This paper addresses local H ∞ controller design problems for continuous-time TakagiSugeno (T-S) systems with magnitude-and energy-bounded disturbances. The design procedure is formulated as optimizations subject to linear matrix inequalities (LMIs) which can be solved by means of convex optimization techniques. The designed controllers not only guarantee the H ∞ performance but also ensure the state not to escape an invariant set that is included by the region where the T-S fuzzy model is defined. Finally, an example is given to illustrate the proposed method.

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In this paper, robust H 2 and H ∞ control problems for discrete linear time-invariant (LTI) systems with polytopic uncertainties are addressed. The so-called finite impulse response (FIR) controller incorporating the states over several samples from the past to the present is adopted to design robust control laws with improved performances. For the closed-loop stability, parameter-dependent quadratic Lyapunov functions (PD-QLFs) are employed. Sufficient controller synthesis conditions are derived in the form of linear matrix inequalities (LMIs). Finally, examples are given to demonstrate the usefulness of the proposed methods.

Air spring is used for the suspension system and it affects the vehicle stability and riding comfort by improving the impact-relief, braking, and cornering performance. Air Spring is comprised of the upper plate, lower plate, and rubber sleeve. Rubber sleeve is the composite material, which is made up of combination of rubber and Nylon, and the characteristics are changed according to the shape of rubber-sleeve, the angle of reinforcement cord. In this study, the distribution of internal stresses and the deformation of rubber composite material are analyzed through the nonlinear finite element method. The result showed that the internal maximum stresses and deformations about the changes of cord angle caused the more the Young's modulus decrease, the more maximum stress reduced.