Optimization Study of the Effect of Manufacturing Tolerances on the Kinematic and Dynamic Performances of a Planar Mechanism

In real-life mechanisms, the design parameters differ from their theoretical values. This difference is due to the manufacturing tolerances of link dimensions and revolute joints of mechanisms. In this article, the effect of link dimensions manufacturing tolerances and joints clearance on the kinematic and dynamic performances of a planar mechanism is studied. A slider-crank mechanism with two joint clearances is considered as a case study. Furthermore, an analytical method based on the partial derivatives is used to determine the mathematical equation representing the kinematic errors of the mechanism. This error depends on the manufacturing tolerances of link dimensions and revolute joints of the mechanisms. The Lagrangian equation is adopted to define the mathematical expression of the mechanism motion. Two objectives are considered regarding the acceleration error and the dynamic performance. In the optimization process, particle swarm optimization (PSO) algorithm is used to determine the joint clearance direction and optimize the mass distribution of links, to achieve better kinematic and dynamic performances of the planar mechanism. Simulation results illustrated that the joint clearance and manufacturing tolerances of link length caused a difference on the kinematic and dynamic aspects of the mechanism. Moreover, the used methodology was found to be helpful to achieve the minimum difference for an optimal mechanism.