This paper presents a novel design of four permanent magnet based actuator for magnetic drug targeting of therapeutic microrobots. Drugs are transported through therapeutic magnetic boluses composed of magnetic particles controlled by magnetic gradients. In this study, to maximize the effect of the treatment and minimize adverse effects on the patient, a magnetic actuator have been developed to wirelessly control microrobots in a fluidic environment using four external magnets. Experimental validation is carried using the robotic arm Fanuc LR Mate 200iD to demonstrate the steerability of the magnetic microrobots under different trajectory constraints in viscous fluidic environment.

In this paper, we present a control strategy that enables intuitive physical human-robot collaboration with mobile manipulators equipped with an omnidirectional base. When interacting with a human operator, intuitiveness of operation is a major concern. To this end, we propose a redundancy solution that allows the mobile base to be fixed when working locally and moves it only when the robot approaches a set of constraints. These constraints include distance to singular poses, minimum of manipulability and distance to objects and angular deviation. Experimental results with a Kuka LWR4 arm mounted on a Neobotix MPO700 mobile base validate the proposed approach.

In this paper, we provide a new generalized kinematic formulation of the Remote Center of Motion (RCM) constraint for serial robotic arms to be useful for implementation in torque-controlled robots. A minimally invasive surgery assisted by a serial robot could be used for inserting a surgical tool through a desired insertion position, i.e. trocar position. The restricted movement caused by the trocar, i.e. the RCM constraint, must be guaranteed by the robotic system in order to avoid injury to the patient. The generalized formulation, presented in this paper, associates the task-space with the RCM constraint coordinates, which are described by the minimum distance between the surgical tool and the trocar position. In order to simultaneously achieve the surgical tool-tip trajectory and the RCM constraint, two control methods are proposed and compared, one using a projection in the null-space, the other by combining both tasks using a task-space augmentation method. Moreover, when additional lower priority tasks have to be implemented in the null-space of the two higher priority tasks, the kinematic formulation simplifies the calculation of the null-space projectors. Furthermore, unlike the previous studies, the formulation represented can be applied not only in a kinematic control but also in a dynamic control approach. Simulations were conducted to validate effectiveness of the proposed formulation, using a planar 4-DOF system as well as the dynamic model of a Kuka LBR 7 iiwa R800 robot arm.

In human-robot interaction, the robot must behave safely, especially when an operator is present in its workspace. Even higher safety levels must be attained when physical contact occurs between the two. To this end, standards such as the ISO10218 define the requirements for a robot to be considered safe for interaction with human operators in an industrial environment. In this paper, we propose an adaptive damping controller that fulfills the ISO10218 requirements by limiting the tool velocity, power and contact force online (and only when needed). The controller is experimentally validated on a hand-arm robotic system, in a mock-up collaborative application. For the hand, safe interaction is enhanced by using tactile sensing, both to regulate grasp forces and to provide an intuitive interface for the operator.

In this paper, we present a dynamically consistent control approach for manipulators with Cartesian Admittance Control (CAC) while guaranteeing a Remote Center of Motion (RCM) constraint. The dynamically consistent extended formulation was used in order to achieve a dynamically decoupled redundancy resolution, while a null-motion feedback was implemented that improves the tracking of the null-motion. Minimally Invasive Surgery (MIS) procedures are proposed as applications of the control approach formulated in this paper. The effectiveness of the proposed control approach was verified in simulation by using the Kuka LBR 7 iiwa R800 robot arm.

This paper deals with the optimization of the design of a 4 degree-of-freedom robot dedicated to tele-echography. It has been designed to reproduce in real time on a patient, the medical gestures performed by a remote expert moving a fictive probe. Our goal is to optimize the kinematic structure to determine geometrical parameters, as they have a significant role in the singularities localization. In this paper, we propose optimum solutions obtained from a combination of kinematic performances and compactness indices.

This paper proposes a new ergonomic frame to describe the attitude of a robot arm and to be used for human-machine interface in telerobotic with application to telesonography. A three part psychophysical analysis enabled us to design this new system of angles exhibiting a good decorrelation among its degrees of freedom. A decorrelation improvement of up to 83% can be noticed compare to the standard 3-1-3 Euler angles. This new frame has been exploited to conceive human-machine interface with a low cost input device such as the standard IT mouse. Psychophysical results show indisputable superiority of our new system compare to the standard Euler one for orientation tracking in teleoperation conditions.

This work deals with modeling for the design of a four degree-of-freedom robot dedicated to tele-echography. It is designed to follow the medical gestures of a remote expert moving an ultrasound probe. The goal is to define the kinematic structure with optimal geometric parameters. These parameters have an important role in the robot singularities positions corresponding to the most current medical gestures. In this paper, we propose a value of these parameters validated by the kinematic indices point of view and an optimization.

This paper presents a practical method to design an output feedback controller for a general mechanical system described by Euler Lagrange equations. An application of such an observer is formulated to path following controller for an underactuated surface vessel moving in a horizontal plan. The surface vessel is underactuated in the sway direction and has only position and orientation measurement available. The control development is based on Lyapunov direct method and backstepping technique.

In this paper, we present a control architecture based on the concept of levels. The architecture is composed of two parts called the decision part and the perception part. This organization permits to construct various configurations and is adaptable to any application. We implemented this architecture on different robotic platforms: a mobile robot, an omnidirectional robot and medical one. We focused on the generic aspect of the architecture which has the characteristic to include the tele-operation modes.

This article addresses the omni directional mechanical architectures problematic for mobile robots using 3 motorized axles with 2 spherical orthogonal wheels. These wheels transmit a power torque according to a direction and are completely free with respect to the two others. They are used on 2 mechanical structures: SM1 and SM2. The complete kinematic study emphasizes the facility of controlling such omni-directional robots, and examines the problems involved in the transition of the wheel-to-floor contact on each axle. From this double study emerges an optimal theoretical architecture, but difficult to realize mechanically. We then present a controller which compensates for the errors related to the simplest mechanical structure; and it is validated on a mobile robot ROMNI using mechanical structure SM1

This paper presents a new tool for the evaluation of ultrasound image compression. The goal is to measure the image quality as easily as with a statistical criterion, and with the same reliability as the one provided by the medical assessment. An initial experiment is proposed to medical experts and represents our reference value for the comparison of evaluation criteria. Twenty-one statistical criteria are selected from the literature. A cumulative absolute similarity measure is defined as a distance between the criterion to evaluate and the reference value. A first fusion method based on a linear combination of criteria is proposed to improve the results obtained by each of them separately. The second proposed approach combines different statistical criteria and uses the medical assessment in a training phase with a support vector machine. Some experimental results are given and show the benefit of fusion.

This paper presents a tele-operated robot built within the OTELO European project framework. This six degree-of-freedom non-redundant probe-holder robot with a remote center of motion is dedicated to robotized medical tele-echography. The mechanical structure, chosen by end-users' specifications, presents a self-motion singularity within the working space of the medical expert. A strategy has been developed to counter the effect of the singularity located in the centre of the working space based on an real-time singularity control of the robotic tele-operated system. Thanks to the implementation of this real-time control, several clinical tele-echography tests have been successfully performed where medical specialists were able to propose a diagnosis in 80% of the studied cases.

This paper presents a new tele-operated robotic chain for real-time ultrasound image acquisition and medical diagnosis. This system has been developed in the frame of the Mobile Tele-Echography Using an Ultralight Robot European Project. A light-weight six degrees-of-freedom serial robot, with a remote center of motion, has been specially designed for this application. It holds and moves a real probe on a distant patient according to the expert gesture and permits an image acquisition using a standard ultrasound device. The combination of mechanical structure choice for the robot and dedicated control law, particularly nearby the singular configuration allows a good path following and a robotized gesture accuracy. The choice of compression techniques for image transmission enables a compromise between flow and quality. These combined approaches, for robotics and image processing, enable the medical specialist to better control the remote ultrasound probe holder system and to receive stable and good quality ultrasound images to make a diagnosis via any type of communication link from terrestrial to satellite. Clinical tests have been performed since April 2003. They used both satellite or Integrated Services Digital Network lines with a theoretical bandwidth of 384 Kb/s. They showed the tele-echography system helped to identify 66% of lesions and 83% of symptomatic pathologies.

In this paper, we present a modular method of environment perception for a mobile robot by local mapping. This map building process is done in order to authorize the motions of a mobile robot in unknown indoor environment. To validate it, we have implemented a reactive navigation on a mobile robot which perceives its near environment with two range finders. The map building process is the cluster of several functions: sort of measures in subsets, model of these subsets, elaboration of a map, and updating it with previous measures. Furthermore this process must be quick and sufficiently robust to deliver in real time a safe map to the robot.

An autonomous mobile robot needs externals sensors for its own localization and modeling environment. In order to perform the angular precision of ultrasonic sensor and to improve the number of informations for a given time, we developed an ultrasonic sensor network using the multiple receivers mode. In this paper we introduce the ultrasonic network with its hardware architecture and its functioning mode. We also present a method to localize an echo source with the multiple receivers mode and show how to simply model this echo in the robot frame. We then describe the extraction of environment primitives (segment) by the inertia matrix and Hough transform. Finally, we validate the all process by experiments.