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282                                    Autonomous Mobile Robots

                                   The time derivative of V 2 is given by

                                            m−1
                                                         1                 1

                                    ˙
                                                                                   ˙ z
                                    V 2 (Z 2 ) =  z j,2 ˙z j,2 +  z j,3 ˙z j,3 + ··· +  z j,n j j,n j  (7.51)
                                                                         n j −2
                                                        ρ j,1
                                            j=1                          i=1  ρ j,i
                                Substituting (7.25) into (7.51), we have
                                        m−1
                                                       1              1
                                    ˙
                                    V 2 =    z j,2 u 1 z j,3 −  z j,3 ρ j,1 u 1 z j,2 +  z j,3 u 1 z j,4 + ···
                                                      ρ j,1           ρ j,1
                                         j=1
                                              1                           1
                                        −    n j −3  z j,n j −1 ρ j,n j −3 u 1 z j,n j −2 +    nj−3  z j,n j −1 u 1 z j,n j
                                             i=1  ρ j,i                 i=1  ρ j,i
                                              1
                                                            u
                                        +          z j,n j (L h1 z j,n j 1 + u j+1 )
                                             n j −2
                                             i=1  ρ j,i
                                        m−1
                                                 1

                                      =              z j,n j  ((ρ j,n j −2 z j,n j −1 + L h1 z j,n j )u 1 + u j+1 )  (7.52)
                                               n j −2
                                         j=1   i=1  ρ j,i
                                The time derivative of V 3 is given by

                                                              T
                                                      T
                                                                     T
                                                                           T
                                                                      ˜
                                                                             ˜
                                              ˙
                                              V 3 =− e K I e I + e LI d + e RI + e K a Q
                                                               ˜ ˙
                                                      I       I      I     I
                                                            r           r
                                                      T        −1  ˙        −1  ˙
                                                                  ˜ ˜
                                                                              ˜ ˜
                                                   + e H +    γ L  L i L i +  γ R  R i R i
                                                      I
                                                           i=1         i=1
                                                      r             r
                                                         −1   ˙         −1   ˙
                                                            ˜ ˜
                                                                          ˜
                                                                             ˜
                                                   +    γ  K ai K ai +  γ  K Ni K Ni      (7.53)
                                                         a             N
                                                     i=1           i=1
                                   For stability analysis, let us consider the following Lyapunov function
                                candidate:
                                                        V = V 1 + V 2 + V 3               (7.54)
                                   Combining Equation (7.50), Equation (7.52), and Equation (7.53), and
                                using the adaptation laws (7.35), (7.40), (7.42) to (7.44), the derivative of V
                                can be obtained as
                                             m−1
                                                    1
                                        ˙                    2     T T        T
                                       V =−                  z  −˜u S K e S 3 ˜u − e K I e I  (7.55)
                                                   n j −2  k u j+1 j,n j  3   I
                                             j=1   i=1  ρ j,i
                                 © 2006 by Taylor & Francis Group, LLC
                                FRANKL: “dk6033_c007” — 2006/3/31 — 16:43 — page 282 — #16
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