Mode Switching Control from Vibration Reduction to Positioning for Power Assisted Moving Flexible Structures

This study discusses the problem that a worker conveys a flexible structure and positions it to the goal position with power assist. For the problem, this paper proposes the control method of the smooth switching from vibration reduction, when a worker conveys flexible structures, to their positioning taking power assist into account. The technical issues are: firstly, displacement of the goal position is unknown until the object conveys near the goal position. So, this displacement has to be determined before positioning the object. Secondly, one of sensors has a limit of its measurement range. So, there are unknown variables which have to be determined while conveying an object. Thirdly, we consider to minimize an overshoot. For clearing up the first and second issues, we discuss the method for determining the displacement of the goal position and unknown variables while conveying the object. Then we consider that two modes: in the first mode, we consider the control system which includes unknown variables. In the second one, we consider the system which all the variables are known. The two modes are connected smoothly by applying an adaptive nonstationary control method. For clearing up the third issue, the method for preventing collision occurrence is discussed. In order to verify the effectiveness of the proposed method, we conduct the experiments and their corresponding simulations. The results indicate that the proposed method is useful to position flexible structures to the goal position with minimum overshoot.