Haptic devices driven by DC motors are usually controlled in current mode due to the direct relationship between current and torque. This work analyzes the performance of voltage-mode controllers whose main drawback is that the torque of the actuator depends on its electrical dynamics. However, the electrical dynamics of the motor add the viscosity generated by the back-electromotive force. Since the motor damping seen from the handle of the interface is increased by the square of the transmission ratio, the physical damping of the mechanism can be very high, maintaining low inertia. As a result, very high performance in terms of critical stiffness can be achieved, even using cost-effective electronics. There is a trade-off between the achievable virtual stiffness during the haptic interaction and the backdrivability in free movement, if the damping is set too high. To investigate the benefits of this motor control strategy, CEIT's haptic gearshift is used as a testbed. The experimental results confirm that a very high critical stiffness can be achieved using this strategy

Robotic rehabilitation for poststroke therapies is an emerging new domain of application for robotics with proven success stories and clinical studies. New robotic devices and software applications are hitting the market, with the aim of assisting specialists carrying out physical therapies and even patients exercising at home. Rehabilitation robots are designed to assist patients performing repetitive movements with their hemiparetic limbs to regain motion. A successful robotic device for rehabilitation demands high workspace and force feedback capabilities similar to a human physiotherapist. These desired features are usually achieved at the expense of other important requirements, such as transparency and backdrivability, degrading the overall human-machine interaction experience.

Virtual Reality environments are being used on a mass scale in fields, such as Industry and Medicine. These virtual scenarios serve very different purposes such as prototyping, gaming and exercising. Interaction with the virtual environment is mainly achieved by senses of sight and hearing through devices, such as a mouse or VR glasses. To this end, haptic research started a few decades ago with the aim of improving this interaction through a sense of touch. A key element, hitherto not researched, is the effective combination of virtual elastic, viscous, and inertial effects in haptic feedback restored to the user and the safety implications of these feedback effects. It is of particular importance in neurological rehabilitation exercising, as interaction realism and safety are of great importance in therapy and for the patient. Therefore, this work addresses the stability analysis of the combination of three haptic effects-elastic, viscous, and inertial-and the subjective feeling on the part of users regarding different combinations of these effects. A theoretical analysis is presented with a view to establishing stable control principles, and a user-study was carried out in order to help understand the perception of users to different combinations of haptic effects.

Purpose: Recent innovations in robotics have enabled the development of automatic bone drilling tools which allows surgeons toimprove the precision of their surgical operations. However, these tools still lack valuable tactile information about the material proper-ties of the bone, preventing surgeons from making decisions while operating. The aim of this work is to explore whether robotic drillingtools can infer bone condition on the basis of certain key measures, particularly thrust force. Methods: To infer material properties inrobotic bone drilling processes 1) a complete database of experimental operations with an automatic bone drilling tool is implementedand 2) binary logistic regression models are developed to estimate the type of material from the observed values (mainly the centraltendency of the thrust force). This work compares three different materials: bovine bone specimens, porcine bone specimens and Full-Cure 720, which is a general-purpose resin with, a priori, much less feed resistance. The DRIBON automatic bone drilling tool developedat CEIT is used for the experiments. Results: The classification matrices derived using the logistic models show that it is possible torecognize a bovine bone vs. a porcine bone with a relatively high success rate rate (approximately 90%). In contrast, it is possibleto recognize bone material vs. another material (in our case a resin) with a 100% of success.

This paper deals with the stability analysis of two haptically-coupled devices. It describes how to model this kind of systems and shows how to obtain stable linking impedances. The approach is applied to an experimental setup that consists of a bimanual driving system in which both devices are haptically coupled. Four different cases depending on system dynamics are considered: 1) identical rigid devices, 2) different rigid devices, 3) different devices with vibration modes, and 4) mechanically-linked devices with vibration modes. The theoretical analysis is validated with experiments carried out on a driving simulation platform. The influence of the human operator is also experimentally discussed. Results can be extended to other applications where two haptic devices are used to hold virtual objects.

This work deals with the complex mechanical design task of converting a large pneumatic rehabilitation robot into an electric and compact system for in-home post-stroke therapies without losing performance. It presents the new HomeRehab robot that supports rehabilitation therapies in three dimensions with an adaptive controller that optimizes patient recovery. A preliminary usability test is also conducted to show that its performance resembles that found in RoboTherapist 2D commercial system designed for hospitals. The mechanical design of a novel and smart two-dimensional force sensor at the end-effector is also described.

Allergy tests are routinely performed in most hospitals everyday. However, measuring the outcomes of these tests is still a very laborious manual task. Current methods and systems lack of precision and repeatability. This paper presents a novel mechatronic system that is able to scan a patient's entire arm and provide allergists with precise measures of wheals for diagnosis. The device is based on 3-D laser technology and specific algorithms have been developed to process the information gathered. This system aims to automate the reading of skin prick tests and make gains in speed, accuracy, and reliability. Several experiments have been performed to evaluate the performance of the system.

The prick test is one of the most common medical methods for diagnosing allergies, and it has been carried out in a similar and laborious manner over many decades. In an attempt to standardize the reading of the test, many researchers have tried to automate the process of measuring the allergic reactions found by developing systems and algorithms based on multiple technologies. This work reviews the techniques for automatic wheal measurement with the aim of pointing out their advantages and disadvantages and the progress in the field. Furthermore, it provides a classification scheme for the different technologies applied. The works discussed herein provide evidence that significant challenges still exist for the development of an automatic wheal measurement system that not only helps allergists in their medical practice but also allows for the standardization of the reading and data exchange. As such, the aim of the work was to serve as guideline for the development of a proper and feasible system.

En la actualidad muchas empresas se plantean automatizar sistemas o procesos. Automatizar quiere decir cambiar el control manual de un sistema físico por un control automático, es decir, un funcionamiento sin intervención humana. Dentro de la Ingeniería, la Automática es la disciplina que diseña los algoritmos que permiten este cambio de paradigma de control. El ejemplo más habitual de sistema automático es el robot industrial, que opera por sí mismo de acuerdo con unas reglas programadas. En este manual se presentan los conceptos básicos del control automático. Los primeros capítulos se dedican a la modelización matemática de señales y sistemas. A continuación, se estudian diversos aspectos del comportamiento de los sistemas físicos: el régimen transitorio, la estabilidad y el error en régimen permanente. Finalmente, se explican algunas herramientas de diseño de controladores proporcionales (el método de lugar de las raíces y el ajuste usando diagramas de Bode) y controladores PID (principalmente el método de Ziegler-Nichols).