR in order to\nverify the effectiveness of the proposed control strategy. It is confirmed that the control scheme can be used to improve fuel economy\nand emission of the hybrid vehicles....
A nonlinear integral sliding-mode control (NISMC) scheme is proposed for second order nonlinear systems. The new control\nscheme is characterized by a nonlinear integral sliding manifold which inherits the desired properties of the integral sliding\nmanifold, such as robustness to system external disturbance. In particular, compared with four kinds of slidingmode control (SMC),\nthe proposed control scheme is able to provide better transient performances. Furthermore, the proposed scheme ensures the zero\nsteady-state error in the presence of a constant disturbance or an asymptotically constant disturbance is proved by Lyapunov stability\ntheory and LaSalle invariance principle. Finally, both the theoretical analysis and simulation examples demonstrate the validity of\nthe proposed scheme...
This paper explicates a new method of designing a preview controller for a class of continuous-time systems. The augmented error\nsystem is constructed by the error system with the derivative of the tracking error signal, the state equation, and an identical equation\nof the derivative of the control input, which transforms a tracking problem into a regulation problem. Therefore, in the paper, the\nperformance index contains the derivative of the control input. Based on the theory of optimal control, the regulator problem of the\naugmented error system is solved.Thus, the controller with preview compensation for the original system is deduced.The response\nspeed of the closed-loop system is accelerated by the previewed demand output. A final numerical example is given to illustrate the\nvalidity of the proposed method....
To deal with the problemof obstacle avoidance for redundant robots, an obstacle avoidance algorithmbased on the internalmotion\nof the 7-DOF redundant anthropomorphic armis presented.Themotion of that critical pointsmove away from the closest points on\nthe obstacles is defined as obstacle avoidingmotion. Two transitioning variables were used to make a smooth, continuous transition\nbetween the primary and the secondary tasks. Using this approach, the robot can get the target configuration while avoiding the\nobstacles. Finally, the validity of the obstacle avoidance algorithm based on transitioning between tasks is manifested by simulation.\nThe results show that, for the obstacle avoiding problem, the redundant robot not only can realize the obstacle avoidance, but also\nprevents the conflict between tasks by the proposed approach....
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