53 research outputs found
Uncalibrated Visual Compass from Omnidirectional Line Images with Application to Attitude MAV Estimation
International audienceThis paper presents a new algorithm based on previous results of the authors, for the estimation of the yaw angle of an omnidirectional camera robot undergoing a 6-DoF rigid motion. Our real-time algorithm is uncalibrated, robust to noisy data, and it only relies on the projection of 3-D parallel lines as image features. Numerical and real-world experiments conducted with an eye-in-hand robot manipulator, which we used to simulate the 3-D motion of a Micro unmanned Aerial Vehicle (MAV), show the accuracy and reliability of our estimation algorithm
Cooperative human-robot haptic navigation
International audienceThis paper proposes a novel use of haptic feedback for human navigation with a mobile robot. Assuming that a path-planner has provided a mobile robot with an obstacle-free trajectory, the vehicle must steer the human from an initial to a desired target position by only interacting with him/her via a custom-designed vibro-tactile bracelet. The subject is free to decide his/her own pace and a warning vibrational signal is generated by the bracelet only when a large deviation with respect to the planned trajectory is detected by the vision sensor on-board the robot. This leads to a cooperative navigation system that is less intrusive, more flexible and easy-to-use than the ones existing in literature. The effectiveness of the proposed system is demonstrated via extensive real-world experiments
Uncalibrated Visual Compass from Omnidirectional Line Images with Application to Attitude MAV Estimation
International audienceThis paper presents a new algorithm based on previous results of the authors, for the estimation of the yaw angle of an omnidirectional camera robot undergoing a 6-DoF rigid motion. Our real-time algorithm is uncalibrated, robust to noisy data, and it only relies on the projection of 3-D parallel lines as image features. Numerical and real-world experiments conducted with an eye-in-hand robot manipulator, which we used to simulate the 3-D motion of a Micro unmanned Aerial Vehicle (MAV), show the accuracy and reliability of our estimation algorithm
Evaluation of a predictive approach in steering the human locomotion via haptic feedback
In this paper, we present a haptic guidance policy
to steer the user along predefined paths, and we evaluate
a predictive approach to compensate actuation delays that
humans have when they are guided along a given trajectory
via sensory stimuli. The proposed navigation policy exploits
the nonholonomic nature of human locomotion in goal directed
paths, which leads to a very simple guidance mechanism.
The proposed method has been evaluated in a real scenario
where seven human subjects were asked to walk along a set of
predefined paths, and were guided via vibrotactile cues. Their
poses as well as the related distances from the path have been
recorded using an accurate optical tracking system. Results
revealed that an average error of 0.24 m is achieved by using
the proposed haptic policy, and that the predictive approach
does not bring significant improvements to the path following
problem for what concerns the distance error. On the contrary,
the predictive approach achieved a definitely lower activation
time of the haptic interfaces
Cooperative human-robot haptic navigation
International audienceThis paper proposes a novel use of haptic feedback for human navigation with a mobile robot. Assuming that a path-planner has provided a mobile robot with an obstacle-free trajectory, the vehicle must steer the human from an initial to a desired target position by only interacting with him/her via a custom-designed vibro-tactile bracelet. The subject is free to decide his/her own pace and a warning vibrational signal is generated by the bracelet only when a large deviation with respect to the planned trajectory is detected by the vision sensor on-board the robot. This leads to a cooperative navigation system that is less intrusive, more flexible and easy-to-use than the ones existing in literature. The effectiveness of the proposed system is demonstrated via extensive real-world experiments
Design, characterization and control of thermally-responsive and magnetically-actuated micro-grippers at the air-water interface
The design and control of untethered microrobotic agents has drawn a lot of attention in recent years. This technology truly possesses the potential to revolutionize the field of minimally invasive surgery and microassembly. However, miniaturization and reliable actuation of micro-fabricated grippers are still challenging at sub-millimeter scale. In this study, we design, manufacture, characterize, and control four similarly-structured semi-rigid thermoresponsive micro-grippers. Furthermore, we develop a closed loop-control algorithm to demonstrate and compare the performance of the said grippers when moving in hard-to-reach and unpredictable environments. Finally, we analyze the grasping characteristics of three of the presented designs. Overall, not only does the study demonstrate motion control in unstructured dynamic environments-at velocities up to 3.4, 2.9, 3.3, and 1 body-lengths/s with 980, 750, 250, and 100 μm-sized grippers, respectively-but it also aims to provide quantitative data and considerations to help a targeted design of magnetically-controlled thin micro-grippers
Predictors of mortality and adverse events in patients with infective endocarditis: a retrospective real world study in a surgical centre
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