Economic design of two-stage control charts with skewed and dependent measurements

In many instances, the cost is high to monitor primary quality characteristic called performance variable, but it could be more economical to monitor its surrogate. To cover asymmetric processes in an alternating fashion of two-stage charting design using either performance variable or surrogate variable, both process variables are modeled by a skew normal distribution, respectively. The proposed two-stage control charts are constructed with an economic viewpoint using Markov chain approach. Two algorithms are provided to implement the proposed charting method. The application of the proposed charting method and its advantages over the existing methods are presented through an illustrating example.     

A new Smith predictor and controller for control of processes with long dead time

Good control of processes with long dead time is often achieved using a Smith predictor configuration. Typically a PI or PID controller is used; however, it is shown in this paper that for some situations improved set point and disturbance responses can be obtained if a PI-PD controller is used. Several methods are possible for selecting the parameters of the PI-PD controller but when the plant transfer function has no zeros, the use of the standard forms provides a simple algebraic approach, and also reveals why difficulties may be encountered if a PID controller is used. Some examples are given to show the value of the approach presented.     

A comparison study of three non-parametric control charts to detect shift in location parameters

Control charts are used as a statistical process control or SPC tool to identify the presence of assignable cause of variation in the process. Despite immense use and acceptability of parametric control charts, non-parametric control charts are an emerging area of recent development in the theory of SPC. The main advantage of non-parametric control charts is that they do not require any knowledge about the underlying distribution of the variable. In this work, we have summarized the different non-parametric control charts for controlling location from a literature survey, viz. control charts based on the sign test, control charts based on the Hodges–Lehmann estimator and control charts based on the Mann–Whitney statistic and compared their efficiency to detect the shift in location while in out of the control state under different situations and identified the best method under the prevailing situation.     

反向响应过程控制的新方法

本文在反向响应过程传统控制方法和Dahlin算法控制的基础上,提出了一种新的控制方法,该方法较其它控制方法在控制性能上有显著的提高,且具有良好的鲁棒性。     

一种可提高皮带粘接强度的新工艺

通过对皮带粘接技术的研究制定一种全新皮带粘接工艺,从而强化粘接效果提高皮带粘强度,以延长皮带使用寿命减少材料,降低生产成本确保生产正常进行。     

A new EWMA monitoring design for multivariate quality control problem

In this paper, a new approach is proposed to detect shifts of a multivariate quality control system. To do this, first, the decomposition method in multivariate normal distribution is introduced. Then, a control statistics is defined, and its properties are explained. In order to understand the proposed methodology and to evaluate its performance, a numerical example is provided by simulation. Moreover, the in- and out-of-control average run length of the proposed method are compared with the ones from the well-known multivariate cumulative sum and multivariate exponential weighted moving average in different scenarios of shifts. The results of the simulation study show that the proposed methodology performs better than the other methods in detecting the shifts of the standard deviation and correlation.     

A new adaptive control chart for monitoring process mean and variability

Traditionally, an $\bar{X}$ chart is used to control the process mean, and an R chart is used to control the variance. However, these charts are not sensitive to the small shifts in the processes. The adaptive charts might be considered if the aim is to detect process changes quickly. In this paper, we propose a new adaptive single control chart which integrates the exponentially weighted moving average procedure with the generalized likelihood ratio test statistics for jointly monitoring both the process mean and variability. This new chart is effective in detecting the disturbances that shift the process mean, increase or decrease the process variance, or lead to a combination of both effects.     

A new chart based on sample variances for monitoring the covariance matrix of multivariate processes

In this article, we propose a control chart for detecting shifts in the covariance matrix of a multivariate process. The monitoring statistic is based on the standardized sample variance of p quality characteristics we call the VMAX statistic. The points plotted on the chart correspond to the maximum of the values of these p variances. The reasons to consider the VMAX statistic instead of the generalized variance |S| are faster detection of process changes and better diagnostic features, which mean that the VMAX statistic is better at identifying the out-of-control variable. User’s familiarity with sample variances is another point in favor of the VMAX statistic. An example is presented to illustrate the application of the proposed chart.     

A new mathematical approach to improve residual stress measurement in ring-core method

Journal of Mechanical Science and Technology - III-conditioning at the inverse equation of integral method in ring-core residual stress measurement leads to high stress sensitivity to strain...     

Multivariate control charts for monitoring internal camera parameters in digital photogrammetry for LSDM (Large-Scale Dimensional Metrology) applications

Industrial non-contact dimensional measurements using photogrammetry rely critically upon stability in time of camera calibration. This is particularly relevant for multi-camera systems employed for continuous and/or long term monitoring of some dimensional process, e.g. dimensional checks of the same manufactured component as it comes off the production line. In most of these cases, camera calibration is updated regularly to ensure optimal accuracy. Specifically, the use of photogrammetric systems requires the knowledge of both internal and external camera parameters estimated by calibration. Constancy of both sets is required during use. Internal parameters, pertaining to camera-specific properties, require stability over the operational lifespan of the system, while external parameters, concerning location and orientation, may change between calibrations. A diagnostic method for internal parameters based on multivariate control charts is proposed. The purpose of this method is to provide a comprehensive stability control over all the performed calibrations, especially for those systems used for regular monitoring of production lines. By integrating chart building into calibration software, no additional steps are added to the operator's workload for the calibration process. A practical application of the described methodology is presented at the end of the paper.     

新型摆杆减速器的研究

本文给出了一种新型摆杆减速器的结构组成和工作原理,能过对该减速器摆机构运动的分析,推导出了内齿圈齿廓的方程式,同时对机构的传动特性进行了讨论。通过对机构和初步试制和试验,证明了理论分析的正确性,为这种减速器的进一步研究打了基础。     

A valveless piezoelectric pump with novel flow path design of function of rectification to improve energy efficiency

Existing valveless piezoelectric pumps are mostly based on the flow resistance mechanism to generate unidirectional fluid pumping, resulting in inefficient energy conversion because the majority of mechanical energy is consumed in terms of parasitic loss. In this paper, a novel tube structure composed of a Y-shaped tube and a ȹ-shaped tube was proposed considering theory of jet inertia and vortex dissipation for the first time to improve energy efficiency. After verifying its feasibility through the flow field simulation, the proposed tubes were integrated into a piezo-driven chamber, and a novel valveless piezoelectric pump with the function of rectification (NVPPFR) was reported. Unlike previous pumps, the reported pump directed the reflux fluid to another flow channel different from the pumping fluid, thus improving pumping efficiency. Then, mathematical modeling was established, including the kinetic analysis of vibrator, flow loss analysis of fluid, and pumping efficiency. Eventually, experiments were designed, and results showed that NVPPFR had the function of rectification and net pumping effect. The maximum flow rate reached 6.89 mL/min, and the pumping efficiency was up to 27%. The development of NVPPFR compensated for the inefficiency of traditional valveless piezoelectric pumps, broadening the application prospect in biomedicine and biology fields.     

控制有源功率滤波器的一种新方法

该文研究了带有模糊逻辑控制器和积分比例器的有源功率滤波器电路,分析了该电路的控制特征,通过模糊逻辑算法和数值模拟,结果表明：该控制电路具有良好的控制功能和输出电流的追踪能力.     

Frequency response function of motors for switching noise energy with a new experimental approach

Switching energy in electrical vehicles can create serious noise from the motors. However, the characteristics of switching noise in vehicle motors are not clear due to the complexity of measuring them. This study proposes a new experimental method to investigate the switching noise energy of a vehicle motor based on frequency response functions. A function generator-amplifier system is used to generate the switching energy instead of the complex battery-inverter system that has previously been used to examine the noise energy characteristics. Even though newly adapted experimental method is simple, the switching noise energy was explicitly investigated under various input signals. Thus, this simple new method can be used to investigate the dynamic characteristics of noise energy in a vehicle motor.     

Automatic control of manufacturing processes: A model

A model is proposed for the automatic control of manufacturing processes and the necessary preparations. The model is based on step-by-step implementation of a systematic approach and a feedback mechanism. In automated control, the preparations, involving CAD/CAPP/CAM/PDM systems, are integrated with control of the manufacturing process. The model permits the use of paperless technology based on a 3D model of the part and three important stages in the derivation and analysis of information regarding the operation of the working centers. Subsystems permit monitoring of the equipment and the cutting tool and analysis of product quality so as to formulate corrective measures on the basis of feedback mechanisms.     

动物机器人新型智能监控系统设计

利用USB通信和无线通信,设计了新型动物机器人智能监控系统.系统由PC监控软件、信号发射器、接收控制器等部分组成.与以往系统相比,该系统不仅可实现动物机器人行为控制,还可实现行为监测以及环境数据实时采集,具有微体积、微功耗等特点.经动物实验表明,该系统通信可靠、工作时间长、控制准确、操作方便、数据采集精确,将为动物机器人的实时监控提供有力的技术支持.     

A new approach to event-triggered static output feedback control of networked control systems

This paper is concerned with the event-triggered static output feedback control of networked control systems. The event-triggered mechanism is represented by a time-delay model and some latest techniques are employed to deal with the induced time-delay. Furthermore, a novel strategy is developed to eliminate the coupling among control gain, input matrix and output matrix. With these techniques, a new sufficient condition for system stability is established in the framework of linear matrix inequalities. The effectiveness of the proposed method is shown by two numerical examples.