Hierarchical design of electro-hydraulic actuator control for vehicle dynamic purposes

Abstract

The paper proposes a hierarchical control design of an electro-hydraulic actuator, which is incorporated in the active anti-roll bars. The aim of the control system is to generate a reference torque, which is required by the vehicle dynamic control. The control-oriented model of the actuator is formulated in two subsystems. The upper-level hydromotor is described in a linear form, while the lower-level spool valve is a polynomial system. These subsystems require different control strategies. At the upper-level a Linear Parameter Varying control is used to guarantee performance specifications. At the lower-level a Control Lyapunov Function-based algorithm, which creates discrete control input values of the valve, is proposed. The interaction between the two subsystems is guaranteed by the spool displacement, which is control input for the upper-level and must be tracked by the lower-level control. The spool displacement has physical constraints, which must also be incorporated into the control design. The operation of the actuator control system is illustrated through a simulation example.