Compensation of Nuisance Factors for Speaker and Language Recognition

The variability of the channel and environment is one of the most important factors affecting the performance of text-independent speaker verification systems. The best techniques for channel compensation are model based. Most of them have been proposed for Gaussian mixture models, while in the feature domain blind channel compensation is usually performed. The aim of this work is to explore techniques that allow more accurate intersession compensation in the feature domain. Compensating the features rather than the models has the advantage that the transformed parameters can be used with models of a different nature and complexity and for different tasks. In this paper, we evaluate the effects of the compensation of the intersession variability obtained by means of the channel factors approach. In particular, we compare channel variability modeling in the usual Gaussian mixture model domain, and our proposed feature domain compensation technique. We show that the two approaches lead to similar results on the NIST 2005 Speaker Recognition Evaluation data with a reduced computation cost. We also report the results of a system, based on the intersession compensation technique in the feature space that was among the best participants in the NIST 2006 Speaker Recognition Evaluation. Moreover, we show how we obtained significant performance improvement in language recognition by estimating and compensating, in the feature domain, the distortions due to interspeaker variability within the same language.     

低码率视频编码的优化方法

采用的低码率视频编码方法是以全局运动补偿和局部运动补偿为核心的混合编码方法.主要针对MPEG-4中原有算法计算量大、复杂度高的特点进行了编码系统优化,将这一编码方法实用化.该优化方法是针对占编码系统70%计算量的全局运动估计进行的,采用了基于运动特征的运动估计方法和鲁棒的目标函数,并在优化方法中引入了三级金字塔的分层计算.从对比实验结果来看,优化方法对不同运动类别视频的编码都是有效的,系统编码速度提高了3倍以上.目前,这项优化方法已经被MPEG-4视频编码优化小组采用.     

Gravity compensation in robotics

The actuator power required to resist joint torque caused by the weight of robot links can be a significant problem. Gravity compensation is a well-known technique in robot design to achieve equilibrium throughout the range of motion and as a result to reduce the loads on the actuator. Therefore, it is desirable and commonly implemented in many situations. Various design concepts for gravity compensation are available in the literature. This paper proposes an overview of gravity compensation methods applied in robotics. The examined properties of the gravity compensation are disclosed and illustrated via kinematic schemes. In order to classify the considered balancing schemes three principal groups are distinguished due to the nature of the compensation force: counterweight, spring or active force developed by an auxiliary actuator. Then, each group is reviewed through sub-groups organized via structural features of balancing schemes. The author believes that such an arrangement of gravity compensation methods allows one to carry out a systematized analysis and provides a comprehensive view on the problem.     

Modelling and simulation of matrix converter under distorted input voltage conditions

Matrix converter is an energy conversion device which directly connects a three-phase voltage source to a three-phase load without dc-link components. Therefore, the output of the matrix converter is directly affected by the disturbance or imbalance in the input voltages. Many researchers have made an effort to overcome this problem in recent years. In this paper, the behaviors of the matrix converter controlled with the optimum-amplitude Venturini method are investigated and a novel compensation technique based on fuzzy logic controller is proposed to eliminate the undesirable influences of the input voltage under the distorted input voltage conditions. The proposed technique is based on closed loop control of the three-phase output current to enhance the output performance of the matrix converter. The mathematical model of the proposed system is developed. The simulation of the development model is performed in Matlab&Simulink. Some results demonstrating validity of the proposed compensation technique are presented.     

递归网络模型在传感器动态补偿中的应用

为改善传感器的动态响应特性 ,对其输出结果进行动态补偿是一个有效方法。本文介绍了传感器动态补偿的原理 ,基于递归网络模型的良好的动态映射能力 ,探讨了应用该模型进行传感器动态补偿的实现方法 ,实验结果表明补偿后传感器具有理想的输入输出特性 ,从而验证了该方法的可行性和有效性。     

超声检测机器人误差补偿技术

针对多自由度检测机器人位姿调整困难问题,通过分析超声检测机器人误差的来源和特点,阐述了机体外误差补偿的原理.通过误差补偿,为计算机控制超声探头进行曲面检测提供准确的控制参数,实现曲面形工件的连续超声检测.最后通过穿透法水柱的对准及其误差分析,对机体外误差补偿方法进行了验证.     

Scene-based nonuniformity compensation for imaging sensors

Multidetector imaging focal plane arrays like CCD TV cameras and infrared arrays possess large detector-to-detector dark current (offset) and responsivity (gain) variations which can completely mask the useful information. Conventional compensation techniques require temperature references of constant radiance over the entire field of view and a mechanical/electrooptical shutter to calibrate the focal plane. This detracts from the mechanical simplicity of multi-detector staring (nonscanning) focal planes. This correspondence describes a real-time offset and responsivity (gain) compensation technique which dispenses with temperature references and shutters in staring focal planes. It makes use of the scene statistics for calibration and continuously updates the compensation coefficients without interrupting the field of view. The results of real-time simulations of this technique with a number of sensors are presented. Real-time LSI/VLSI hardware architectures are addressed. The technique can be implemented with the addition of very little hardware to a conventional compensation technique requiring temperature references. The technique is also suitable for multi-detector scanning focal planes and for the removal of shading in TV sensors as well.     

Iterative-learning error compensation for autonomous parking of mobile manipulator in harsh industrial environment

In wide-area and multi-sites manufacturing scenarios, the mobile manipulator suffers from inadequate autonomous parking performance due to the harsh industrial environment. Instead of struggling to model various errors or calibrate multiple sensors, this paper resolves the above challenge by proposing an iterative-learning error compensation scheme that consists of offline pre-regulation and online compensation, which can improve the compensation efficiency and accommodate the error fluctuations caused by environmental fluctuations. Integrating an improved Monte-Carlo localization and eye-in-hand vision technique, an effective measurement system is firstly developed to accurately obtain the parking data without requiring superfluous facilities or cumbersome measurement. Then, after removing the data outliers utilizing the Grubbs test, offline pre-regulation is achieved to give a suitable initial value and increase the compensation convergence. To reduce the time-varying systematic errors and parking error fluctuations, online compensation is presented by offering an efficacious estimation of environmental fluctuations using fuzzy logic rules and providing an adaptive iterative-learning law. Finally, the feasibility and effectiveness of the presented compensation method are validated by extensive experiments implemented on a self-developed mobile manipulator.     

Smart变送器实现高精度检测机理分析

基于Smart变送器的基本结构模型及性能特点，阐述了mart变送器实现高精度检测的三大技术途径：复合传感器制造技术、计算机补偿技术、数字通讯技术，并着重分析了采用上述三大技术途径实现高精度检测变送的机理．     

用电阻网络对医用传感器的特性进行补偿

医用传感器的特性补偿方法非常多。文章介绍了采用简单的电阻网络对一些医用传感器的特性进行补偿的技术     

苯氧化固定床顺（反）丁烯二酸生产计算机先进控制

本文研究了时间分割预估控制和内模块控制技术在苯氧化固定床反应器中的应用，它对于克服系统滞后，改善调节品质有明显的效果，经二所的实际使用，效果良好，具有实用性。     

传感器实时自校准/自补偿技术的研究

提出了对传感器进行实时自校准／自补偿的一种新方法。首先从原理上进行分析论证,给出了用单片机系统对传感器进行自校准／自补偿的方案,并提供了相应的实验数据,证明所提出的自校准／自补偿方法是切实可行的。     

Uncertainty learning and compensation: An application to pressure tracking of an electro-hydraulic proportional relief valve

In this paper, uncertainty learning and a compensation technique are incorporated into a classical sliding mode control for a pressure tracking control of a low-cost electro-hydraulic proportional valve. Unknown nonlinear characteristics and disturbances of the valve system can be eliminated and surmounted by the proposed uncertainty compensation and conventional boundary layer technique, respectively. Lumped-system uncertainty is calculated from the first derivative of a sliding function, which can be determined by feeding an equivalent control into the system. It is then used to eliminate the uncertainty of the system. However, this technique requires a proper control distribution matrix. Therefore, a new adaptation of the control gain is introduced. The adaptation law uses a linear combination of magnitude of the calculated lumped-system uncertainty as an adaptive function. As a result, even with an inaccurate actuator model, tracking control is possible and the stability in the boundary layer is guaranteed everywhere outside the uniform ultimate bound, which is dependent on the accuracy of the uncertainty estimation.     

An exponentially stable adaptive friction compensator

This note presents a novel adaptive compensation scheme for Coulomb friction in a servocontrol system. An adaptive observer for estimating the unknown Coulomb friction coefficient is also derived on the basis of the Lyapunov technique. In addition, a linearizing control law is developed to compensate for the friction force and obtain the tracking objective. The proposed adaptive compensation guarantees an exponential convergence for state errors and parameter error, and known adaptive schemes guarantee only an asymptotic (or stable) convergence. Simulation results demonstrate the effectiveness of the proposed method for a single-mass servocontrol system     

Adaptive output feedback control of nonlinear systems with actuator failures

In this paper, a modified adaptive actuator failure compensation scheme is proposed for a class of uncertain multi-input and single-output (MISO) nonlinear systems in the output-feedback form. We first establish a new parametric model with unknown plant parameters and actuator failure parameters, which differs from some existing results. Then, an adaptive compensation controller is constructed by utilizing the backstepping technique. The boundedness of all closed-loop signals is guaranteed. The tracking error is proved to converge to zero asymptotically. Finally, two simulation examples are provided to demonstrate the effectiveness of the proposed design scheme.     

Compliance error compensation technique for parallel robots composed of non-perfect serial chains

The paper presents the compliance errors compensation technique for over-constrained parallel manipulators under external and internal loadings. This technique is based on the non-linear stiffness modeling which is able to take into account the influence of non-perfect geometry of serial chains caused by manufacturing errors. Within the developed technique, the deviation compensation reduces to an adjustment of a target trajectory that is modified in the off-line mode. The advantages and practical significance of the proposed technique are illustrated by an example that deals with groove milling by the Orthoglide manipulator that considers different locations of the workpiece. It is also demonstrated that the impact of the compliance errors and the errors caused by inaccuracy in serial chains cannot be taken into account using the superposition principle.     

Mixed environment compensation based on maximum a posteriori estimation for robust speech recognition

Noise robustness is a fundamental problem for speech recognition system in the real environments. The paper presents mixed environment compensation technique in which feature compensation algorithm and acoustic model compensation algorithm is combined together. The target is to obtain the fine compensated static acoustic model and the dynamic compensated speech. Therefore, the modified speech sequence can well match the modified acoustic model. The experimental results show that significant performance improvement has been observed.     

微压式液位传感器热灵敏度漂移的补偿

介绍了微压式液位传感器的工作原理、总体结构设计及热灵敏度漂移的补偿技术与方法,给出了补偿结果,验证了补偿技术与方法的有效性和可行性,为提高硅压阻式传感器的温度稳定性与准确度提供了一种实用有效的新方法。     

Unbalance compensation for AMB systems with input delay: An output regulation approach

Unbalance compensation is an important technique for reducing rotor vibration in high speed rotating machines caused by residual rotor unbalance. As rotating machines in remote applications aim for higher speeds to gain efficiency and to reduce footprint, there is a need to extend the unbalance compensation techniques to active magnetic bearing (AMB) systems with delays in the control loop. This paper investigates the unbalance compensation problem for AMB systems with input delays. An unbalance compensation method is developed based on a solution to the output regulator problem for systems with input delay. The proposed unbalance compensation method is verified through simulation, and experimentally validated on an AMB test rig.