Resource-aware motion control:feedforward, learning, and feedback

Controllers with new sampling schemes improve motion systems’ performanc

Robust periodic disturbance compensation via multirate control

Master'sMASTER OF ENGINEERIN

Multirate input based quasi-sliding mode control for permanent magnet synchronous motor

Permanent magnet synchronous motor field oriented control system often uses dual-loop (speed and current) cascade structure, and the dynamics speeds of the two loops mismatch. The motor’s mechanical and electrical subsystems have the typical multirate characteristics. Based on the multirate control theory, this paper proposes multirate input quasi-sliding mode algorithm for the speed control loop. Under the situation of the output data loss, the proposed algorithm builds the extended input vector with the output prediction information. Due to the extended input vector, the proposed algorithm reduces the system steady state chatterring, and then improves the performance of the whole system. Simulation and experimental results demonstrate the effectiveness of the proposed algorithm

Enhanced Speed and Current Control of PMSM Drives by Perfect Tracking Algorithms

Abstract-Speed and current closed loops control represent the heart of any advanced AC servo drive. These inner loops usually feature high-dynamic feedback control, with possible axes decoupling and a straight feedforward action of the backelectromotive force (back-EMF). More sophisticated techniques as single-rate or multi-rate control could be exploited for both speed and current closed loops, and their performances compared to that of the classic cascade feedback controllers. This represents the goal of the present work, focusing on permanent magnet synchronous motor (PMSM) drives

HIGH-BANDWIDTH IDENTIFICATION AND COMPENSATION OF HYSTERETIC DYNAMICS

Ph.DDOCTOR OF PHILOSOPH

Dual-rate modified stochastic gradient identification for permanent magnet synchronous motor

The high-performance application of high-power permanent magnet synchronous motor (PMSM) is increasing. This paper focuses on the parameter estimation of PMSM. A novel estimation algorithm for PMSM’s dual-rate sampled-data system has been developed. A polynomial transformation technique is employed to derive a mathematical model for PMSM’s dual-rate sampled-data system. The proposed modified stochastic gradient algorithm gets more excellent convergence performance for smaller index ε. Simulation and experimental results demonstrate the effectiveness and performance improvement of the proposed algorithm

High-Precision Control of Ball-Screw-Driven Stage Based on Repetitive Control Using n-Times Learning Filter

Abstract-This paper presents a novel learning control method for ball-screw-driven stages. In recent years, many types of friction models that are based on complicated equations have been studied. However, it is difficult to treat friction models with equations because the level of precision that is associated with real friction characteristics and parameter tuning are difficult to achieve. In contrast, repetitive perfect tracking control (RPTC) is a repetitive control technique that achieves high-precision positioning. In this paper, we propose the use of RPTC with n-times learning filter. The n-times learning filter has a sharper rolloff property than conventional learning filters. With the use of the n-times learning filter, the proposed RPTC can converge tracking errors n times faster than the RPTC with the conventional learning filter. Simulations and experiments with a ball-screw-driven stage show the fast convergence of the proposed RPTC. Finally, the proposed learning control scheme is combined with data-based friction compensation, and the effectiveness of this combination is verified for the x-y stage of a numerically controlled machine tool. Index Terms-n-times learning, perfect tracking control, repetitive control, zero-phase low-phase filter

Multirate Frequency Transformations: Wideband AM-FM Demodulation with Applications to Signal Processing and Communications

The AM-FM (amplitude & frequency modulation) signal model finds numerous applications in image processing, communications, and speech processing. The traditional approaches towards demodulation of signals in this category are the analytic signal approach, frequency tracking, or the energy operator approach. These approaches however, assume that the amplitude and frequency components are slowly time-varying, e.g., narrowband and incur significant demodulation error in the wideband scenarios. In this thesis, we extend a two-stage approach towards wideband AM-FM demodulation that combines multirate frequency transformations (MFT) enacted through a combination of multirate systems with traditional demodulation techniques, e.g., the Teager-Kasiser energy operator demodulation (ESA) approach to large wideband to narrowband conversion factors. The MFT module comprises of multirate interpolation and heterodyning and converts the wideband AM-FM signal into a narrowband signal, while the demodulation module such as ESA demodulates the narrowband signal into constituent amplitude and frequency components that are then transformed back to yield estimates for the wideband signal. This MFT-ESA approach is then applied to the various problems of: (a) wideband image demodulation and fingerprint demodulation, where multidimensional energy separation is employed, (b) wideband first-formant demodulation in vowels, and (c) wideband CPM demodulation with partial response signaling, to demonstrate its validity in both monocomponent and multicomponent scenarios as an effective multicomponent AM-FM signal demodulation and analysis technique for image processing, speech processing, and communications based applications

Design, Construction and Control of a Quadrotor Helicopter Using a New Multirate Technique

This thesis describes the design, development, analysis and control of an autonomous Quadrotor Uninhabited Aerial Vehicle (UAV) that is controlled using a novel approach for multirate sampled-data systems. This technique uses three feedback loops: one loop for attitude, another for velocity and a third loop for position, yielding a piece-wise affine system. Appropriate control actions are also computed at different rates. It is shown that this technique improve the system's stability under sampling rates that are significantly lower than the ones required with more classical approaches. The control strategy, that uses sensor data that is sampled at different rates in different nodes of a network, is also applied to a ground wheeled vehicle. Simulations and experiments show very smooth tracking of set-points and trajectories at a very low sampling frequency, which is the main advantage of the new technique