Manel Frigola

Bandwidth Management for Distributed Control of Highly Articulated Robots

An optimal bandwidth allocation policy for axis distributed control using networked control systems (NCS) is presented. First, the benefits of structuring highly articulated robots using networked control systems are discussed. Afterwards, an optimal bandwidth allocation policy for axes distributed control that allows to enhance robot tracking within the available bandwidth is introduced. It will be shown that axes control performance and thus tracking can be significantly improved by using feedback to dynamically allocate bandwidth to axis controllers as a function of the current state of each axis. Simulation results on a multiple axes robot corroborate our approach.

Stereoscopic system for human body tracking in natural scenes

Human body detection and tracking in a scene constitutes a very active working field clue to their applicability to many areas, specially as a man-machine interface (MMI) means. The system presented aims to improve the reliability and efficiency of teleoperation. The system is of application to teleoperated manipulation in civil applications such as big robots in shipyards, mines, public works or even cranes. Image segmentation is performed from movement detection. The recognition of moving bodies is verified by means of a simplified articulated cylindrical model, thus allowing to operate with a low computational cost.

Human-Robot Interaction Based on a Sensitive Bumper Skin

In order to enable robots to work in close contact with humans or in environments with unknown obstacles, new reactive control strategies based on sensitive bumper skins are proposed. The aim of this work is to provide a robot with contact and force control based strategies that make it dependable, safe and with foreseeable behaviours. The sensory skin is composed of rigid-bumpers provided with deformation sensors incorporated in a flexible substrate. This solution is a compromise between a simple bumper skin and current array-based robot skins, with better potential performances but, more costly and with usability problems. Such sensitive bumpers cover all moveable links of the robot allowing the detection of collisions, measuring the force involved and locating the point of contact with reasonable precision and cost

Visual human machine interface by gestures

Like oral communication, gestures are a natural way to carry out human machine interface. In the early days of robotic systems, human gesture was used to control robot movements by means of a master-slave structure. In spite of the use if robot programming languages, manual control is the most reliable way to carry out complex tasks in unstructured environments. In these situations, a non-contact, passive and remote system can be helpful to control a teleoperated robot by means of human gestures. In this paper, a vision system able to detect, locate and track the head and hands of a human body is presented. The system uses several calibrated cameras placed around the operator scenario to locate the body parts of a person in 3D. The system combines different computer vision techniques to increase the reliability of the body parts detection: image movement detection, user skin colour segmentation and stereo. The data provided by these modules are focused looking for coherence according to the human body dimensions. With the scheme proposed it is possible to obtain a low-cost real-time system for human computer interfacing based in a natural way of communication (gestures). Civil area such as big robots in shipyards, mines, public works or cranes is some possible applications.

Selection of the best stereo pair in a multi-camera configuration

The analysis of the error of stereo measurements by triangulation is revisited from three points of view: geometrical, statistical and visual quality. When the target is visible by a set of distributed cameras in the workspace, there are multiple combinations of camera pairs adequate to be considered for the location, by triangulation, of the target position. Three-camera placements are analysed evaluating their precision in a short-medium distance. The work presented analyses which combination of stereo measurements gives the best results, and proposes a method for the automatic selection of the most adequate cameras pair.

Virtual Exoskeleton for Telemanipulation

The growing number of robotics application fields, mainly in services, has led to the increase of new needs as well as the development of new facilities for teleoperation. Research in the design of more efficient and easy to use human-machine interfaces has propitiated the development of friendly communication systems such as those based on voice or gesture recognition. This work describes a vision based human-machine communication system that allows a computer or a control unit to “see and track” the position of the hands of a human. Thus, the vision system can be used as a virtual exoskeleton for simple telemanipulation tasks.

Motor-Model-Based Dynamic Scaling in Human–Computer Interfaces

This paper presents a study on how the application of scaling techniques to an interface affects its performance. A progressive scaling factor based on the position and velocity of the cursor and the targets improves the efficiency of an interface, thereby reducing the users workload. The study uses several human-motor models to interpret human intention and thus contribute to defining and adapting the scaling parameters to the execution of the task. Two techniques addressed to vary the control-display ratio are compared, and a new method for aiding in the task of steering is proposed.

Human robot interaction from visual perception

As robotics evolves towards application fields in which humans cooperate with robots, working closer and closer, the requirements for human robot interactions increase. This paper presents new advances in gesture based guidance and control of a robot in assistant tasks. The work described includes the integration of force and vision for the quantitative and qualitative appreciation of human intention and the robot behaviors to respond in real time to these human orders.

Experimental Bilateral Control Telemanipulation Using a Virtual Exoskeleton

The introduction of less invasive interfaces in control usually carry with them new drawbacks such as less perception, less dexterity, etc. This work tackles the experimentation of new means of perceptual feedback in teleoperation, when the operator guides the task by means of a virtual exoskeleton, and consequently without any mechanical device that can be provided with haptic devices. The work describes the evaluation of augmented images and sound feedback as alternative means for the bilateral control.

La robótica una valiosa herramienta en cirugía

Continuous advances on diagnostic techniques based on medical images, as well as the incorporation of new techniques in surgical instruments are progressively changing the new surgical procedures. Also, new minimally invasive techniques, which are currently highly consolidated, have produced significant advances, both from the technological and from the surgical treatment perspectives. The limitations that the manual realization of surgical interventions implies, in what refers to precision and accessibility, can be tackled with the help of robotics. In the same way, sensor based robot control techniques are opening new possibilities for the introduction of more improvements in these procedures, either relying on teleoperation, in which the surgeon and the robot establish their best synergy to get the optimal results, or by means of the automation of some specific actions or tasks. In this article the effect of robotics in the evolution of surgical techniques is described. Starting with a review of the robotics application fields, the article continues analyzing the methods and technologies involved in the process of robotizing surgical procedures, as well as the surgeon-robot interaction systems