A novel method of decomposing the dynamical equations of a three-link flexible manipulator is described. The concept of a 'pseudolink' is used to separate the full manipulator-system model into a pseudolink subsystem model and a flexible subsystem model. A composite controller is designed for achieving accurate end-point positioning and trajectory tracking of a predetermined trajectory described in terms of pseudolinks, and for stabilizing the flexible subsystem. Simulation results are presented to demonstrate the effectiveness of the control method. Practical steps for implementing this strategy in an actual system are also discussed.>

Controller designs for the guarded and compliant phases of a robot arm task are proposed. For the guarded-motion phase a state-feed-back controller with linearized decoupling is proposed. This controller is cascaded with a force-feedback loop during the compliant phase. This differs from those schemes already presented in the literature in that position and velocity feedback are retained along the force-controlled axes. The guarded and compliant controllers take over from a proportionalderivative free-motion controller near the end of the free-motion path. Simulation studies on a two-link robot arm are carried out to evaluate the proposed desing as well as to compare it with a more conventional proportional-integral-derivative design.

Shannon's mutual information is proposed as a measure of lagged statistical dependence between the temporal patterns of economic/demographic growth for subregions, where the year-to-year ratio of births is taken as the growth index for each subregion. Application of the measure to 31 of the 36 counties in Oregon, using vital statistics for the years 1919-1968, yields results that seem, for the most part, consistent with certain theories about the diffusion of economic development.