A new, seven parameter class of micromanipulators is found with decoupled dynamics. The flexibility of the new class is demonstrated by designing a Stewart platform with fully equalized and decoupled dynamics (i.e., all resonant frequencies are equal). Although this has been attempted before by other researchers, it has not been previously accomplished. The ability to design the dynamics so they are amenable to control leads to significant increases in closed loop performance and robustness. The dynamically decoupled and equalized manipulator is compared to an asymmetric manipulator in closed loop. Even though both manipulators control the same payload over the same bandwidth with exactly the same struts, the H∞controller for the equalized manipulator is five times less sensitive to worst case disturbances than the H∞controller for the asymmetric manipulator. Moreover, the decoupling facilitates the design of Nyquist stable compensators which give the decoupled manipulator one hundred times higher performance at low frequencies. This greatly increased performance and robustness requires implementation of only the six compensators along the diagonal of the six degree-of-freedom system, versus implementation of all 36 compensators for the asymmetrical manipulator.

This paper analytically finds a new, significantly more general class of locally decoupled 2p - UPS, parallel manipulators encompassing and expanding several earlier classes. Its closed form solution leads directly to simple analytic formulas for the system eigenvalues in terms of geometric design parameters. To illustrate the power of the theory, the new methods are used to re-design an actual manipulator currently in use on the International Space Station. Unlike the existing manipulator, the new design is dynamically decoupled and isotropic.

New methods are found for arranging force actuators around a rigid body so that the system has locally decoupled and optimal manipulation characteristics. The closed-form solution leads directly to simple analytic formulas for the singular values of the manipulator Jacobian in terms of geometric design parameters. This makes it possible to easily design the local kinematics so that they meet desired specifications. Explicit formulas for designing the wrench/twist capabilities, achieving isotropy, maximizing the volume of achievable motions, and maximizing the minimum singular values are derived. Applications include design of generalized Gough-Stewart platforms (GSPs) and other parallel machines. To illustrate the power of the theory, the new methods are used to redesign an actual manipulator currently in use on the International Space Station (ISS). Unlike the existing manipulator, the new design is kinematically decoupled, isotropic, and fault tolerant - all highly desirable properties, especially in aerospace applications.