Nonlinear Passivity Based Control Law with Application to Electropneumatic System

This paper presents a synthesis of a nonlinear controller to an electropneumatic system. Nonlinear passivity based control law is applied to the system under consideration. First, the nonlinear model of the electropneumatic system is presented. It is transformed to be a nonlinear affine model and a coordinate transformation is then making possible the implantation of the nonlinear controller. A nonlinear control law is developed to track desired position. Experimental results are also presented and discussed. Nomenclature b viscous friction coefficient (N/m/s) k polytropic constant M total load mass (kg) p pressure in the cylinder chamber (Pa) qm mass flow rate provided from servodistributor to cylinder chamber (kg/s) r perfect gas constant related to unit mass (J/kg/K) S area of the piston cylinder (m 2 ) T temperature (K) V volume (m 3 ) y, v, a position (m), velocity (m/s), acceleration(m/s 2 ) φ(.) leakage polynomial function (kg/s) ψ(.) polynomial function (kg/s/V) l length of stroke (m) Fext External force (N) Ff dry friction force (N) u control input x slide valve position Subscript D dead volume S supply N chamber N P chamber P d desired