复合型直线超声波马达

国内外对直线型超声波马达的理论探索和研制进行了大量的研究。根据近十几年来国内外的有关文献资料,从振动模态的角度分类总结了国内外纵弯型、纵扭型、纵振型、弯振型四类典型直线型超声波马达的发展及其研究现状,并概述了其工作原理和特点。     

DRM系统的关键技术--信源编码方法

简要指出模拟AM广播数字化的意义和DRM系统的产生，着重讨论了数字AM广播对信源编码的特殊要求，介绍了为适应特殊要求在DRM系统中使用的信源编码方法及频带恢复(SBR)原理。     

Automated tuning of a closed-loop hand grasp neuroprosthesis

An automated tuning algorithm was developed to reduce the time and skill required to tune a closed-loop hand grasp neuroprosthesis. The time reduction results from simultaneous tuning of four gain parameters controlling the dynamic response of the system, and from automation of the calculation and decision processes. The method is therefore an automated parallel tuning method, replacing a manual sequential method in which only one parameter at a time was tuned. RMS error between the step input and the grasp output is minimized, with absence of oscillation as a constraint. The difference between the system's RMS ramp tracking errors for the two tuning methods was less than 1% of the ramp size regardless of the initial values of the parameters, implying that the tuning methods were equivalent. However, the parallel tuning method was faster and required fewer trials than the sequential method. The capability of the closed-loop system to regulate grasp output in the presence of disturbances was shown to be better than the capability without feedback     

In-line lead connector for use with implanted neuroprosthesis

The design, implementation, and preliminary testing of an implantable in-line connector for individual lead-wires is presented. The connector provides for replacement of implanted components without disturbing other elements of the implanted system. Its flexibility and size makes it suitable for implantation in neuromuscular applications.     

Visual neuroprosthesis: a non invasive system for stimulating the cortex

This paper describes a complete visual neuroprosthesis wireless system designed to restore useful visual sense to profoundly blind people. This visual neuroprosthesis performs intracortical microstimulation through one or more arrays of microelectrodes implanted into the primary visual cortex. The whole system is composed by a primary unit located outside the body and a secondary unit, implanted inside the body. The primary unit comprises a neuromorphic encoder, a forward transmitter, and a backward receiver. The developed neuromorphic encoder generates the spikes to stimulate the cortex by approximating the spatio-temporal receptive fields characteristic response of ganglion cells. Power and stimuli information are carried to inside the cranium by means of a low-coupling transformer, which establishes a wireless inductive link between the two units. The secondary unit comprises a forward receiver, microelectrode stimulation circuitry and a backward transmitter that is used to monitor the implant. Address event representation is used for communicating spike events. Data is modulated with binary frequency-shift keying and differential binary phase-shift keying in the forward and in the backward directions, respectively. A prototype of the proposed system was developed and tested. Experimental results show that the spikes to stimulate the visual cortex are accurately generated and that the efficiency of the inductive link is relatively high, about 28% in average for 1 cm intercoil distance providing a power of about 50 milliwatts to the secondary implanted unit. Application specific integrated circuits were designed for this secondary unit, showing that, with current technology, it is possible to implement such a unit, respecting the power constraints.     

A microelectrode/microelectronic hybrid device for brain implantable neuroprosthesis applications

We have designed, fabricated, and characterized a microminiaturized "neuroport" for brain implantable neuroprosthesis applications, using an analog CMOS integrated circuit and a silicon based microelectrode array. An ultra-low power, low-noise CMOS preamplifier array with integral multiplexing was designed to accommodate stringent thermal and electrophysiological requirements for implantation in the brain, and a hybrid integration approach was developed to fabricate a functional microminiaturized neuroprobe device. Measurements showed that our fully scalable 16-channel CMOS amplifier chip had an average gain of 44 dB, bandwidth from 10 Hz to 7.3 kHz, and an equivalent input noise of approximately 9 microVrms with an average power consumption per preamplifier of 52 microW, which is consistent with simulation results. As a proof-of-concept demonstration, we have measured local field potentials from thalamocortical brain slices of rats, showing oscillatory behavior with an amplitude about 0.5 mV and a period ranging 80-120 ms. The results suggest that the hybrid integrated neuroport can form a prime platform for the development of a next level microminiaturized neural interface to the brain in a single implantable unit.     

Modeling the human knee for assistive technologies

In this paper, we use motion capture technology together with an EMG-driven musculoskeletal model of the knee joint to predict muscle behavior during human dynamic movements. We propose a muscle model based on infinitely stiff tendons and show this allows speeding up 250?times the computation of muscle force and the resulting joint moment calculation with no loss of accuracy with respect to the previously developed elastic-tendon model. We then integrate our previously developed method for the estimation of 3-D musculotendon kinematics in the proposed EMG-driven model. This new code enabled the creation of a standalone EMG-driven model that was implemented and run on an embedded system for applications in assistive technologies such as myoelectrically controlled prostheses and orthoses.     

Proxy-based impedance control of a cable-driven assistive system

In rehabilitation robotics, rehabilitation algorithms determine an appropriate magnitude and direction of assistive force, which is to help the patient perform desired motions. In this paper, proxy-based impedance control is proposed as a possible rehabilitation algorithm of a cable-driven assistive system that is designed for rehabilitation exercise of the wrist. The proposed method applies an assistive joint torque when the wrist angle deviates from the position of a proxy. A free space is assumed around the proxy such that a free motion of the wrist is allowed in a certain range. When the desired inertia of the hand is different from a nominal value, the proposed method also applies assistive torques to compensate for the inertia mismatch. The implementation of rehabilitation algorithms is challenged by actuator dynamics. The proposed algorithm is designed considering the actuator dynamics, and thus it shows the desired performance and stability in practice.     

Hybrid rotor position observer for wide speed-range sensorless PM motor drives including zero speed

This paper addresses the problem of wide speed-range sensorless control of a surface-mount permanent-magnet (SMPM) machine including zero-speed operation. A hybrid structure integrating a flux observer and signal-injection techniques is proposed, which results in a rotor position signal independent of motor parameters at low and zero speed. Although the SMPM machine typically has a very low geometric saliency, the injection technique is effective in tracking the saturation-induced saliency produced by the stator flux. Experimental results are presented showing an excellent performance for both the sensorless speed and position control using an off-the-shelf SMPM machine.     

Signal processing challenges in cognitive assistive technology [Exploratory DSP]

Technological supports for people with disabilities are usually referred to as assistive technology. There has been significant work in developing technologies to support people with mobility and sensory disabilities. Developing these tools for people with cognitive disabilities has not been as widespread. In this article, we briefly outline causes and consequences of cognitive disabilities and then concentrate on smart home technologies. One such challenge in smart homes is the desire to have inexpensive components easily installed and selfcalibrating. We briefly mention work in brain-computer interfaces (BCIs).     

Discriminant analysis of changes in human muscle function wheninteracting with an assistive aid

The authors examines the changes of human muscle function when the arm's simple antagonist tricep-bicep muscle pair is aided by a mechanical assistive device. The assistive aid changes how the muscles are used, and this shift in muscle activity is determined objectively by using discriminant analysis. Surface EMG signals from the biceps and triceps provide the electric signals. Four types of primitive arm movements are used in the detection of the muscle changes     

Sleep assistive dynamic bandwidth assignment scheme for passive optical network (PON)

In passive optical network (PON), in addition to efficient bandwidth management, a dynamic bandwidth assignment (DBA) scheme can also enhance the energy efficiency performance of the optical networks units (ONUs) during sleep mode. A few such green DBA schemes have been proposed in literature for EPON, however, ITU compliant PONs have not got attention. In this study, the role of a DBA scheme during the cyclic sleep mode for XGPON has been investigated. A sleep assistive (SA)-DBA scheme is proposed that not only improves the energy saving performance of cyclic sleep mode but also reduces the upstream delays and variance for all the type-2 (T2), type-3 (T3) and type-4 (T4) traffic classes. Although, the upstream delay of type-1 (T1) traffic class slightly increases, the average upstream delay of all the traffic classes remains below the set target delay limit of 56 ms.     

混合的ATM技术

ＡＴＭ协议体系结构分为物理层，ＡＴＭ层，ＡＬＬ层和高层，如果在终端用户处完全实现这些功能，不仅造价大，还要放弃用户在网卡，网络软件上的投资。而在终端用户的协议栈中采用混全的方案，则能保留现有网络技术的一些协议层次，又加入ＡＴＭ的协议层次，可以在将用户接入ＡＴＭ网的同时，保护用户已有的网络投资。     

Hybrid nanopolymers

Solar cells that combine nanotechnology with plastic electronics are emerging with the development of a semiconductor-polymer PV device. Researchers at the Lawrence Berkeley National Laboratory and the University of California at Berkeley claim such hybrid cells will be cheaper and easier to make than semiconductors, and could be made in the same, nearly infinite variety of shapes as pure polymers.     

混合动态连接结构的多用户多流混合预编码

混合预编码对于提高多用户毫米波大规模多输入多输出(MIMO)系统的性能至关重要,但目前基于全连接结构与子连接结构的混合预编码分别存在高能耗与性能损失严重的问题.该文综合考虑系统的频谱效率与能量效率,提出混合动态连接结构,并设计该结构下的混合预编码算法.该算法通过最大化信干噪比(SINR)的增量来设计混合动态连接结构的模...     

混合动态连接结构的多用户多流混合预编码

混合预编码对于提高多用户毫米波大规模多输入多输出(MIMO)系统的性能至关重要,但目前基于全连接结构与子连接结构的混合预编码分别存在高能耗与性能损失严重的问题.该文综合考虑系统的频谱效率与能量效率,提出混合动态连接结构,并设计该结构下的混合预编码算法.该算法通过最大化信干噪比(SINR)的增量来设计混合动态连接结构的模拟域预编码,然后基于等效信道运用块对角化(BD)设计数字域预编码抑制多用户多流干扰.仿真实验表明,该文所提出的混合动态连接结构的频谱效率介于全连接结构与混合固定连接结构之间且获得的能量效率最高.     

为电器马达提供动力

马达类型 近一个世纪以来,感应马达一直是电器行业的动力提供部件.在新型的变频驱动器中,也有许多使用感应马达.但有部分新的电器开始采用更高效、更紧凑轻巧的马达系统.     

NanoMuscle马达技术

NanoMuscle马达 与常规的把电磁用作运动来源的马达不同,NanoMuscle马达用形状记忆合金来产生运动。形状记忆合金是在五十年代发展出的一种材料,当将电流传给制成     

Digital cities of the future: Extending @home assistive technologies for the elderly and the disabled

In the digital city of the future there is the vision of seamless virtual and physical access for every home and between each home and the workplace, as well as critical city infrastructure such as the post office, the bank, hospitals, transportation systems, and other entities. This paper provides an overview of technical and other issues in extending at home (@home) assistive technologies for the elderly and the disabled. The paper starts by giving a vision of what this city is supposed to look like and how a human is to act, navigate and function in it. A framework for extending assistive technologies is proposed that considers individuals belonging to special groups of interest and locations other than their home. Technology has already reached the state of ubiquitous and pervasive sensor devices measuring everything, from temperature to human behavior. Implanting intelligence into and connecting such devices will be of immense use in preventive healthcare, security in industrial installations, greater energy efficiency, and numerous other applications. The paper reviews enabling technologies that exist and focuses on healthcare applications that support a longer and higher quality of life at home for the elderly and the disabled. It discusses intelligent platforms involving agents, context-aware and location-based services, and classification systems that enable advanced monitoring and interpretation of patient status and optimization of the environment to improve medical assessments. The paper concludes with a discussion of some of the challenges that exist in extending @home assistive technologies to @city assistive technologies.