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Flexible double inverted pendulum system is a higher order, nonlinear and strong coupling unstable system. In order to achieve the steady control of the pendulum, an improved method of sliding mode control with boundary layer is put forward. Linear feedback is replaced with nonlinear feedback within the boundary layer. A mathematical model of flexible double inverted pendulum which is based on mechanism modeling method is established. Then the sliding mode controller is designed. The system has good stability control and robustness. The simulation results show that, the improved method not only realizes stable control of inverted pendulum but also ensures the system states reach sliding surface in a limited time. The robustness is stronger than the conventional boundary layer method.

At present, micrometer is used for measure the shape edge of automobile airbag. There are some shortcomings in this method. The number of test points is limited. Test data is not comprehensive. Detection speed is slow and a fixture can only test a kind of airbag. The method of airbag shape edge detection based on image processing is researched in this paper. The image of airbag is collected by CCD, and then it is sent to the computer to be processed and segmented. The edge of image is extracted through Canny edge detection algorithm in order to acquire shape edge of airbag in this paper, and the image similarity degree are calculated to provide the information of matching in the template matching process. Finally the comprehensive test shape edge of airbag is realized. The experimental results show that the detection method is effective feasible, intuitive and clear.

The trajectory tracking control problem of the uncertain mobile robot with nonholonomic constraints is analyzed. Sliding mode control is presented based on the kinematics models analysis. Switching function of sliding model control is designed according to back-stepping method. Trending law control is selected to improve the system dynamic performance. In order to solve the constant speed problem caused by conventional trending law control, fuzzy control is used to adjust trending speed in the real time. The simulation results demonstrate that the fuzzy sliding mode controller improves the rapidity of trajectory tracking, and reduces the tracking error and the chattering of the control output.

Space-based laser communication (LASERCOM) requires precision tracking and pointing in the microradian range. However, the angular vibrations of a satellite platform may be of the magnitude of milliradian and the frequency of 100 Hz or higher. For rejection of the platform vibrations there are two ways: line-of-sight stabilization technology or a fine steering mirror (control system with high closed-loop bandwidth. The former is much more complex in structure and difficult in implement than the latter. So, the latter is always adopted in actual space optical communication engineering. This paper describes a linear quadratic (LQ) optimal controller based on modern control theory for FSM system. Compared with classical controller, the proposed LQ has several advantages: (1) the LQ controller widens the system's closed loop bandwidth; (2) the large improvement in the system dynamic performance; (3) the significant improvement of the system rejection capability on high frequencies disturbance. The FSM system with the LQ controller have been designed and tested. The results confirm the advantages of the LQ controller above and show that it is an efficient control approach for FSM system in LASERCOM.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.