Arnaud Lelevé

Telerobotics over IP networks: Towards a low-level real-time architecture

Long distance teleoperation over asynchronous transmission links makes many classical teleoperation schemes unstable. The use of this kind of media involves varying transmission delays that may become prohibitive even at short distance. However, they are standardized, cheap and widespread over the planet. The paper presents our latest works on the improvement of teleoperation loops, by providing a low-level architecture which permits the use of classical teleoperation controls over asynchronous digital links.

Teleoperation Over IP Network: Network Delay Regulation and Adaptive Control

This paper proposes a solution to control a remote manipulator robot (PUMA560) using IP network. A method is described to control this remote manipulator based on High-Order Sliding Mode so as to obtain a constant product time delay × bandwidth. Since previous method supposes a constant transmission delay, we put it over a low level mechanism (Network Delay Regulator) satisfying this criterion. This method eliminates the delay jitter in order to make remote estimation, prediction and control with a constant mean time delay. Under this condition, the stability condition of this algorithm is then studied. Some simulation results illustrate the performance of the High-Order Sliding Mode to dynamically force the remote system according to the Network Round Trip Time (NRTT).

Generic framework for remote laboratory integration

Similar to classical in-situ laboratories, remote laboratories are necessary in e-learning environments, especially in scientific and technical disciplines. This paper outlines our current research on this particular way of learning. Our research objectives consist in proposing a generic framework (independent of educational content) to allow, in one hand, tutors to integrate (both remote and virtual) laboratories in their LMS (learning management system), and in the other hand, to enable creation, distribution and exchange of pedagogical scenarios for practical works. So, authors are able to deal their scenarios through LCMS (learning content management system) and to reuse scenarios from other authors (as for any classical e-learning content). Furthermore, scenarios are no more written for a specific apparatus, but for a class of them (inverted pendulum, optical bench, ...). Two main topics are developed. First one consists of modelling laboratory and scenario structures regarding IMS-LD specification to separate content from containers. Second one consists of describing system components and functionalities using ontologies (OWL standard in our case). A prototype for automation discipline is presented.

Remote laboratories: new technology and standard based architecture

E-Laboratories development appears to be more complex than other e-learning contexts such as online courses, virtual classrooms, e-projects, role-playing, etc. However, this kind of training is essential for scientific and technical disciplines and fits a real need. Recently we initiated a project [A. Leleve et al., (2003)] whose main goal is to build a complete remote laboratory system with an open, extensible and reusable architecture. This paper gives a global context of electronic, remote and virtual laboratories. Concerning e-lab scenario structure, our works are currently focusing on IMS learning design appropriateness.

Modeling and simulation of robotic tasks teleoperated through the Internet

According to their research activities, some laboratories have to set up expensive full-scale experiments requiring the use of teleoperated robots. In order to limit these costs, it is of interest to share the same equipment between laboratories and to teleoperate it directly from each laboratory through the Internet. In this context, we have initiated a study on a basic teleoperation scheme. Starting from experiments with a land mobile manipulator, we have built a generic simulation model that has been used to find improvements for later teleoperation experiments. The results presented in this paper are mainly based on simulations. However, they can be very useful for the real experiments we are currently preparing.

Remote laboratories: AIP-Primeca RAO platform

During last decade, Internet and related web technologies development enabled the arising of e-learning services and made distant learning a reality. As traditional face to face classroom became virtual classroom through Internet, traditional laboratories found their equivalent in e-Laboratories. These e-Labs enable learners to train on remote real or virtual systems. They represent essential components in e-learning environments, especially in scientific and technical disciplines. In this context, AIP-Primeca RAO is a pool of resources and competencies for industrial topics for many universities in Rhone. Due to the constraints of using heavy and shared resources, AIP is setting up new laboratories related to automation as both local and distant resources. After recalling the global context of e-laboratories, this paper describes this platform. It evokes first returns of use and it depicts evolutions to come.

On the use of SysML for manufacturing execution system design

In this paper, we show that the integration of a new MES within an existing manufacturing system requires to appeal to a method enabling the modeling of interactions between hardware and software components, the modeling of their behavior and their use by production staff. We show how SysML is a language fitting this need and we illustrate this discussion on a real sample.

A dual-user teleoperation system with Online Authority Adjustment for haptic training

This paper introduces a dual-user teleoperation system for hands-on medical training. A shared control based architecture is presented for authority management. In this structure, the combination of control signals is obtained using a dominance factor. Its main improvement is Online Authority Adjustment (OAA): the authority can be adjusted manually/automatically during the training progress. Experimental results are provided to validate the performances of the system.

Dynamical Model Averaging and PWM Based Control for Pneumatic Actuators

A pneumatic actuator with solenoid valves is a discontinuous-input system because each valve can be either in on or off state. For such an actuator, this paper proposes a sliding-mode control scheme based on an averaged continuous-input equivalent model for the open-loop system. The averaged model is obtained from the nonlinear dynamics of the open-loop discontinuous-input system undergoing pulse-width-modulation (PWM) at the input (i.e., valve open/close action). The PWM duty cycle will be regarded as a continuous input to the proposed averaged model, and thus generated by the proposed sliding-mode controller. By adjusting the PWM duty cycle, the controller switches between seven modes of operation of the open-loop system in order to select the ones with necessary and sufficient amounts of drive energy to achieve position tracking. We will show that this results in reduced position error and valve switching activity for the actuator. The proposed control scheme is experimentally used in the position control of a pneumatic actuator and the results are presented.

Configuration and Management Tool for laboratory training

Electronic Laboratories have been growing during the last decade, but till now, configuring a complex automated system shared between several institutes and used for several disciplines, is a process restricted to qualified staff. Moreover, authoring and managing lab resources (programs, learning scenarios, documentation for both instructors and trainees) is a complex task as soon as the number of instructors, disciplines, different levels... grows up. This paper introduces a software tool aiming at helping in the lab resource management and session configuration.