Positioning-control Based on Trapezoidal Velocity Curve for High-precision Basis Weight Control Valve

Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matlab/Simulink indicates that there is much more overshoot and fluctuating during the valve-positioning process. In order to improve the valve-positioning precision, the control method of trapezoidal velocity curve was studied. The simulation result showed that the positioning steady-state error was less than 0.0056%, whereas the peak error was less than 0.016% by using trapezoidal velocity curve at 10 positioning steps. A valve-positioning precision experimental device for the stepper motor of basis weight control valve was developed. The experiment results showed that the error ratio of 1/10000 positioning steps was 4% by using trapezoidal velocity curve. Furthermore, the error ratio of 10/10000 positioning steps was 0.5%. It proved that the valve-positioning precision of trapezoidal velocity curve was much higher than that of the constant frequency pulse signal control strategy. The new control method of trapezoidal velocity curve can satisfy the precision requirement of 10000 steps.

METHODS OF VISUAL RECOGNITION,POSITIONING AND ORIENTATING OF 3 D SIMPLE GEOMETRIC WORKPIECE

The methods of visual recognition,positioning and orienting with simple 3 D geometric workpieces are presented in this paper.The principle and operating process of multiple orientation run length coding based on general orientation run length coding and visual recognition method are described elaborately.The method of positioning and orientating based on the moment of inertia of the workpiece binary image is stated also.It has been applied in a research on flexible automatic coordinate measuring system formed by integrating computer aided design,computer vision and computer aided inspection planning,with a coordinate measuring machine.The results show that integrating computer vision with measurement system is a feasible and effective approach to improve their flexibility and automation.

Robot Positioning Based on Multiple Quick Response Code Landmarks

The scheme of robot positioning based on multiple quick response(QR)code landmarks is proposed.Firstly,the pose of the robot relative to the QR code landmarks is obtained by extracting the feature points of the QR code,combined with the visual computing technology.Then,the conversion of the absolute pose of the robot is completed based on the absolute position of the QR code landmark,and thus the real-time position of the robot is obtained.The proposed scheme makes full use of the QR code fault tolerance and multiple QR code landmarks to improve the calculation accuracy.It has good robustness and versatility,and it is easy to implement.It can help the robot to complete the positioning in the actual work,making robot navigation more accurate.

Effects of Uncertainties in the Position and Orientation of Both the Transmitter and Receivers on Marine Controlled-Source Electromagnetic Data

Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a flat seabed.Actually,however,the transmitter dipole source will be rotated,tilted and deviated from the survey profile due to ocean currents.And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor.In this paper,we investigate the effects of uncertainties in the transmitter tilt,transmitter rotation and transmitter deviation from the survey profile as well as in the receiver's location and orientation on marine CSEM data.The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties,but to a different extent.In interpreting marine data,field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.

BP-LMS-based BDS-3 power system positioning method

The BeiDou-3 navigation satellite system(BDS-3)provides a full-domain high-precision positioning service for the power system to ensure safe and stable operation.However,BDS-3 power system positioning faces certain challenges,such as complex electromagnetic interference and incomplete error elimination.Herein,a back propagation neural network-improved least mean square(BP-LMS)adaptive filtering method is proposed for the BDS-3 full-domain and high-precision power system positioning,which utilizes the loss function to update the weight of the BP hidden layer,computes the pseudo compensation range,and eliminates the impact of electromagnetic interference to enhance the accuracy of power system positioning.Simulation results confirm the superior performance of BP-LMS in positioning accuracy and error elimination.Compared with LMS and normalized least mean square(NLMS),the filtering error of the proposed BP-LMS adaptive filtering method is decreased by 57.14%and 51.38%,respectively.

A Position and Orientation Compensation Mechanism for Automatic Docking Device of Launch Rocket

A position and orientation compensation mechanism for the automatic docking device of a launch rocketwas established.The docking process was simulated,and the maximum docking deviation was used for the prototype testing of the compensation mechanism.The compensation mechanism mainly comprises four column pairmotion branch chains with the same structure.When the position of the ground connector panel changes relative to the moving platform,the sliding rods in the four motion branch chains move and rotate to either compress or stretch the connected spring,thereby compensating the position and orientation.First,the dynamic simulation model of the compensation mechanism was established.The docking process was then simulated under the maximum docking deviation.Bench testing of the automatic docking device prototype was carried out.Afterwards,the device was manufactured,and a maximum load test and maximum deviation test were carried out.The results demonstrate that the compensation mechanism meets the design requirements,and the spring stiffness was found as the most important factor in determining the mechanical properties of the system.The proposed compensation mechanism has a number of advantages,including a simple structure,large load bearing capacity,small size,simple installation,and adjustment.

Characterization of (100)-orientated diamond film grown by HFCVD method with a positive DC bias voltage

The (100)-orientated diamond film was deposited by hot-filament chemical vapor deposition (HFCVD) technology with a positive DC bias voltage. The morphology, X-ray diffraction (XRD), RAMAN spectrum and dark current versus applied voltage characteristics analysis show that the positive dc bias can increase the nucleation density and (100)-orientated growth, making the growth of the high quality diamond film easier and cheaper than using other methods.

积极青少年发展理论的演进与意涵

积极青少年发展是发展科学理论范式的重大转变,极大推动了全球青少年发展研究和教育政策的进程。积极青少年发展突破“问题视角”和“缺陷模型”,主张关注青少年的优势和相对可塑性,强调个体与情境的互惠互动,凸显青少年之于社会进步和人类发展的贡献与方法论价值。在历经生态情境取向向历史文化取向的演进过程中,积极青少年发展研究逐步在世界范围内开展、推广和践行,彰显出鲜明的理论更新自觉和实践品格,这对推动对青少年的认识论发展、我国积极青少年发展研究以及政策制定实施,具有多重启示。

永磁定位系统磁传感器的两步迭代优化标定方法

为减小磁传感器位置、方向和灵敏度系数误差对永磁定位系统定位定向精度的影响,提出了一种基于最小二乘法的两步迭代(TSI)磁传感器标定方法。首先,校准磁传感器的方向和灵敏度系数,再进行位置校准,多次迭代后可以得到稳定的标定参数。其次,使用粒子群优化(PSO)算法与序列二次规划(SQP)算法结合进行迭代求解,在算法优化过程中,增加三组未知数约束,提高求解精度。最后对比使用不同标定方法的永磁定位系统定位定向精度,测试结果表明,所提标定方法较传统基于最小二乘的标定方法的系统定位精度提高20.48%,定向精度提高35.55%。

无寄生运动3-DOF 2T1R并联机构拓扑设计与分析

为充分研究少自由度并联机构所具备优势,拓宽其应用领域,设计并研究一种含冗余支链且无寄生运动三自由度两平移一转动(2T1R)并联机构,完成运动学和动力学分析。基于方位特征集(POC)的拓扑机构学理论方法,设计了一种含冗余支链且无寄生运动的两平移一转动并联机构,并进行拓扑分析,结果表明:该机构还具有部分运动解耦特性;根据基于拓扑特征运动学的建模方法,求得机构位置正反符号解;又基于位置反解分析了机构奇异性,基于位置正解给出了工作空间;基于虚功原理的序单开链法对机构进行动力学建模,求得了该机构移动副处的驱动力以及两个子运动链(SKC)连接处的支反力;概念设计了该机构的一种应用场景。

一维光学位置传感器融合的非接触多自由度位姿测量系统

为实现机器人末端位姿多自由度实时测量反馈,融合一维光学位置传感器(Position Sensitive Detector,PSD)建立了平面3自由度非接触测量系统,对其测量原理,信号处理电路,环境光干扰去除和非线性标定算法等进行研究。根据PSD传感器测量特性和平面3自由度测量要求设计了4-PSD测量系统,并建立测量系统数学模型。研究了PSD传感器的信号处理电路,通过运放和除法器实现了单个PSD的信号处理,结合单片机与A/DC采样电路,实现了上位机的高频率信号采集。对4-PSD测量系统进行预实验,为消除环境光干扰,通过激光调制和数字滤波等方法进行验证。最后,通过激光位移传感器标定4-PSD测量系统,介绍了4-PSD的标定步骤(原点、转角、长度和二阶非线性标定),测定了系统标定后的误差分布。该测量系统具有较高的测量频率(50 Hz)。标定实验结果表明:标定后的4-PSD测量系统在70 mm×70 mm内,测量精度平均为0.49 mm,比标定前降低了90%的误差,能满足大部分高速、高精度机器人末端的非接触式实时测量反馈需求。

新型4RPUR并联机器人机构运动学分析与尺度综合

以支链为RPUR的4RPUR并联机器人机构为研究对象,首先根据方位特征集理论验证运动性质,利用SolidWorks软件建立三维模型图,其次利用杆长约束条件进行运动学位置逆解分析,再次利用图形化方法得到工作空间与转动能力性能图谱,最后选择鲸鱼优化算法(WOA)完成参数尺度综合。结果表明:优化后的工作空间边界光滑、对称分布,为机构应用设计提供了参考依据。

边缘企业网络位置跃迁的机理研究——以商汤科技为例

网络位置跃迁是新创边缘企业实现成长的重要手段。以商汤科技为研究对象,探究边缘企业实现网络位置跃迁的内在机理,结果发现:网络位置跃迁是资源情境和企业战略相互匹配、协同演化的结果;边缘企业实现网络位置跃迁的关键在于正确感知自身资源情境,选择、制定并执行适配的发展战略,实现资源情境、战略导向、资源行动及网络能力的有效适配;资源行动和网络能力在不同资源情境下的交互适配与优化升级,使网络位置的关键构成要素呈现动态演化,推动边缘企业呈现出“边缘型网络位置—局部中心型网络位置—全域中心型网络位置”的演化态势。

“机车行车安全与设备”课程岗位能力数字化培养研究

针对教学内容和岗位实际脱节、岗位能力培养的实施步骤和方法不够完善和思政育人路径不够全面等铁路机务岗位能力培养过程中面临的实际问题,依托铁道机车运用与维护专业核心课程“机车行车安全与设备”,提出了相应的三方面六种解决方法,形成了理实一体的行动导向模式和育训并举的实践训练模式,旨在通过数字化教学改革提升铁路机务岗位能力的培养实效。

论习近平文化思想的人民立场

习近平文化思想是新时代新征程指导文化工作的强大思想武器和科学行动指南。习近平文化思想具有鲜明的人民立场,源于马克思主义理论和中国共产党文化观的人民性品格、中华优秀传统文化蕴含的民本理念和新时代坚守以人民为中心的文化工作实践。文化建设、发展和繁荣要坚持全心全意为人民服务的根本宗旨,文化建设依靠人民、文化发展为了人民、文化发展成果由人民共享、文化发展成效由人民评判是习近平文化思想人民立场的核心要义。践行习近平文化思想人民立场,要坚持党对文化工作的全面领导,保证人民立场的价值取向;尊重人民主体地位,发挥人民群众在文化建设中的作用;提升文化服务效能,不断增进人民的文化福祉;推进文化领域制度建设,切实保障人民群众的文化权益;坚持“以文化人”,助力实现中华民族伟大复兴。

基于标准砂轮的立铣刀精确螺旋槽磨削位姿算法研究

为了提高整体式立铣刀螺旋槽结构参数的磨削精度,通过完善螺旋槽轮廓成形计算方法,提出了一种基于标准砂轮的立铣刀精确螺旋槽磨削位姿算法。对螺旋槽磨削过程的砂轮和运动关系进行参数化建模;根据砂轮的运动轨迹计算出砂轮做空间螺旋运动形成的包络面,并由空间包络原理接触条件计算砂轮磨削形成的螺旋槽轮廓方程;根据螺旋槽的前角、芯厚、槽宽参数的几何定义,建立各参数关于砂轮位姿的函数关系;将砂轮位姿求解问题转换成数学优化问题,采用智能算法进行快速求解。通过仿真试验对算法的求解精度和适应性进行了分析,验证了算法的有效性。

冗余铺放机器人的自运动流形及逆解优化研究

针对用于复合材料铺放成型的八自由度冗余机器人系统的逆运动学问题,提出了一种求解其自运动流形及逆解优化的算法。首先,基于位姿分离思想定义了位置子流形和姿态子流形,采用几何求解法得到了基于自运动变量的参数化方程形式的位置子流形和姿态子流形;然后,根据机器人的关节约束和实际铺放工艺过程,对给定的铺放位姿进行了位置子流形和姿态子流形配对的仿真,并用流形中若干组逆解通过正向运动学得到了末端位姿矩阵(其结果均与给定位姿相符,从而验证了自运动流形求解过程的正确性);最后,在完成自运动流形求解的基础上,从机械臂运动的平滑性和关节运动变化量两个方面出发,提出了一种基于自运动变量参数化方程的全局优化目标函数;以飞机尾椎模型为实验研究对象,对其中一条铺放路径进行了逆解全局优化仿真,得到了自运动变量和机器人各关节角在铺放路径上的优化曲线,将仿真结果与一种多目标优化算法进行了比较。研究结果表明:针对相同的铺放路径,采用上述优化算法后关节角变化总量降低了11.25%;该算法能够有效地求解八自由度冗余铺放机器人系统的自运动流形,基于全局优化目标函数,其能够在自运动流形中寻找出自运动变量和机器人各关节的最优解。该算法同样也适用于其他位姿解耦的冗余机器人系统逆解问题的求解。

功能型国有煤炭贸易企业市场化业务探索与实践

做好市场化业务是功能型国有煤炭贸易企业实现企业转型升级和提升经济效益的重要手段。从内、外部环境两方面分析了功能型国有煤炭贸易企业面临国内国际煤炭市场竞争加剧、煤炭生产及消费量保持扩增、煤炭库存结构不平衡问题突出和国有企业转型改革加速等挑战和机遇,并指出功能型国有煤炭贸易企业的优势。重点阐述了市场化业务开拓策略需要综合考虑业务战略定位、业务模式选择、市场开拓及客户挖掘、品牌建设以及信息技术创新应用等因素。以浙江浙能富兴燃料有限公司为例,介绍了该公司在市场化业务实践中的战略定位选择、“富动”品牌建设、市场化制度建设以及信息技术应用等方面成果。

酒店机器人包容性服务定位与社会阶层的交互作用对顾客公民行为的影响

基于共情理论,探讨酒店机器人包容性服务定位和社会阶层的交互作用对顾客公民行为的影响机制及边界条件。通过3个情境实验,研究发现:对于低社会阶层,相比非包容性服务定位,机器人包容性服务定位更能促进其顾客公民行为;对于高社会阶层,机器人包容性服务定位和非包容性服务定位对顾客公民行为的影响不存在显著差异。机器人包容性服务定位与社会阶层的交互作用对顾客公民行为产生影响,顾客情感共情在其中起到中介作用,其他群体导向存在显著调节作用。若个体的其他群体导向较高,则高社会阶层消费者面对机器人包容性服务定位时,其顾客公民行为会显著增加。

基于粒子-人工蜂群算法的3RPUP_(c)-UPS并联机构运动学正解研究

针对3RPUP_(c)-UPS并联机构运动学正解求解困难的问题,对新型3RPUPc-UPS并联机构的运动学特性进行了研究,并构建出位置正解求解模型,进而提出了一种基于粒子-人工蜂群算法(P-ABC)的并联机构运动学求解方法。首先,根据机构的拓扑特性,计算得到了方位特征集、自由度和耦合度;然后,根据机构的几何特征,基于姿态变换矩阵和动平台投影方程,建立了机构的运动学逆解方程,并对比了MATLAB和SOLIDWORKDS的仿真结果,验证了逆解分析的正确性;最后,将运动学逆解方程转化为最小化求解问题,构建出了适合优化算法的运动学正解模型,并利用MATLAB的软件交互界面(GUI)功能,开发出用于计算并联机构运动学正解的软件,分别基于粒子群算法(PSO)、人工蜂群算法(ABC)和P-ABC算法,对该并联机构的运动学正解进行了计算。研究结果表明:P-ABC算法单次求解时间在0.5 s内,求解误差级别为10-20,相对于ABC算法,运行时间缩短了50.02%;而相对于POS算法,其求解精度提高了10个数量级。P-ABC算法能够用于求解该并联机构运动学正解,具有计算速度快、精度高的特点,可以为研究并联机构运动学正解提供新方法。