A survey of some results on spatial stiffness matrices

We survey some work on the problem of realizing a spatial stiffness matrix with a parallel connection of springs. The techniques described can be used to realize an arbitrarily specified stiffness dominated spatial impedance through the use of a mechanism constructed of passive springs. The article includes a new method for finding a minimal realization of a positive definite spatial stiffness matrix using only line springs. We also introduce a method for finding an isostiffness realization of a 3/spl times/3 stiffness matrix.