The robust stability of systems under both plant and controller perturbations is analyzed, with anemphasis on additive norm-bounded perturbation. Choosing the interconnection matrix M makes Δ（s） blockdiagonal matrices and absorbing any matrix makes ||Δ（s）||∞<1, the problem can be recast into a smallstructured singular value （μ） problem. If 2S+F≤3, μ（M）=inf σ(DMD-1). In this paper, the
In order to solve the problems that make the orientation of pneumatic rotary actuator inaccurate, anewly intelligent PID control algorithm is proposed. Pneumatic rotary actuator angle servo-system useselectropneumatic proportional valve as control device, which changes the pressure of cavity and then pushes theactuator to revolve to the expected position. Using intelligent PID control algorithm, several special methods
The robust stabilization problem (RSP) for a plant family P(s,δ,δ) having real parameter uncertainty δ will be tackled. The coefficients of the numerator and the denominator of P(s,δ,δ) are affine functions of δ with ‖δ‖p≤δ. The robust stabilization problem for P(s,δ,δ) is essentially to simultaneously stabilize the infinitely many members of P(s,δ,δ) by a fixed controller. A necessary solvability condition is that every member plant of P(s,δ,δ) must be stabilizable, that is, it is free of unstable pole-zero cancellation. The concept of stabilizability radius is introduced which is the maximal norm bound for δ so that every member plant is stabilizable. The stability radius δmax(C) of the closed-loop system composed of P(s,δ,δ) and the controller C(s) is the maximal norm bound such that the closed-loop system is robustly stable for all δ with ‖δ‖p<δmax(C). Using the convex parameterization approach it is shown that the maximal stability radius is exactly the stabilizability radius. Therefore, the RSP is solvable if and only if every member plant of P(s,δ,δ) is stabilizable.
