Both the energy efficiency and correlation characteristics are important in airborne sonar systems to realize multichannel ultrasonic transducers working together. High energy efficiency can increase echo energy and measurement range, and sharp autocorrelation and flat cross correlation can help eliminate cross-talk among multichannel transducers. This paper addresses energy efficiency optimization under the premise that cross-talk between different sonar transducers can be avoided. The nondominated sorting genetic algorithm-II is applied to optimize both the spectrum and correlation characteristics of the excitation sequence. The central idea of the spectrum optimization is to distribute most of the energy of the excitation sequence within the frequency band of the sonar transducer; thus, less energy is filtered out by the transducers. Real experiments show that a sonar system consisting of eight-channel Polaroid 600 series electrostatic transducers excited with 2 ms optimized pulse-position-modulation sequences can work together without cross-talk and can measure distances up to 650 cm with maximal 1% relative error.

Ultrasonic crosstalk is one of the main causes of false distance measurements that reduce the work efficiency of sonar sensors in mobile robots. To enhance the real-time performance of sonar systems, short digital pulse-position modulation (PPM) sequences are used to trigger ultrasonic transducers. Due to their properties of sharp autocorrelation and flat cross correlation, chaotic and pseudorandom number series are used to modulate pulse positions. A genetic algorithm is adopted to optimize the range of duration between pulses. Real experiments using Polaroid 600 series instrument-grade electrostatic transducers validate the suitability of the proposed method.

A polynomial y=y0+α1x+α2x2+α3x3+...can be used for matching a non-linear functiony=f(x). The key is how to obtain its coefficients. In this paper, a normalized method is presented for matching any non-linear functions. There is a corresponding normalized polynomial y=y0+an+bn2+cn3+..., n=x/x1, n1=x1/x1=1, nmax=xmax/x1.ni is an integral, x1 is a ratio ruler of the abscissa x, then (α1α2α3...)T=(ax1−1bx1−2cx1−3...)T. a, b, c... can be obtained from the multiplication of normalized matrices. Two examples taken from transducers are presented. When the polynomial matches are used for two different sections in x abscissa, the conditions for continuation of the calculated values for these functions and their derivatives are discussed and the development of sine function in different sections of abscissa is presented as an example.

In this paper, an AEKF algorithm is used to localize a mobile robot equipped with eight Polaroid sonars in an indoor structured environment. The system state equation and sonar measurement models used for locating the mobile robot are set up. The localization process based on the AEKF algorithm is given. Four criteria used to judge the validity of predictive measurements of sonars are presented, which can increase the probability of the matching between predictive measurements and actual measurements. Experiments show that the localization precision based on our methods is greater than that using the conventional EKF algorithm.

In this paper, the wall-following problem of an AGV is characterized by keeping a constant distance from a wall. Four Polaroid ultrasonic range sensors (sonar) are used to obtain information of the distance between the AGV and the wall. Four sonars are divided into two groups being placed at the front and back end on the right side of the AGV, respectively. A digital filter is used to get rid of disturbance and wrong readings. The former results mainly from the door and the latter from the specular reflection and accidental scattering. To obtain good dynamic and steady performances, a new compound fuzzy-I control algorithm is presented. Our methods have been verified by following a 15-meter-long wall with one door by using our TIT-1 AGV (TIT: Tianjin Institute of Technology). The results show a good performance with an error of ±2 cm from the desired distance to the wall.

Crosstalk is one main problem which leads to false distance measurement and reduces work efficiency of ultrasonic range sensor systems in mobile robots. The reason which results in ultrasonic crosstalk is briefly analyzed. To enhance the SNR (Signal Noise Ratio) and work efficiency, different methods used to avoid ultrasonic crosstalk have been put forward in the past decade. Such representative methods are classifled into two categories, which are called heuristic soft-rocessing strategy and hardware based coding strategy in this paper. The advantage and disadvantage of each method are analyzed. Suggestions and comments on designing non-crosstalk ultrasonic range system are proposed at the end.

给出了一种用于实现主动嗅觉（也称气味/气体源定位或化学烟剁跟踪）的多机器人协同搜索策略。将蚁群算法与逆风搜索相结合用于协调多机器人的运动方向。蚁群算法可有效调动机器人朝信息素高的区域运动且保证机器人之间的距离不会过大；逆风搜索可降低算法过早地陷入局部最优的概率。为正确判断转移方向，蚁群算法中还增加了对历史信息的考虑。在源头确认方面，本文提出了气味/气体浓度持久性判断结合机器人旋转计算流体质量通量散度的方法。仿真表明，本文的主动嗅觉搜索策略可适用于湍流烟剁环境，且可有效地逃脱浓度局部最优和风场的漩涡，另外可最终确认源头位置。

对主动嗅觉（或称移动机器人气味/气体定位）问题的研究现状进行了较为详细的介绍。分析了当前此研究所使用的具有代表性的气味/气体和风向传感器原理。总结了主动嗅觉所包含的三个步骤，即气味/气体烟羽的发现、跟踪和气味/气体源确认，及每一步所采取的主要策略。最后，指出了当前主动嗅觉研究的主要难点。

本文采用Quine-McCluskey(Q-M)提出的用逻辑方法寻找素蕴涵（prime implicants）的思想，提取给定环境中所有基本矩形自由区域（prime rectangle free area），并将这些区域表示为连通图（我们称之为Q-M图）的节点，提出首先使用双向A算法搜寻连通图中的最优节点路径，然后采用超前尽可能多个节点的思想规划实际几何路径，通过住址研究表明，本文提出的方法计算简单，规划的路径可以达到或接近最优路径。