HRV控制对数控机床加工质量的作用及方法

数控机床为了提高定位、加工面和加工形状精度以及缩短加工时间，需要对数控系统进行伺服调整。本文阐述了数控系统伺服HRV控制的重要作用和伺服HRV控制的设定的方法。     

数控磨床的完全闭环控制与精度分析

普通数控机床采用半闭环、全闭环或双位置环的控制方式可将机床控制精度提高到50um以上，但对零件加工精度要求更高的磨床而言，采用这几种控制方式显然满足不了加工要求。增加“在线检测系统”，实现“完全闭环控制”后，可使零件加工精度控制在5um以内，完全满足工艺要求：通过优化数控伺服参数，改善机械与电气的匹配性，提高机床动态响应，使零件加工尺寸更加稳定：通过对数控磨床完全闭环控制方式的进一步优化，可大大改善数控磨床的稳定性和控制精度。     

基于操作者满意度的质量控制系统分析

对质量控制系统中3条信息传递路线分析，以安装有加工现象可视化装置和加工振动显示盘的机加工系统为实例，对在系统中如何调动人的主观能动性进行了论述，并根据试验评价结果，说明改善工序加工方式、加强人机有效结合会相应提高操作者满意度，从而提高工作质量和产品质量。     

弧齿锥齿轮定制研磨加工模型研究

介绍了一种弧齿锥齿轮数控研齿机实现定制研磨的控制过程,建立了研齿的数学模型,利用轮齿接触分析（TCA）技术实现定制研磨控制,与传统机械式研齿机相比,该研磨方式无论在控制和改善接触区方面,还是在提高加工精度与效率方面都具有明显优势。通过实验验证了该加工模型的准确性。     

整体解决方案的诱惑

在精益化生产制造高速发展的今天,加工制造企业对加工生产的方式每时每刻都可能会有不同的要求。这也对加工设备的自动化程度、加工流程的信息传递提出了不同的要求。当然,这也为承担着改善加工方式任务的自动化企业创造了更多的市场机会。     

油缸缸体加工工艺及质量管理分析

详细介绍了油缸加工的基本特点与加工工艺的要点,从实际生产的角度对加工中遇到的问题进行了分析,并提出了一些改进策略;以加工流程为基础提出了提高加工质量的措施,利用规范标准、流程控制、直接管理的方式对加工过程进行直接控制,从而提高油缸的加工质量。     

零件转角加工方式的研究及优化

针对不同的零件转角类型和加工条件,对零件转角的加工方式进行了研究,列举了转角减速、插铣后轮廓切削、轴向分层轮廓切削等三种优化后的转角加工方式,在此基础上详细介绍了每种加工方式的程序编制过程及其参数设置,并对各种加工方案进行了对比,分析了各自的优势和不足.为改善零件转角的加工品质,提高零件的加工合格率及加工效率,针对各种不同情况,制定了不同的加工方案,以保证零件转角加工的优质及高效.     

密封板的工艺优化

密封板零件是一种难加工的薄壁类零件,加工中经常出现变形。对零件的结构及材质进行分析,改善零件的加工工艺,对工艺路线、刀具、切削用量、进刀方式、装失方式等进行合理调整,较好地解决了密封板零件的加工变形问题。     

曲面零件铣削加工表面粗糙度控制技术研究与应用

在分析曲面铣削加工机理的基础上,通过对切削过程中的理论模型进行计算,分析了铣削加工中切削深度和残余高度等参数对表面粗糙度的影响方式,提出了表面粗糙度的控制方式。     

振动辅助电解车削加工技术研究

为提高电解车削材料去除率和改善加工表面质量,提出了振动辅助电解车削加工方法。采用阴极机械振动的方式使得加工间隙呈周期性变化状态,改善电解车削加工性能。进行了添加振动辅助前后的对比验证试验,研究了相关参数对振动辅助电解车削加工影响。结果表明:振动辅助电解加工能明显改善极间状态,提高材料去除率以及减小加工表面粗糙度值;材料去除率和表面粗糙度随着振动频率、加工电压、占空比、加工间隙和电解液温度呈规律性变化。     

Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing

In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.     

Sliding mode based trajectory linearization control for hypersonic reentry vehicle via extended disturbance observer

This paper proposes a novel hybrid control framework by combing observer-based sliding mode control (SMC) with trajectory linearization control (TLC) for hypersonic reentry vehicle (HRV) attitude tracking problem. First, fewer control consumption is achieved using nonlinear tracking differentiator (TD) in the attitude loop. Second, a novel SMC that employs extended disturbance observer (EDO) to counteract the effect of uncertainties using a new sliding surface which includes the estimation error is integrated to address the tracking error stabilization issues in the attitude and angular rate loop, respectively. In addition, new results associated with EDO are examined in terms of dynamic response and noise-tolerant performance, as well as estimation accuracy. The key feature of the proposed compound control approach is that chattering free tracking performance with high accuracy can be ensured for HRV in the presence of multiple uncertainties under control constraints. Based on finite time convergence stability theory, the stability of the resulting closed-loop system is well established. Also, comparisons and extensive simulation results are presented to demonstrate the effectiveness of the control strategy.     

数控加工与编程实践教学模式的研究

对数控机床编程与操作课程的教学改革作了简要分析,提出了数控实践和蝙程教学模式深化改革的对策,以探索适应社会发展的新型教学模式.     

采用集散控制的多通道远程温控系统

该系统采用分组温度采集、批均值数据处理算法，孵化室、出雏室单侧独立加热控制，使室内平均温度和局部温度基本相同。系统温度处理算法能有效去除错误和失真信号，提高采集数据的正确性和系统的可靠性；集散式温度控制结构整合了局部温度信息并采用局部控制和整体控制结合的控制方式，降低了失控风险，提高了控制的效率。系统电路简单、处理速度高、可靠性好、成本低、是一种实用新型智能温控设备。     

小批量生产模式下工序质量统计控制研究

提出了加工误差等效变换原理和计算方法,在此基础上建立了一种等效的统计过程控制模型,为小批量加工模式的统计过程控制提供了一种可行的方法.     

FANUC系统(i)系列中HRV控制的作用与调整方法

阐述了FANUC系统(i)系列中数控系统伺服HRV控制的重要作用和调整方法.     

Comparison of heart rate variability (HRV) and nasal pressure in obstructive sleep apnea (OSA) patients during sleep apnea

In this study, a novel R wave detection algorithm was developed and used to analyze the heart rate variability (HRV) of obstructive sleep apnea patients with obstructive sleep apnea (OSA). The purpose of our study was to investigate the biosignal changes in the synchronization between HRV, nasal pressure, and the effect of OSA. HRV, nasal pressure, and sleep electroencephalogram (EEG) signals recorded in control and OSA patients with sleep apnea who were matched according to EEG arousal in OSA during sleep apnea. Experiment steps were completed for R–R interval calculation and to estimate its power spectral density (PSD) over several frequency ranges of apnea states (severe, moderate and mild). Patients with severe OSA had persistently longer R–R intervals compared to patients with mild OSA. As a measure of apnea classification accuracy, the algorithm correctly classified 99.7% of the evaluation database. An advantage of the proposed method is the combination of R wave detection techniques to enhance the accuracy of wave detection that is easily implemented with HRV verified by accurate classification and quantification.     

A three-lead, programmable, and microcontroller-based electrocardiogram generator with frequency domain characteristics of heart rate variability

The objective of this study is to design and develop a programmable electrocardiogram (ECG) generator with frequency domain characteristics of heart rate variability (HRV) which can be used to test the efficiency of ECG algorithms and to calibrate and maintain ECG equipment. We simplified and modified the three coupled ordinary differential equations in McSharry's model to a single differential equation to obtain the ECG signal. This system not only allows the signal amplitude, heart rate, QRS-complex slopes, and P- and T-wave position parameters to be adjusted, but can also be used to adjust the very low frequency, low frequency, and high frequency components of HRV frequency domain characteristics. The system can be tuned to function with HRV or not. When the HRV function is on, the average heart rate can be set to a value ranging from 20 to 122 beats per minute (BPM) with an adjustable variation of 1 BPM. When the HRV function is off, the heart rate can be set to a value ranging from 20 to 139 BPM with an adjustable variation of 1 BPM. The amplitude of the ECG signal can be set from 0.0 to 330 mV at a resolution of 0.005 mV. These parameters can be adjusted either via input through a keyboard or through a graphical user interface (GUI) control panel that was developed using LABVIEW. The GUI control panel depicts a preview of the ECG signal such that the user can adjust the parameters to establish a desired ECG morphology. A complete set of parameters can be stored in the flash memory of the system via a USB 2.0 interface. Our system can generate three different types of synthetic ECG signals for testing the efficiency of an ECG algorithm or calibrating and maintaining ECG equipment.     

Cross-coupling control method of the two-axis linear motor based on second-order terminal sliding mode

When the dual-axis linear motor is processing components, its accuracy will be affected by the uncertainty and nonlinearity of the system, and the complexity of the processing curve trajectory. The goal is to improve the machining accuracy and response speed of the XY dual-axis permanent magnet synchronous linear motor two-dimensional platform, improve the anti-interference ability, and reduce the contour error. This paper proposes a coupled control method based on dual closed-loop single-axis high-order terminal sliding mode position control (TSMC). First, an improved mathematical model of equivalent contour error is established. Combine the coordinated controller to get the coupling link. Then, to accelerate error convergence and suppress chattering, a high-order terminal sliding mode controller is designed. The single-axis current controller is designed using high-order sliding mode algorithms. Simulations and experiments show the effectiveness and feasibility of the proposed method.

     

大直径深盲孔难加工材料加工方法研究

分析了深盲孔加工难点,针对大直径深盲孔难加工材料的特点,阐述了套料加工对于大直径深孔加工是一种高效率、低成本的加工方法.通过实例分析套料加工工艺及套料刀、切断刀设计的要点.采取相应的控制措施,实现了难加工材料大直径深盲孔的高效加工.该加工方法具有一定的通用性.