An effective method is presented for modeling the full three-dimensional dynamics of high performance spatial machine systems, including the vibrations of their links, supporting structure and enclosures, and impacts in their connection clearances. The method combines four-by-four matrix modeling techniques with finite-element techniques. The system’s elements can be described in rich detail, including detailed models of the internal structure of the connections, yet the dynamic calculations are performed efficiently. The method is formulated for implementation on computer-aided design systems. Examples are presented.

A dynamic modeling method is presented for spatial elastic manipulators that can account for a number of their realistic properties, including bearing clearances, actuator dynamics, and control system characteristics. Forces in the bearing clearances are modeled by nonlinear functions of the links’ relative motions and the internal geometry of the connection, or by experimentally measured properties. A detailed model is given for a revolute connection with radial and axial clearances. Results obtained for a SCARA manipulator show that the combined dynamic effects of bearing clearances, link elasticity, and control system characteristics can significantly degrade the system’s performance.

The results of experimental and analytical studies of the dynamic response of machines with flexible links and connection clearances are presented. These results suggest that both a large amount of variability and high sensitivity to small parameter changes and operating conditions are inherent properties of the dynamic response of such systems. This work indicates that the accuracy of dynamic force predictions given by computer simulations for such systems may be fundamentally limited, and therefore such simulations should be used with care in system design.

The results of experimental and analytical studies of the dynamic response of machines with flexible links and connection clearances are presented. These results suggest that the actual dynamic response of such systems inherently exhibits both a large amount of variability and high sensitivity to small parameter changes and operating conditions. This work suggests that the accuracy of the dynamic force predictions given by computer simulations for such systems is fundamentally limited, and therefore such simulations should be used in system design with care.

No abstract