Asynchronous Event-based Line Tracking for Time-to-Contact Maneuvers in UAS

Eguíluz, A. Gómez; Dios, J.R. Martínez-de; Ollero, A.

doi:10.1109/iros45743.2020.9341240

Cited by 9 publications

(8 citation statements)

References 32 publications

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“…Our first approach of local detection with a line-scan sensor would also be limited. New camera-based methods, which are currently being investigated, would greatly increase precision improvements in trajectory planning and close-range active control 37 . Finally, in terms of physical interaction, new materials and soft-robotic methods for the claw, such as shape-memory alloy (SMA), will further improve the conformability around a different variety of branch sizes and shapes 38 .…”

Section: Discussionmentioning

confidence: 99%

How ornithopters can perch autonomously on a branch

et al. 2022

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Flapping wings produce lift and thrust in bio-inspired aerial robots, leading to quiet, safe and efficient flight. However, to extend their application scope, these robots must perch and land, a feat widely demonstrated by birds. Despite recent progress, flapping-wing vehicles, or ornithopters, are to this day unable to stop their flight. In this paper, we present a process to autonomously land an ornithopter on a branch. This method describes the joint operation of a pitch-yaw-altitude flapping flight controller, an optical close-range correction system and a bistable claw appendage design that can grasp a branch within 25 milliseconds and re-open. We validate this method with a 700 g robot and demonstrate the first autonomous perching flight of a flapping-wing robot on a branch, a result replicated with a second robot. This work paves the way towards the application of flapping-wing robots for long-range missions, bird observation, manipulation, and outdoor flight.

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Section: Discussionmentioning

confidence: 99%

How ornithopters can perch autonomously on a branch

et al. 2022

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“…Since the development of event cameras, several works have been dedicated to extracting features from event streams and detecting and tracking features such as lines [13,14] and circles [15]. As a special feature, corner detection has also attracted many researchers.…”

Section: Related Workmentioning

confidence: 99%

DTFS-eHarris: A High Accuracy Asynchronous Corner Detector for Event Cameras in Complex Scenes

Zhao

Wang

et al. 2023

Applied Sciences

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The event camera, a new bio-inspired vision sensor with low latency and high temporal resolution, has brought great potential and demonstrated a promising application in machine vision and artificial intelligence. Corner detection is a key step of object motion estimation and tracking. However, most existing event-based corner detectors, such as G-eHarris and Arc*, lead to a huge number of redundant or wrong corners, and cannot strike a balance between the accuracy and real-time performance, especially in complex scenes with high texture that require higher computational costs. To address these issues, we propose an asynchronous corner detection method: a double threshold filter with Sigmoid eHarris (DTFS-eHarris) and an asynchronous corner tracker. The main contributions are that a double threshold filter is designed to reduce the redundant events and the improved Sigmoid function is utilized to represent the Surface of Active Events (Sigmoid*-SAE). We selected four scenes—shapes, dynamic, poster and boxes—from the public event camera dataset DAVIS240C to compare with the existing state-of-the-art hybrid method; our method has shown more than a 10% reduction in false positive rate and a 5% and 20% improvement in accuracy and throughput, respectively. The evaluations indicate that DTFS-eHarris shows a significant improvement, especially in complex scenes. Thus, it is anticipated to enhance the real-time performance and feature detection accuracy for future robotic applications.

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“…An eventbased optical flow approach for autonomous MAV landing using a downwards orientated event camera is presented in [18]. The event-based line tracker in [19] provides fast and stable references for quadrotor visual servoing to perform bionspired landing trajectories. The drone racing dataset [20] including event data intends to encourage the development of perception methods for high-speed drone maneuvers.…”

Section: Related Workmentioning

confidence: 99%

Free as a Bird: Event-Based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

Tapia

Garcia

Dios

et al. 2022

IEEE Robot. Autom. Lett.

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Autonomous flight of flapping-wing robots is a major challenge for robot perception. Most of the previous senseand-avoid works have studied the problem of obstacle avoidance for flapping-wing robots considering only static obstacles. This paper presents a fully onboard dynamic sense-and-avoid scheme for large-scale ornithopters using event cameras. These sensors trigger pixel information due to changes of illumination in the scene such as those produced by dynamic objects. The method performs event-by-event processing in low-cost hardware such as those onboard small aerial vehicles. The proposed scheme detects obstacles and evaluates possible collisions with the robot body. The onboard controller actuates over the horizontal and vertical tail deflections to execute the avoidance maneuver. The scheme is validated in both indoor and outdoor scenarios using obstacles of different shapes and sizes. To the best of the authors' knowledge, this is the first event-based method for dynamic obstacle avoidance in a flapping-wing robot.

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Asynchronous Event-based Line Tracking for Time-to-Contact Maneuvers in UAS

Cited by 9 publications

References 32 publications

How ornithopters can perch autonomously on a branch

How ornithopters can perch autonomously on a branch

DTFS-eHarris: A High Accuracy Asynchronous Corner Detector for Event Cameras in Complex Scenes

Free as a Bird: Event-Based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

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