Vision-based foothold contact reasoning using curved surface patches

Kanoulas, Dimitrios; Zhou, Chengxu; Nguyen, Anh; Kanoulas, Georgios; Caldwell, Darwin G.; Tsagarakis, Nikos G.

doi:10.1109/humanoids.2017.8239546

Cited by 27 publications

(22 citation statements)

References 26 publications

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“…The dynamics of the support phase could then be handled by considering contact with only that patch. In this paper we focus mostly only on perception, but in [87], [88] we implemented fast footstep planning using the curved patches introduced here.…”

Section: Discussionmentioning

confidence: 99%

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Curved patch mapping and tracking for irregular terrain modeling: Application to bipedal robot foot placement

Kanoulas

Tsagarakis

Vona

2019

Robotics and Autonomous Systems

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Legged robots need to make contact with irregular surfaces, when operating in unstructured natural terrains. Representing and perceiving these areas to reason about potential contact between a robot and its surrounding environment, is still largely an open problem. This paper introduces a new framework to model and map local rough terrain surfaces, for tasks such as bipedal robot foot placement. The system operates in real-time, on data from an RGB-D and an IMU sensor. We introduce a set of parametrized patch models and an algorithm to fit them in the environment. Potential contacts are identified as bounded curved patches of approximately the same size as the robot's foot sole. This includes sparse seed point sampling, point cloud neighborhood search, and patch fitting and validation. We also present a mapping and tracking system, where patches are maintained in a local spatial map around the robot as it moves. A bio-inspired sampling algorithm is introduced for finding salient contacts. We include a dense volumetric fusion layer for spatiotemporally tracking, using multiple depth data to reconstruct a local point cloud. We present experimental results on a mini-biped robot that performs foot placements on rocks, implementing a 3D foothold perception system, that uses the developed patch mapping and tracking framework.Index Terms-irregular surface modeling, foothold contact modeling, bounded curved patch modeling, curved patch fitting and tracking, 3D perception for bipedal robots, bipedal robot foot placement, rough terrain stepping, legged robot locomotion ! • Dimitrios Kanoulas and Nikos G. Tsagarakis are with the Humanoids and

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Section: Discussionmentioning

confidence: 99%

“…Third, curved patches could also be used to represent surfaces on the robot itself, as shown in Fig. 9, so that robot-environment interactions could be reasoned about as homogeneous patch-patch contacts [87].…”

Section: Discussionmentioning

confidence: 99%

Curved patch mapping and tracking for irregular terrain modeling: Application to bipedal robot foot placement

Kanoulas

Tsagarakis

Vona

2019

Robotics and Autonomous Systems

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“…Future work will also involve testing the combined Pronto+LOAM estimator with the robot walking on rough and non-flat surfaces. Furthermore, the Pronto+LOAM estimates will be used for dynamic navigation planning on non-flat and irregular surfaces as well as for dynamic control, while walking on irregular surfaces [21], using also our newly developed real-time dense surface mapping and tracking system [22].…”

Section: Discussionmentioning

confidence: 99%

A Study on Low-Drift State Estimation for Humanoid Locomotion, Using LiDAR and Kinematic-Inertial Data Fusion

Raghavan

Kanoulas

Zhou

et al. 2018

2018 IEEE-RAS 18th International Conference on Humanoid Robots (Humanoids)

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Several humanoid robots will require to navigate in unsafe and unstructured environments, such as those after a disaster, for human assistance and support. To achieve this, humanoids require to construct in real-time, accurate maps of the environment and localize in it by estimating their base/pelvis state without any drift, using computationally efficient mapping and state estimation algorithms. While a multitude of Simultaneous Localization and Mapping (SLAM) algorithms exist, their localization relies on the existence of repeatable landmarks, which might not always be available in unstructured environments. Several studies also use stop-andmap procedures to map the environment before traversal, but this is not ideal for scenarios where the robot needs to be continuously moving to keep for instance the task completion time short. In this paper, we present a novel combination of the state-of-the-art odometry and mapping based on LiDAR data and state estimation based on the kinematics-inertial data of the humanoid. We present experimental evaluation of the introduced state estimation on the full-size humanoid robot WALK-MAN while performing locomotion tasks. Through this combination, we prove that it is possible to obtain low-error, high frequency estimates of the state of the robot, while moving and mapping the environment on the go.

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“…[1][2][3][4] Although most approaches require the terrain to be flat around the contemplated footholds, recent work exists on vision-based foothold planning for irregularly protruded terrain. 5 Vision-based planning, however, greatly depends on the quality of the sensor signals. Ground height estimation errors can reach the centimeter range 1,2 and have a significant effect on the performance of the overall system.…”

Section: Introductionmentioning

confidence: 99%

A force-control scheme for biped robots to walk over uneven terrain including partial footholds

Sygulla

Rixen

2020

International Journal of Advanced Robotic Systems

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The robustness of biped walking in unknown and uneven terrains is still a major challenge in research. Traversing such environments is usually solved through vision-based reasoning on footholds and feedback loops—such as ground force control. Uncertain terrains are still traversed slowly to keep inaccuracies in the perceived environment model low. In this article, we present a ground force-control scheme that allows for fast traversal of uneven terrain—including unplanned partial footholds—without using vision-based data. The approach is composed of an early-contact method, direct force control with an adaptive contact model, and a strategy to adapt the center of mass height based on contact force data. The proposed method enables the humanoid robot Lola to walk over a complex uneven terrain with 6 cm variation in ground height at a walking speed of 0.5 m/s. We consider our work a general improvement on the robustness to terrain uncertainties caused by inaccurate or even lacking information on the environment.

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Vision-based foothold contact reasoning using curved surface patches

Cited by 27 publications

References 26 publications

Curved patch mapping and tracking for irregular terrain modeling: Application to bipedal robot foot placement

Curved patch mapping and tracking for irregular terrain modeling: Application to bipedal robot foot placement

A Study on Low-Drift State Estimation for Humanoid Locomotion, Using LiDAR and Kinematic-Inertial Data Fusion

A force-control scheme for biped robots to walk over uneven terrain including partial footholds

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