Multi-objective Optimization of Mechanisms with Clearances in Revolute Joints

Abstract

Despite extensive work on the evaluation of the dynamic performances of various mechanisms and multi-body mechanical systems with revolute joint clearances, limited work has been conducted in optimizing the performances of these systems. A multi-objective optimization technique is presented to examine and to quantify the effect of combined objective functions with several design variables on the response of the systems. In particular, a Kriging meta-model based on the Design-of-Experiment method is utilized to optimize the systems' performance. The reason for implementing this meta-model is to replace the computational intensive simulations with a more efficient mathematical model. In this study, a simple slider-crank mechanism with a revolute clearance joint at the slider pin is modeled, and its dynamic response is analyzed using the multi-body dynamic software, MSC ADAMS. The revolute joint clearance is modeled as a pin-in-hole dry contact utilizing the Hertzian contact force model with hysteresis damping. Response surfaces are generated on the prediction of the system's performances for three different objective functions and for different range of design variables. The objective functions are combined to develop a single response surface characterizing the dynamic responses of the system at different range of design variables in order to optimize its performance.

Optimization research on hinge points of the grader’s working device based on ADAMS

“…Establish optimization variables for all hinge points involved in the working device of the grader and correlate the relationships among variables [6][7] ,to ensure that there is only one optimization variable for the same parameter and make sure that the constraint pair can move with it.…”

Dynamics of a four-bar mechanism with clearance and springs - Modeling and experimental analysis

“…To reduce the effect of the clearance on the dynamic behavior of the mechanism, several authors used optimization techniques to find the best parameters of the mechanism. The authors of [19] used the clearance in the joint and the stiffness of the material as design variables to improve the dynamic response of a crank slider mechanism. The authors of [21], [22], [23], and [25] proposed modifying…”

“…To reduce the effect of the clearance, several authors formulated the problem as an optimization problem ( [14], [16], [19], [20], [21], [22], [23], [24], [25], [26]). Singleobjective and multi-objective optimization problems were addressed.…”

“…Feng et al [24] and Varedi et al [20] minimized the impact forces by redistributing the mass of the different links. In [19], Zhang et al considered four objective functions to be optimized simultaneously, i.e., the slider's acceleration, the contact force at the revolute joint clearance, the required input torque, and the power consumption of the system. The design variables to be found are the size of the clearance and the stiffness of the contact.…”

Vibration performance evaluation of planar flexible multibody systems with joint clearance

“…They showed that the joint clearances have considerable effects on the displacement and velocity of the moving platform, and have great influence on the acceleration and driving moments. Zhang et al [29] presented a multiobjective optimization problem in which the effect of the clearance on the slider acceleration, contact force and power consumption was investigated. For more information on the optimization of the mechanical systems with clearance, the reader is referred to [4][5][6]30].…”