基于STM32F103的自主肌电控制功能性电刺激的研究与设计

为解决不同患者对于功能性电刺激强度的适应能力和肢体角度的控制,设计了一款自主肌电控制功能性电刺激。该系统以STM32F103为开发平台,对肌电信号进行采集和刺激输出控制。硬件电路包含运算放大电路、全波整流电路、有源滤波电路和电流镜电路等。软件实现通过STM32F103的直接寄存器访问技术、数模转换模块和模数转换模块进行肌电信号峰值探测和刺激信号输出强度控制。测试表明:该系统能够实现肌电峰值探测,并使用肌电信号峰值控制刺激信号动态输出。     

基于神经网络的假肢无线控制系统的设计

为了改善残疾人生活水平和促进医疗事业发展,提出一种基于神经网络的假肢无线控制系统设计方案。该系统以STM32为核心芯片,通过采集上肢肱二头肌、肱三头肌、指浅屈肌、指伸肌4块肌肉的肌电信号,使用BP神经网络与SOFM神经网络相结合对肌电信号进行模式识别,实时控制肌电假肢的完成伸臂、屈臂、腕内旋、腕外旋、握拳、张手6种动作行为。实验结果表明,该系统对6种动作的整体识别率可达97%,并且采用无线实时的控制方式,能够更方便地帮助部分肢体残疾患者完成这些基本的操作行为。     

连续反馈式电刺激系统的设计

目前第二代电刺激技术存在的不足之处有:刺激和肌电信号采集不能同时进行以及刺激强度不能随患者肌电信号大小而调节。文章基于电刺激技术的原理,采用WIN CE数字系统搭建了连续反馈式电刺激系统模拟板电路。设计得到了具有闭锁功能、快速恢复的肌电信号的放大器和快速、耐高压的电极通道切换电子开关,并且优化了肌电采集与刺激之间的对应关系。最终建立了完整的肌电生物反馈电刺激循环并实现恢复患者意识对肌肉的控制能力。     

肌电生物反馈法康复治疗仪的设计

设计并研发一种通过肌电生物反馈法重建人体神经网络系统的医疗仪器,为神经肌肉系统类疾病患者的全面康复提供一种新的治疗平台.治疗仪由硬件电路和PC机控制软件两部分构成,下位机（MCU）包括体表肌电采集放大电路、神经肌肉电刺激电路两大部分;上位机（PC）的软件系统主要负责视觉信号反馈,治疗参数控制、病历登记、信息查询等功能.治疗仪达到了国家的医用康复治疗的各项指标,能够帮助患者逐步康复,且具有安全、无创、便捷、人机交互能力强等特点.     

A wireless wearable surface functional electrical stimulator

In this paper, a wireless wearable functional electrical stimulator controlled by Android phone with real-time-varying stimulation parameters for multichannel surface functional electrical stimulation application has been developed. It can help post-stroke patients using more conveniently. This study focuses on the prototype design, including the specific wristband concept, circuits and stimulation pulse-generation algorithm. A novel stimulator circuit with a driving stage using a complementary current source technique is proposed to achieve a high-voltage compliance, a large output impedance and an accurate linear voltage-to-current conversion. The size of the prototype has been significantly decreased to 17 × 7.5 × 1 cm³. The performance of the prototype has been tested with a loaded resistor and wrist extension/flexion movement of three hemiplegic patients. According to the experiments, the stimulator can generate four-channel charge-balanced biphasic stimulation with a voltage amplitude up to 60 V, and the pulse frequency and width can be adjusted in real time with a range of 100–600 μs and 20–80 Hz, respectively.     

A multichannel FES system for the restoration of motor functions inhigh spinal cord injury patients: a respiration-controlled system formultijoint upper extremity

A multichannel functional electrical stimulation (FES) system for the restoration of quadriplegic upper extremity function is described. The system is composed of a personal computer NEC PC-8801mkII, peripheral electronic circuits, CRT display and respiratory sensors for volitional control by the patient, and percutaneous electrodes. A C4 quadriplegic patient could drink canned tea by herself by using this FES system. Distinct features of the system are as follows: 1) Versatile volitional control was realized by controlling the memory allocation of the stored stimulation data by voluntary respiratory signals. 2) Sophisticated fine control of the fingers, wrists, and elbow was realized by creating the multichannel stimulation data from recorded myoelectric activities of normal subjects during movements of the upper limb.     

The influence of stimulation pulse frequency on the generation ofjoint moments in the upper limb

Six muscles of the upper limb were stimulated transcutaneously. This communication reports the influence of the stimulation pulse frequency on the isometric joint moment generated by each muscle. A lower frequency of stimulation, the critical fusion frequency, was found for each muscle at which contractions ceased to be tetanic. This fusion frequency was correlated with muscle function. The magnitude of the joint moment was examined as a function of the stimulation pulse frequency for the six muscles tested. Parabolic curves were found to best fit this relationship; the magnitude of the moment reaching a maximum at typically 50 Hz, and often decreasing at higher frequencies. The slope of the linear portion of the relationship between the generated joint moment and the stimulation current intensity was shown to be a function of the stimulation pulse frequency. This function was found to be similar to the form of the joint moment versus pulse frequency curve. Fatigue curves were plotted at different stimulation frequencies; demonstrating reduced fatigue at lower stimulation frequencies. A model was presented of the fatigue curve as an exponential function of time. We conclude that a stimulation frequency of 15 Hz is optimal for the upper limb muscles with a working range of 15-50 Hz where stimulation frequency is one of the parameters used to modulate the muscle contraction force.     

A Computer-Controlled Multichannel Stimulation System for Laboratory Use in Functional Neuromuscular Stimulation

Laboratory instrumentation systems for developing functional neuromuscular stimulation (FNS) orthoses must be flexible in command processing and in multichannel stimulus control and coordination. For research and development of new FNS systems to control the musculoskeletal function of disabled individuals, we have developed a computer-controlled multichannel stimulation system. This system both processes patient generated input commands delivered from a variety of sources, and coordinates the multichannel stimulation to achieve the desired movement. The flexibility provided by this system has proven to be of great value in both upper and lower extremity FNS.     

FNS Control Schemes for the Upper Limb

This paper is concerned with the problems of control associated with the application of functional neuromuscular stimulation of the upper limb, concentrating on elbow flexion/extension and wrist pronation/supination. A closed-loop controller is needed in order to overcome the gain nonlinearities and plant dynamic parameter variations. Controllers were developed based on models and parameters previously established. Two controllers are discussed in detail, a thirdorder feedforward controller and a model reference adaptive controller. There were no striking differences in the performances of the thirdorder controllers. The conventional controllers, however, required a lengthy a priori identification procedure each time they were used. This was performed implicitly by the adaptive controller within a few seconds, making it a practical proposition for an FNS controller.     

Redundancy resolution of the human arm and an upper limb exoskeleton

The human arm has 7 degrees of freedom (DOF) while only 6 DOF are required to position the wrist and orient the palm. Thus, the inverse kinematics of an human arm has a nonunique solution. Resolving this redundancy becomes critical as the human interacts with a wearable robot and the inverse kinematics solution of these two coupled systems must be identical to guarantee an seamless integration. The redundancy of the arm can be formulated by defining the swivel angle, the rotation angle of the plane defined by the upper and lower arm around a virtual axis that connects the shoulder and wrist joints. Analyzing reaching tasks recorded with a motion capture system indicates that the swivel angle is selected such that when the elbow joint is flexed, the palm points to the head. Based on these experimental results, a new criterion is formed to resolve the human arm redundancy. This criterion was implemented into the control algorithm of an upper limb 7-DOF wearable robot. Experimental results indicate that by using the proposed redundancy resolution criterion, the error between the predicted and the actual swivel angle adopted by the motor control system is less then 5°.     

功能覆盖率驱动的自适应遗传算法验证技术

根据不同功能测试点在芯片代码中的逻辑深度与相应测试向量覆盖到的测试点多少的关系,对不同测试点设置了相应的权重,提出一种基于自适应遗传算法的激励向量生成方法。实验结果表明,该方法能减少编写约束文件时间,较快自动搜索有针对性的测试激励,提高芯片功能验证的可靠性和仿真效率。     

FNS Parameter Selection and Upper Limb Characterzation

The design of a controller for functional neuromuscular stimulation requires characterization of the plant, i. e., the neuromuscular system involved. The present paper is concerned with the modeling and identification of the elbow flexion/extension and wrist pronation/supination systems. These movements can be performed successfully by the surface stimulation of the biceps, triceps, and pronator teres. The scatter in the plant parameters between subjects and for a given subject as a function of time, electrode placement, etc., is outlined. The nonlinear muscle gain is approximated by a threshold below which the torque is zero, followed by a linear region. A least squares identification technique using a pseudorandom binary sequence input returned best fit for a third-order model for both the elbow and wrist dynamics. The dependence of the complex poles on the input signal bandwidth and level of coactivation is examined. The differences in parameters between the wrist and elbow systems are calculated. The results are used to establish design requirements for an appropriate controller.     

An externally powered, multichannel, implantablestimulator-telemeter for control of paralyzed muscle

An implantable integrated stimulator and telemetry system has been developed. The system is capable of fulfilling the stimulus and telemetry needs of advanced functional neuromuscular stimulation (FNS) applications requiring multiple channels of stimulation and multiple channels of sensor or biopotential sensing. This system provides a command control structure, an inductive radio frequency link providing power to the implant device as well as two-way transcutaneous communication, an ASIC for decoding the command and for providing functional control within the implant, and modular circuitry providing the application specific implant functions. Biocompatible hermetic packaging, lead systems, and in-line connectors suitable for long-term implantation, provide encapsulation for the circuitry and access to the electrodes and sensors used in the application. The first implant configuration realized from this modular system is targeted for clinical implementation in persons with tetraplegia at the C6 level for restoration of hand function, using wrist position as the command control source. The implant device realized has ten channels of stimulation and telemetry used to control and sense a joint angle transducer implanted in the radio-carpal joint of the wrist. A prototype device has been fabricated and is undergoing testing in an animal     

Upper Extremity Limb Function Discrimination Using EMG Signal Analysis

A signal analysis technique is developed for discriminating a set of lower arm and wrist functions using surface EMG signals. Data wete obtained from four electrodes placed around the proximal forearm. The functions analyzed included wrist flexion/extension, wrist abduction/adduction, and forearm pronation/supination. Multivariate autoregression models were derived for each function; discrimination was performed using a multiple-model hypothesis detection technique. This approach extends the work of Graupe and Cline [1] by including spatial correlations and by using a more generalized detection philosophy, based on analysis of the time history of all limb function probabilities. These probabilities are the sufficient statistics for the problem if the EMG data are stationary Gauss-Markov processes. Experimental results on-normal subjects are presented which demonstrate the advantages of using the spatial and time correlation of the signals. This technique should be useful in generating control signals for prosthetic devices.