The aim of this study is to investigate the dynamic responses of a rub-impacting rotor system. A response integration method is applied to analyze bifurcation and chaotic responses for the rub-impacting rotor system. This integration method numerically integrates the distance between state trajectory and the origin in the phase plane during a specific period. It provides a quantitative characterization of system responses and can replace the role of the traditional stroboscopic technique (Poincaré section method) to observe bifurcations and chaos of the rotor system with rub-impact. According to the result comparisons from the rub-impacting rotor system, it is inferred that during Poincaré section method being applied to be analyzed the system response periods, the sampling points on Poincaré section might be too close to cause disturbances to analyze if the system response is a high-order sub-harmonic vibration. Thus, the misjudgments for system response periods will be made. The simulation results, however, show that the high-order subharmonic and chaotic responses and their bifurcations can be observed effectively.

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ABSTRACT:The issues of automatic car operation aiming at in an unknown complex terrain are the most effective path planning and the obstacles avoiding in this complex terrain. For that, an on-line algorithm for guiding a mobile object in an unexplored terrain filled with convex polygonal obstacles is presented. The mobile object was taken as a point-size auto equipped with a sensor system, which is used to detect previously all visible parts of the obstacles surrounding it. Both the visibility and the tangent graph were modified and used in this algorithm to construct the basic concept. At each stage, the next subgoal was selected from local information provided by the sensor. Furthermore, in order to expand the algorithm to handle nonconvex polygonal obstacles and mazes, it was modified by adding backtracking and by removing visited vertices. The algorithm was implemented in MATLAB language, and several numerical examples are shown to evaluate its feasibility. Moreover, the convergence of the algorithm was examined using the visibility graph, and the performance of the algorithm was evaluated by simply comparing with other algorithms for both the length of the path and the traveling time from the initial point to the target point.

In this paper, we propose an improved hardware-software codesign methodology for implementation on embedded system. The codesign flow begins with profiling of the system algorithm. With the analysis of profiling, constraint of computation requirement for the application system, and the provided software-hardware resources on the specific embedded system platform, we partition the application system and allocate the system blocks on the embedded system with software and hardware resources to be a high performance codesign. For high efficient allocation of the system blocks, we created a cost-efficiency function to evaluate the efficiency of software and hardware on the implementation of the embedded system. In our study, a JPEG system is verified on the specific embedded system with the proposed codesign methodology. To achieve high efficient implementation on the specific embedded system platform, reducing the code size and hardware cost are the main tasks. Thus, low computation complexity and low hardware cost DCT/IDCT IPs are also proposed in this paper. Comparing with the design with pure software, the throughput of hardware-software codesign is 1.6 times of it. The cost-efficiency is improved around 1.715 times.