焊铝合金用IGBT交流矩形波弧焊逆变器

本文介绍了新型开关元件ＩＧＢＴ管作为逆变开关元件的交流矩形波逆变器的原理。并通过实验证明，该电源具有良好的引弧和稳弧性能，在铝合金焊接方面具有较好的工艺性能。     

Fault-accommodation with intelligent sensors

Optimal sensor fault-accommodation is considered for faults modelled by an increase in measurement noise. This noise is taken to be bounded and its probabilistic properties unknown. It is assumed that intelligent (e.g. self-validating) instrumentation is in use and estimates of the noise bounds are available. The fault-tolerant controller is designed to optimize a noise rejection and a nominal reference tracking index and leads to a mixed norm minimization problem (l₁/l₂). We exploit known results and a particular feedback configuration to show that it is possible to optimize simultaneously without a trade-off the two performance indices. The results are applied to systems where the presence of auxiliary measurements allows for an optimal fault-accommodation strategy. Using properties of the optimal solution, we define a factorization for the optimal controller alternative to the Youla parametrization, leading to an algorithm which is optimal, transparent and efficient.     

Tracking trajectories of the cart-pendulum system

The problem of tracking a periodic trajectory of the well-known cart-pendulum system is solved. After a change of coordinates and a change of feedback, the equations of this system are nonlinear but feedforward. This property is extensively used to carry out for this system the design of uniformly asymptotically stabilizing time-varying state feedbacks by using the forwarding approach.     

辽宁省2002年水情趋势预测

针对辽宁省旱涝发生的基本规律,系统介绍多年来开展水文中长期预报所应用的理论和方法,总结水情趋势预测工作的经验,对2002年水情趋势进行分析预测。     

电容检测纱线传感器转换特性对纱线不匀率测试的影响

讨论了纱线测试中受电容检测纱线传感器转换特性的非线性影响，测得的条干不匀率值与纱线的实际条干不匀率值之间的差异，从理论上估计了纱线在不同的电容检测槽内测试时，由于其截面充满系数不同而引起的相对差异，并用试验数据加以验证。     

Chaotic pulse position modulation to improve the efficiency of sonar sensors

Ultrasonic devices are widely used in robotics as exteroceptive sensors for ranging measurements. Robotic applications often involve a large number of sonars operating concurrently, giving rise to the phenomenon of crosstalk. In this work, the problem of improving performance of ultrasonic devices in the presence of crosstalk and noise is addressed. In order for each device to discriminate its own echo, chaos is exploited to create unique firing sequences. In particular, the firing scheme described in this work is inspired to a modulation scheme used in chaotic communications, called chaotic pulse position modulation (CPPM). The evaluation of the time of flight is performed by a detection filter. The experimental setup consists of a Polaroid 600 electrostatic transducer driven by a continuous CPPM modulator. Experimental results confirm the suitability of the approach.