Flexible fluidic actuators: Determining force and position without force or position sensors

Flexible fluidic actuators present a lot of nice features regarding applications in the medical field and in the field of robotics. For example, they own a natural compliance and they can be very lightweight. Besides, an interesting measuring concept seems to be applicable to them: it is possible to determine and control the position of the actuator and the force it develops thanks to the measures of the fluid pressure and of the volume of supplied fluid. This means being able to determine and control the position of the actuator and the force it develops without displacement or force sensors. We validate experimentally this measuring concept in the case of a specific actuator and a method to model the behaviour of flexible fluidic actuators having one degree of freedom is proposed. Besides, the advantages and difficulties brought by this measuring concept are discussed.