Neuro-fuzzy speed tracking control of traveling-wave ultrasonic motor drives using direct pulse width modulation

The traveling-wave ultrasonic motor (TUSM) drive offers many distinct advantages but suffers from severe system nonlinearities and parameter variations especially during speed control. This paper presents a new speed tracking control system for the TUSM drive, which newly incorporates neuro-fuzzy control and direct pulse width modulation to solve the problem of nonlinearities and variations. Increasingly, the proposed control system is digitally implemented by a low-cost digital signal processor (DSP) based microcontroller, hence reducing the system hardware size and cost. Experimental results confirm that the proposed speed tracking controller can offer good steady-state and transient performances.published_or_final_versio

Sensorless Position Control of Piezoelectric Ultrasonic Motors:a Mechatronic Design Approach

This dissertation considers mechatronic systems driven by piezoelectric ultrasonic motors (PUM). The focus is set on optimal system design and sensorless position control. Mechatronic industry faces the challenge to deliver ever more efficient and reliable products while being confronted to increasingly short time to market demands and economic constraints driven by competition. Although optimal design strategies are applied to master this challenge, they do not entirely respond to the given circumstances, as often only local criteria are optimised. In order to obtain a globally optimal solution, the many subfunctions of a mechatronic system and their models must be interrelated and evaluated concurrently from the very beginning of the design process. In this context PUM have been used increasingly during the last decade for various positioning applications in the field of mechatronic systems, laboratory equipment, and consumer electronics where their performances are superior to conventional electromechanical drive systems based on DC or BLDC motors. The position of the mobile component must be controlled. In some cases open-loop control is a solution, but more often than not sensors are used as feedback device in closed-loop control. Sensors are expensive, large in size and add fragile hardware to the device that compromises its reliability. Thus, not only the superior performance is not fully exploited but also the economical feasibility of the PUM drive system is jeopardised. Replacing sensors by advanced control techniques is an approach to these problems that is well established in the field of BLDC motors. Those sensorless control strategies are not directly transferrable, because of the fundamentally different working principles of PUM. Hence, the research of sensorless closed-loop position control techniques applicable to PUM and their validation with digitally controlled functional models is the very topic of this thesis. We propose a dedicated design methodology to this statement of the problem. A core model of the mechatronic system is conceived as general and simple as possible. It then develops for the different interrelated views reflecting the mechanical, electromechanical, drive electronic, sensorial and digital control functions of the global system. Each one becoming more specific and detailed in this process, the different views still enable mutual constraint adjustments and the dynamic integration of results from the other views during the design process. Starting with the stator of the PUM, a view describes the mechanical displacement. An electric equivalent model is written such that power input from the drive electronics is related to the mechanical energy transmitted to the mechanics. The resulting differential equations are solved by the finite element method (FEM). Position feedback configurations in the mobile part of the PUM are modelled analytically in order to be implemented in digital control and their electrical implications are updated to the stator model. In this way, sensors do not necessarily materialise physically any more, but are distributed among the mechanical configuration, the drive electronics and the digital controller. With respect to the sensor data, the controller is not simply receiving finalised data on the measured system parameter, but rather implements the sensor itself in software. Finally, the position detection performance obtained with the aforementioned design methodology was evaluated with the example of mechatronic locking devices actuated by custom-made as well as OEM motors. Functional models of motors, electronics and digital controllers were used to identify the limits of the proposed methods, and suggestions for further research were deduced. These results contribute to the development of robust sensorless position controllers for PUM

Model, design & development of piezoelectric ultrasonic motor

Ph.DDOCTOR OF PHILOSOPH

Mobile Robots Navigation

Mobile robots navigation includes different interrelated activities: (i) perception, as obtaining and interpreting sensory information; (ii) exploration, as the strategy that guides the robot to select the next direction to go; (iii) mapping, involving the construction of a spatial representation by using the sensory information perceived; (iv) localization, as the strategy to estimate the robot position within the spatial map; (v) path planning, as the strategy to find a path towards a goal location being optimal or not; and (vi) path execution, where motor actions are determined and adapted to environmental changes. The book addresses those activities by integrating results from the research work of several authors all over the world. Research cases are documented in 32 chapters organized within 7 categories next described

Development of image processing and vision systems with industrial applications

Ph.DDOCTOR OF PHILOSOPH

Modelado y evaluación en régimen transitorio de respuestas piezoeléctricas y electrónicas en sistemas de visualización ultrasónica

Se proponen Modelos Circuitales Equivalentes, bien sobre nuevos aspectos no antes tratados, o bien con precisión mejorada frente a los modelos convencionales, para la simulación de respuestas en Sistemas de Visualización Ultrasónica, incluyendo sus etapas piezoeléctricas, electrónicas y ultrasónicas. Se incluye la modelización de aspectos importantes presentes en las configuraciones prácticas para diagnóstico industrial y médico, que no son considerados en aproximaciones previas: Excitación impulsiva en Alta Tensión AT (modelización completa con su etapa previa de baja tensión); Efectos no lineales en circuitos de emisión y de recepción; Aspectos no ideales sobre perdidas y distorsiones eléctricas en la electrónica; Cuantificación precisa del comportamiento frecuencial de las pérdidas mecánicas en el elemento piezoeléctrico y en el medio de propagación. Algunos de estos modelos utilizan datos estimados con precisión para los parámetros internos de los transductores piezoeléctricos. Estos datos se obtienen mediante un nuevo método aquí propuesto, basado en técnicas de inteligencia artificial, concretamente en Algoritmos Genéticos (AGs). Se presentan implementaciones Pspice específicas de estos modelos para simular directamente en el dominio del tiempo distintas disposiciones de visualización para ensayos no destructivos (END), por Transmisión (ET) y por Pulso-Eco (EPE), en régimen de alta tensión y con las topologías circuitales no-lineales más usuales en los transceptores electrónicos involucrados. Se aplica todo ello a la evaluación "cuantitativa" de pulsos eléctricos, excitadores AT y respuestas ultrasónicas globales, con transductores concretos, incluyendo efectos eléctricos no-ideales y la topología real de los transceptores ultrasónicos usados en visualización industrial, concretamente para inspecciones END. La contrastación con datos experimentales muestra la clara mejora en precisión de los modelos propuestos. Finalmente, se propone y aplica un método para análisis paramétrico en régimen transitorio, en los dominios del tiempo y la frecuencia, del comportamiento de las etapas electrónicas no-lineales y de AT involucradas en aplicaciones de visualización