Study on path planning and compensation of off-line programming for thick walled curve welding

Thick walled curve welding are usually joined by multi-layer and multi-pass welding, which quality and efficiency could be improved by off-line programming of robot welding. However, the precision of off-line programming welding path was decreased due to the deviation between the off-line planned welding path and the actual welding path. A path planning algorithm and a path compensation algorithm of multi-layer and multi-pass curve welding seam for off-line programming of robot welding are developed in this paper. Experimental results show that the robot off-line programming improves the welding efftcieney and precision for thick walled curve welding seam.

Managerial Compensation Program and Capital Structure： An Empirical Study of Brazilian Companies

The agency theory indicates the existence of costs as a way to mitigate conflicts between shareholders and managers, including： managerial compensation program, acquisition of shares by managers, monitoring of executives, and controlling shareholders. This study aims to determine the relevance of some variables related to compensation programs and of other determinants of the corporate debt level. It has considered a sample of 89 firms, which were analyzed through logistic regression （cross section）. The model created has indicated a level of predictive assertiveness of approximately 87%.

Analysis of Cutter Radius Compensation

Cutter radius compensation （CRC） is a very important function of numerical control（NC） system. We refer to a large number of NC information and sum up the CRC function. We illustrate how to realize rough machining ＆ finish machining by the same program, machining matching surface by the same program, simplify pro- gramming methods, realize direct programming by parts contour, remove machining allowance by the increase of CRC value, control the parts size precision by adjusting the CRC value, state the essence of the CRC, and elucidate the physical meaning of the CRC value.

Optimal design of culling compensation policy under the African swine fever——Based on simulations of typical pig farms in China

This paper aims to optimize the culling compensation policy from a micro perspective through scenario simulation.Based on an investigation of 273 pig farms in eight regions,four typical pig farms were constructed according to farm size and breeding mode,representing the swine producers in China.Besides,a decision objective function of pig farms facing suspected African swine fever(ASF)outbreaks was constructed.This study used a mathematical programming model to design and simulate scenarios based on compensation standards and local implementation levels,aiming to incentivize pig farms to report epidemics.The results show that the optimal decisions on epidemic reports differed among typical farms and by herd daily age.The results suggest the following adjustments for optimizing culling compensation policies:(1)to set culling compensation standards based on the market value and(2)to maintain a high level of epidemic surveillance capability in the animal husbandry and veterinary sector.

“寒门贵子”是“补偿”还是“选拔”出来的?——对两所精英大学2018—2023年高校专项计划招生的追踪研究

高校专项计划是我国促进高质量教育公平、破解农村学生上好大学难而出台的一项入学机会补偿政策。综合运用描述性统计方法,本研究对两所精英大学2018—2023年间高校专项计划的选录情况进行了持续追踪研究。从初审、降分、录取人数的总体规模及变化趋势看,近几年高校专项计划政策力度不断加大,越来越多的寒门子弟进入精英高校。同时,精英大学高校专项计划实际招生呈现“补偿不均,选拔有余”的鲜明特点,经济欠发达、教育发展水平薄弱省域的农村学生和学校在该计划中并未获得更多优质高校入学机会的补偿,一个重要原因在于他们在高校自主选拔和高考选拔中处于劣势。为此,应调整高校专项计划招生办法及相关政策,确立“补偿为主,兼顾选拔”的价值导向并切实付诸实践,推进“实质的公平”。

Advantages of Short-term Personalized Vestibular Rehabilitation at Home Guided by Professional Therapist for Treatment of Decompensated Vestibular Vertigo

Objective Patients suffered a lot from decompensated vestibular vertigo.Pharmacotherapy and vestibular rehabilitation training have been proven to be effective in prompting vestibular compensation.Routine rehabilitation training is faced with the challenges of patients’compliance,completion,the average recuperation time and so on.This study is aimed to investigate advantages of short-term personalized vestibular rehabihitation at home guided by professional therapist.Methods A short-term personalized vestibular rehabilitation program(ST-PVR)was designed for patients with decompensated vestibular vertigo in this study.Results Patients experiencing the ST-PVR program showed significant improvement of Self-Rating Anxiety Scale(SAS),Dizziness Handicap Inventory(DHI),Activities-Specific Balance Confidence Scale(ABC)scores by the second follow-up(at 2nd week after treatment,P<0.05).However-improvement in the medication group occurred slightly later,DHI for 1 month and SAS for 2 months after treatment(P<0.05).Also,the improvement in the onset time of unilateral weakness(UW)at 2nd week after treatment in the personalized vestibular rehabilitation(PVR)group was faster than that in the medication group.Conclusion In general,the short-term PVR program showed great advantages by prompting vestibular compensation quickly and putting forward future direction for clinical treatment on decompensated vestibular vertigo.

The Offline Program Profile Lining and Cutting Robot System

The paper introduces a new type of cutting system: the Offline Program Profile Lining and Cutting Robot System (OPPLCRS). The system adopts the offline program technology without teaching. The system can measure and compensate every profile’s deformation automatically, so it is suit to process any batch of profiles, and the order of processing different profiles can be arranged at will. The OPPLCRS, firstly appearing in China, will have wide application in profile cutting fields.

Digital close loop control system for current-programmed mode arc welding inverter

A small-signal model of current programmed mode pulse width modulation converter including the equivalent sampling effect is introduced and analyzed. In this model, an addition pole is brought out by the sampling effect in the current loop gain, and it affects dynamic bandwidth and stability of the inner current loop. By selecting the appropriate stability parameter which determines the additional pole and describes the degree of peaking in closed loop transfer function, a control model of current programmed full bridge arc welding inverter with maximum frequency bandwidth and stability can be obtained. Small and large amplitude pulse current outputs are employed in simulations and experiments and results validate the design method.

Fault Locator Using Two-end Unsynchronized Measurements for UHV Series Compensated Double-circuit Lines

An accurate fault location algorithm for double-circuit series compensated lines is presented.Use of two-end unsynchronized measurements of current and voltage signals is considered.The algorithm applies two subroutines,designated for locating faults on particular line sections,and additionally the procedure for selecting the valid subroutine.The subroutines are formulated with use of the generalized fault loop model and the distributed parameter line model is applied.Performed ATP-EMTP based evaluation has shown the validity of the derived fault location algorithm and its high accuracy.

基于法向等距法的刀具半径补偿算法及加工应用

刀具补偿技术是根据零件轮廓和预先设定的偏置参数获得铣削程序,在提高编程效率和机床制造精度的同时避免了过切现象。为解决SIEMENS系统在实际加工中采用展成法(X-C插补)加工涡旋盘时无法直接添加刀具半径补偿指令的问题,针对软件获取刀补点方法存在步距大、精度低、通用性差等缺点,提出一种基于法向等距法的刀具半径补偿算法。计算涡旋盘刀具补偿点位置坐标,并对涡旋盘外壁曲线刀补点坐标进行参数化编程。利用NX软件生成刀路轨迹,对整个涡旋型线进行程序仿真,轨迹一致且程序无误,最后在涡旋铣专机上进行了粗、精加工实际验证。结果显示,轨迹满足加工要求,表明本文提出的算法所计算的刀补点可以实现涡旋盘曲线加工,验证了算法的合理可行性,有效解决了生产实际难题,也为其他采用展成法无法直接增加刀补指令的参数化编程提供了有效的方案。

基于抗扰动Smith预估补偿的磨煤机出口风粉温度优化控制

“双碳”背景下,作为高能耗高排放的火电机组,其燃烧性能直接影响发电效率和碳排放量。锅炉燃烧优化控制对运行优化和灵活调峰是有重要意义。电站锅炉磨煤机的出口风粉温度控制面临大延迟、多干扰问题,对燃煤机组安全稳定运行具有重要影响。基于Smith预估控制器,在补偿回路中增设反馈环节,实现了高效抗干扰,提升磨煤机风粉温度控制性能。通过Taylor级数展开和待定系数法求取模型近似转换参数,获得一阶惯性纯滞后模型,进而设计抗扰动型Smith预估补偿控制器。通过与单回路PID控制试验对比,发现Smith预估补偿控制算法可有效补偿控制对象的纯延迟滞后环节,单位阶跃响应超调量降低36.5%,调节时间缩短65.8%。相比经典Smith预估补偿控制算法,抗扰动Smith预估补偿控制算法可提高控制算法的抗扰动性能,并显著改善控制对象的动态特性,单位阶跃响应超调量减小44.7%,调节时间缩短15.7%。同时,实现了扰动最大偏差和收敛时间的降低。最后,在某660 MW超临界一次再热燃煤机组上应用该方法,实现了磨煤机出口风粉温度实际值对设定值的平稳跟踪,进一步验证了该方法的有效性。

基于SKIP宏程序编程CNC无线测头在线智能检测系统设计

针对数控铣削加工精密零件尺寸精度测量时,因离线测量易产生测量误差、效率低、成本高等问题,通过赋值相关检测路径及补偿的参数,编写零件在线检测及误差补偿宏程序,开发了基于三菱M70数控系统跳过指令SKIP在线检测与误差补偿宏程序控制系统。应用结果表明:该系统在线检测重复定位精度能达到0.001~0.003 mm,能适用于精密零件数控铣削加工,具有一定的推广使用价值。

Optimization Design of Two-Stage Operational Amplifier with Frequency Compensation via Geometric Programming

An optimization design technique to obtain global solution for a two-stage operational amplifier(op-amp) with frequency compensation is presented.This frequency compensation technique can adjust the equivalent resistance to guarantee that the phase margin is stable even though circumstance temperature varies.Geometric programming is used to optimize the component values and transistor dimensions.It is used in this analog integrated circuit design to calculate these parameters automatically.This globally optimal amplifier obtains minimum power while other specifications are fulfilled.

光伏接入中低压配网下的无功补偿优化配置

为提升光伏发电机组接入中低压配网后的电能输送质量、降低网损率,基于混合整数凸规划,完成配电网的无功补偿配置研究。该方法以含光伏发电的中低压配网最小网损为目标,构建配电网无功补偿数学模型。实验结果表明:该方法应用后中低压配网节点电压标幺数值得到有效提升,且随着配电网运行时间的增加,其降低幅度较小;可有效降低中低压配网的网损率,应用效果显著。

基于FANUC系统I/O LINK轴的一种新型垂度补偿功能

由于自身重力的原因,配置多附件头的数控落地镗铣床的滑枕在长行程伸出时会在垂直方向上产生相应的形变。为降低由于形变引入的误差对加工精度所造成的影响,以FANUC 0i MF数控系统作为控制平台,结合I/O LINK轴的应用,提出了一种不使用FANUC系统“平直度补偿”功能的补偿方案。运用区间补偿的思想,将整个滑枕的行程划分为多个运动区间,以误差测量实验的方式将滑枕垂向的误差转换为补偿轴的坐标并得出补偿数据,通过PLC程序将补偿轴坐标与滑枕实际位置进行匹配,以同一运动区间调用固定补偿值的方式对滑枕进行线性补偿。通过对不同的附件头创建不同的补偿程序,并使用K地址调用相应补偿数据的方式,排除了不同补偿数据间相互干扰的隐患。所提方案在实际机床中的应用结果表明:其补偿效果可达到与FANUC系统“平直度补偿”功能相一致的水平。

发动机生产线中三坐标测量程序设计与优化对测量精度的影响

本文探究了发动机生产线中三坐标测量程序的设计要点,并对比验证了不同测量方式和评价方式以及温度补偿对测量精度的影响。在三坐标测量程序设计中,首先要配置并校准测针,在此基础上创建工件坐标系、确立测量安全平面和测量方案,并按照该方案寻找提高测量精度的方法。试验表明,测量方式选用扫描测量,数据评价方法选用最大内切圆法,实行温度补偿,对提高测量精度有显著效果。

数控机械加工中在机测量技术分析

随着加工产业的升级优化,各行各业对于数控机械加工精度及质量的要求也不断提高。在此背景下,机测量技术的应用越来越广泛。基于此,简要介绍在机测量技术的工作原理及技术内容,并分析其在数控机械加工中的应用,旨在为后续相关工艺技术的使用提供参考。

基于牛顿插值的批量轴类零件加工误差补偿

为提高批量轴类零件加工精度及加工效率,通过分析批量轴类零件加工数据,得到加工误差分布规律;运用牛顿插值理论建立批量轴类零件加工误差数学模型;应用用户宏程序按工件序号及切削位置进行误差实时补偿。该误差补偿方法综合考虑切削力引起的误差、热误差、刀具磨损误差、机床几何误差、编程误差、检测调整误差等误差因素,全面分析各误差因素与误差分布规律的关系,避免了误差因素分析不全的影响。得出切削力是影响单件工件加工误差分布的主要因素,刀具磨损是影响批量轴类零件加工误差分布的主要因素,热误差是导致误差分布规律畸变的主要因素。实践表明,应用该误差补偿方法可使批量轴类零件最大加工误差由60μm降低到4μm,补偿了93.3%;减少在机检测调整时间,加工效率提高13%,有效提高批量轴类零件加工精度和加工效率。

贫困地区农户参与生态补偿自愿性影响因素分析:以退耕还林和公益林补偿为例

生态补偿政策中的自愿性能在很大程度上影响政策的实施效果。基于云南省屏边县和西畴县的615份农户访谈数据,运用二元Logistic模型,从参与条件、参与动力、参与能力和政策吸引力4个维度分别研究退耕还林和公益林政策中影响农户自愿性的因素,为更好地提高农户参与政策的自愿性、提升政策的执行效率提供技术支撑。结果表明,参与动力和政策吸引力对农户自愿性的影响较大;退耕还林政策中,自愿参与和非自愿参与的农户比例分别为84.4%和15.6%,农户对周围人和村干部的信任程度越高、有外出打工经历、政策了解程度越深以及补偿标准越高、政策预期评价越好,其参与生态补偿政策的自愿性越高,农户年龄和家庭劳动力数量越大则自愿性越低。公益林政策中,自愿和非自愿参与的农户比例分别为36.0%和64.0%,农户对周围人和对村干部的信任程度越高,政策了解程度越深,补偿标准越高,政策预期评价越好,其参与生态补偿政策的自愿性越高。可以通过有效政策宣传、用市场化手段引入社会资本以适当提高补偿标准、积极创造非农就业机会等手段,来促进退耕还林和公益林补偿政策目标更好地实现。

静止无功补偿器自适应动态规划电压控制方法

为解决传统比例?积分?微分(proportional integral differential,PID)控制应用于静止无功补偿器(static var compensator,SVC)非线性控制系统存在的不足,提出了一种基于自适应动态规划(adaptive dynamic programming,ADP)的SVC自适应优化控制策略。采用小波神经网络和BP神经网络分别设计执行依赖启发式动态规划(action dependent heuristic dynamic programming,ADHDP)的执行网络和评价网络,以增强ADHDP对性能指标函数的逼近能力和控制律优化能力,然后用其设计了SVC控制系统的电压调节器。在Matlab/Simulink仿真平台对所提出的ADHDP控制方法进行了仿真,并与执行网络、评价网络均采用BP神经网络设计的经典ADHDP控制方法的控制效果进行了对比,验证了基于ADHDP的SVC电压优化控制方法的可行性和有效性。相比之下,所提出的ADHDP控制方法具有更好的电压稳定和控制效果,控制系统具有较快的响应速度、较好的动态和静态稳定性和较强的自适应能力。