Impedance control for legged robots: an insight into the concepts involved

The application of impedance control strategies to modern legged locomotion is analyzed, paying special attention to the concepts behind its implementation which is not straightforward. In order to implement a functional impedance controller for a walking mechanism, the concepts of contact, impact, friction, and impedance have to be merged together. A literature review and a comprehensive analysis are presented compiling all these concepts along with a discussion on position-based versus force-based impedance control approaches, and a theoretical model of a robotic leg in contact with its environment is introduced. A theoretical control scheme for the legs of a general legged robot is also introduced, and some simulations results are presented.

Dynamic control of a reconfigurable stair-climbing mobility system

Electric-powered wheelchairs improve the mobility of people with physical disabilities, but the problem to deal with certain architectural barriers has not been resolved satisfactorily. In order to solve this problem, a stair-climbing mobility system (SCMS) was developed. This paper presents a practical dynamic control system that allows the SCMS to exhibit a successful climbing process when faced with typical architectural barriers such as curbs, ramps, or staircases. The implemented control system depicts high simplicity, computational efficiency, and the possibility of an easy implementation in a microprocessor-/microcontroller-based system. Finally, experiments are included to support theoretical results.

Advanced Control for Very Fast DC-DC Converters Based on Hysteresis of the C-out Current

The bandwidth achievable by using voltage mode control or current mode control in switch-mode power supply is limited by the switching frequency. Fast transient response requires high switching frequency, although lower switching frequencies could be more suitable for higher efficiency. This paper proposes the use of hysteretic control of the output capacitor $(C_{out})$ current to improve the dynamic response of the buck converter. An external voltage loop is required to accurately regulate the output voltage. The design of the hysteretic loop and the voltage loop are presented. Besides, it is presented a non-invasive current sensor that allows measuring the current in the capacitor. This strategy has been applied for DVS (dynamic voltage scaling) on a 5 MHz buck converter. Experimental results validate the proposed control technique and show fast transient response from 1.5 V to 2.5 V in 2 $mu{rm s}$.

Control y Monitorización de un Invernadero a través de una Aplicación Móvil

Los invernaderos permiten tener un mayor control del entorno donde crecen las plantas. Son utilizados para aumentar la calidad y rendimiento de las plantaciones en ciertas ubicaciones que tienen estaciones cortas de crecimiento, o bien malas condiciones de iluminación debido a las localizaciones geográficas, por lo que permiten mejorar la producción de alimentos vegetales en entornos extremos. En este proyecto se ha desarrollado una maqueta de un invernadero y se propone el uso del microcontrolador Arduino y del sistema operativo Android, con el objetivo de lograr una tarea de control y monitorización sobre dicha maqueta. Por una parte, se utiliza la placa Arduino como tarjeta controladora del sistema y, a su vez, como tarjeta adquiridora de datos, y por otra parte se ha desarrollado una aplicación Android capaz de monitorizar y supervisar el estado del invernadero. Para llevar a cabo el flujo de información entre el invernadero y los dispositivos de monitorización, se ha desarrollado una aplicación servidor bajo código C++, capaz de administrar la información del invernadero en una base de datos MySQL y, de forma concurrente, atender las peticiones de los clientes Android registrados, proporcionándoles la información que soliciten, y ejecutando las acciones que reciben.

Optimal Control Using Feedback Linearization for a Generalized T-S Model

In this paper, a fuzzy feedback linearization is used to control nonlinear systems described by Takagi-Suengo (T-S) fuzzy systems. In this work, an optimal controller is designed using the linear quadratic regulator (LQR). The well known weighting parameters approach is applied to optimize local and global approximation and modelling capability of T-S fuzzy model to improve the choice of the performance index and minimize it. The approach used here can be considered as a generalized version of T-S method. Simulation results indicate the potential, simplicity and generality of the estimation method and the robustness of the proposed optimal LQR algorithm.

Advanced Control Strategies for a 6 DoF Hydraulic Parallel Robot Based on the Dynamic Model

Nowadays robots have made their way into real applications that were prohibitive and unthinkable thirty years ago. This is mainly due to the increase in power computations and the evolution in the theoretical field of robotics and control. Even though there is plenty of information in the current literature on this topics, it is not easy to find clear concepts of how to proceed in order to design and implement a controller for a robot. In general, the design of a controller requires of a complete understanding and knowledge of the system to be controlled. Therefore, for advanced control techniques the systems must be first identified. Once again this particular objective is cumbersome and is never straight forward requiring of great expertise and some criteria must be adopted. On the other hand, the particular problem of designing a controller is even more complex when dealing with Parallel Manipulators (PM), since their closed-loop structures give rise to a highly nonlinear system. Under this basis the current work is developed, which intends to resume and gather all the concepts and experiences involve for the control of an Hydraulic Parallel Manipulator. The main objective of this thesis is to provide a guide remarking all the steps involve in the designing of advanced control technique for PMs. The analysis of the PM under study is minced up to the core of the mechanism: the hydraulic actuators. The actuators are modeled and experimental identified. Additionally, some consideration regarding traditional PID controllers are presented and an adaptive controller is finally implemented. From a macro perspective the kinematic and dynamic model of the PM are presented. Based on the model of the system and extending the adaptive controller of the actuator, a control strategy for the PM is developed and its performance is analyzed with simulation.

The national estuarine pollution study : a report to the Congress.

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The national estuarine pollution study : a report to the Congress.

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The national estuarine pollution study : a report to the Congress.

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Opportunity bulletins.

Mode of access: Internet.

Cooperative research and development agreement with ABB Environmental Systems : emission control from coal-fired boilers and municipal and hazardous waste incinerators.

Mode of access: Internet.

Performance testing of the Tetradyne high speed air jet skimmer /

Mode of access: Internet.

Integrated land use/air quality/water quality control study for Sonoma County, California /

Mode of access: Internet.

Control techniques for carbon monoxide emissions from stationary sources.

Includes bibliographies.