Optimal synthesis of a four-bar linkage by method of controlled deviation

This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves’s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line.

OPTIMIZATION OF THE BOX SECTION OF THE MAIN GIRDER OF THE DOUBLE BEAM BRIDGE CRANE ACCORDING TO THE CRITERIA OF LATERAL STABILITY AND LOCAL STABILITY OF PLATES

Abstract The paper considers the problem of optimization of the box section of the main girder of the double beam bridge crane for the case of placing the rail above the web plate. Reduction of the girder mass is set as the objective function. Research on the mutual dependence of geometric parameters of cross section, and their ratio, using the method of Lagrange multiplier as characteristic criteria is done. Also, the paper shows an algorithm for selection of the optimal criteria and determining the optimal geometric parameters of cross section. The criteria of lateral stability and local stability of plates were applied as the contraint functions. The obtained results of optimization of geometrical parameters were verified on numerical examples

Improved Cuckoo Search (ICS) algorthm for constrained optimization problems

Constrained optimization is very important issue in engineering design. The problem of constrained optimization contains the objective function with linear and nonlinear constraint equations. In this paper the Improved Cuckoo Search (ICS) algorithm has been applied for solving problems of constrained engineering optimization, which gives better solutions than the standard CS algorithm and the other optimization algorithms used in solving engineering problems from the literature. In the proposed ICS algorithm, dynamic change of parameters of probability and step size is introduced, which are constant in the standard algorithm