Development of synchronized control system through a pneumatic parallel mechanism and its 3D CG model

This study developed a rehabilitation system that can improve the patient care services provided by physical therapists. Wristparalyzed patients were given arbitrary force through a six-Degree of freedom (6DoF) parallel mechanism composed of six pneumatic cylinders, and recovery training was performed. Each pneumatic cylinder was used to apply force control using a pulse width modulation control, and the force of the 6DoF direction was directed to the wrist of the patient. The thrust force of each cylinder and the force of the 6DoF direction of the parallel mechanism were analyzed. The analysis results conformed well to the experimental results. The developed rehabilitation system was designed to help a physical therapist remotely treat multiple patients at the same time. To monitor the operation of the parallel mechanism of each patient’s side, a 3D computer graphic model was created through OpenGL. The movement of this model was investigated to further examine the movement of the 6DoF direction of the parallel mechanism. Results confirmed that both movements can be controlled synchronously.     

A modular rehabilitation system with enhanced functionality and safety to support improved recovery from injury and quality of life

The rehabilitation of the range of individuals covering medical patients to elite athletes is a costly and time-consuming process involving the knowledge of experienced physical therapists, medical practitioners, coaches, and dedicated training facilities. In order to improve the effectiveness and efficiency of the rehabilitation process, a modular variable-resistance rehabilitation device has been developed. The mechanical, electromechanical, and software systems identified during this research have been shown to provide a step change in exercise functionality, real-time patient monitoring, performance feedback, and safety. Using distributed network concepts, the physical therapist will be able to design and implement training regimes remotely, which can subsequently be downloaded to the localized resistance devices. The patient and/or athlete is able to complete the required exercises without personal supervision. The data from these sessions can be saved and accessed for assessment at a convenient time, thereby maximizing therapist productivity and optimizing the utilization of medical resources.     

CPM康复器中的直流电机PID调速控制

采用梯形法和微分先行算法对传统的数字PID算法进行改进,提高了直流电机的PID调速稳定性和精度。基于调节电枢电压的调速方法和PWM原理,给出了通过测量电枢电流实现电机输出扭矩测量的方法。在LabVIEW软件开发环境和NIELVISⅡ＋实验平台基础上,构建直流电机调速系统,通过实验验证了对PID算法改进的有效性,以及在CPM康复器中不用扭矩传感器而实现电机扭矩测量的可行性。     

A high accuracy dilution system for generating low concentration reference standards of reactive gases

We have developed a unique dynamic dilution system for generating high accuracy reference standards of reactive gases at concentrations which are unstable in high pressure cylinders. It uses state of the art ‘Molbloc’ flow elements and is capable of generating adjustable reference standards with an estimated relative expanded uncertainty lower than 1%. This is a significant development, improving the accuracy of primary reference gas mixtures used to provide and disseminate traceability for measurements of many key gaseous air pollutants.     

The URAGAN wide-aperture large-area muon hodoscope

The URAGAN wide-aperture large-area multilayer muon hodoscope is developed for the NEVOD experimental complex of the Moscow Engineering Physics Institute. The hodoscope will be used to study atmospheric and heliospheric processes responsible for variations in the muon flux at the Earth’s surface. The structures of the detector and its system of data acquisition and processing are described. The data obtained during continuous sets of measurements in 2005–2006 using the first two supermodules of the setup are analyzed, and preliminary results of this analysis are discussed.     

Prediction of Wear in Reciprocating Dry Sliding via Dissipated Energy and Temperature Rise

An alternative technique aimed at facilitating the calculation of frictional power dissipation in reciprocating dry sliding is presented. The proposed technique can be employed for the prediction of wear in circumstances where the direct measurement of power dissipation is encumbered by practical limitations. Experimental tests are carried out to investigate the relationship between the system’s wear rate, power dissipation, and thermal response. A convenient technique is also proposed to estimate the average contact temperature in a reciprocating sliding contact. The predicted temperatures agree with the experimental measurements. It is also shown how the predicted temperatures can be used for the estimation of wear under reciprocating dry sliding configuration.     

High-resolution optical inspection system for fast detection and classification of surface defects

A high-resolution automated optical inspection (AOI) system based on parallel computing is developed to achieve fast inspection and classification of surface defects. To perform fast inspection, the AOI apparatus is connected to a central computer which executes image processing instructions in a graphical processing unit. Defect classification is simultaneously implemented with Hu’s moment invariants and back propagation neural (BPN) approach. Experiments on touch panel glass show that using 100 training samples and 1000?cycle iterations in BPN, the accurate classification of surface defects for a 350?×?350 pixels image can be completed in less than 0.1 ms. Moreover, the inspection of a 43?mm?×?229?mm sample that yields an 800 megapixel raw data can be completed remarkably fast in less than 3?s. Thus, the AOI system is capable of performing fast, reliable, and fully integrated inspection and classification equipment for in-line measurements.     

Modeling of the mechanical behavior of polyethylene/polypropylene blends using artificial neural networks

Polymers possess good thermal and electrical insulation properties, low density, and high resistance to chemicals, thus they have been widely used in industrial applications. Nevertheless, they are mechanically weaker and exhibit lower strength and stiffness than metals. However, their mechanical behavior can be enhanced through different techniques such as blending. Accurate estimation of the mechanical behavior is essential in structural design. Since the process of experimental measurements of a blend’s properties can be costly and time consuming, this paper explores the potential use of artificial neural networks (ANNs) in the field of polymer characterization. It addresses the use of ANNs in modeling the tensile curves and mechanical properties of two commonly utilized polymers (polyethylene PE and polypropylene PP) and their blends. Blends of different proportions have been considered. The experimentally acquired data is used to train and test the neural network’s performance. The key system inputs for the ANN modeler are blend ratio and percent strain, and the system output is the stress. The ANN-predicted outputs were compared and verified against the experimental date. The study indicates that a multilayered ANN can simulate the effect of the blending ratio on the mechanical behavior and properties to a high degree of accuracy. It also demonstrates that ANN approach is an effective tool that can be adopted to reduce cost and time of the experimental work. Moreover, the results show that ANNs demonstrate promising potential in the area of polymer characterization.     

步行康复机器人轨迹控制方法研究

为了满足神经受损患者步行康复训练需要,设计了以外骨骼助行腿为核心的步行康复机器人,其重要的要求是保证机器人的运动轨迹符合患者康复训练要求。为使机器人能模拟步态为患者提供康复训练,在合理的步态规划后对轨迹的控制方法进行了研究,在控制系统软、硬件平台上完成了步行康复机器人助行腿的两种轨迹控制方式(位置控制和速度控制)。通过实验验证了控制方式的可行性,满足了患者步态训练需要。同时实验结果表明,速度控制方式比位置控制方式更加适合步行康复机器人。     

An eight-degree-of-freedom upper extremity exoskeleton rehabilitation robot: design,optimization, and validation

Upper extremity exoskeleton rehabilitation robots can be used for the training of patients with upper extremity motor dysfunction. In most cases, the design of such robots focuses on the configuration and the human-machine compatibility. For patients, the use of an exoskeleton rehabilitation robot mainly aims to improve their movement ability, which depends on the range of movement of the upper extremity joints. This paper proposes an eight-degree-of-freedom (DOF) upper extremity exoskeleton rehabilitation robot to improve the movement range of the patient’s upper extremity joints. The structural parameters of the shoulder joint are optimized and analyzed by the kinematic equations of the mechanism and the cyclic iteration algorithm such that the movement range of the patient joint can be maximized. The movement space of the robot is then simulated. Finally, the movement range of the rehabilitation robot joints and the movement space of the rehabilitation robot were measured. Experimental results show that the upper extremity exoskeleton rehabilitation robot can meet the patient’s shoulder, elbow, and wrist movement range, and the overlap with the human upper extremity movement space is 97.1 % and 95.7 % in the coronal and sagittal planes, respectively.

     

软质肘关节外骨骼的肌力矩估计与神经网络补偿协调控制

为辅助偏瘫患者进行多模式肘关节康复训练,研制了一种软质肘关节康复外骨骼机器人,并提出了一种基于人体肌力矩估计与自适应神经网络补偿的协调控制策略。利用表面肌电信号来识别人体的运动意图并调整康复训练轨迹,采用Lyapunov方法证明了控制算法的闭环控制稳定性。搭建了实时控制实验平台,并开展了基于运动意图的轨迹跟踪实验与自由主动训练实验。实验结果表明,所提控制策略能保证被动训练过程的轨迹跟踪精度,并且可以根据患者的运动意图调整主动训练过程的运动轨迹,实现不同强度的主动康复训练。     

基于数字微镜器件的并行彩色共聚焦测量系统

彩色共聚焦技术因其高分辨率、高测速的特点,在表面形貌测量领域备受关注,然而现有的彩色共聚焦技术多为单点测量,一定程度上限制了测量效率。本文在彩色共聚焦技术的基础上,以DMD作为光分束器件,结合自主研发的大口径色散管镜,利用面阵彩色相机作为光电接收器件,研究和建立了基于数字微镜器件的并行彩色共聚焦实验平台,实现了对被测物面上多个探测点的并行图像处理。最终,利用所搭建的并行彩色共聚焦测量系统,对50μm高的台阶和自制台阶进行了测量,并对硬币的表面形貌进行了三维恢复。实验结果表明,该测量系统的轴向测量范围为300μm,测量精度达到微米级;同时,能够较好地恢复硬币的表面形貌特征,具有较好的测量效率与可靠性。     

直热式热泵热水器冷凝器结构优化试验研究

搭建了空气源热泵热水器试验台.在标准工况下,分别比较了普通套管式冷凝器,3套管式冷凝器和板式冷凝器对热泵系统运行性能的影响.结果表明,板式换热器在热泵热水器系统中换热性能大大优于另外两种常规换热器,使系统性能系数达到4.1,比使用其他两种冷凝器时系统的性能系数提高20％左右.试验结果为如何提高热泵热水器性能提供了依据.     

Statistical tests for measures of colocalization in biological microscopy

Colocalization analysis is the most common technique used for quantitative analysis of fluorescence microscopy images. Several metrics have been developed for measuring the colocalization of two probes, including Pearson's correlation coefficient (PCC) and Manders’ correlation coefficient (MCC). However, once measured, the meaning of these measurements can be unclear; interpreting PCC or MCC values requires the ability to evaluate the significance of a particular measurement, or the significance of the difference between two sets of measurements. In previous work, we showed how spatial autocorrelation confounds randomization techniques commonly used for statistical analysis of colocalization data. Here we use computer simulations of biological images to show that the Student's one‐sample t‐test can be used to test the significance of PCC or MCC measurements of colocalization, and the Student's two‐sample t‐test can be used to test the significance of the difference between measurements obtained under different experimental conditions.     

Ultrasound Measurement of Two-Filler Concentrations in Polypropylene Compounds. Part 1: Static Calibration

Ultrasound waves are used to measure the concentration levels of mica and glass, simultaneously, in polypropylene polymer compounds. A test chamber was designed to accommodate a 1 MHz ultrasound transducer for static calibration of the system response to various levels of glass and mica concentration in the polymer blend. Temperature and pressure calibrations of the transducer response were also performed under controlled experiments. Attenuation and time-of-flight measurements of ultrasound waves propagating through the polymer blend were used to determine the relative concentrations of the fillers. The experimental results show that the system is capable of measuring the filler concentration of mica and glass fibres within _0.5% and _1.0%, respectively.     

Microstructure-property relationships in silicate-matrix composites

Electron microscopy and associated analytical spectroscopic techniques have been used to characterize interfaces in SiC-fibre/silicate-matrix composites. Interface structure, formed via reaction during hot-press fabrication, is a function of time, temperature, matrix composition and fibre type. Interfaces with Nicalon or Tyranno fibres vary from amorphous carbon in fine precipitated form to continuous graphitic layers. Interface behaviour in a stressed composite, and hence the matrix microcracking stress, is a sensitive function of microstructure. Interface debond and shear properties have been assessed using indent-based ‘push-down’ and ‘push-through’ tests using a specially developed instrument within a scanning electron microscope. This uses piezoload measurement and translation, and is capable of dynamic image recording of the indentation sequence. Interface micromechanical (indent) measurements have been correlated with structure and macromechanical response in bend testing for a range of fibre/matrix types, processing and post-processing thermal treatments. An example is also given of interfaces prepared by fibre precoating.     

A terahertz spectrometer with a pulsed high magnetic field

A terahertz (THz) spectrometer based on backward-wave tubes and combined with a pulsed-magnetic-field generator with a pulse duration of ～100 μs and an amplitude of up to 50 T is described. This spectrometer is indented for studying magnetic resonances of various magnets in the THz frequency range (30 GHz-1.5 THz) in the Faraday (longitudinal field) and Voigt (transverse field) geometries. Its operating principle is based on measurements of the change in the transmission of polarized THz radiation by studied samples exposed to an applied pulsed magnetic field. Its advantage over the magnetic-resonance technique, in which radiation guides with uncontrolled radiation polarization are used, is the possibility of performing precise polarization measurements necessary for determining the conditions for excitation of resonance magnetic modes and yielding important information on the magnetic structure of materials. The results of polarization measurements of test samples are presented. The degree of radiation polarization is 99.99%; the dynamic measurement range is 25 dB; the measurement accuracy is no worse than 1%; the time resolution of the recording system is 1s; the magnetic-field inhomogeneities at the solenoid’s center at a base of ±2 mm are no worse than 1 (experimental) and 5% (calculated) for the axial and radial components, respectively; and the maximum stored energy is 40.5 kJ.     

Design and implementation of an efficient acoustically levitated drop reactor for in stillo measurements

We present the details necessary for building an efficient acoustic drop levitator with reduced electrical power consumption and greater drop stability compared to previous designs. The system is optimized so that the levitated drop may be used as a chemical reactor. By introducing a temperature, pressure, and relative humidity sensor for feedback control of a linear actuator for adjusting resonator length, we have built a completely automated system capable of continuous levitation for extended periods of time. The result is a system capable of portable operation and interfacing with a variety of detection instrumentation for in stillo (in drop) measurements.     

基于单片机的DMX512信号监控系统设计

应用MCS51系列8位单片机设计了一套DMX512信号监控系统。该系统通过单片机对数字灯光系统中DMX512信号进行解码、测量和分析,并通过LCD模块实时显示出DMX512信号的参数,同时,还具有DMX512信号中继和输出特定场景信号的功能。该系统成本低廉,方便了数字灯光控制系统施工、测试与运行阶段对DMX512信号的监控与分析。     

Active disturbance rejection control based human gait tracking for lower extremity rehabilitation exoskeleton

This paper presents an active disturbance rejection control (ADRC) based strategy, which is applied to track the human gait trajectory for a lower limb rehabilitation exoskeleton. The desired human gait trajectory is derived from the Clinical Gait Analysis (CGA). In ADRC, the total external disturbance can be estimated by the extended state observer (ESO) and canceled by the designed control law. The observer bandwidth and the controller bandwidth are determined by the practical principles. We simulated the proposed methodology in MATLAB. The numerical simulation shows the tracking error comparison and the estimated errors of the extended state observer. Two experimental tests were carried out to prove the performance of the algorithm presented in this paper. The experiment results show that the proposed ADRC behaves a better performance than the regular proportional integral derivative (PID) controller. With the proposed ADRC, the rehabilitation system is capable of tracking the target gait more accurately.