Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains

As legged robots are sent into unstructured environments, the ability to robustly manage contact transitions will be a critical skill. This paper introduces an approach to probabilistically fuse contact models, managing uncertainty in terrain geometry, dynamic modeling, and kinematics to improve the...

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Main Authors: Wensing, Patrick M., Bledt, Gerardo, Ingersoll, Samuel, Kim, Sangbae
מחברים אחרים: Massachusetts Institute of Technology. Department of Mechanical Engineering
פורמט: Article
יצא לאור: Institute of Electrical and Electronics Engineers (IEEE) 2019
גישה מקוונת:http://hdl.handle.net/1721.1/120350
https://orcid.org/0000-0001-7137-5932
https://orcid.org/0000-0002-0218-6801
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author Wensing, Patrick M.
Bledt, Gerardo
Ingersoll, Samuel
Kim, Sangbae
author2 Massachusetts Institute of Technology. Department of Mechanical Engineering
author_facet Massachusetts Institute of Technology. Department of Mechanical Engineering
Wensing, Patrick M.
Bledt, Gerardo
Ingersoll, Samuel
Kim, Sangbae
author_sort Wensing, Patrick M.
collection MIT
description As legged robots are sent into unstructured environments, the ability to robustly manage contact transitions will be a critical skill. This paper introduces an approach to probabilistically fuse contact models, managing uncertainty in terrain geometry, dynamic modeling, and kinematics to improve the robustness of contact initiation at touchdown. A discrete-time extension of the generalized-momentum disturbance observer is presented to increase the accuracy of proprioceptive force control estimates. This information is fused with other contact priors under a framework of Kalman Filtering to increase robustness of the method. This approach results in accurate contact detection with 99.3 % accuracy and a small 4-5ms delay. Using this new detector, an Event-Based Finite State Machine is implemented to deal with unexpected early and late contacts. This allows the robot to traverse cluttered environments by modifying the control actions for each individual leg based on the estimated contact state rather than adhering to a rigid time schedule regardless of actual contact state. Experiments with the MIT Cheetah 3 robot show the success of both the detection algorithm, as well as the Event-Based FSM while making unexpected contacts during trotting.
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spelling mit-1721.1/1203502022-09-27T17:42:37Z Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains Wensing, Patrick M. Bledt, Gerardo Ingersoll, Samuel Kim, Sangbae Massachusetts Institute of Technology. Department of Mechanical Engineering Bledt, Gerardo Ingersoll, Samuel Kim, Sangbae As legged robots are sent into unstructured environments, the ability to robustly manage contact transitions will be a critical skill. This paper introduces an approach to probabilistically fuse contact models, managing uncertainty in terrain geometry, dynamic modeling, and kinematics to improve the robustness of contact initiation at touchdown. A discrete-time extension of the generalized-momentum disturbance observer is presented to increase the accuracy of proprioceptive force control estimates. This information is fused with other contact priors under a framework of Kalman Filtering to increase robustness of the method. This approach results in accurate contact detection with 99.3 % accuracy and a small 4-5ms delay. Using this new detector, an Event-Based Finite State Machine is implemented to deal with unexpected early and late contacts. This allows the robot to traverse cluttered environments by modifying the control actions for each individual leg based on the estimated contact state rather than adhering to a rigid time schedule regardless of actual contact state. Experiments with the MIT Cheetah 3 robot show the success of both the detection algorithm, as well as the Event-Based FSM while making unexpected contacts during trotting. 2019-02-13T14:44:05Z 2019-02-13T14:44:05Z 2018-09 2018-05 2018-12-10T20:30:06Z Article http://purl.org/eprint/type/ConferencePaper 978-1-5386-3081-5 http://hdl.handle.net/1721.1/120350 Bledt, Gerardo, Patrick M. Wensing, Sam Ingersoll, and Sangbae Kim. “Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains.” 2018 IEEE International Conference on Robotics and Automation (ICRA), 21-25 May 2018, Brisbane, Queensland, Australia, IEEE, 2018. https://orcid.org/0000-0001-7137-5932 https://orcid.org/0000-0002-0218-6801 http://dx.doi.org/10.1109/ICRA.2018.8460904 2018 IEEE International Conference on Robotics and Automation (ICRA) Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Institute of Electrical and Electronics Engineers (IEEE) Other repository
spellingShingle Wensing, Patrick M.
Bledt, Gerardo
Ingersoll, Samuel
Kim, Sangbae
Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title_full Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title_fullStr Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title_full_unstemmed Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title_short Contact Model Fusion for Event-Based Locomotion in Unstructured Terrains
title_sort contact model fusion for event based locomotion in unstructured terrains
url http://hdl.handle.net/1721.1/120350
https://orcid.org/0000-0001-7137-5932
https://orcid.org/0000-0002-0218-6801
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AT ingersollsamuel contactmodelfusionforeventbasedlocomotioninunstructuredterrains
AT kimsangbae contactmodelfusionforeventbasedlocomotioninunstructuredterrains