Optimal design of high-speed machinery with integrated smart actuators

In this dissertation, the results of research in a number of areas related to the kinematics and dynamics and optimal design of high-speed machinery and methods to increase their operating speed and precision are reported. Optimal design of high-speed machinery with integrated smart materials based actuators for the purpose of minimizing or eliminating the high harmonic components of the output motion and/or joint or object motions and/or required actuating torques (forces) constitutes one part of the study. In general, the primary source of such high harmonic components is the nonlinearity in the closed-loop kinematics and dynamics. By eliminating the high harmonic component of the output/joint/object motions and/or actuating torques with properly sized and positioned smart actuators, the potential vibrational excitation that the mechanical system can impart on the overall system and its own structure is greatly reduced. The resulting system should therefore be capable of operating at higher speeds and with greater precision and minimal vibration and control problems. A number of numerical examples are provided together with a discussions of the related topics of interest.; A new method for the modification of the output motion of linkage mechanisms with closed-loop chains using cams positioned at one or more of its joints is also presented in this dissertation together with its experimental investigation. A four-bar linkage mechanism with an integrated cam mechanism properly designed for the purpose of eliminating the high harmonic component of the output link motion is designed, constructed and tested. With the present method, a selected range or ranges of high harmonic motions generated due to kinematics nonlinearities may be eliminated by integrating appropriately designed cams that are used to vary the effective length of one or more of the links during the motion. As the result, the potential excitation of vibration and the related control problems can be greatly reduced, thereby allowing a mechanical system to operate at higher speeds with greater precision.; A new method, which was recently developed to determine the steady state response of nonlinear dynamics systems with structural flexibility was further investigated and its proof and limitations are provided. The study clearly illustrates the mechanisms with which link and joint flexibilities affect the kinematics and dynamics of high speed machinery. The natural application of this method to optimal integration of smart material into the structure of high speed and precision machinery with structural flexibility is discussed. A number of examples and computer simulation results are presented.