Automation, Control and Intelligent Systems 2013; 1 (1) : 1-7 Published online February 20, 2013 (http://www.sciencepublishinggroup.com/j/acis) doi: 10.11648/j.acis.20130101.11 Flatness control of a crane H. Souilem 1 , H. Mekki 2 and N. Derbel 1 Control, Energy and Management Lab (CEM Lab) 1 National School of Engineers of Sfax BP.W, 3038, Sfax-Tunisia 2 National School of Engineers of Sousse Email address: haifa.souilem@gmail.com (H. Souilem); hassen.mekki@eniso.rnu.tn (H. Mekki); nabil.derbel@ieee.org (N. Derbel) To cite this article: H. Souilem ,H. Mekki and N. Derbel. Flatness Control of a Crane. Automation, Control and Intelligent systems. Vol. 1, No. 1, 2013, pp. 1-7. doi: 10.11648/j.acis.20130101.11 Abstract: The aim of this work is to propose a flatness control of a crane detailing adopted mechanisms and approaches in order to be able to control this system and to solve problems encountered during its functioning. The control objective is the sway-free transportation of the crane’s load taking the commands of the crane operator into account. Based on the mathematical model linearizing and stabilizing control laws for the slewing and luffing motion are derived using the input/output linearization approach. The method allows for transportation of the payload to a selected point and ensures minimisation of its swings when the motion is finished. To achieve this goal a mathematical model of the control system of the displacement of the payload has been constructed. A theory of control which ensures swing-free stop of the payload is presented. Selected results of numerical simulations are shown. At the end of this work, a comparative study between the real moving and the desired one has been presented. Keywords: Crane, Flatness Control, Path Planning, Path Tracking 1. Introduction Flatness-based control techniques have been developed and applied in many industrial processing with a great success in solving planning and tracking problems of reference trajectories such as thermal process control [15], motors control [1], chemical reactor control [16], crane control [10] etc… This theory was introduced in 1992 by M. Fliess and al. [6]. The existence of a variable called a flat output permits to define all other system variables. The dynamics of such process can be then deduced without solving differential equations. Therefore, it is possible to express the state, as well as the input and the output system, as differential functions of the flat output [6] [11]. Conventionally, it is difficult to resolve the path planning problem due to the necessity to solve the differential system equations from the initial conditions to obtain the solution at the final time. In the case of flat systems, this problem can be solved easily without approximation and without solving differential systems equations. Indeed, flatness property ensures the existence of a flat output which allows the parameterization of all system variables as a function of finite number of its derivatives. The goal of this work is to solve problems encountered during the motion of the load using the technique known by control by fatness whose main objective is to attenuate the undesirable swings of the load [7], [9], [13]. In fact, the differential flatness has been introduced by Fliess and al. [5] in 1995. The states and the in puts of the flat system can be expressed in function of the particular out puts and their successive derivatives. We can find a lot of the literature uses a linear approaches [3], [8], [19] or an approaches of optimal control [12], [20]. Also, several methods are proposed in [9] and [14] in order to decrease the oscillations created by the outsides disruptions. Authors of [2] and [4] use energizing techniques by exploiting the fact that a crane can be identified to a pendulum if we fixes the length of the vertical cable bound to the load. Other techniques can be useful: technique of in put / out put linearization, technique of in put / state linearization, but these techniques present several problems which are so difficult to solve it. We here interested to exploit the concept of the flatness in order to control the system crane: in section 2, we present the dynamic model of the crane. In section 3, the crane is modeled by a flat system. Section 4 deals with flatness and linearization. Section 5 deals with flatness and trajectories generation. Finally, in section 6, we present the flatness and the tracking of trajectory.