Coordinated Compensation Between Active and Semi-Active Actuators for Suspension Control System

Abstract

This paper presents coordinated compensation schemes between active and semi-active actuators in suspension control system. Generally in active suspension systems, active actuators have been adopted to generate a control force calculated by a controller. However, active actuators adopted in actual vehicles have physical constraints such as maximum force, bandwidth and force-velocity limitation. On the other hand, a semi-active actuator can be a good alternative to active one in view of maximum force and bandwidth despite it cannot generate an active control force. However, the performance of semi-active actuators is limited by half of active ones. Hence, it is necessary to compensate the control force of semiactive actuators by active ones. In this paper, it is assumed that a vehicle has both of active and semi-active actuators. A control force needed to enhance ride comfort is generated by linear quadratic regulator (LQR). The controller is designed with 2-DOF quarter-car model and applied into 7-DOF full-car one. To generate the control force with active and semi-active actuators, several coordinated compensation schemes are proposed. A simulation on a simulation package show that the proposed coordinated compensation schemes are effective in reducing the control force of the active actuator over the wider range of frequencies.

A New Design method of LQR Control of Single-Phase Grid-Tied Inverter With LCL Filter

“…Assume the structure of the real diagonal matrix Q as follows: (12) Assume the structure of the real symmetric matrix P as follows: (13) Substituting the state space model of LCL filter (5) into Riccati equation ( 9), each parameter satisfies the following equation( 14):…”

“…As for a model control method, the kernel of the LQR control is to use state feedback to optimize the performance of the system [12]. It provides good robustness by minimizing a quadratic cost function [13] as well as performance index including settling time, overshoot during transient, and steadystate error, fast response speed [14], considerable tracking ability in output current of the inverter, which ensure the power factor (PF) of the output to the grid and low total harmonic distortion (THD) [15].…”

State-Feedback-Critical Super Twisting Sliding Mode Control for a Half-Car Suspension System

“…The following linear sliding surface with full information on the displacement and velocity states is considered for the FS-STC. Taking the derivative of the sliding surface (11) and substituting the system dynamics ( 9) into the derived equation, we obtain:…”

“…Other common objectives include guaranteeing system state constraints so that the criteria of driving comfort and safety can be satisfied. Various control algorithms have been proposed to achieve these goals, for instance, H ∞ [3], backstepping [1], [4], Fuzzy-PID [10], linear quadratic regulator [11], or sliding mode control (SMC) [6], [12], [13], to name just a few.…”