Backstepping Method for a Single-link Flexible-joint Manipulator Using Genetic Algorithm

Flexible manipulators are extensively used in industries. In this paper, backstepping method (BM) is used to control flexible manipulator. BM consists of parameters which accept positive values. The parameters are usually chosen variously. The system responses differently for each value. In this method, some paremeters exist, which, if not defined well, may cause some performance degrade. It is necessary to select proper parameters to obtain a good response because the improper selection of the parameters leads to inappropriate responses or even may lead to instability of the system. Genetic algorithms (GA) are used to compute the optimal parameters for the backstepping controller of single-link flexible-joint manipulator systems. GA can select appropriate and optimal values for the parameters. GA minimize the fitness function, so the optimal values for the parameters will be found. Selected fitness function is defined to minimize the least square error. Fitness function enforces the system error to decay to zero rapidly. Hence, it causes the system to have a short and optimal setting time. Fitness function also makes an optimal controller and causes overshoot to reach to its minimum value. This hybrid leads to optimal backstepping controller (OBM).