Modelling, design and control of a modern electropneumatic actuator

Presents an analysis of a pneumatic actuator system with response characteristics that are much improved compared with those available from conventional spring-opposed-diaphragm units. The equations are developed which characterise the behaviour of the pneumatic actuator, and comparisons of experimental and simulated results show the accuracy of the model to be good. Linear approximate models of the pneumatic actuator system then form a basis for the application of two linear controller-design procedures. The design methods employed are the linear quadratic optimal control with extended cost functions and the Horowitz approach to sensitivity reduction. The resulting closed-loop designs are found to be robust and to achieve their required performance specifications under both emergency and normal actuator operations.