CHIMAN KWAN

A desired compensation adaptive law-based neural network (DCAL-NN) controller is proposed for the robust position control of rigid-link robots. The NN is used to approximate a highly nonlinear function. The controller can guarantee the global asymptotic stability of tracking errors and boundedness of NN weights. In addition, the NN weights here are tuned on-line, with no off-line learning phase required. When compared with standard adaptive robot controllers, we do not require linearity in the parameters, or lengthy and tedious preliminary analysis to determine a regression matrix. The controller can be regarded as a universal reusable controller because the same controller can be applied to any type of rigid robots without any modifications. A comparative simulation study with different robust and adaptive controllers is included.

This note presents an approach to exploit symmetry in the synthesis of solutions for the SCP. The basic idea underlying the method is to perform the computation of the maximal controllable sublanguage of a given language over reduced automaton representations of the plant and specification. The reduction in state spaces can be significant when the degree of symmetry is high. In general the determination of symmetric groups of languages is a very complex task. When dealing with systems with replicated structures, however, the symmetric group emerges naturally as being formed by the rotations over the similar components. Besides the gain in computational complexity, our approach also provides a way to implement supervision using the reduced automaton representation for the supervisor instead of its corresponding expanded representation. We are currently investigating methods for relaxing the notion of symmetry considered here, in order to use the idea of reduced automata for a larger class of problems. Some preliminary results of this work can be found in [6]. Also, motivated by the robustness problem studied in [2], we are investigating the possibility of using the idea of quotient structure to derive results where we could implement a robust parametrized supervisor as the solution for a class of different plants. Abstract—Zak and Hui [1] proposed a sliding mode controller for linear multiple-input–multiple-output (MIMO) systems using static output feedback. The note in [2] provided an improvement of the output feedback controller in [1] for a class of linear single-input–single-output (SISO) systems that eliminated two important limitations of [1]: (a) system uncertainties must be bounded by the system output; and (b) a requirement of a matrix inequality [1, eq. (4.3)]. The controller in [2] can guarantee global closed-loop stability. This note extends the results of [2] to linear MIMO systems. It is emphasized that the proposed MIMO controller yields global closed-loop stability whereas the one in [1] can only guarantee local stability. An application of the proposed MIMO controller to an aircraft model is included to show the effectiveness of the method.

In the above paper, 1 some typographical errors appeared that need to be corrected. In (17), the sign = should be dropped. The (2; 2) block of matrix 51 at the bottom of page 494 and the matrix in (28) at the bottom of p. 495 should be 0m(1 + 2) 01 P: The first block of matrices B2 and B3 should be m0 and m, respectively. V (e; t) = ke(t)k 2 P + 0 0 t t+ 01 1 kNe(s)k 2 P ds + t t+0 01 2 kN d e(s)k 2 P ds d where ke(t)k 2 P = e T (t)Pe(t) and inequality (27) should be _ V (e; t) e T (t) (N + N d) T P + P (N + N d) + m (1 + 2)PN d P 01 N T d P + m (01 1)N T PN + m 01 2 N T d PN d e(t)