Development and evaluation of interactive humanoid robots

We report the development and evaluation of a new interactive humanoid robot that communicates with humans and is designed to participate in human society as a partner. A human-like body will provide an abundance of nonverbal information and enable us to smoothly communicate with the robot. To achieve this, we developed a humanoid robot that autonomously interacts with humans by speaking and gesturing. Interaction achieved through a large number of interactive behaviors, which are developed by using a visualizing tool for understanding the developed complex system. Each interactive behavior is designed by using knowledge obtained through cognitive experiments and implemented by using situated recognition. The robot is used as a testbed for studying embodied communication. Our strategy is to analyze human-robot interaction in terms of body movements using a motion-capturing system that allows us to measure the body movements in detail. We performed experiments to compare the body movements with subjective evaluation based on a psychological method. The results reveal the importance of well-coordinated behaviors as well as the performance of the developed interactive behaviors and suggest a new analytical approach to human-robot interaction.     

The area of safe operation of transistors for switching operation

A thermal feedback model is presented for the analytical definition of the ASO (Area of Safe Operation) for transistors in switching operations. This area is narrowed by the "second breakdown in p-n junction," and the approximate representation of the breakdown threshold is presented. This model consists of a forward and feedback energy flow with gains A and B, respectively.A = V_{CE} times M, B = K times theta times alpha_{R} times I_{e}. Therefore, the condition of the breakdown can be introduced as1 - AB = 0, whereMis the current multiplication factor, θ is transient thermal resistance,Kis a newly introduced current concentration factor, and αRis the temperature coefficient of Ie. Experimental results are also reported for a germanium alloy type transistor.     

A random switching method for HPWM full-bridge inverter

To overcome the problem of unequal switching loss in power switches, in conventional hybrid pulse width modulation (HPWM) full-bridge inverters, a random switching method for HPWM full-bridge inverters is proposed. The proposed method equalizes switching losses of the four switches, while also providing good output performance     

The double discontinuous mode operation of a converter: a method for soft switching

This paper describes a way of ensuring soft switching in a converter without using additional components. This method is called double discontinuous mode (DDM). In particular, it permits any free wheeling diode to switch off at zero current, and for transistors to switch on at zero current and to switch off at zero voltage. The method illustrated here refers to a buck, but this concept may be applied to any type of converter, with or without transformer. Various mathematical models of this method are developed, and its characteristics and fields of application highlighted in this paper.     

A method of task allocation and automated negotiation for multi robots

A method of task allocation and automated negotiation for multi robots was proposed. Firstly, the principles of task allocation were described based on the real capability of robot. Secondly, the model of automated negotiation was constructed, in which Least-Squares Support Vector Regression (LSSVR) was improved to estimate the opponent??s negotiation utility and the robust controller of H ^?? output feedback was employed to optimize the utility performance indicators. Thirdly, the protocol of negotiation and reallocation was proposed to improve the real-time capability and task allocation. Finally, the validity of method was proved through experiments.     

A method for reducing the energy consumption of pick-and-place industrial robots

The interest in novel methods and tools for optimizing the energy consumption in robotic systems is currently increasing. From an industrial point of view, it is desirable to develop energy saving strategies also applicable to established manufacturing systems with no need for either hardware substitution or further investments. Within this scenario, the present paper reports a method for reducing the total energy consumption of pick-and-place manipulators for given TCP position profiles. Firstly, electromechanical models of both serial and parallel manipulators are derived. Then, the energy-optimal trajectories are calculated, by means of constant time scaling, starting from pre-scheduled trajectories compatible with the actuation limits. In this manner, the robot work cycle can be energetically optimized also when the TCP position profiles have been already defined on the basis of technological constraints and/or design choices aimed at guaranteeing manufacturing process efficacy/robustness. The effectiveness of the proposed procedure is finally evaluated on two simulation case studies.     

Dynamic operation and maintenance systems for switching networks

Some important concepts and techniques related to dynamic operation and maintenance (O&M) systems for switching networks are demonstrated. Five types of node that comprise the dynamic network O&M system being developed by the authors are discussed. They are local exchanges, a centralized operation system, a database system, a diagnostics expert system, and maintenance workstations. The nodes are implemented on an efficient distributed system and use a standardized interface. This O&M system, which is geared toward improved maintenance, focuses on the switching network as a whole, rather than on individual exchanges. In the case of alarms and fault messages, O&M takes corrective action automatically     

A three-dimensional registration method for automated fusion of micro PET-CT-SPECT whole-body images

Micro positron emission tomography (PET) and micro single-photon emission computed tomography (SPECT), used for imaging small animals, have become essential tools in developing new pharmaceuticals and can be used, among other things, to test new therapeutic approaches in animal models of human disease, as well as to image gene expression. These imaging techniques can be used noninvasively in both detection and quantification. However, functional images provide little information on the structure of tissues and organs, which makes the localization of lesions difficult. Image fusion techniques can be exploited to map the functional images to structural images, such as X-ray computed tomography (CT), to support target identification and to facilitate the interpretation of PET or SPECT studies. Furthermore, the mapping of two functional images of SPECT and PET on a structural CT image can be beneficial for those in vivo studies that require two biological processes to be monitored simultaneously. This paper proposes an automated method for registering PET, CT, and SPECT images for small animals. A calibration phantom and a holder were used to determine the relationship among three-dimensional fields of view of various modalities. The holder was arranged in fixed positions on the couches of the scanners, and the spatial transformation matrix between the modalities was held unchanged. As long as objects were scanned together with the holder, the predetermined matrix could register the acquired tomograms from different modalities, independently of the imaged objects. In this work, the PET scan was performed by Concorde's microPET R4 scanner, and the SPECT and CT data were obtained using the Gamma Medica's X-SPECT/CT system. Fusion studies on phantoms and animals have been successfully performed using this method. For microPET-CT fusion, the maximum registration errors were 0.21 mm +/- 0.14 mm, 0.26 mm +/- 0.14 mm, and 0.45 mm +/- 0.34 mm in the X (right-left), Y (upper lower), and Z (rostral-caudal) directions, respectively; for the microPET-SPECT fusion, they were 0.24 mm +/- 0.14 mm, 0.28 mm +/- 0.15 mm, and 0.54 mm +/- 0.35 mm in the X, Y, and Z directions, respectively. The results indicate that this simple method can be used in routine fusion studies.     

A new method of analysis for PWM switching power converters

A new method of analysis for pulse-width modulation (PWM) switching power converters is presented. It allows one to find an approximate periodic solution for the converter vector state variable. The converter is modelled by a differential equation with periodic coefficients. This equation is substituted by an equivalent system of linear differential equations with constant coefficients. Only the forced (steady-state) solutions should be found for each equation of this system. The equations are solved in sequence. The final steady-state solution of the PWM differential equation is obtained as the sum of these forced solutions. The method allows one to find the converter dc transfer function and efficiency, to evaluate their frequency dependences, and to find the critical frequency and ripple. The first three equations of the equivalent system are usually adequate for practical purposes, and these equations are obtained by an easy formal procedure. One can also obtain the dynamic equation of the state variable dc component, and calculate the converter line to output and duty cycle to output transfer functions. A boost converter is used as an example to confirm the analytical results by numerical simulation.     

A novel droop method for converter parallel operation

For the converter parallel operation, the current sharing between modules is important for the reliability of the system. Among several current sharing schemes, the droop method needs no interconnection between modules, which implies true redundancy. But the droop method has poor voltage regulation and poor current sharing characteristics. In this paper, a novel droop method is proposed for the converter parallel operation, which adaptively controls the reference voltage of each module. This greatly improves the output voltage regulation and the current sharing of the conventional droop method. The analysis of the proposed method and design procedure are provided and experimental results verify the excellent performance of the proposed method     

A PWM method for reduction of switching loss in a full-bridgeinverter

This paper presents the “hybrid pulsewidth modulation” (HPWM) method which requires only two of the four switches in a full-bridge inverter to be pulsewidth-modulated at high frequency, thus significantly reducing the switching losses in the other two switches. For triangular carriers, HPWM has the same frequency spectrum and switching losses as the conventional unipolar PWM (UPWM). A low-frequency model for a fast-switching HPWM full-bridge inverter with high-quality output is described, and is substantiated by experimental data     

A quantum switching architecture on the basis of limited nonlocal operation

1 Introduction Since Shor's discovery of an efficient algorithm for prime factorization [1] in 1994, the field of quantum computing has been rapidly developed [2?4]. Due to the exploitation of superposition of quantum state, quantum algorithms can greatly…     

一种SDH网络倒换测试的新方法

文章通过SDH网络倒换测试方法分析,给出了2种环网倒换测试方案术方案,指出了现有倒换测试方法存在的问题,提出了SDH网络倒换测试的新方法。     

A novel method for elimination of line-current harmonics insingle-stage PFC switching regulators

This paper studies a particular single-stage power-factor-correction (PFC) switching regulator employing a discontinuous-conduction-mode (DCM) boost-input cell and a continuous-current-mode (CCM) forward output cell. Although this single-stage PFC regulator can provide a reasonably high power factor when its PFC stage is operating in discontinuous mode, substantial reduction in line-current harmonics is possible by applying a suitable frequency-modulation scheme. This paper derives a frequency-modulation scheme and proposes a practical implementation using a simple translinear analog circuit. A quantitative analysis on the total harmonic distortion (THD) of the line current when the circuit is subject to a limited range of frequency variations is presented along with some considerations for practical design. Experimental data obtained from a prototype confirms the effectiveness of the proposed frequency-modulation scheme. The proposed analog translinear circuit allows custom integrated circuit implementation, making it a viable low-cost solution to the elimination of line-current harmonics in switching regulators     

Gigabit-per-second dual-gate MESFET switching and multiplexer operation for high-speed fiber-optic systems

The operation of dual-gate GaAs MESFET's in gigabit-per-second switching applications for high-speed fiber-optic systems is investigated, and a full nonlinear modeling procedure is presented for general switching simulations. The model is characterized via a new and efficient technique which only requires two-ports-parameter measurements to determine the nonlinear element variations. Circuit simulations implemented on program SPICE 2 have been applied to evaluate the transient switching response of dual-gate MESFET's in several circuits involving 1-Gbit/s pulse conversion and synchronization, pulse-width reduction and 2-Gbit/s multiplexing, and results show good agreement between predicted and experimental switching waveforms.     

A new model of switching operation in fully depleted ultrathin-filmCMOS/SIMOX

An analysis is made of the switching performances of fabricated ultrathin-film submicrometer-gate CMOS/SIMOX ring oscillators. A time-dependent gate capacitance model is proposed to explain the switching operation mechanism. It is found that reducing the gate capacitance by full depletion of the body silicon dramatically improves the propagation delay time of CMOS/SIMOX     

Novel buffer engineering: A concept for fast switching and low loss operation of planar IGBT

For the first time, an insulated gate bipolar transistor with a novel buffer is proposed and verified by two-dimensional (2D) mixed device-circuit simulations. The structure of the proposed device is almost identical with that of the conventional IGBT, except for the buffer layer which is formed by employing a three-step, gradually changing doping n⁺ structure. Compared with the conventional IGBT, the proposed device exhibits better trade-off relation between the conduction and switching losses. The turn-off time is halved from 9.4 μs of the conventional IGBT to 4.5 μs of the proposed device, so the operation speed of the proposed device is greatly improved. Further, the forward blocking voltage is enormously increased from 907 V of the proposed device to 1278 V of the proposed device, which is required for high power operation.     

A stable transition controller for constrained robots

This paper addresses the problem of contact transition from free motion to constrained motion for robots. Stability of transition from free motion to constrained motion is essential for successful operation of a robot performing general tasks such as surface following and surface finishing. Uncertainty in the location of the constraint can cause the robot to impact the constraint surface with a nonzero velocity, which may lead to bouncing of the robot end-effector on the surface. A new stable discontinuous transition controller is proposed to deal with contact transition problem. This discontinuous transition control algorithm is used when switching from free motion to constrained motion. Control algorithm for a complete robot task is developed. Extensive experiments with the proposed control strategy were conducted with different levels of constraint uncertainty and impact velocities. Experimental results show much improved transition performance and force regulation with the proposed controller. Details of the experimental platform and typical experimental results are given     

Parallel operation of power transistors in switching amplifiers

The previous literature has considered the equalization of collector currents of paralleled transistors in switching-mode power amplifiers by adding emitter resistors. This letter presents the possibility of equalizing the collector currents by using base resistors; the advantage is lower power dissipation. Experimental confirmation is given.     

Comprehensive analysis of two cascaded semiconductor optical amplifiers for all-optical switching operation

This paper presents numerical calculations and experimental results for two cascaded semiconductor optical amplifiers (SOAs) in a counterpropagating configuration for an all-optical switching operation. A detailed theoretical analysis with regard to the gain evolution and the extinction ratio (ER) through the SOAs' cavities show that the two cascaded SOAs have improved performance over the single SOA configuration. A measured ER up to 20 dB is obtained for close contra-directional signal wavelengths and for a wide range of optical input powers. An all-optical switching operation is realized for 2.5-GHz data pulses, and its feasibility is demonstrated with an ER higher than 12 dB over a wide range of wavelength.