Papers by Author: Kai Xue

Abstract: Human ability to explore planets (e.g. the moon, Mars) depends on the autonomous mobile performance of planetary exploration robots, so studying on terrain classification is important for it. Vibration-based terrain classification unlike vision classification affected by lighting variations, easily cheated by covering of surface, it analyses the vibration signals from wheel-terrain interaction to classify. Three accelerometers in x, y, z direction and a microphone in z direction were mounted to arm of the left-front wheel. The robot drove on the sand, gravel, grass, clay and asphalt at six speeds, three groups of acceleration signal and one group of sound pressure signal were received. The original signals were dealt using Time Amplitude Domain Analysis. Original data were divided into segments, each segment was a three centimeters distance of driving; eleven features from every segment were normalized. The data from four sensors were merged into a forty-four dimensions feature vector. Ten one against one classifiers of Support Vector Machine (SVM) were used to classify; one against one SVM program from LibSVM was applied to multi-class classification using voting strategy in MATLAB. Facing to the same number of votes, we propose a new algorithm. Experimental results demonstrate the effectiveness of the feature extraction method and the multi-class SVM algorithm.

Abstract: This paper concerns a venation-like design method of rib layout and its application on some plates subjected to bending loads. Main topological characters of dicotyledonous venation and two determinative mechanical parameters in leaf venation morphogenesis theories are extracted, on the basis of those elicitations, a venation growing algorithm is proposed as an attempt at the proper layout of ribs in plate. Energy criterion and shear stress is specified as the factor orienting mainvein and subveins respectively. Vectorial equation equilibrium is used in reorganization to calculate widths and adjust vein cells slightly. Finite element method functions as background technique, under which several simple-shaped plates under bending loads are designed by venation growing algorithm. The resultant venation-like ribs offer multi-balanced improvements.

Abstract: H-beam wedge heads are traditionally cut by manual operation. Considering the complex operation, high labor intensity and poor quality of the manual operation, a dimensional variable groove cutting machine of CNC H-beam wedge head is developed in the research, which concerns mechanical components and numerical systems. The mechanical structure are introduced first, especially gradeless piercing gas line. In the CNC system, based on minimum deviation method, a real-time interpolation algorithm is adopted and successfully applied. The human-computer interface of CNC system is also represented. Some machinable typical work pieces are illustrated also

Abstract: A mobile robot prototype with independent propulsion and individual steering and a 5th steerable propulsive wheel has been developed. Different prototypes with diversified wheelbase, wheel stance, clearance, stability margin, altitude of center of gravity and 5th wheel posture can be achieved by reconfiguration. And a special prototype has been made to deal with the situation that the robot will go on traverse after it is flipped over.

Abstract: The purpose of this paper is to solve the positioning problem of a double body working ship. Dynamic characteristics of mooring system are analyzed with the effect of wind, wave and current. According to the dynamic equations of the system in the horizontal plane, longitudinal force coefficient, lateral force coefficient and yawing moment coefficient are obtained by towing test. The wind lord, wave load, current load and chain force can be calculated by empirical formulas. The motions of a mooring system are simulated in MATLAB. The results show that yawing motion would be occurred for the mooring system with single anchor at one point. The motions of the system have similar forms under the same amplitude of external loads. The results are agreed well with the observation data from documents about this relation. It is also can be point out that single point mooring system has poor stability and can not control the motion accurately. Thus dynamic positioning/mooring system should be developed for anchored working ships. This research in this paper provides the theoretical support and the analysis foundation for the further studies.

Abstract: The purpose of this paper is to investigate the optimal placement of piezoelectric actuator for active vibration control of smart structure. The structures can be described in the modal space based on the independent modal space control method and dynamic equations derived from finite element model. The modal damping ratios are derived from modal equations and an optimal target is given by maximizing the modal damping ratios. Accumulation method is adopted to the optimization calculation. Simulations are carried out for active vibration control of a conical shell with distributed piezoelectric actuators. Control effects proved the validity of the optimal method above by compared with the non-optimal results. The optimal method in this paper gives a useful guide for quantity optimization of actuators to piezoelectric structures.