A NEW REDUCTION METHOD ON CONSTANT CONSTRAINTS WITH NATURALCOORDINATES

摘要

With the strategy "Automatically Reduce Natural-Coordinate DAEs Assembled Automatically" in mind, the authors have developed a new reduction method on natural-coordinate constant constraint (NCCC). A NCCC constrains a state variable to a constant, leading to a simplest constraint equation which often appears in the joints which connect elements defined with natural coordinates to the ground.rnThe new reduction method can be performed once for every NCCC, with the result that one column and one row are removed from the system mass matrix. The new reduction operation can be used independently and repeatedly, a characteristic suitable for computer implementation.rnFor the purposes of illustration, after a double-wishbone suspension is modeled with 48 natural coordinates and 12 NCCCs, its DAE is reduced by the new reduction method, with 36 natural coordinates remaining.