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108
A non-invasive brain-actuated wheelchair based on a P300 neurophysiological protocol and automated navigation
- IEEE Trans. on Robotics
, 2009
"... Abstract—This paper describes a new noninvasive brainactuated wheelchair that relies on a P300 neurophysiological protocol and automated navigation. When in operation, the user faces a screen displaying a real-time virtual reconstruction of the scenario and concentrates on the location of the space ..."
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Cited by 38 (11 self)
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Abstract—This paper describes a new noninvasive brainactuated wheelchair that relies on a P300 neurophysiological protocol and automated navigation. When in operation, the user faces a screen displaying a real-time virtual reconstruction of the scenario and concentrates on the location of the space to reach. A visual stimulation process elicits the neurological phenomenon, and the electroencephalogram (EEG) signal processing detects the target location. This location is transferred to the autonomous navigation system that drives the wheelchair to the desired location while avoiding collisions with obstacles in the environment detected by the laser scanner. This concept gives the user the flexibility to use the device in unknown and evolving scenarios. The prototype was validated with five healthy participants in three consecutive steps: screening (an analysis of three different groups of visual interface designs), virtual-environment driving, and driving sessions with the wheelchair. On the basis of the results, this paper reports the following evaluation studies: 1) a technical evaluation of the device and all functionalities; 2) a users ’ behavior study; and 3) a variability study. The overall result was that all the participants were able to successfully operate the device with relative ease, thus showing a great adaptation as well as a high robustness and low variability of the system. Index Terms—Neurorobotics, rehabilitation robotics. I.
A short paper about motion safety,”
- in Int. Conf. on Robotics and Automation. IEEE,
, 2007
"... Abstract-Motion safety for robotic systems operating in the real world is critical (especially when their size and dynamics make them potentially harmful for themselves or their environment). Motion safety is a taken-for-granted and ill-defined notion in the Robotics literature and the primary cont ..."
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Cited by 37 (10 self)
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Abstract-Motion safety for robotic systems operating in the real world is critical (especially when their size and dynamics make them potentially harmful for themselves or their environment). Motion safety is a taken-for-granted and ill-defined notion in the Robotics literature and the primary contribution of this paper is to propose three safety criteria that helps in understanding a number of key aspects related to the motion safety issue. A number of navigation schemes used by robotic systems operating in the real-world are then evaluated with respect to these safety criteria. It is established that, in all cases, they violate one or several of them. Accordingly, motion safety, especially in the presence of moving objects, cannot be guaranteed (in the sense that these robotic systems may end up in a situation where a collision inevitably occurs later in the future). Finally, it is shown that the concept of Inevitable Collision States introduced in [1] does respect the three above-mentioned safety criteria and therefore offers a theoretical answer to the motion safety issue.
Lessons learned in integration for sensor-based robot navigation systems
- International Journal of Advanced Robotic Systems
"... Abstract: This paper presents our work of integration during the last years within the context of sensor‐based robot navigation systems. In our motion system, as in many others, there are functionalities involved such as modeling, planning or motion control, which have to be integrated within an arc ..."
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Cited by 20 (13 self)
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Abstract: This paper presents our work of integration during the last years within the context of sensor‐based robot navigation systems. In our motion system, as in many others, there are functionalities involved such as modeling, planning or motion control, which have to be integrated within an architecture. This paper addresses this problematic. Furthermore, we also discuss the lessons learned while: (i) designing, testing and validating techniques that implement the functionalities of the navigation system, (ii) building the architecture of integration, and (iii) using the system on several robots equipped with different sensors in different laboratories. Keywords: Mobile robots, Sensor‐Based Robot Navigation, Robot Architectures and Integration. 1.
An inevitable collision statechecker for a car-like vehicle
- in Proc. of the IEEE Int. Conf. on Robotics and Automation, Roma (IT
, 2007
"... Abstract — An Inevitable Collision State (ICS) for a robotic system is a state for which, no matter what the future trajectory followed by the system is, a collision with an obstacle eventually occurs [1]. The ICS concept takes into account both the dynamics of the robotic system and the future moti ..."
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Cited by 17 (6 self)
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Abstract — An Inevitable Collision State (ICS) for a robotic system is a state for which, no matter what the future trajectory followed by the system is, a collision with an obstacle eventually occurs [1]. The ICS concept takes into account both the dynamics of the robotic system and the future motion of the moving objects of the environment. For obvious safety reasons, a robotic system should never ever end up in an ICS hence the interest of the ICS concept when it comes to safely drive robotic systems in dynamic environments. In theory, determining whether a given state is an ICS requires to check for collision all possible future trajectories of infinite duration that the robotic system can follow from this particular state! In practise, it is fortunately possible to build a conservative approximation of the ICS set by considering only a finite subset of the whole set of possible future trajectories. The primary contribution of the paper is a general principle to select the subset of trajectories based upon the concept of imitating manoeuvres, ie trajectories leading the robotic system to duplicate the behaviour of the environment objects (fixed or moving), it is shown how a good approximation of the ICS set can be obtained. The second contribution of the paper is an ICS-Checker for a car-like vehicle moving in a dynamic environment. This ICS-Checker integrates the abovementioned selection principle. It is efficient and could be used in practise to compute truly safe motions for a car-like vehicle amidst moving objects.
Sensor-based robot motion generation in unknown, dynamic and troublesome scenarios
- ROBOT AUTON. SYST
, 2005
"... A sensor-based motion control system was designed to autonomously drive vehicles free of collisions in unknown, troublesome and dynamic scenarios. The system was developed based on a hybrid architecture with three layers (modeling, planning and reaction). The interaction of the modules was based on ..."
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Cited by 16 (8 self)
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A sensor-based motion control system was designed to autonomously drive vehicles free of collisions in unknown, troublesome and dynamic scenarios. The system was developed based on a hybrid architecture with three layers (modeling, planning and reaction). The interaction of the modules was based on a synchronous planner–reactor configuration where the planner computes tactical information to direct the reactivity. Our system differs from previous ones in terms of the choice of the techniques implemented in the modules and in the integration architecture. It can achieve robust and reliable navigation in difficult scenarios that are troublesome for many existing methods. Experiments carried out in these scenarios with a real vehicle confirm the effectiveness of this technique.
Abstracting vehicle shape and kinematics constraints from obstacle avoidance methods
- AUTONOMOUS ROBOTS
, 2006
"... Most obstacle avoidance techniques do not take into account vehicle shape and kinematic constraints. They assume a punctual and omnidirectional vehicle and thus they are doomed to rely on approximations when used on real vehicles. Our main contribution is a framework to consider shape and kinemati ..."
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Cited by 15 (6 self)
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Most obstacle avoidance techniques do not take into account vehicle shape and kinematic constraints. They assume a punctual and omnidirectional vehicle and thus they are doomed to rely on approximations when used on real vehicles. Our main contribution is a framework to consider shape and kinematics together in an exact manner in the obstacle avoidance process, by abstracting these constraints from the avoidance method usage. Our approach can be applied to many non-holonomic vehicles with arbitrary shape. For these vehicles, the configuration space is three-dimensional, while the control space is two-dimensional. The main idea is to construct (centred on the robot at any time) the two-dimensional manifold of the configuration space that is defined by elementary circular paths. This manifold contains all the configurations that can be attained at each step of the obstacle avoidance and is thus general for all methods. Another important contribution of the paper is the exact calculus of the obstacle representation in this manifold for any robot shape (i.e. the configuration regions in collision). Finally, we propose a change of coordinates of this manifold so that the elementary paths become straight lines. Therefore, the three-dimensional obstacle avoidance problem with kinematic constraints is transformed into the simple obstacle avoidance problem for a point moving in a two-dimensional space without any kinematic restriction (the usual approximation in obstacle avoidance). Thus, existing avoidance techniques become applicable. The relevance of this proposal is to improve the domain of applicability of a wide range of obstacle avoidance methods. We
Safe vehicle navigation in dynamic urban scenarios
- In: Proc. 11th International IEEE Conference on Intelligent Transportation Systems ITSC
, 2008
"... This paper describes the deliberative part of a navigation architecture designed for safe vehicle navigation in dynamic urban environments. It comprises two key modules working together in a hierarchical fashion: (a) the Route Planner whose purpose is to compute a valid itinerary towards the a given ..."
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Cited by 15 (5 self)
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This paper describes the deliberative part of a navigation architecture designed for safe vehicle navigation in dynamic urban environments. It comprises two key modules working together in a hierarchical fashion: (a) the Route Planner whose purpose is to compute a valid itinerary towards the a given goal. An itinerary comprises a geometric path augmented with additional information based on the structure of the environment considered and
Modeling Dynamic Scenarios for Local Sensor-Based Motion Planning
"... This paper addresses the modeling of the static and dynamic parts of the scenario and how to use this information with a sensor-based motion planning system. The contribution in the modeling aspect is a formulation of the detection and tracking of mobile objects and the mapping of the static structu ..."
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Cited by 14 (10 self)
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This paper addresses the modeling of the static and dynamic parts of the scenario and how to use this information with a sensor-based motion planning system. The contribution in the modeling aspect is a formulation of the detection and tracking of mobile objects and the mapping of the static structure in such a way that the nature (static/dynamic) of the observations is included in the estimation process. The algorithm provides a set of filters tracking the moving objects and a local map of the static structure constructed on line. In addition, this paper discusses how this modeling module is integrated in a real sensor-based motion planning system taking advantage selectively of the dynamic and static information. The experimental results confirm that the complete navigation system is able to move a vehicle in unknown and dynamic scenarios. Furthermore, the system overcomes many of the limitations of previous systems associated to the ability to distinguish the nature of the parts of the scenario. Key words: Mobile robots, mapping dynamic environments, sensor-based motion
Towards an intelligent wheelchair system for cerebral palsy subjects
- IEEE Trans. Neural Syst. Rehabil. Eng
"... Abstract—This paper describes and evaluates an intelligent wheelchair, adapted for users with cognitive disabilities and mobility impairment. The study focuses on patients with cerebral palsy, one of the most common disorders affecting muscle control and coordination, thereby impairing movement. The ..."
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Cited by 13 (6 self)
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Abstract—This paper describes and evaluates an intelligent wheelchair, adapted for users with cognitive disabilities and mobility impairment. The study focuses on patients with cerebral palsy, one of the most common disorders affecting muscle control and coordination, thereby impairing movement. The wheelchair concept is an assistive device that allows the user to select arbitrary local destinations through a tactile screen interface. The device incorporates an automatic navigation system that drives the vehicle, avoiding obstacles even in unknown and dynamic scenarios. It provides the user with a high degree of autonomy, independent from a particular environment, i.e., not restricted to predefined conditions. To evaluate the rehabilitation device, a study was carried out with four subjects with cognitive impairments, between 11 and 16 years of age. They were first trained so as to get acquainted with the tactile interface and then were recruited to drive the wheelchair. Based on the experience with the subjects, an extensive evaluation of the intelligent wheelchair was provided from two perspectives: 1) based on the technical performance of the entire system and its components and 2) based on the behavior of the user (execution analysis, activity analysis, and competence analysis). The results indicated that the intelligent wheelchair effectively provided mobility and autonomy to the target population. Index Terms—Cerebral Palsy, intelligent wheelchairs, tactile interface.
