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Improved sampling scheme for LiDAR in Lissajous scanning mode

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Microsystems & Nanoengineering 2022年第3期8卷 29-37页

作者： Junya Wang gaofei zhang Zheng You School of Mechanical Science and Engineering Huazhong University of Science and Technology430074 WuhanChina Department of Precision Instrument Tsinghua University10084 BeijingChina State Key Laboratory of Precision Measurement Technology and instruments Tsinghua University10084 BeijingChina

MEMS light detection and ranging(LiDAR)is becoming an indispensable sensor in vehicle environment sensing systems due to its low cost and high *** beam scanning trajectory,sampling scheme and gridding are the key technologies of MEMS LiDAR *** Lissajous scanning mode,this paper improves the sampling scheme,through which a denser Cartesian grid of point cloud data at the same scanning frequency can be *** summarizing the rules of the Cartesian grid,a general sampling scheme independent of the beam scanning trajectory patterns is *** and experiment results show that compared with the existing sampling scheme,the resolution and the number of points per frame are both increased by 2 times with the same hardware configuration and scanning frequencies for a MEMS scanning miror(MEMS-SM).This is beneficial for improving the point cloud imaging performance of MEMS LiDAR.

关键词： LiDAR scheme mode

Design rules for dense and rapid Lissajous scanning

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Microsystems & Nanoengineering 2020年第1期6卷 158-164页

作者： Junya Wang gaofei zhang Zheng You Department of Precision Instrument Tsinghua UniversityBeijingChina State Key Laboratory of Precision Testing Technology and Instruments Tsinghua University10084 BeijingChina Information Engineering University ZhengzhouChina

Lissajous microscanners are very popular in compact laser-scanning applications,such as solid-state light detection and ranging(LIDAR),owing to their high-quality factor and low power *** the Lissajous scanner driven by a two-axis micro-electro-mechanical system scanning mirror(MEMS-SM),the design theory is insufficient to meet the temporal and spatial resolution at the same *** this paper,the greatest common divisor of the two-axis driving frequency is used as the temporal resolution,the concept of the fill factor(FF)is used to describe the spatial resolution of the scanner,and a general algorithm for calculating the FF is *** with the characteristics of the Lissajous trajectory,three design rules of the general Lissajous scanner are proposed,and the design theory of the Lissajous scanner enabling MEMS LIDAR is *** results show that the proposed design rules can effectively meet the LIDAR design requirements.

关键词： scanner LIDAR scanning

A motion characteristics modeled angular position sensor by nonlinear transfer of differential capacitance for miniaturized scanning mirrors

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Microsystems & Nanoengineering 2023年第6期9卷 129-147页

作者： Songtao Liu gaofei zhang Lingyun zhang Junya Wang Minghao Gong Zheng You Department of Precision Instrument Tsinghua UniversityBejing 100084China Key Laboratory of Smart Microsystem(Tsinghua University) Ministry of EducationBeijing 100084China State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua UniversityBeijing 100084China School of Mechanical Science&Engineer Huazhong University of Science and TechnologyWuhan 430074China

In this paper,an angular position sensor(APS)designed for a resonant miniaturized scanning mirror(M-SM)is *** APS operates based on the principle of differential variable capacitance,significantly expanding the detectable bandwidth from a few hertz to several *** modeling the motion characteristics,the sampling rates of the biaxial scanning angles are 1473.6 times and 539.4 times higher than those of conventional ***,the motion characteristics model is presented as a simple harmonic motion,converting sampled capacitance into continuous ***,the nonparallel state of the M-SM and sensor is transformed into a parallel state through the space coordinate system ***,a 2D nonlinear angle transfer function is developed to convert the differential capacitance into an angle,thereby mitigating the nonlinear errors resulting from large *** an accuracy better than 0.014°,the measuring range expands from±0.5729°(±10 mrad)to±5.026°(±87 mrad).Additionally,the capturing mode and tracking mode are proposed to monitor real-time angular changes of the M-SM with an accuracy of 0.017°.High-precision APSs have enhanced beam pointing accuracy and resolution and can thereby be used to advance the development of laser components,including light detection and ranging(LiDAR).

关键词： capacitance angular nonlinear

Applications of MEMS devices in nanosatellite

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Engineering Sciences 2012年第5期10卷 33-35,57页

作者： You Zheng Li Bin Yu Shijie zhang gaofei Department of Precision Instruments and Mechanotogy Tsinghua University Beijing 100084 China

micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smaller nanosatellites with higher performance and longer lifecyele. The power consumption of MEMS devices is usually much lower than that of traditional devices, which will greatly reduce the consumption of power. For its small size and simple architecture, MEMS devices can be easily integrated together and achieve redundancy. Launched on April 18, 2004, NS - 1 is a nanosatellite for science exploration and MEMS devices test. A mass of science data and images were acquired during its running. NS - 1 weights less than 25 kg. It consists of several MEMS devices, including one miniature inertial measurement unit（MIMU） , three micro complementary metal oxide semiconductor （CMOS）cameras, one sun sensor, three momentum wheels, and one micro magnetic sensor. By applying micro components based on MEMS technology, NS - 1 has made success in the experiments of integrative design, manufacture, and MEMS devices integration. In this paper, some MEMS devices for nanosatellite and picosatellite are introduced, which have been tested on NS -1 nanosatellite or on the ground.

关键词： MEMS devices NS - 1 nanosatellite lighter weight and lower power consumption

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微型二维扫描镜的原理性实验研究

清华大学学报（自然科学版） 2008年第11期48卷 1919-1922页

作者：张弛张高飞尤政清华大学精密仪器与机械学系精密测试技术及仪器国家重点实验室北京100084

为满足激光扫描装置微型化的要求,设计了一种微型二维扫描镜,能够通过反射激光束实现二维扫描。对这种结构建立了理论模型,分析了2个方向上的扫描频率和最大扫描角;对微型二维扫描镜原理样机进行了实验研究。结果表明:2个一维扫描频率... 详细信息

为满足激光扫描装置微型化的要求,设计了一种微型二维扫描镜,能够通过反射激光束实现二维扫描。对这种结构建立了理论模型,分析了2个方向上的扫描频率和最大扫描角;对微型二维扫描镜原理样机进行了实验研究。结果表明:2个一维扫描频率分别为170.1H z和378.8H z;同时施加这2种谐振频率的激励时,可实现该扫描镜的二维大角度偏转;2个方向上的最大扫描角随激励位移的增加而变大;在10μm驱动位移的激励下,该微型二维扫描镜可达到大于30°×20°的扫描范围。

关键词：二维扫描镜微型化扫描频率扫描范围

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一种面向空间应用的激光测距方案设计与实验

红外与激光工程 2014年第3期43卷 700-706页

作者：杨冉张高飞张紫辰尤政清华大学精密仪器系北京100084 清华大学精密测试技术及仪器国家重点实验室北京100084

针对空间应用背景对激光测距系统"宽测程、高精度、实时测量"的要求,使用相位式激光测距法中分散的直接法设计了一种激光测距方案,其理论测程可以达到10km,测距精度可以达到0.1m。对激光器和窄带滤光片提出了技术指标要求,对雪崩光电二... 详细信息

针对空间应用背景对激光测距系统"宽测程、高精度、实时测量"的要求,使用相位式激光测距法中分散的直接法设计了一种激光测距方案,其理论测程可以达到10km,测距精度可以达到0.1m。对激光器和窄带滤光片提出了技术指标要求,对雪崩光电二极管(APD)进行了选型,并通过对空间环境背景噪声的分析和对空间非合作目标测程方程的分析验证了技术指标选择和APD选型的合理性。实验结果表明:该系统最大测距误差为8.71 cm,符合"测距精度优于0.1 m"的技术指标要求,同时具有较高的动态性能,测距时间不超过1 ms。此外,系统具有较小的整体功率和质量,分别为13.29 W和693 g,可作为天基应用的有效载荷。

关键词：相位式激光测距空间应用测距精度动态性能

^(63)Ni-Si辐射伏特电池镍薄膜源设计与制备

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清华大学学报（自然科学版） 2017年第8期57卷 810-814页

作者：李浩张高飞尤政清华大学精密仪器系精密测试技术及仪器国家重点实验室北京100084

在辐射伏特电池换能器件表面直接制备^(63)Ni辐射源的方法存在加载量少、活性低、PN结性能退化等问题。该文提出一种利用氧化铟锡(ITO)薄膜作为导电层材料实现在透明封装玻璃表面电镀^(63)Ni源的方法。根据辐射源自吸收效应理论模拟计算... 详细信息

在辐射伏特电池换能器件表面直接制备^(63)Ni辐射源的方法存在加载量少、活性低、PN结性能退化等问题。该文提出一种利用氧化铟锡(ITO)薄膜作为导电层材料实现在透明封装玻璃表面电镀^(63)Ni源的方法。根据辐射源自吸收效应理论模拟计算了^(63)Ni-Si辐射伏特电池辐射源的最佳厚度。采用磁控溅射工艺在400μm玻璃基底上制备了厚度为180nm的ITO导电薄膜,利用电化学工作站,对ITO薄膜表面进行电镀镍,对镀镍之后的薄膜材料微观形貌、薄膜厚度进行表征,并对基于该辐射源制备方法的^(63)Ni-Si辐射伏特型同位素电池电学输出性能进行理论仿真,仿真结果表明:在厚度为2μm、活度为7.25×108Bq、面积为36mm2辐射源的辐照下,辐射伏特电池理论上能够输出85.4nW输出功率。

关键词：辐射伏特电池 63Ni 电镀辐射源

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多样化软件系统量化评估方法

通信学报 2020年第3期41卷 120-125页

作者：姚远潘传幸张铮张高斐信息工程大学网络空间安全学院河南郑州450001 数学工程与先进计算国家重点实验室河南郑州450001

为了指导多样化软件系统在不同应用场景下的冗余变体选取,在研究多样化软件评价指标的基础之上,建立针对软件多样化系统的可用性评价指标体系、安全性评价指标体系、性能指标评价体系,并在此基础上构建了针对多样化软件系统的层次评价... 详细信息

为了指导多样化软件系统在不同应用场景下的冗余变体选取,在研究多样化软件评价指标的基础之上,建立针对软件多样化系统的可用性评价指标体系、安全性评价指标体系、性能指标评价体系,并在此基础上构建了针对多样化软件系统的层次评价体。采用实例验证了所提层次评价体系在小规模变体数目下的可行性。

关键词：拟态防御多样化软件量化评估层次分析

Observation on the Clinical Effect of Stereotactic Body Radiotherapy in Patients with Oligometastatic Tumors

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Journal of Clinical and Nursing Research 2022年第6期6卷 12-25页

作者： Jiao Yu gaofei zhang Long Jin Xin Chen Hui Gao Shaojun Ma Zhuo Wu Department of Radiation Oncology Shaanxi Provincial People’s HospitalXi’an 710068China Department of Radiology Shaanxi Provincial People’s HospitalXi’an 710068China Department of Medical Equipment Shaanxi Provincial People’s HospitalXi’an 710068China

Objective:To observe the efficacy and safety of stereotactic body radiotherapy(SBRT)in the treatment of extracranial ***:A retrospective analysis of 70 patients with extracranial oligometastasis of malignant tumors who underwent SBRT in our hospital(Shaanxi Provincial People’s Hospital)from January 2019 to December 2021 with≤5 metastases,≤3 metastatic organs,and metastases with diameters of≤5 *** to the clinical data of patients,the dose-fractionation mode of SBRT is mainly determined according to the pathology of the primary tumor,the location of the metastatic tumor,and the important structures around the *** local control,survival and adverse reactions were ***:A total of 219 oligometastatic lesions in 70 patients were treated with *** median follow-up time was 24 months(12-40 months).The local control rate(LCR)of all target lesions assessed 3 months after radiotherapy was 94.1%;the 1-,2-,and 3-year LCRs were 88.6%,74.6%,and 64.9%,*** median progression-free survival(PFS)was 11.8 months(95%CI,8.9-14.7 months),and the 1-and 2-year PFS rates were 48.6%and 32.6%,respectively;the median overall survival(OS)was 31.9 month(95%CI 26.0-37.8 months),the 1-year OS rate was 84.3%.The local control time,PFS,and OS of patients with metastases≤3 cm were significantly better than those with metastases>3 cm,and the differences were statistically significant(P<0.05).Acute adverse reactions after SBRT treatment in oligometastatic patients were mainly bone marrow suppression and gastrointestinal reactions,with incidence rates of 48.98%and 30.61%,respectively;chronic adverse reactions were mainly pain(bone,muscle),radiation enteritis,and radiation pneumonitis,with incidence rates of 38.57%,30.00%,and 24.29%,*** treatment-related adverse reactions were mainly grade 1,which were all improved after symptomatic treatment,except for one patient with bone metastases from lung cancer who had grade 4 myelosuppress

关键词： Stereotactic body radiotherapy Extracranial oligometastases Efficacy Adverse reactions