Yann Perrot

ABLE, an innovative transparent exoskeleton for the upper-limb

This paper presents ABLE, an innovative exoskeleton for the upper limb currently under development at CEA-LIST Interactive Robotics Unit. Its distinctive high performance mechanical transmissions - screw and cable patented arrangement - and its integrated architecture makes it the very first of its category. The first 4 axis model is described here but more complete models are already planned: a 7 axis model as well as portable versions. Its back-drivable, high efficiency, low inertia actuators provide a high capacity (around 40 N continuous effort at the hand) and allow hybrid force-position control without requiring any force sensor. Its first application is currently a research program in rehabilitation (BRAHMA project) and professional use is already in view. Assistance tasks for disabled persons (carrying a bottle) are also typical tasks to be performed by ABLE as well as intuitive telerobotics, haptic device for VR, and sport training, etc. Furthermore, its versatility and simple design allow industrial versions to become soon available.

Design and acceptability assessment of a new reversible orthosis

We present a new device aimed at being used for upper limb rehabilitation. Our main focus was to design a robot capable of working in both the passive mode (i.e. the robot shall be strong enough to generate human-like movements while guiding the weak arm of a patient) and the active mode (i.e. the robot shall be able of following the arm without disturbing human natural motion). This greatly challenges the design, since the system shall be reversible and lightweight while providing human compatible strength, workspace and speed. The solution takes the form of an orthotic structure, which allows control of human arm redundancy contrarily to clinically available upper limb rehabilitation robots. It is equipped with an innovative transmission technology, which provides both high gear ratio and fine reversibility. In order to evaluate the device and its therapeutic efficacy, we compared several series of pointing movements in healthy subjects wearing and not wearing the orthotic device. In this way, we could assess any disturbing effect on normal movements. Results show that the main movement characteristics (direction, duration, bell shape profile) are preserved.

Development of a long reach articulated manipulator for ITER in vessel inspection under vacuum and temperature

This project takes place in the EFDA Remote Handling (RH) activities for the fusion reactor International Thermonuclear Experimental Reactor (ITER). The aim of the R&D program is to demonstrate the feasibility of in-vessel RH intervention by a long reach, limited payload manipulator which penetrates the first wall using the six IVVS penetrations. Potential activities for this device include close inspection of the plasma facing surfaces and leak detection. The work includes the design, manufacture and testing of a demonstrator articulated manipulator called the In-Vessel Penetrator (IVP). The first part of this work concerned the analysis of the requirements and resulted in the development of the conceptual design of the overall manipulator, comprising a 5 module, 11 d.o.f robot based on a parallelogram structure. A scale one mock up of a representative segment was manufactured and tested. In parallel, a feasibility study of the IVP operation was made and provided recommendations to modify the design for intervention under vacuum and temperature. Some technologies were selected and analysed to determine their suitability to the IVP application and items identified for further validation. This paper presents the whole robot concept, the results of the test campaign on the prototype demonstrator and the vacuum and temperature technologies study.

Design and flexible modeling of a long reach articulated carrier for inspection

This work concerns the development of advanced robotic systems for nuclear application. The manipulator will be used for light intervention in spent fuel management facilities. The robot must meet severe specifications: small diameter, long reach within a minimum range of 6 m, high dexterity to move in constrained environment and lots of degrees of freedom (DOF) for obstacle avoidance. In order to meet these requirements, a very challenging robotic carrier (called P.A.C.) which is able to perform light intervention tasks inside high range of blind hot cells using existing engineering penetrations is developed. This long reach multi-link carrier has 11 DOF and weighs less than 30 kg. The gravity effect in the manipulator is largely compensated by a special mechanical structure (the parallelogram) that helps reducing the size of the rotation actuators used to operate the robot. Also, a glass fiber epoxy equilibrium spring is used to compensate the gravity effect over the elevation actuators. A field test is made to measure the robots repeatability and accuracy by using a laser tracker to measure the end effectors position. Due to its size and weight, this large robot manipulator holds lots of elastic and geometric deformations. Thus it possesses a very low accuracy. A mechanical model is developed to take into account the flexibilities of the structure. This flexible model will be used to improve the accuracy of the manipulator. Applications tests were made to evaluate the ability and performances of the system to meet the operational requirements. The operation took place in an existing decontaminated hot cell and it turned out to be successful.

Dedicated and standard industrial robots used as force-feedback telemaintenance remote devices at the AREVA recycling plant

CEA LIST and AREVA have been developing remote operations devices, also called telerobotics for 15 years. These tools were designed for interventions in the AREVA nuclear spent fuel facilities hot cells. From these 15 years of joint research and development, several technological bricks have been industrialized and used at the AREVA La Hague facilities. This article presents some of these bricks and their industrial developments. The “TAO2000” CEA LIST telerobotics generic software controller will be first discussed. This controller has been used to teleoperate dedicated slave arms like the MT200 TAO (an evolution of the conventional wall-transmission mechanical telemanipulator (MSM) [3]) as well as industrial robotic arms like the Stäubli RX robots. Both the MT200 TAO and Stäubli RX TAO telerobotics systems provide force-feedback and are now ready to be used as telemaintenance tools at the AREVA La Hague facilities. Two recent maintenance operations using these tools will be detailed at the end of this paper.

Long reach articulated robots for inspection in hazardous environments, recent developments on robotics and embedded diagnostics

The Interactive Robotics Laboratory of CEA LIST is in charge of the development of remote technologies in order to meet the energy industry requirements. This paper reports the recent Research & Development activities in advanced remote systems for inspection or light intervention in hazardous environment with limited access as blind hot cells in nuclear fission industry and fusion facility vessels. A long reach carrier called Articulated Arm Inspection (AIA) will be described and current development of diagnostics and tools embedded for inspection or intervention will be presented.

Demonstration of an ITER relevant remote handling equipment for Tokamak close inspection

This work concerns the development of an ITER relevant advanced robotic systems for fusion reactor. The feasibility demonstration will be performed on the thermonuclear experimental Tokamak: Tore Supra, located in Cadarache facilities. The manipulator developed by the interactive robotics unit of CEA-LIST will be used for close inspection intervention tasks in a Tokamak. The robot must meet severe specifications: small diameter, long reach with a 9.5 m cantilever length, high dexterity to move in a Torus shape environment and able to carry a 10 kg payload on its end effector. As the robot must be introduced without breaking the machine conditioning, it has to cope with the vacuum and temperature constraints: Ultra High Vacuum (10-6 Pa) and 120degC in use, 200degC during baking phase. This long reach multi-link carrier has 10 DOF (9 rotary joints and 1 prismatic joint). It is composed of 5 modules and a precise guiding and pushing system (the deployer) for a total weight of about 300 kg. The gravity effect in the manipulator is largely compensated by a special mechanical structure (the parallelogram) that helps reducing the size of the actuators. The severe operating conditions impose a selection of several vacuum and temperature technologies that have been tested, qualified or optimized to cope with the requirements.In September 2007, the Remote Handling Equipment deployment under atmospheric conditions in a real Tokamak environment (Tore Supra) enabled to qualify the entire prototype. The scenario has to be rehearsed under vacuum and temperature to achieve the complete feasibility demonstration of a Tokamak close inspection by means of a robotic equipment under real operating conditions. The demonstration is an important step in the project but further developments are or could be necessary to cope with 100% of the requirements toward a reliable industrial prototype. In particular, due to its size and weight, this large robot manipulator holds lots of elastic and geometric deformations. Thus its accuracy is a challenge. A mechanical model could be developed to take into consideration the flexibilities of the structure and by means of calibration, the model parameters could be identified and then integrated in a real time controller. Further advanced developments on the on line monitoring system are also necessary for operator assistance and fault detection.

A New Force-Feedback, Morphologically Inspired Portable Exoskeleton

This paper presents a new portable exoskeleton design for superior limbs by the CEA-LIST laboratories. The first model described here (4 axis) is designed to apply forces in 3 directions. The first application is foreseen as an assistance device to enable a disabled person to carry an object such as a teapot or water bottle. It is designed as a base for more complete systems. A partial realization of it is presented for the first time. The high potential of the actuators used both in terms of back drivability and force capacity, allows hybrid force-position control laws making it possible to cover a broad range of applications: rehabilitation, assistance, force feedback master arm for telerobotics, sport training, and a virtual reality workbench

EMY: a dual arm exoskeleton dedicated to the evaluation of Brain Machine Interface in clinical trials

EMY (Enhancing MobilitY) is an exoskeleton dedicated to the evaluation of Brain Machine Interface during clinical trials. This paper presents the first version of EMY restricted to upper limbs with four actuated joints per arm. Since an evaluation of a BMI controlled exoskeleton by a disabled person requires clinical trials, a risk management process should be conducted with medical standards as references. More than an exhaustive architecture description of EMY, this paper details relationships between risk management and the proposed technical solutions in order to justify design options. EMYs design is upgradable and future versions of EMY will concern the addition of lower limbs and prehension capability to ultimately obtain a full-body exoskeleton suitable for testing brain controlled locomotion and manipulation tasks.

Hardening Inspection Devices to Ultra-High Vacuum, Temperature and High Magnetic Field

In order to demonstrate the feasibility of a mini-invasive inspection arm in ITER, the next step in fusion energy research machines, and to match the need for such a device in the French tokamak Tore Supra, a hardened long-reach robot has been developed by the CEA-LIST robotics team. The AIA (Articulated Inspection Arm), a 8 m long, highly articulated dexterous carrier with a 10 kg payload has been developed to be deployed anywhere in the Tore Supra vacuum vessel from one single Ø250 mm entry point, while the vessel is kept at the operating temperature (120) and pressure . Since its successful demonstration in Tore Supra in September 2008, the robot has been identified by different teams of scientists working on the tokamak for various potential tasks, from vision to diagnostic calibration or component analysis. In order to make such a device even more available, the CEALIST team is now working on the magnetic field constraint on robots. The goal being to demonstrate capabilities of intervention in ITER conditions, the considered field is 4 to 8 T. Technologies, command schemes and design strategies available for an inspection robot tolerant to high magnetic field have been studied. This paper first details the different technologies chosen for the AIA. How such an inspection device has been integrated on a multidisciplinary research machine such as Tore Supra is then detailed in a second part. The paper finally presents various concepts and experimentations to be used in a magnetic field tolerant robot for inspection of a large superconductor machine.