Recursive computation of the Slotine-Li regressor

The Slotine-Li (S-L) regressor is a popular software device for adaptive control of robots. Many adaptive controllers use it to estimate the uncertain robot parameters. Despite its popularity, the S-L regressor is not easy to compute, because it requires a proper substitution of a “reference” velocity vector plus the satisfaction of a skew-symmetric identity (detailed in the text). This problem is solved in the the paper. A recursive algorithm is developed to implement the S-L adaptive control law for a general n-link robot