Kinematic and Dynamic Design of Four-Bar Linkages With Variable Input Speed and External Applied Loads

Abstract

A novel approach that integrates the kinematic synthesis, dynamic design and servo control in one design stage is presented for designing four-bar linkages with external applied loads. This approach satisfies kinematic design requirements and constraints and also attains trade-off of dynamic balance. By properly designing the speed trajectory of the input link, the balancing parameters of moving links and link dimensions of the given or desired mechanisms, the expected output motion characteristics and dynamic balancing performance are obtained. And, the input motion characteristics are designed with Bezier curves. Optimization is aided to find out optimal design parameters for achieving kinematic and dynamic design requirements and constraints. The speed trajectory of the input link could be generated by a servomotor. Examples are given to demonstrate the feasibility of this approach.

Balancing and Simulation of a Double Crank-Rocker Engine Model for Optimum Reduction of Shaking Forces and Shaking Moments

“…For driving torque reduction, results from the paper [10,26] introduce best results by about 45% and 41% respectively, while this study introduces about 25 to 27% reduction in driving torque values.…”

“…It can be noticed that case-2, (σ 1 , σ 2 ) values (0.7, 0.3), gives best results in term of reducing shaking forces and driving torque, while all cases giving close results in term of reducing shaking moments. 3 introduced a comparison between the three cases introduced in this study, full force balance method (FFB) in the paper [20], optimization methods by Yan et al [10], and Demeulenaere et al [26]. It can be noticed that FFB and case-2 of this study give best results in term of shaking force reduction by about 91%.…”

“…In this section, a dynamic analysis considering the addition of balancing counterweights to the four-bar mechanism is introduced [10,28]. Then, a mathematical model for the DCR mechanism is derived based on basic analysis for design purposes.…”

“…Based on the free body diagram shown in Figure 1b, we can use the following equations to find the reaction forces on the coupling link joints A and B as follows [10]:…”

“…For applications where the crank speed is high, a dynamic balancing to reduce shaking forces and shaking moments are required. Ultimate dynamic balancing of a CR mechanism is considered a challenge because it is a trade-off between balancing forces and moments [10].…”