This thesis deals with the concept of remote centre of compliance (RCC) in a variable stiffness system. Starting from a novel linear pneumatic actuator in which membranes act as elastic elements, a study was conducted in order to find the position of the RCC when an asymmetry condition is realised. This is obtained by giving a vertical displacement to the piston. Several FEM simulations of the behaviour of the system were carried out and a first formulation able to describe RCC's trend in a certain pressure range has been found. Finally, a comparison between theoretical model and experimental results is presented.