H. Angue Mintsa

Bio: H. Angue Mintsa is an academic researcher from Université de Moncton. The author has contributed to research in topics: Particle & Viscosity. The author has an hindex of 2, co-authored 2 publications receiving 1223 citations.

An Alternative Nonlinear Lyapunov Redesign Velocity Controller for an Electrohydraulic Drive

Abstract: This research aims at developing control law strategies that improve the performances and the robustness of electrohydraulic servosystems (EHSS) operation while considering easy implementation. To address the strongly nonlinear nature of the EHSS, a number of control algorithms based on backstepping approach is intensively used in the literature. The main contribution of this paper is to consider an alternative approach to synthetize a Lyapunov redesign nonlinear EHSS velocity controller. The proposed control law design is based on an appropriate choice of the control lyapunov function (clf), the extension of the Sontag formula and the construction of a nonlinear observer. The clf includes all the three system variable states in a positive define function. The Sontag formula is used in the time derivative of our clf in order to ensure an asymptotic stabilizing controller for regulating and tracking objectives. A nonlinear observer is developed in order to bring to the proposed controller the estimated values of the first and the second time output derivatives. The design, the tuning implementation and the performances of the proposed controller are compared to those of its equivalent backstepping controller. It is shown that the proposed controller is easier to design with simple implementation tuning while the backstepping controller has several complex design steps and implementation tuning issue. Moreover, the best performances especially under disturbance in the viscous damping are achieved with the proposed controller.

Analysis of the Gains Tuning Problem in a Backstepping Controller Applied to an Electrohydraulic Drive

Abstract: This paper highlights the problem of tuning the gains of a non-adaptive backstepping controller in an electrohydraulic servo system. While the other non-adaptive controllers in the literature have precise gains tuning methods, the non-self-tuning backstepping controller has no rigorous gain tuning method. The proposed study aims to analyze the contribution of each backstepping controller gain in the closed-loop performance. Our final goal is to establish a rigorous gains-tuning method for the non-adaptive backstepping controller. The study starts with the development of three-stage gains backstepping controller using a non-conventional time derivative Lyapunov function. This particular Lyapunov function makes it possible to analyze the response of the system when all the controller gains are cancelled. Then, we analyze the effect of each gain by cancelling out the values of the others. The first simulation results show that the convergence of the tracking error to zero is not maintained when all gains are set to 0 despite the presence of a negative definite of the Lyapunov function time derivative. In this case, the equilibrium point is not the expected one as time goes to infinity. The second set of results indicates that adjusting the gain related to the feedback of the actual output only ensures the asymptotic convergence of the tracking error to zero as time goes to infinity. However, developing a heuristic tuning of the three controller gains like Ziegler Nichols tuning remains a challenge.