Page 131 - Distributed model predictive control for plant-wide systems
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Cooperative Distributed Predictive Control                             105


             Table 6.1  Notations definition
             Notations        Explanations

             diag {A}         Diagonal block matrix made by a blocks equal to A
                a
                {A}           The jth eigenvalue of a square matrix A
              j
             O(a)             To be proportional to a
             0                An a × b null matrix
              a × b
             0 a              An a × a null matrix
             I a              An a × a identity matrix
             ̂ x (l|h)        Predictions of x (l) computed by C at time h
              i
                                                      i
                                         i
             ˆ y (l|h)        Predictions of y (l) computed by C at time h
                                                      i
              i
                                         i
             u (l|h)          Input u (l) computed by C at time h
                                   i
                                                i
              i
             Δu (l|h)         Input increment Δu (l) computed by C at time h
                                                         i
               i
                                            i
              d
             y (l|h)          Set-point of y (l|h)
              i                         i
              d
             y (l|h)          Set-point of y(l|h)
              i
             ̂ x (l|h)        Predictions of x(l) computed by C at time h
                                                      i
              i
             ˆ y (l|h)        Predictions of y(l) computed by C at time h
                                                      i
             U (l, p|h)       A complete input vector
              i
                                          T
                                                 T
                                                                T
                               U (l, p|h)=[u (l|h)  u (l + 1|h)  ···  u (l + p|h)] T
                                                                i
                                                 i
                                 i
                                          i
             ΔU (l, p|h)      Input increment sequence vector,
               i
                                         [  T        T               T      ] T
                               ΔU (l, p|h)= Δu (l|h)  Δu (l + 1|h)  · · ·  Δu (l + p|h)
                                  i
                                                                     i
                                            i
                                                     i
             U(l, p|h)        Complete stacked input vector,
                                        [                              ] T
                                         T
                                                                T
                                                 T
                               U(l, p|h)= u (l|h)  u (l + p|h)  · · ·  u (l + p|h)
             ̂ i
             X (l, p|h)       Sacked distributed state vector,
                                        [  iT     iT             iT      ] T
                                ̂ i
                               X (l, p|h)= ̂ x (l |h)  ̂ x (l + 1|h)  · · ·  ̂ x (l + p|h)
             X (l, p|h)       Stacked distributed state vector,
             ̂
              i                         [                               ] T
                                                  T
                                                                 T
                                          T
                               X (l, p|h)= ̂ x (l |h)  ̂ x (l + 1|h)  · · ·  ̂ x (l + p|h)
                                ̂
                                 i        i       i              i
             X(l, p|h)        Complete stacked state vector,
             ̂
                                        [                             ] T
                                                               T
                                                 T
                                         T
                               X(l, p|h)= ̂ x (l|h)  ̂ x (l + 1|h)  · · ·  ̂ x (l + p|h)
                                ̂
             ˆ i
             Y (l, p|h)       Stacked distributed state vector,
                                        [                               ] T
                                                 iT
                                          iT
                                                                iT
                                ̂ i
                               Y (l, p|h)= ̂ y (l|h)  ̂ y (l + 1|h)  · · ·  ̂ y (l + p|h)
             Y(l, p|h)        Complete stacked state vector,
                                        [                             ] T
                                                               T
                                                 T
                                         T
                               Y(l, p|h)= y (l|h)  y (l + 1|h)  · · ·  y (l + p|h)
              d
             Y (l, p|h)       Set-point of Y(l, p|h);
             ̂   (l, p|h)     Complete stacked state vector,
                                        [                     ] T
                                                        ̂ T
                                ̂   (l, p|h)= ̂ T  ···  X (l, p|h)
                                         X (l, p |h)
                                                         m
                                          1
                               d
                                             d
              d
                (l, p|h)         (l, p|h)= diag (Y );
                                          m
               (l, p|h)       Complete stacked state vector,
                                        [                     ] T
                                          T
                                                        T
                                 (l, p|h)= U (l, p |h)  ···  U (l, p|h)
                                          1             m
             1. a and b are constants; p, l, h are positive integers, and h < l ;Ais amatrix.
             • communication channel introduces a delay of a single sampling time interval, since an
               instantaneous data transfer is not possible in real situations;
             • controllers communicate only once within a sampling time interval;
             • local states x (k), i = 1, 2, … , m, are accessible.
                         i
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