Step 1. The Open Chain Solution

In this first step, the solution to the Direct Dynamics problem for an open, unconstrained configuration of the manipulator is found. This corresponds to 

The efficient computation of fl and A was discussed in detail in Chapt 4. The most efficient method known for the computation of both fl and A for iV 21 is the Unit Force Method (Method II), which is O(AT ) for an A/ degree-of-freedom manipulator with revolute and/or prismatic joints. For N 21, the 0(N) Force Propagation Method (Method III) is the most efficient. The use of these two methods will be discussed further in Section 5.1. 

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