基于STM32的短距离激光测距仪设计

为了解决传统人工测距存在测量精度低、误差大,且耗时费力等问题,设计了一种基于STM32的短距离激光测距仪。介绍了该激光测距仪的系统组成和原理,给出了软硬件实现的方法,并进行实验测试。实验结果表明,该激光测距仪可以快速实现对目标距离的准确测量,测距范围为0.03m～80m,测量精度为±2mm,且具有面积测量、体积测量、连续测量距离和数据存储等功能,能够满足人们日常生活的测距需求。     

正交调制降频相位式激光测距

为了提高激光测距的精度与稳定性,通过改良传统相位激光测距仪,设计了新型正交调制降频与最小二乘法解相位的相位式激光测距仪。使用反射镜实现内外测距光路,通过正交调制技术对发射激光进行幅度调制,接收模块接收到的回波信号经过混频器后再经过低通滤波器将回波信号降频,降低解相难度并提升解相精度。改用分时测量得到距离相位从而消除二次混频方法所产生的附加相移,分别对内外光路低频回波信号采样进行模数转换后使用最小二乘法求解相位。采用多频率调制测量兼顾激光测距范围与测量精度,最后通过超定方程解模糊算法求解多频测距的待测距离。在国家标准基线上进行样机测试,实验结果表明,在60m量程内正交调制激光测距仪的测量平均误差控制在1.5mm以内,测距量程内标准差保持在0.9mm以内。     

基于CPLD的面阵CCD驱动时序发生器设计

CCD技术在图像传感和非接触测量领域发展前景广阔。CCD驱动时序的产生是其应用的关键。在分析Sony公司的ICX205AL型面阵CCD器件驱动时序关系的基础上,设计了其驱动时序发生器。选用复杂可编程逻辑器件(CPLD)作为硬件设计平台,使用Verilog硬件描述语言对该驱动时序发生器进行了硬件描述。所设计的驱动时序发生器采用ispLEVER软件进行了功能仿真,并针对Lattice公司的可编程逻辑器件LC4256V-75T100I进行了硬件适配。实际测试表明,所设计的驱动时序发生器能够满足面阵CCD的驱动要求,实现了设计目的。     

高精度激光测距仪在大物位上的应用研究

工业上有很多物位需要精确测量,虽然有一些仪表能够测量,满足了生产工艺要求,但是对于大量程的物位,要么测量的量程不够,要么测量精度不够,要么满足不了仪表安装要求等,而激光测距仪有着良好的抗电磁波干扰,很高的精度,方向性强及测量长度大,基于以上原因,高精度激光测距仪在大物位测距上就有了独特优势和应用前景。     

数字相关检测技术扩大脉冲式激光测距测量范围的研究

分析了普通激光测距仪远端测距受限的原因,提出了运用数字相关检测技术来对信号进行处理,从而扩大测量范围的方法,并对某型号激光测距仪采用数字相关检测技术后测距范围的扩大进行了理论推导.     

基于超定方程组的相位激光测距解模糊算法

快速准确的测距解模糊算法是相位式激光测距仪实现快速测距的关键问题。研究了一种基于超定线性方程组的相位测距解模糊算法,该算法避免了对最优解的搜索,因而运算量小、求解速度快。首先使用差频测相法在较大的不模糊距离上捕获到目标,获得近似距离值,然后使用这一距离值准确求解出不同频率调制波之间的周期数之差,从而构建超定线性方程组,最后应用最小二乘法求解出准确距离。同时还对该算法的2种解法进行计算机仿真,比较仿真结果,选取用间接法求解目标距离,并对该解法进行了精度分析。对3台K-60系列激光测距仪在精度为0.18 mm的国家标准基线上进行了测距试验,结果表明,3台样机的平均测量误差小于2 mm,测量标准差小于1 mm,验证了该算法是有效的。     

基于LIN总线的矿用超声测距系统设计

针对煤矿井下超声辅助倒车装置抗干扰能力较弱的问题,设计基于LIN总线的超声测距系统,以提高系统整体的抗干扰能力。首先设计LIN主节点电路并改善其驱动能力,然后分析e524.06芯片的测距时序,明确测距流程并编写程序完成系统,最后对系统进行测距精度和稳定性试验。结果表明,控制器可以通过LIN主节点电路与e524.06所组成的超声收发单元之间完成双向可靠通信,系统可以实现250～2 700 mm范围内的距离测量,测量误差小于30 mm,测量波动小于10 mm。     

基于激光测距的大尺寸测量应用研究

为了实现工业大尺寸几何形状的测量,基于激光测距原理,构建测量系统,提出通过极坐标转化为直角坐标系的方法,在二维平面内拟合测量对象的表面轮廓.首先,从多种反射率材料分析激光测距测距延迟时间.然后,以800mm标准宽座角尺对激光测距仪进行了精度校准,标准差最大1.5mm,最小值0.2mm,适于大尺寸测量范围.利用Visual C+ + 6.0中MSComm控件实现了激光测距仪与计算机之间的数据通信.最后,以800mm标准宽座角尺和凹凸海绵表面为测量对象,利用本方法进行实验,得到了相应表面轮廓,并计算了标准角尺拟合直线的标准差最大为0.7mm.实验结果表明,测距仪毫米级精度可以实现二维平面拟合,体现了手持式激光测距仪在工业大尺寸测量方面的应用前景.     

线阵CCD阵列检测系统设计

以TCD1208AP为例，叙述了线阵CCD的时序逻辑，并设计了相应的阵列检测系统。系统使用单片机作为控制单元，使用在系统可编程器件设计了CCD的时序发生器，使用模数转换器AD9243和FIFO缓存器构成高速数据采集系统。分析了时序发生器的组成原理，并基于ispLSI1016实现设计，给出了实测波形。分析了14位3 MHz模数转换器AD9243和9位4k容量的FIFO存储器IDT7204的时序，设计中使用2片IDT7204构成一个14位的缓存器．给出了数据采集系统接口电路图，并对电路设计进行了说明。     

基于ARM的智能超声波测距仪

以研制低成本高精度的测距仪为目的,提出了一种基于ARM的超声波测距系统的设计方案.介绍了超声波测距的工作原理,设计了系统的整体框架和各单元硬件电路,给出了程序控制流程图,详细分析了影响测距系统精度的主要因素,并提出误差修正的方法.在实验室对系统进行了实地测试,实验表明:系统精度可达cm数量级,电路具有结构简单、操作方便、精度高的特点.     

一种基于双目相机与单点激光测距仪的标定方法

近年来,随着工业机器人技术的不断完善,利用相机与激光测距仪结合测量的应用不断增多。为了使两者之间配合的更加便利,两者之间的标定是必不可少的。本文提出了一种基于双目相机与单点激光测距仪的标定方法,以双目相机光心为原点,建立相机坐标系。将单点激光测距仪光点打到标定板上,并在标定板上形成光斑,通过灰度重心法提取光斑中心像素点,利用双目相机的内参矩阵及深度数据获取光斑点的三维坐标值。然后利用两个三维坐标点建立公式求取外参参数的粗略解,同时通过相机坐标系下多个光斑点的三维坐标建立约束方程,并利用优化算法对约束方程进行优化,得到精确的外参参数值。该方法做法简单,且对标定器件无特殊要求,通过该方法得到的外参参数精度高,鲁棒性好。实测结果表明,通过该算法得到的外参参数进行重投影后,平均相对误差小于0.30%,能够应用于实际生产过程中。     

用于激光雷达的高精度脉冲延时及脉宽控制研究

针对激光雷达距离选通可实现不同距离雷达回波信号的选通采集,采用AD9501延时芯片和单片机设计了脉冲延时时间和脉宽可调的延时电路。其中,采用LabVIEW编写上位机控制软件,2片延时芯片级联实现了16位精度的延时调节,第3片延时芯片及R-S触发器实现了8位精度的脉宽的调节。实验中,3片AD9501由单片机进行控制,通过调整电路参数和上位机参数,延时范围达到1.8 μs可调,延时精度大约为30 ps,存在固有延时280 ns,完全满足激光雷达距离选通的要求。     

Note: Optical trigger device with sub-picosecond timing jitter and stability

We are presenting the design, construction, and overall performance of the optical trigger device. This device generates an electrical signal synchronously to the detected ultra-short optical pulse. The device was designed for application in satellite laser ranging and laser time transfer experiments, time correlated photon counting and similar experiments, where picosecond timing resolution and detection delay stability are required. It consists of the ultrafast optical detector, signal discriminator, output pulse forming circuit, and output driver circuits. It was constructed as a single compact device to optimize their matching and maintain stability. The detector consists of an avalanche photodiode--both silicon and germanium types may be used to cover the wavelength range of 350-1550 nm. The analogue signal of this photodiode is sensed by the ultrafast comparator with 8 GHz bandwidth. The ps clock distribution circuit is used to generate the fast rise/fall time output pulses of pre-set length. The trigger device timing performance is excellent: the random component of the timing jitter is typically 880 fs, the temperature dependence of the detection delay was measured to be 370 fs/K. The systematic error contribution depends on the laser used and its stability. The sub-ps values have been obtained for various laser sources.     

Health management of laser rangefinder considering maximum continuous working time

High-power lasers have severe thermal effects. The heat buildup during long-term operation will increase the threshold current of the laser and the internal defects, which will seriously affect the lifetime of the device. A temperature sensor is difficult to install on the laser rangefinder due to the small size of the solid-state laser device. Considering this situation, this work analyses the thermal mechanism of the laser rangefinder and proposes a temperature calculation method for the crystal working substance inside the laser rangefinder based on the finite element simulation to obtain the crystal center temperature and thermal model with the working time. Then, the prediction model of the maximum continuous working time of the laser can be obtained. The proposed model can provide an early scientific warning for the remaining continuous working time of the solid-state laser and improve the single-shot utilization of the solid-state laser to a certain extent. A comprehensive health management framework of laser rangefinders including FMEA is also proposed.

     

组合CCD图像和稀疏激光测距 数据的建筑物三维信息提取

对组合高分辨率航空CCD图像和机载稀疏激光扫描测距数据自动提取城市建筑物的三维信息进行了研究。航空CCD图像能清晰地给出建筑物的几何形状和分布,因此采用了自适应的Canny边缘检测算法来提取CCD图像上的全部边缘信息,然后根据双向投影直方图和线段匹配方法来自动而准确地提取建筑物的平面轮廓信息,最后根据CCD提取的轮廓信息从机载激光扫描测距数据中提取建筑物的高度信息,从而实现了每栋建筑物的三维信息提取。通过实际数据的处理和提取,说明了组合CCD图像和机载激光扫描测距数据可以自动重建建筑物的三维信息。     

Design and Development of a Miniature Digital Delay Generator for Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is widely used for atomic emission spectroscopy. The delay time is a significant factor that affects the selection of the optimal plasma conditions. In this study, a miniature digital delay generator was designed and built for time-resolved LIBS with a widely adjustable time delay with 0.1 ns resolution. Experimental observations were used to examine and perform a diagnosis study of the delay time accuracy and a series of time-resolved LIBS spectra with satisfactory signal-to-noise ratios were obtained. Therefore, this delay generator is suitable for replacing the widely used delay generators in LIBS instrumentation and may have widespread application in portable instrumentation.     

脉冲激光测距中高精度时间间隔测量方法的研究

高精度时间间隔测量对脉冲激光测距系统具有重要意义,为此提出了一种新的高精度时间间隔测量方法。该方法在FPGA中实现了脉冲计数法、多相采样法和延迟链法的结合。采用脉冲计数法对被测时间间隔进行“粗值”测量,保证大的动态测量范围。利用FPGA内部锁相环产生N路同频率,相位均匀分布的时钟信号作为计数时钟,基于等精度测频原理,将被测时间间隔的测时分辨率提高到Tclk/N。利用FlipFlop锁存器形成延时链,对被测信号与相邻计数时钟的时间间隔进一步量化。该方法解决了传统多相采样技术中倍频次数高则相移分辨率降低的问题,在不增加计数时钟和有限延迟链数量的前提下,得到较高测时分辨率。测试结果表明,该时间间隔测量模块不但可以实现大的动态测量范围,而且测时过程相对较短,具有较高测时精度。     

一种简便实用的半导体激光器调制电路

半导体激光器是实用中最重要的一类激光器,它具有可直接调制的特点。本文介绍了一种简单有效的半导体激光器调制电路,给出了电路原理图,元件的选择原则,最后介绍了在非合作目标相位式激光测距系统中实现正弦调制的应用。     

Modelling,kinematic parameter identification and sensitivity analysis of a Laser Tracker having the beam source in the rotating head

This paper presents a new kinematic model, a parameter identification procedure and a sensitivity analysis of a laser tracker having the beam source in the rotating head. This model obtains the kinematic parameters by the coordinate transformation between successive reference systems following the Denavit–Hartenberg method. One of the disadvantages of laser tracker systems is that the end-user cannot know when the laser tracker is working in a suitable way or when it needs an error correction. The ASME B89.4.19 Standard provides some ranging tests to evaluate the laser tracker performance but these tests take a lot of time and require specialized equipment. Another problem is that the end-user cannot apply the manufacturer’s model because he cannot measure physical errors. In this paper, first the laser tracker kinematic model has been developed and validated with a generator of synthetic measurements using different meshes with synthetic reflector coordinates and known error parameters. Second, the laser tracker has been calibrated with experimental data using the measurements obtained by a coordinate measuring machine as nominal values for different strategies, increasing considerably the laser tracker accuracy. Finally, a sensitivity analysis of the length measurement system tests is presented to recommend the more suitable positions to perform the calibration procedure.