On nonlinear stiffness of the sleeve actuator

Abstract

The paper presents the stiffness evolution with the stroke, in pneumatic sleeve actuator, gives the elements implied in it and thus the possibility to adjust it. When the actuator has closed all connections with the outside, the volume variation with the stroke is strongly affected and thus the inner pressure generates nonlinear actuator stiffness and thus the suspension behavior. A slow stiffness growing has a good effect by reducing the number and amplitude of the suspension limiter bumper collisions on compression, but a big stiffness growing will increase strongly the gas pressure generating inner tensions, above the mechanical resistance in the pneumatic components. To avoid these inconveniences the paper defines each element implied in stiffness evolution and expresses the pressure and stiffness evolution with the stroke, in function of the initial gas pressure. For better understanding, the paper shows images of the system in each main position and presents result tabular and by diagram.