GESTS Int’l Trans. Computer Science and Engr., Vol.20, No.1 89 GESTS-Oct.2005 New Software Dedicated to the Design and Simulation of Nonlinear Controllers Based on Feedback Linearization Technique Azeddine Kaddouri 1 , Sébastien Blais 1 , Mohsen Ghribi 1 , and Ouassima Akhrif 2 1 GRETER Research group, Faculty of Engineering, Université de Moncton, (NB), Canada E1C 7A9, {kaddoua, sblais, ghribim}@umoncton.ca 2 GREPCI Research group, Department of electrical engineering, École de Technologie Supérieure, Montreal, (QC), Canada, wassima@ele.etsmtl.ca Abstract: - This paper describes new software (NLSoft) developed for the design of nonlinear controllers based on feedback linearization technique. NLSoft is a software package containing several symbolic manipulation modules including differential geometric tools for the design and simulation of control systems. NLSoft presents a user-friendly graphical user interface (GUI) as well as a new and powerful module allowing the calculation time of linearizing control laws considering several Digital Signal Processors (DSPs) characteristics. These facilitate the real-time implementation of the control system. NLSoft is validated considering two illustrated examples. 1. Introduction The nonlinearities of nonlinear dynamic systems have been traditionally handled in the literature by the use of classical linear control methods, which rely on linearized models approximating the dynamic system’s equations. These methods are just valid in a small operation range. When the required operation range has to be larger, the linear controller is likely to perform poorly. Nonlinear controllers, however, may handle the nonlinearities in large range operations directly. The nonlinear control considered here is based on the feedback linearization technique (static and dynamic) which gives a good solution for tracking control problems. Several accessible references describing its constructions are now available ([1] to [4]] as examples). This well-known nonlinear control technique has been successfully applied to the control of dynamic systems, even those with high nonlinearities in their model. However, this technique needs an extensive knowledge of differential geometry which provides a very useful framework for the analysis of nonlinear control systems. Differential geometric objects (Lie brackets, Lie derivatives, etc.) are not easily manipulated by hand. In order to facilitate this process, many new CAD tools appeared in the last decade (AISYS, AP_LIN, SCILAB, CONDENS, REDUCE, PROPAC etc). They offer the possibility of designing and/or simulating nonlinear dynamic systems. In the real-time applications, the main problem encountered with these nonlinear control techniques is that they need an important calculation time which makes implementation extremely difficult on a general use microprocessor.