Noise Weighting in the Design of {\Delta}{\Sigma} Modulators (with a Psychoacoustic Coder as an Example)

A design flow for {\Delta}{\Sigma} modulators is illustrated, allowing quantization noise to be shaped according to an arbitrary weighting profile. Being based on FIR NTFs, possibly with high order, the flow is best suited for digital architectures. The work builds on a recent proposal where the modulator is matched to the reconstruction filter, showing that this type of optimization can benefit a wide range of applications where noise (including in-band noise) is known to have a different impact at different frequencies. The design of a multiband modulator, a modulator avoiding DC noise, and an audio modulator capable of distributing quantization artifacts according to a psychoacoustic model are discussed as examples. A software toolbox is provided as a general design aid and to replicate the proposed results.Comment: 5 pages, 18 figures, journal. Code accompanying the paper is available at http://pydsm.googlecode.co

Feedback-control of quantum systems using continuous state-estimation

We present a formulation of feedback in quantum systems in which the best estimates of the dynamical variables are obtained continuously from the measurement record, and fed back to control the system. We apply this method to the problem of cooling and confining a single quantum degree of freedom, and compare it to current schemes in which the measurement signal is fed back directly in the manner usually considered in existing treatments of quantum feedback. Direct feedback may be combined with feedback by estimation, and the resulting combination, performed on a linear system, is closely analogous to classical LQG control theory with residual feedback.Comment: 12 pages, multicol revtex, revised and extende

Implementation of Field Oriented Control in Simulink

Indukční stroje jsou jedním z nejpoužívanějších elektrických strojů v mnoha průmyslových a dopravních aplikacích. Je proto důležité mít zařízení pro jejich ovládání. Naproti tomu, DC stroje je možné řídit pomocí mnohem jednodušších schémat, ale kvůli jejich technickým nevýhodám se v současnosti nejeví jako nejlepší volba pro průmyslové použití. Pro řízení rychlosti a točivého momentu indukčních strojů bylo vyvinuto mnoho řídicích strategií a stále probíhá další výzkum pomocí modernějších technik, jako například „Fuzzy logic“ nebo neuronové sítě. Tématem práce je polem orientované vektorové řízení, které je jedním z nejpoužívanějších způsobů řízení. Implementovali jsme schéma s polem orientovaným řízením v softwaru Simulink na indukční stroj se skutečnými parametry. Pro zkoumaný řadič jsme vyzkoušeli různé scénáře s cílem zjistit jeho fungovaní a možná vylepšení. Rovněž jsme implementovali bezsenzorové řízení stroje s odhadem otáček.Induction machines are one of the most widely used electric machines on many industrial and transportation applications. It is, therefore, important to have a facility to control these machines for the wide range of applications. On the other hand, it is possible to control DC machines with much simpler control schemes, but their technical drawbacks do not make them the preferable choice for the industry nowadays. Many control strategies have been developed for the speed and torque control of induction machines and more research is still ongoing using more modern techniques, such as “fuzzy logic” and “neural networks”. One of the most widely used control techniques is the “field-oriented control”, which is the topic of this thesis. With the parameters of a real induction machine, we implemented a control scheme based on the field-oriented control in the Simulink software. Various scenarios were applied to the controller in order to study its functioning and possible improvements. Furthermore, a speed estimation part was implemented for a sensorless control of the machine

Data-based design of high-performance motion controllers

This paper presents a data-based design of a linear feedback controller which realizes desired closed-loop sensitivity and complementary sensitivity transfer functions. These transfer functions are specified via a single model-based performance cost. The data-based equivalent of this cost is derived, and its utility for the feedback design is demonstrated. A designer can prescribe the controller structure and complexity. Experimental results obtained in a direct-drive robot motion control problem confirm the effectiveness of the design

Influence of the controller design on the accuracy of a forward dynamic simulation of human gait

The analysis of a captured motion can be addressed by means of forward or inverse dynamics approaches. For this purpose, a 12 segment 2D model with 14 degrees of freedom is developed and both methods are implemented using multibody dynamics techniques. The inverse dynamic analysis uses the experimentally captured motion to calculate the joint torques produced by the musculoskeletal system during the movement. This information is then used as input data for a forward dynamic analysis without any control design. This approach is able to reach the desired pattern within half cycle. In order to achieve the simulation of the complete gait cycle two different control strategies are implemented to stabilize all degrees of freedom: a proportional derivative (PD) control and a computed torque control (CTC). The selection of the control parameters is presented in this work: a kinematic perturbation is used for tuning PD gains, and pole placement techniques are used in order to determine the CTC parameters. A performance evaluation of the two controllers is done in order to quantify the accuracy of the simulated motion and the control torques needed when using one or the other control approach to track a known human walking pattern.Postprint (author's final draft

Computer Simulation of PMSM Motor with Five Phase Inverter Control using Signal Processing Techniques

The signal processing techniques and computer simulation play an important role in the fault diagnosis and tolerance of all types of machines in the first step of design. Permanent magnet synchronous motor (PMSM) and five phase inverter with sine wave pulse width modulation (SPWM) strategy is developed. The PMSM speed is controlled by vector control. In this work, a fault tolerant control (FTC) system in the PMSM using wavelet switching is introduced. The feature extraction property of wavelet analysis used the error as obtained by the wavelet de-noised signal as input to the mechanism unit to decide the healthy system. The diagnosis algorithm, which depends on both wavelet and vector control to generate PWM as current based manage any parameter variation. An open-end phase PMSM has a larger range of speed regulation than normal PMSM. Simulation results confirm the validity and effectiveness of the switching strategy