This paper proposes an FES upper and lower limbs interlocking motion control system to induce periodic rhythm for rehabilitation of the interlocking rhythms of upper and lower limbs during exercise, such as walking. This system, which consists of the human body and the proposed mechanism, can be regarded as a closed chain mechanism with a six-link and five-joint system. In particular, input force is modeled by considering the monoarticular and biarticular muscle groups as actuators. Because the effective muscle force values are very different, inputs of upper and lower limbs are modeled respectively. The control objective can be achieved by RISE control for the FES upper and lower limbs interlocking motion control system.

This paper presents a pose synchronization method for semi-autonomous dynamic robotic swarms with a passivityshort human operator. In the human-robot network, a human operator sends a command signal to and receives visual information from only a part of the robotic group. In this setting, the proposed dynamic control scheme achieves not only pose synchronization of all mobile robots but also convergence to the reference pose that the human operator specifies. The main advantage of the proposed method is to guarantee convergence of not only the position but also the orientation to the reference ones in the human-robot network. Finally, we provide human-in-the-loop simulation results through the human operation using a tablet PC to illustrate the performance of the proposed control method.

This paper considers an FES-supported standing-up control system that incorporates the center of mass (COM) motion for rehabilitation of patients with neurological disabilities. The COM motion is controlled by electrical current input which is delivered through the upper limbs and adjusted according to the velocity of the COM motion. The upper limbs should be given as minimum input as possible to reduce the strain on users since control input is also delivered to the lower limbs to activate the standing-up motion. Therefore, the proposed controller does not send the input current to the upper limbs when the tracking error is small by using zeroing control barrier function (ZCBF). Experimental results are presented to validate the effectiveness of the proposed method in comparison to the previous method.

This paper considers the control method for functional electrical stimulation (FES) alternate knee bending and stretching trike system that takes into account the running velocity in outdoor environments for rehabilitation for patients with a motor system disorder (e.g., spinal cord injury or Parkinson's disease). The control objective of the proposed controller is to make the running velocity of the trike follow the desired one. FES trike and a rider are modeled by considering running resistances, characteristics of the freewheel, and force direction of each lower limb's 2 muscle groups. Stability of the developed controller is analyzed through Lyapunov-based methods.

A cycling system using functional electrical stimulation (FES) provides effective rehabilitation for patients with neurological disorders. Designing a FES-based cycling system with antagonistic bilateral muscles and Repetitive learning controller (RLC) can reduce physical discomfort for patients. In addition, previous studies have shown that control measurements require human body parameters, and thus, it is difficult to make control measurements that correspond to individual users. Therefore, in this paper, we constructed the FES cycling system that considers the antagonistic biarticular muscles using RLC and a semi-global control law that does not require human body parameters The stability of the controller was determined in the Lyapunov's stability theorem, and the asymptotic stability was proved.

In this paper, we consider a Passive-type Traversing Wind Turbine (PTWT) and propose a control system to improve power generation and windbreaker effect of the wind turbine. Wind power has been becoming more popular worldwide and several types of wind turbines to match different operating environments and objectives have been researched. As one of them, we have started to study a special type of Vertical-Axis Wind Turbine (VAWT) which may also solve wind disaster problems in agricultural areas. The parallel mechanism in this type of wind turbine makes it difficult to adjust blades angle, therefore the mechanism has trouble changing blade angle during sudden inversions in wind direction. However, by using a passive mechanism that only uses the power of the wind, the wind turbine can keep up with sudden inversions in wind direction. In addition, active control is possible by attaching actuators, and hybrid control (passive and active) may increase the efficiency of power generation and windbreaker effect. We conduct wind-tunnel tests to evaluate the incleased effectiveness of power generation using the hybrid control system. Additionally, we investigate drag of the wind turbine to clarify the windbreaker effect using the developed system.

This paper presents passivity-based visual feedback control for an endpoint closed-loop system with a movable camera. The objective of the system is that a controlled mobile vehicle tracks a target object vehicle by using only aerial vehicle's visual information. First, a brief summary of the estimation and pose error systems for the camera-mounted aerial vehicle is presented. Second, we design a novel nonlinear observer to estimate the pose of the controlled mobile vehicle. Next, we propose a visual feedback control law for the constructed visual motion error system based on the passivity. After discussing stability analysis of the closed-loop system through Lyapunov stability theorem, simulation results are provided to illustrate the performance of the proposed control method.

In this paper, we consider a vision-navigated bilateral control for master-slave teleoperation system. Firstly, a brief summary of the passivity-based visual feedback system is provided. Next, a vision-navigated teleoperation system is constructed by combining the visual feedback system and the master-slave teleoperation system. After that, we propose the vision-navigated bilateral control law and discuss the stability analysis based on the Lyapunov method. Finally, the simulation results show the validity of the proposed vision-navigated bilateral control.

Sensor nodes are used extensively in order to gather real-time information in the social environment and natural environment. And the production volume of sensor nodes is much increased with the development of cyber-physical systems. Therefore, it becomes important how to reduce the power consumption of huge sensor nodes. In this work, normally-off architecture of microcontroller for future low-power sensor node is proposed. To realize true low-power effects with normally-off computing technology, a co-design of hardware and software technology is much important. In this work, the power consumption of sensor nodes is possible to reduce of around 70% by using normally-off MCU architecture in sensor node.

This paper investigates passivity-based pose control via an obstacle avoidance navigation function for three-dimensional (3-D) eye-in-hand visual feedback systems. Firstly, visual motion observer-based pose control for 3-D eye-in-hand visual feedback systems is presented. Next, a path planner to be appropriate for the visual motion error system is designed through an obstacle avoidance navigation function to keep collision-free during servoing. Finally, the effectiveness of the proposed method is verified through computer simulations.

In information dissemination problem on interconnection networks, problems of broadcasting and gossiping have been widely studied. In this paper, we study the other problem, called multi-source broadcasting, defined as follows: there are some (but not all) vertices each of which has the unique item of information and needs to disseminate to every other vertex. This problem is located at an intermediate position between broadcasting and gossiping. We analyze the multi-source broadcasting problem on the cycle-rooted tree and the de Bruijn digraph as an interconnection network.

In this paper, we propose a novel macro-micro tele-manipulation system based on body image embedding with contact feel, spatial motion and stereo vision for micro-manipulation under a microscope. The basic concept of body image embedding for macro-micro tele-manipulation has been already proposed by the authors. The system proposed here has three new realization ideas. The first idea is the realization of realistic contact feeling which is attained by driving a voice coil motor according to the binary on/off information of the switch between micro-tools. The use of a voice coil motor not only saves the cost of the system, but also generates clearer tactile and auditory stimuli than a piezo actuator for sending contact information in a micro world to an operator. The switch between micro-tools does not detect the contact between the object to be manipulated and the tool for manipulation directly, but can be useful for some tasks. The second idea is the realization of spatial motion of the manipulation tool relative to the object to be manipulated, which is realized by the appropriate coordination of the 2-degree-of-freedom motions of the slave manipulators. The third idea is the realization of stereo vision under the constraint of the position/orientation consistency of an operator's body image between proprioception and vision, which is achieved by the special placement of the dual joysticks of the dual micro-manipulators. The effectiveness of the proposed realization method is verified experimentally by micro-drawing tasks where we need appropriate hybrid position/force control of the micro-tool for manipulation in a three-dimensional space.

The long-term evolution (LTE), which was specified as the release 8 specification in the 3rdgeneration partnership project (3GPP), will achieve broadband services with the peak data rate of 100 Mbps in the downlink. This paper presents the measured throughput performance and power consumption performance of the implemented demodulation and decoding LSI for 2-by-2 MIMO-OFDM in the Rel-8 LTE downlink. The implemented LSI comprises FFT timing detection, a 2048-point FFT, a channel estimation filter, maximum likelihood detection (MLD) based signal detection, a channel deinterleaver, and a turbo decoder with the max-log-MAP (maximum a posteriori) algorithm. The most prominent feature of the implemented LSI is MLD based signal detection with low power consumption and a low required received signal-to-noise power ratio (SNR) for 2-by-2 MIMO multiplexing. Experiments show that the implemented LSI achieves the measured throughput of 100 Mbps at the average received SNR of 22 dB with a low power consumption level of approximately 40 mW with 16QAM and the channel coding rate of 8/9.

This paper presents a new maximum likelihood detection (MLD)-based signal detection method for orthogonal frequency division multiplexing (OFDM) multiple input multiple output (MIMO) multiplexing with frequency domain spreading and code multiplexing. The proposed MLD reduces the computational complexity by utilizing signal orthogonalization based on QR decomposition of the product of the channel and spreading code matrices. Simulation results show that when the spreading factor and number of code multiplexing are 16, the proposed MLD reduces the average received signal energy per bit-to-noise spectrum density ratio (Eb/N0) for the average packet error rate (PER) of 10"2 by approximately 12 dB compared to the conventional minimum mean squared error (MMSE)-based filtering for 4-by-4 MIMO multiplexing (16QAM with rate-3/4 Turbo code is assumed).

A pattern recognition system that can process a large amount of image data at high speed is required in many fields. In this paper, we propose an on-chip pattern recognition system that utilizes the reconfigurability of the FPGA. The features of the system are not only very high recognition speed but also an adaptive function. For example, when objects to be detected change appearance, recognition parameters must be changed to retain the recognition accuracy. The system can automatically adjust by executing on-chip partial reconfiguration. The system runs at 25MHz and can return a recognition result in one clock cycle, 40ns. To update the system, all processes needed for searching for the best recognition parameters, generating configuration data and reconfiguring the system are carried out within 30s.

This paper proposes the application of closed-loop type antenna switching transmit diversity (ASTD) associated with frequency domain channel-dependent scheduling to single-carrier frequency division multiple access radio access in the evolved UTRA (UMTS terrestrial radio access) uplink. In the proposed scheme, virtual resource units (RUs) are assigned to the optimum transmitter antenna in the spatial domain, while they are also assigned to the optimum frequency band (i.e., physical RUs) in the frequency domain according to the propagation channel conditions of each user. The reference signal overhead is the same as that for single-antenna transmission and the impact on the hardware implementation in the user equipment is slight since only one RF chain is necessary. Simulation results show that the gain of the closed-loop type ASTD is approximately 1.2-1.5 dB at the 1% level in the cumulative distribution function, assuming unequal antenna gain, i.e., the difference in the average transmission power of 3 dB and the fading correlation between transmitter antennas of 0.3 when frequency domain channel-dependent scheduling is applied with hybrid ARQ and soft-combining.

This paper proposes a method to improve the operability of micro-macro tele-operations in biological researches and developments. In such fields, there are lots of labor intensive works and the smooth execution of the works requires some trained human skills. Thus, if we can improve the operability of the equipments, the efficiency of the researches and developments will be improved remarkably. The idea is to add a pseudo haptic feedback and artificial responding sounds beside the real magnified image. The image itself has enough information to operate, but adding other sensory information may ease the operation. Naturally, the real magnified haptic feedback must be helpful, but its realization is not so easy. Even pseudo or artificial sensory feedback may help enough to improve the operability. As a start of our research, this paper shows a simple experiment to ensure the effectiveness of adding the other sensory feedback.

We propose a pseudo-inverse minimum mean squared error (MMSE) based QR decomposition (QRD) M-algorithm (QRD-M) for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. The proposed algorithm can effectively mitigate the detrimental effect of MIMO channel ill-conditions on the bit error rate (BER) performance. As a result, the number of retained branches (M value) can be reduced to half of the original QRD-M algorithm in [1] in order to achieve the same performance for both the uncoded and coded systems. The detection complexity is therefore greatly reduced.

This paper presents experimental results on real-time packet transmission of greater than 1 Gb/s using 4-by-4 multiple-input-multiple-output (MIMO) multiplexing and maximum-likelihood detection (MLD)-based signal detection with a decreased level of computational complexity in orthogonal frequency-division multiplexing (OFDM) radio access. We apply our previous algorithm called adaptive selection of surviving symbol replica candidates (ASESS) based on the maximum reliability in MLD employing QR decomposition and the M-algorithm (QRM-MLD) to reduce the extremely high level of computational complexity in the conventional MLD. The experimental results using multipath fading simulators are in good agreement with the computer simulation results. The loss in the required received signal energy per bit-to-background noise power spectrum density ratio (Eb/N0) is suppressed to within approximately 1-2 dB. Therefore, through experiments, we demonstrate that the QRM-MLD employing ASESS is very beneficial in reducing the influence of hardware implementation loss, as well as in decreasing the required received Eb/N0. We further show that the extremely high-speed real-time packet transmission of greater than 1 Gb/s in a 100-MHz channel bandwidth (i.e., 10 bit/s/Hz) is achieved at the average received Eb/N0per receiver antenna of approximately 12 dB using 16QAM modulation and turbo coding with the coding rate of 8/9 in 4-by-4 MIMO multiplexing

This paper proposes adaptive control of the number of surviving symbol replica candidates, Sm(m denotes the stage index), based on the minimum accumulated branch metric of each stage in maximum-likelihood detection employing QR decomposition and the M-algorithm (QRM-MLD) in orthogonal frequency-division multiplexing with multiple-input-multiple-output (MIMO) multiplexing. In the proposed algorithm, Smat the mth stage (1lesmlesNt, Ntis the number of transmission antenna branches) is independently controlled using the threshold value calculated from the minimum accumulated branch metric at that stage and the estimated noise power. We compared the computational complexity of QRM-MLD employing the proposed algorithm with that of conventional methods at the same average packet error rate assuming the information bit rate of 1.048 Gb/s in a 100-MHz channel bandwidth (i.e., frequency efficiency of approximately 10 bit/s/Hz) using 16QAM modulation and turbo coding with the coding rate of 8/9 in 4-by-4 MIMO multiplexing. Computer simulation results show that the average computational complexity of the branch metrics, i.e., squared Euclidian distances, of the proposed adaptive independent Smcontrol method is decreased to approximately 38% that of the conventional adaptive common Smcontrol and to approximately 30% that of the fixed Smmethod (Sm=M=16), assuming fair conditions such that the maximum number of surviving symbol replicas at each stage is set to Mcirc=16

The paper proposes an adaptive selection algorithm for surviving symbol replica candidates based on the maximum reliability in ML detection with QR decomposition and M-algorithm (QRM-MLD) for OFCDM MIMO multiplexing. In the proposed algorithm, symbol replica candidates newly-added at each stage are ranked for each surviving symbol replica from the previous stage using multiple quadrant detection. Then, branch metrics are calculated only for the limited number of symbol replica candidates with high reliability based on an iterative loop in increasing order of the accumulated branch metrics from the candidate with the minimum one. Simulation results show that the computational complexity of the proposed algorithm from the viewpoint of the number of real multiplications is reduced to approximately 1/6 and 1/1900, respectively, compared to that of the original QRM-MLD and that of the conventional MLD with squared Euclidian distance calculations for all symbol replica candidates, assuming the identical achievable average block error rate (BLER) performance in 4-by-4 MIMO multiplexing with 16QAM data modulation. The results also show that 1-Gbps throughput is achieved at the E/sub b//N/sub 0/ per receiver antenna of approximately 9 dB using the adaptive selection algorithm in QRM-MLD associated with 16QAM modulation and turbo coding with coding rate of 8/9, assuming a 100-MHz bandwidth for a twelve-path Rayleigh fading channel (rms delay spread, 0.26 /spl mu/sec; maximum Doppler frequency, 20 Hz).

This paper proposes likelihood function generation of complexity-reduced maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD) suitable for soft-decision turbo decoding and investigates the throughput performance using QRM-MLD with the proposed likelihood function in multipath Rayleigh fading channels for orthogonal frequency and code division multiplexing (OFCDM) with multiple-input multiple-output (MIMO) multiplexing. Simulation results show that by using the proposed likelihood function generation scheme for soft-decision turbo decoding following QRM-MLD in 4-by-4 MIMO multiplexing, the required average received signal energy per bit-to-noise power spectrum density ratio (E/sub b//N/sub o/) at the average block error rate (BLER) of 10/sup -2/ at a 1-Gbps data rate is significantly reduced compared to that using hard-decision decoding in OFCDM access with 16 QAM modulation, the coding rate of 8/9, and 8-code multiplexing with a spreading factor of 8 assuming a 100-MHz bandwidth. Furthermore, we show that by employing QRM-MLD associated with soft-decision turbo decoding for 4-by-4 MIMO multiplexing, the throughput values of 500 Mbps and 1 Gbps are achieved at the average received E/sub b//N/sub o/ of approximately 4.5 and 9.3 dB by QPSK with the coding rate of R = 8/9 and 16 QAM with R = 8/9, respectively, for OFCDM access assuming a 100-MHz bandwidth in a twelve-path Rayleigh fading channel.

A novel interference reduction method, transmit power and window control (TPWC), is proposed to enhance the system capacity in the downlink of CDMA cellular packet systems. TPWC measures the propagation conditions such as the required instantaneous transmit power between a base station (BS) and a mobile station (MS). Then, TPWC sends packets only during a transmit time-window, in which the packets can be sent with less power than a predetermined threshold. TPWC reduces the average transmit power at the cost of an extra transmission delay at the BS. Computer simulations show that, in a two-path Rayleigh fading environment with maximum Doppler frequency of 80 Hz, TPWC enhances the system capacity by 1.8-fold in a CDMA cellular packet system when each MS has a load of 0.5 and a 90% delay allowance of 5 ms. In order to confirm the implementation feasibility and to evaluate the performance of TPWC, an experimental TPWC processor is developed and its performance is measured.

The paper presents the architecture of a newly developed highly parallel DSP suited for realtime image recognition. The programmable DSP was designed for a variety of image recognition systems, such as computer vision systems, character recognition systems and others. The DSP consists of optimized functional units for image recognition: SIMD processing core, a hierarchical bus, address generation unit, data memories, DMAC, link unit, and control unit. The DSP can process a 5/spl times/5 spatial filtering for 512/spl times/512 images within 13.1 msec. Adopting the DSP to a Japanese character recognition system, the speed of 924 characters/sec can be achieved for feature extractions and feature vectors matchings. The DSP can be integrated in a 14.5/spl times/14.5 mm/sup 2/ single-chip, using 0.5 um CMOS technology. In the paper, the key features of the architecture and the new techniques enabling efficient operation of the eight parallel processing units are described. Estimation of the performance of the DSP is also presented.

The authors describe a testable design method and the corresponding support tool for testing large-scale cells embedded on LSIs. The testable design method requires very little extra hardware to increase testability. The support tool enables users to test the large-scale cells by using already prepared test patterns. Consequently, test generation, and fault simulation times are decreased.>