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Page 10 of 18                   Guo et al. Intell Robot 2023;3(4):596-613  I http://dx.doi.org/10.20517/ir.2023.32





                                                           ∈ (0, 1)                                    (36)

               Proof: Choose the Lyapunov function as



                                                            
                                                        =    (   ⊗       )                             (37)

               in which



                                                       "             #
                                                              e        e Γ
                                                          e
                                                          (   +    )    
                                                      =                                                (38)
                                                              e Γ  e
                                                                   Γ
               Define    =        , where
                            
                      e

                                                                0
                                                          =                                            (39)
                                                           −       
                                                               
               The contract transformation does not change the positivity of the matrix, and



                                                     "                 #
                                                                  2
                                                            e        e Γ
                                                        e
                                                        (   +    ) −  0
                                                    =                 2                                (40)
                                                 e
                                                            0         Γ
                                                                      e
               Since condition (31) implies that Γ is a positive definite matrix, one has that    > 0. Therefore,    is a positive
                                                                               e
               definite matrix.
               Differentiate    to obtain that



                                                    
                                                                      
                                                 
                                             =    (      +     ) ⊗          + 2        ⊗               (41)
                                           ¤
                                                              
                                                  
                                            = −      ⊗          + 2        ⊗         
               in which
                                                     
                                               = −(      +     )

                                                   1     2
                                              =
                                                                                                       (42)
                                                  2      4
                                                "                          #
                                                     2  (   +    )    (   −   )
                                                       e   
                                                                  e
                                                    e
                                                                     e
                                              =    
                                                       e   
                                                  e   
                                                              e e   
                                                                         Γ
                                                   (   −    )    (   +    ) −  2   e
                                                                          
                           
               And    =    . Performing the contract transformation on matrix   , one can obtain that
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