Clad height control in laser cladding using a nonlinear optimal output tracking controller

Abstract

In this paper a nonlinear optimal output tracking controller is designed to control the deposition height during laser cladding. The substrate’s moving speed is used as the control action. An approximate nonlinear model obtained by previous researchers is linearized in the neighborhood of the desired clad height. The linearized model is found to be in the form of a bilinear system. A novel control technique is proposed to develop an optimal output tracking controller for the bilinear system. First, an optimal output regulator algorithm is developed. The optimal output tracking problem is solved by two separate methods in order to obtain a sub optimal output tracking controller. The method is then applied to the laser cladding model. The designed controller is verified in different clad height ranges.In this paper a nonlinear optimal output tracking controller is designed to control the deposition height during laser cladding. The substrate’s moving speed is used as the control action. An approximate nonlinear model obtained by previous researchers is linearized in the neighborhood of the desired clad height. The linearized model is found to be in the form of a bilinear system. A novel control technique is proposed to develop an optimal output tracking controller for the bilinear system. First, an optimal output regulator algorithm is developed. The optimal output tracking problem is solved by two separate methods in order to obtain a sub optimal output tracking controller. The method is then applied to the laser cladding model. The designed controller is verified in different clad height ranges.