Curved surface contact patches with quantified uncertainty

Vona, Marsette; Kanoulas, Dimitrios

doi:10.1109/iros.2011.6094990

Cited by 10 publications

(17 citation statements)

References 20 publications

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“…The framework is experimentally validated on the newly developed mini-biped robot, called Rapid Prototyped Biped (RPBP), for foot placement contacts on rocky surfaces. Some earlier results of this work were presented in prior conference papers [9], [10], [11]. This paper, is the first presentation of the work as a whole, including also the patch tracking system (Sec.…”

Section: Introductionmentioning

confidence: 95%

“…points that deviate from the underlying ground truth surface. In [9], we express the 3D point uncertainty using Gaussian modeling, with 3 × 3 covariance matrices. To estimate these matrices, we experimented with constant, linear, and quadratic error model assumptions, but we preferred Murray and Little's [61] two-parameter error model for stereo disparity uncertainty, which experimentally appears to follow better the distribution of the input point cloud data.…”

Section: Range Sensingmentioning

confidence: 99%

“…Inspired by natural systems like humans, we introduce a set of patch models, to sparsely model potential contacts. We first review the patch modeling, fitting, and validation process that we previously introduced in [9], [10], [11]. We introduce a set of ten curved/flat patch types (Table 1; eight of them are shown in Fig.…”

Section: Surface Modeling Using Curved Patchesmentioning

confidence: 99%

“…We now, present the details of the elliptic and hyperbolic paraboloid patch models, which are two out of the ten proposed surfaces. Due to space constraints we must refer readers to [9] for further details on: (1) the intrinsic and extrinsic parametrization in the case of symmetries, (2) the methodology to avoid singularities, by a fast dynamic reparameterization, and (3) the circular cylindrical and spherical patch models.…”

Section: Extrinsic and Intrinsic Surface Parametersmentioning

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: Introductionmentioning

confidence: 95%

Section: Range Sensingmentioning

confidence: 99%

Section: Surface Modeling Using Curved Patchesmentioning

confidence: 99%

Section: Extrinsic and Intrinsic Surface Parametersmentioning

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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“…The representation of the foothold affordances is also a crucial aspect of the perception system, which was used only for rough terrain locomotion on the bricks and the steps. For this a set of circular planar patches of the size of the foothold were used (Kanoulas, ; Kanoulas & Vona, , ; Vona & Kanoulas, ). Even though these patches could be used in a fully automated local footstep planner method, to ensure reliability and safety, the process was semiautonomous.…”

Section: Walk‐man Motion Controlmentioning

confidence: 99%

WALK‐MAN: A High‐Performance Humanoid Platform for Realistic Environments

Tsagarakis

Caldwell

Negrello

et al. 2017

Journal of Field Robotics

203

109

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In this work, we present WALK-MAN, a humanoid platform that has been developed to operate in realistic unstructured environment, and demonstrate new skills including powerful manipulation, robust balanced locomotion, high-strength capabilities, and physical sturdiness. To enable these capabilities, WALK-MAN design and actuation are based on the most recent advancements of series elastic actuator drives with unique performance features that differentiate the robot from previous state-of-the-art compliant actuated robots. Physical interaction performance is benefited by both active and passive adaptation, thanks to WALK-MAN actuation that combines customized high-performance modules with tuned torque/velocity curves and transmission elasticity for high-speed adaptation response and motion reactions to disturbances. WALK-MAN design also includes innovative design optimization features that consider the selection of kinematic structure and the placement of the actuators with the body structure to maximize the robot performance. Physical robustness is ensured with the integration of elastic transmission, proprioceptive sensing, and control. The WALK-MAN hardware was designed and built in 11 months, and the prototype of the robot was ready four months before DARPA Robotics Challenge (DRC) Finals. The motion generation of WALK-MAN is based on the unified motion-generation framework of whole-body locomotion and manipulation (termed loco-manipulation). WALK-MAN is able to execute simple loco-manipulation behaviors synthesized by combining different primitives defining the behavior of the center of gravity, the motion of the hands, legs, and head, the body attitude and posture, and the constrained body parts such as joint limits and contacts. The motion-generation framework including the specific motion modules and software architecture is discussed in detail. A rich perception system allows the robot to perceive and generate 3D representations of the environment as well as detect contacts and sense physical interaction force and moments. The operator station that pilots use to control the robot provides a rich pilot interface with different control modes and a number of teleoperated or semiautonomous command features. The capability of the robot and the performance of the individual motion control and perception modules were validated during the DRC in which the robot was able to demonstrate exceptional physical resilience and execute some of the tasks during the competition

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