基于全景环视的端到端停车位检测方法

现有停车位检测方案大多将目标检测方案和人工设计的后处理模块进行简单结合,各阶段提取的特征存在大量冗余信息.并且,人工设计的后处理模块通常适应面窄,计算量大,最终导致停车位检测效果难以实用.针对这些问题,本文引入全景视觉,结合现有算法的优点与环视图像的特点,设计端到端的无锚框停车位检测算法.该算法对停车位进行进入线朝向建模,而非单独考虑两个入口点,省去了停车位入口点匹配和朝向判断流程,最终实现完全一体化的停车位位置、朝向和占用情况检测.考虑到实用性,在网络结构设计上进行了速度和精度的平衡、正负样本均衡,以及无后处理等多方面优化.最终,在ps2.0数据集上,本文提出的AFPSD模型以88.7的FPS(每秒帧数)达到68.7%的AP,相较VPS-Net和DMPR-PS方案精度分别提升1.2%和2.1%.由此可知,本文设计的一阶段端到端方案可以代替三阶段方案,在环视图像上实现停车位的稳定检测.

动态场景下基于语义分割与运动一致性约束的车辆视觉SLAM

传统的车辆同时定位与建图方法多依赖于静态环境假设,在动态场景下易引起位姿估计精度下降甚至前端视觉里程计跟踪失败。本文结合Fast-SCNN实时语义分割网络与运动一致性约束,提出一种动态场景视觉SLAM方法。首先利用Fast-SCNN获取潜在动态目标的分割掩码并进行特征点去除,以获取相机位姿的初步估计;随后基于运动约束与卡方检验完成潜在动态目标中静态点的重添加,以进一步优化相机位姿。验证集测试表明,所训练的语义分割网络平均像素精度和交并比超过90%,单帧图片处理耗时约14.5 ms,满足SLAM系统的分割精度与实时性要求。慕尼黑大学公开数据集和实车数据集测试表明,融合本文算法的ORB-SLAM3部分指标平均提升率超过80%,显著提升了动态场景下的SLAM运行精度与鲁棒性,有助于保障智能车辆的安全性。

改进的翻转课堂模型用于大学C语言教学

本文在Robert Talbert翻转课堂结构模型的基础上,提出一种基于慕课资源的改进型翻转课堂结构模型。以大学计算机C语言课程作为实验内容,把基于慕课资源的翻转课堂新结构模型运用到实际教学,取得了较好的教学效果。该教学模型能够增强学生团队合作能力和交际能力,提高学生自主学习能力和创新能力,提高学习效果。

Planning method of droplet fusion scheduling based on mixedinteger programming

The emergence of new display devices,such as organic light-emitting diodes,has brought about numerous advantages,including high material utilization,low cost,and high adaptability.These devices are manufactured using inkjet printing and possess the potential to become a key technology for display transformations.However,a challenge in achieving this is the display effect that reveals uneven brightness and darkness,which can be avoided by controlling the volume of ink solution in a pixel to within 5%.Currently,the volume difference among the nozzles of commercial printheads does not meet the requirements for volume uniformity,thus challenging the printing process.Therefore,designing a suitable printing method that allows for the fusion of different volumes of ink droplets,ultimately reducing the error of the post fusion process,is necessary.In this study,we propose a print display droplet fusion scheduling method comprising two main steps.First,we use a dichotomous trust domain algorithm to obtain a feasible range of printhead docking point spacings for different nozzle and pixel panel resolutions.Second,we model the printing process as a droplet fusion scheduling model based on mixed integer programming,with the optimization objective of achieving intra pixel volume uniformity via ensuring the volume uniformity of ink droplets within all pixels.We verified this method through numerical simulations and printing experiments using 394 pixels per inch(ppi)pixel panels and successfully reduced the volume uniformity error among pixels to within 5%.

面向新工科的智能制造创新人才培养体系构建与实践

针对新工科背景下智能制造创新人才培养中存在的学科交叉封闭、实践创新能力不足、“教与学”方式陈旧等问题,以实践驱动创新的智能制造工程引领教育理念,构建贯穿本科全过程、开放协同的智能制造创新人才培养体系,实施多学科交叉融合、多方协同育人、以学生为中心的智能制造实践与创新教育措施,夯实拔尖创新人才培养基础,满足知识、能力和素养三位一体培养需求。

机器人加工几何误差建模研究:Ⅰ空间运动链与误差传递

以机器人作为制造装备执行体,集成视觉等智能传感器,实现大型复杂零件小余量磨削/铣削/切边/制孔是智能制造的前沿研究方向之一,目前加工误差难以降低是制约其应用的主要难题。以加工误差降低为主要目标,以机器人、视觉传感器、工件、工具为主要对象,研究视觉引导的机器人加工几何误差建模与精度控制,具体包括:在第Ⅰ部分介绍几何误差建模与参数辨识国内外研究现状,研究机器人加工空间运动链与加工误差度量指标定义,推导静态误差(源于工件/工具位姿误差)定量传递模型与动态误差(源于关节运动学误差/关节弱刚度)定量传递模型;在第Ⅱ部分建立手眼位姿参数、工件位姿参数、工具位姿参数等精确辨识的目标函数与计算方法,在考虑关节运动学误差和弱刚度变形的情况下,提出面向整体误差控制的机器人加工(磨削/铣削/切边/制孔等)位姿优化通用模型。

机器人加工几何误差建模研究:Ⅱ参数辨识与位姿优化

根据所构建的空间运动链,机器人加工几何误差一方面与手眼/工件/工具位姿参数辨识误差有关,另一方面与机器人关节运动学误差与弱刚度变形有关。针对这一问题,研究基于运动学误差补偿的手眼位姿参数辨识、考虑测量缺陷影响的工件位姿参数辨识、基于实际加工曲面误差估计的工具位姿参数辨识等新方法,解决位姿参数辨识精度受限于机器人运动精度、现场测点不封闭/密度不均/高斯噪音、加工抖动/受力变形/回转轴误差等多种因素影响的问题;综合考虑关节运动学误差、弱刚度变形、误差补偿,以整体误差控制为目标,建立加工误差补偿与机器人位姿优化通用模型,可推广应用于法向深度(磨削/铣削)、切向滑移(制孔)、角度倾斜(切边)等多种机器人加工误差控制;完成手眼/工件/工具位姿参数辨识试验、整体误差补偿与机器人加工试验,验证所提方法的有效性。

柔性电子制造关键技术与应用

柔性电子在柔性显示、智能蒙皮、健康医疗等领域具有广阔应用前景,已成为各国政府竞相发展的前沿领域,亟待在柔性电子制造关键技术与装备方面有所突破。本文综述了数字制造装备与技术国家重点实验室在柔性电子制造领域的最新研究进展,针对微纳结构跨尺度图案化、柔性致密薄膜高效低温制备、柔性混合系统高效集成、高速视觉在线缺陷检测制造需求,分别提出并发展了空间隔离原子层沉积技术、高分辨率电流体喷印技术、超薄芯片倒装键合技术及自动光学检测技术,阐述了这些技术在印刷显示、智能蒙皮、表皮电子、曲面电路等柔性电子领域的重要应用及突破性进展。

柔性电子喷印制造液滴沉积控制研究综述

喷墨打印技术在柔性电子制备中得到了广泛应用,液滴精确沉积控制是实现高效率、高精度、高分辨率图案化控制的关键.基于单液滴沉积理论,分析了液滴飞行速度、黏度、几何尺寸、基板粗糙度与疏水特性等多种参数对铺展的影响;总结了流体体积(volume of fluid,VOF)、格子玻尔兹曼方法(lattice Boltzmann method,LBM)、多体耗散粒子动力学(many-body dissipative particle dynamics,MDPD)等不同尺度液滴沉积问题的数值模拟方法与开展液滴沉积研究的实验方法.介绍了多液滴沉积融合机理以及通过喷墨打印制备点、线、膜结构的方法,针对液滴精确沉积定位问题,还分析了通过控制基板润湿性梯度、气流辅助、静电聚焦等方法,最后展望了喷墨打印的工程化应用及其研究和应用前景.

Driving force planning in shield tunneling based on Markov decision processes

In shield tunneling, the control system needs very reliable capability of deviation rectifying in order to ensure that the tunnel trajectory meets the permissible criterion. To this goal, we present an approach that adopts Markov decision process (MDP) theory to plan the driving force with explicit representation of the uncertainty during excavation. The shield attitudes of possi- ble world and driving forces during excavation are scattered as a state set and an action set, respectively. In particular, an evaluation function is proposed with consideration of the stability of driving force and the deviation of shield attitude. Unlike the deterministic approach, the driving forces based on MDP model lead to an uncertain effect and the attitude is known only with an imprecise probability. We consider the case that the transition probability varies in a given domain estimated by field data, and discuss the optimal policy based on the interval arithmetic. The validity of the approach is discussed by comparing the driving force planning with the actual operating data from the field records of Line 9 in Tianjin. It is proved that the MDP model is reasonable enough to predict the driving force for automatic deviation rectifying.

Flexible smart sensing skin for“Fly-by-Feel”morphing aircraft

Flexible smart sensing skin is a key enabling technology for the future"Fly-by-Feel"control of morphing aircraft.It represents the next-generation skin of aircraft that can exhibit a more powerful sensing function than a conventional one and could be mounted on arbitrary curvilinear surfaces,especially for advanced autonomic,morphing aircraft.Recent significant technical advances in flexible electronics have overcome many historic drawbacks of conventional smart skin,e.g.,only a limited number of discrete block sensors can be integrated due to the inevitable structural damage and heavy guidelines.Herein,we review the key developments in flexible sensors technology and highlight both the state-of-the-art devices and the potential applications for the measurement of aircraft.We begin with the importance of flexible smart skin for morphing aircraft and then expand to the latest progress in various types of flexible sensors.Then we highlight flexible sensors as smart skin to measure aerodynamic parameters and monitor the structural health,and further to achieve the Fly-by-Feel control.Finally,the challenges and opportunities on flexible smart sensing skin are discussed,from the functional design to practical applications.

Theoretical and experimental study of 2D conformability of stretchable electronics laminated onto skin

Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approach to study interfacial mechanics of the 2D planar EEDs on the checkerboard buckling patterns of human skin.Energy variation method is proposed to determine a criterion whether EEDs laminate conformally onto the skin surface under undeformed and stretched cases.EEDs with low bending stiffness(thin,soft devices/backing layer),smooth and soft skin,and strong adhesion promote conformal contact.Furthermore,the adhesion energy at the EED/skin interface is measured by the homemade peeling experiment platform with different substrate thicknesses and areal coverages.The upper limit of the areal coverage for EED conformal contact with the skin is proposed with given EED/skin properties.Conformability of EEDs are validated by experiments with different substrate thickness,areal coverage and external loadings.It provides a design guideline for EED to conformally contact with the skin surface for more accurate biological signal monitoring.

Experimental study of laser lift-off of ultra-thin polyimide film for flexible electronics

It is increasingly crucial for flexible electronics to efficiently and reliably peel large-area, ultra-thin flexible films off from rigid substrate serving as substrates of flexible electronics device, especially in industrial production. This paper experimentally investigated the mechanism and technologic characteristics of laser lift-off(LLO) process of ultra-thin(～ 2 μm) polyimide(PI)film. It was found increasingly difficult to obtain desirable ultra-thin PI film by LLO with the decrease of the film thickness. The optimal process parameters were achieved considering laser fluence and accumulated irradiation times(AIT), which were found to be strongly correlative to the thickness of PI film. The process mechanism of LLO of PI film was disclosed that laser ablation of interfacial PI will result in the formation of gas products between the PI and glass substrate, enabling the change of interface microstructures to reduce the interface bond strength. The amount of gas products mainly determines the result of LLO process for ultra-thin PI film, from residual adhesion to wrinkles or cracking. The strategy of multi-scanning based on multiple irradiations of low-energy laser pulses was presented to effectively achieve a reliable LLO process of ultra-thin PI film. This study provides an attractive route to optimize the LLO process for large-scale production of ultra-thin flexible electronics.

Flexible hybrid electronics:Enabling integration techniques and applications

The conventional electronic systems enabled by rigid electronic are prone to malfunction under deformation,greatly limiting their application prospects.As an emerging platform for applications in healthcare monitoring and human-machine interface(HMI),flexible electronics have attracted growing attention due to its remarkable advantages,such as stretchability,flexibility,conformability,and wearing comfort.However,to realize the overall electronic systems,rigid components are also required for functions such as signal acquisition and transmission.Therefore,flexible hybrid electronics(FHE),which simultaneously possesses the desirable flexibility and enables the integration of rigid components for functionality,has been emerging as a promising strategy.This paper reviews the enabling integration techniques for FHE,including technologies for two-dimensional/three-dimensional(2 D/3 D) interconnects,bonding of rigid integrated circuit(IC) chips to soft substrate,stress-isolation structures,and representative applications of FHE.In addition,future challenges and opportunities involved in FHE-based systems are also discussed.

Flexible electronics manufacturing technology and equipment

Flexible electronics such as mechanically compliant displays,sensors and solar cells,have important applications in the fields of energy,national defence and biomedicine,etc.Various types of flexible electronics have been proposed or developed by the improvements in structural designs,material properties and device integrations.However,the manufacturing of flexible electronics receives little attention,which limits its mass production and industrialization.The increasing demands on the size,functionality,resolution ratio and reliability of flexible electronics bring several significant challenges in their manufacturing processes.This work aims to report the state-of-art technologies and applications of flexible electronics manufacturing.Three key technologies including electrohydrodynamic direct-writing,flip chip and automatic optical inspection are highlighted.The mechanism and developments of these technologies are discussed in detail.Based on these technologies,the present work develops three kinds of manufacturing equipment,i.e.,inkjet printing manufacturing equipment,robotized additive manufacturing equipment,and roll-to-roll manufacturing equipment.The advanced manufacturing processes,equipment and systems for flexible electronics pave the way for applications of new displays,smart sensing skins and epidermal electronics,etc.By reviewing the developments of flexible electronics manufacturing technology and equipment,it can be found that the existing advances greatly promote the applications and commercialization of flexible electronics.Since flexible electronics manufacturing contains many multi-disciplinary problems,the current investigations are confronted with great challenges.Therefore,further developments of the reviewed manufacturing technology and equipment are necessary to break the current limitations of manufacturing resolution,efficiency and reliability.

Real-time adaptive particle image velocimetry for accurate unsteady flow field measurements

Almost all conventional open-loop particle image velocimetry(PIV) methods employ fixed-interval-time optical imaging technology and the time-consuming cross-correlation-based PIV measurement algorithm to calculate the velocity field.In this study,a novel real-time adaptive particle image velocity(RTA-PIV) method is proposed to accurately measure the instantaneous velocity field of an unsteady flow field.In the proposed closed-loop RTA-PIV method,a new correlation-filter-based PIV measurement algorithm is introduced to calculate the velocity field in real time.Then,a Kalman predictor model is established to predict the velocity of the next time instant and a suitable interval time can be determined.To adaptively adjust the interval time for capturing two particle images,a new high-speed frame-straddling vision system is developed for the proposed RTA-PIV method.To fully analyze the performance of the RTA-PIV method,we conducted a series of numerical experiments on ground-truth image pairs and on real-world image sequences.

Tracking and grasping of moving target based on accelerated geometric particle filter on colored image

Visual tracking and grasping of moving object is a challenging task in the field of robotic manipulation,which also has great potential in applications such as human-robot collaboration.Based on the particle filtering framework and position-based visual servoing,this paper proposes a new method for visual tracking and grasping of randomly moving objects.A geometric particle filter tracker is established for visual tracking.In order to deal with the tracking efficiency issue for particle filter,edge detection and morphological dilation are employed to reduce the computation burden of geometric particle filtering.Meanwhile,the HSV image feature is employed instead of the grayscale feature to improve the tracking algorithm’s robustness to illumination change.A grasping strategy combining tracking and interception is adopted along with the position-based visual servoing(PBVS)method to achieve stable grasp of the target.Comprehensive comparisons on open source dataset and a large number of experiments on real robot system are conducted,which demonstrate the proposed method has competitive performance in random moving object tracking and grasping.

Automatic surface localization by defining weighted-iteration distance function and Lyapunov-test statistic

Automatic localization,aligning the measured points with the design model,is a basic task in free-form surface inspection.The main difficulty of current localization algorithms is how to define effective distance function and localization reliability index.This paper proposes a new method of calculating motion parameters and evaluating localization reliability.First,improved modified coefficient is defined and applied to weighted-iteration distance function,which better approximates the point-to-surface closest distance.It can control the contribution ratios of different measured points by considering the curvature feature and iterative residual.Second,the mapping relationship between localization error and geometric error is analyzed,from which a Lyapunov-test statistic is derived to define a frame-independence index.Then,the determination of localization reliability changes into a supposition examination problem.This can avoid rejecting correct motion parameters,which exists in the traditional judgment of absolute root-mean-square distance.In addition,two test experiments are implemented to demonstrate the proposed localization algorithm.

Analytical investigation on thermal-induced warpage behavior of ultrathin chip-on-flex(UTCOF) assembly

The serious warpage issues of ultrathin chip-on-flex(UTCOF) assembly induced by mismatched thermal stresses have greatly affected the mechanical stability and reliability of emerging ultrathin chip packaging technology. Currently, a theoretical prediction as a convenient and straightforward approach is still lacked for describing effectively the thermal-mechanical behavior of UTCOF during the adhesive curing and cooling process. In consideration of the adhesive thickness approximating to ultrathin chip and flexible substrate thickness, we develop a layerwise-model of ultrathin chip-adhesive-flex structure under plain strain condition, where the behavior of thick adhesive bonding can be described precisely through increasing the subdivided mathematical plies. Further, the analytical results show that the concave and convex forms of ultrathin chip warpage yield at the end of the curing and cooling process respectively. Meanwhile, the effects of its structure dimensions and material properties are also revealed for discussing a way to relieve the extent of ultrathin chip warpage. Additionally, in order to verify the validity of the theoretical prediction, we also introduce the corresponding numerical technique and experimental method. These results suggest that a kind of rigid and ultrathin flexible substrate such as metal foil should be adopted for small warpage of ultrathin assembly.

Preface:Celebrating the 70th Anniversary of School of Mechanical Science and Engineering,Huazhong University of Science and Technology

Huazhong University of Science and Technology (HUST) is a key research-based comprehensive university in Wuhan, China,under the direct supervision of the Ministry of Education of China. Renowned as the epitome of the development of higher education in new China, it is a “211” Project,“985” Project,“Double First-Class” university in China.