Simulation of optimal drive systems consisting of gear-cam mechanisms with brushless DC servometers.

摘要

This study presents the development of flexible tools for the numerical simulation of processing machine drives that consist of servomotors, mechanisms, and machine tools. The simulation allows predicting the motions or vibrations of linkages, forces and torques in joints, motor currents, and system response times as well as evaluating stability and characteristic frequencies of the drive system. The simulation tools were implemented as macro components in macro component libraries using the EASY5RTM Dynamic System Modeling, Simulation, and Analysis software by the Boeing Company. Application of the developed macro components allows fast and efficient modeling of a variety of different drive systems. The simulation models include interaction effects between mechanical and electrical components of the drive system and consider elasticity as well as non-linearity that results from friction and backlash. This comprehensive approach overcame limitations of previous strategies that designed and optimized the mechanism and servomotor systems separately. The modular structure of the developed libraries made them applicable to many different drive system structures thus decreasing modeling time and promoting reuse of previous work.;Modeling and simulation with the developed libraries was demonstrated on the example of gear-cam mechanisms, a group of mechanisms that combine planetary gear and cam elements. For a meaningful selection of examples, the study included a structural investigation of these mechanisms. Gear-cam mechanisms were enumerated using graph theory. A procedure was developed that ensures finding an exhaustive set of gear-cam mechanisms. This procedure is based on evaluations of the Link Adjacency Matrix that leads to a characteristic code to find isomorphic graphs. The procedure was applied to enumerate all gear-cam mechanisms with four linkages.;A gear-cam mechanism structure for the generation of step motions was selected as an example for demonstrating the simulation tools. Using this mechanism, drive systems that create step motions were designed, and simulation models were built. For comparison, a simpler drive system consisting only of servomotor and gear reduction stage was designed for a similar motion task. The simulation results indicated that this simpler drive system is superior to the gear-cam mechanism drive system.