Safe 3D Bipedal Walking through Linear MPC with 3D Capturability

Pajon, Adrien; Wiebe, Pierre-Brice

doi:10.1109/icra.2019.8794117

Cited by 13 publications

(21 citation statements)

References 20 publications

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“…Remark 2: It is worth mentioning that the ICI concept induces linear CoM motions as pointed out in Remark 1, and related capturability conditions considering such linear motions have been investigated in the literature [18], [19]. Work in [18] studies multi-contact capturability, and considers general CoM motion along the line in this case.…”

Section: A Inner Approximation Of the Capture Basinmentioning

confidence: 99%

“…Work in [18] studies multi-contact capturability, and considers general CoM motion along the line in this case. Work in [19] heuristically fixes a value of λ governing motion along a line, with the resulting CoM dynamics similar to those here. However, our ICI concept computes the value of λ based on the state of the CoM and induces the above presented capturability condition, which differs fundamentally from the previous results.…”

Section: A Inner Approximation Of the Capture Basinmentioning

confidence: 99%

“…The balance control problem, on the other hand, can be tackled with ICP feedback controllers [4], [14], while paying special attention to keep the ICP inside the support polygon for maintaining capturability. The ICP notion has also been extended to derive capturability constraints for walking pattern generation [19] as well as multicontact balancing [18].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Instantaneous Capture Input for Balancing the Variable Height Inverted Pendulum

Liu

Chen

Wensing

et al. 2021

Preprint

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Balancing is a fundamental need for legged robots due to their unstable floating-base nature. Balance control has been thoroughly studied for simple models such as the linear inverted pendulum thanks to the concept of the instantaneous capture point (ICP), yet the constant center of mass height assumption limits the application. This paper explores balancing of the variable-height inverted pendulum (VHIP) model by introducing the instantaneous capture input (ICI), an extension of the ICP based on its key properties. Namely, the ICI can be computed as a function of the state, and when this function is used as the control policy, the ICI is rendered stationary and the system will eventually come to a stop. This characterization induces an analytical region of capturable states for the VHIP, which can be used to conceptually guide where to step. To further address state and control constraints during recovery, we present and theoretically analyze an explicit ICI-based controller with online optimal feedback gains. Simulations demonstrate the validity of our controller for capturability maintenance compared to an approach based on the divergent component of motion.

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Section: A Inner Approximation Of the Capture Basinmentioning

confidence: 99%

Section: A Inner Approximation Of the Capture Basinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Instantaneous Capture Input for Balancing the Variable Height Inverted Pendulum

Liu

Chen

Wensing

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…These nonlinearities are sometimes neglected, but to a risk of failure. We handle them explicitly by considering a piecewise linear 3D trajectory of the Divergent Component of Motion (DCM) [11], or we bound them by constraining the height variations of the CoM above the ground, adapting the capturability and boundedness accordingly [15].…”

Section: B Walkingmentioning

confidence: 99%

Humanoid Robots in Aircraft Manufacturing: The Airbus Use Cases

Kheddar

Roa

Wieber

et al. 2019

IEEE Robot. Automat. Mag.

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We report results from a collaborative project that investigated the deployment of humanoid robotic solutions in aircraft manufacturing for some assembly operations where access is not possible for wheeled or rail-ported robotic platforms. Recent developments in multi-contact planning and control, bipedal walking, embedded SLAM, whole-body multi-sensory task space optimization control, and contact detection and safety, suggest that humanoids could be a plausible solution for automation given the specific requirements in such large-scale manufacturing sites. The main challenge is to integrate these scientific and technological advances into two existing humanoid platforms: the position controlled HRP-4 and the torque controlled TORO. This integration effort was demonstrated in a bracket assembly operation inside a 1:1 scale A350 mock-up of the front part of the fuselage at the Airbus Saint-Nazaire site. We present and discuss the main results that have been achieved in this project and provide recommendations for future work.

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“…Reasoning about safety from both levels has been largely under-explored in the field. As one closely-related line of research, Wieber's recent studies [7], [8] proposed a model predictive control (MPC) method to address safe navigation problems for bipedal walking robots in a crowded environment. Nevertheless, their work mainly focused on passive safety, i.e., the robot comes to a stop for collision avoidance.…”

Section: Introductionmentioning

confidence: 99%

Towards Safe Locomotion Navigation in Partially Observable Environments with Uneven Terrain

Warnke

Shamsah

et al. 2020

Preprint

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This study proposes an integrated task and motion planning method for dynamic locomotion in partially observable environments with multi-level safety guarantees. This layered planning framework is composed of a high-level symbolic task planner and a low-level phase-space motion planner. A belief abstraction at the task planning level enables belief estimation of dynamic obstacle locations and guarantees navigation safety with collision avoidance. The high-level task planner, i.e., a two-level navigation planner, employs linear temporal logic for a reactive game synthesis between the robot and its environment while incorporating low-level safe keyframe policies into formal task specification design. The synthesized task planner commands a series of locomotion actions including walking step length, step height, and heading angle changes, to the underlying keyframe decision-maker, which further determines the robot center-of-mass apex velocity keyframe. The low-level phase-space planner uses a reduced-order locomotion model to generate non-periodic trajectories meeting balancing safety criteria for straight and steering walking. These criteria are characterized by constraints on locomotion keyframe states, and are used to define keyframe transition policies via viability kernels. Simulation results of a Cassie bipedal robot designed by Agility Robotics demonstrate locomotion maneuvering in a three-dimensional, partially observable environment consisting of dynamic obstacles and uneven terrain.

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Safe 3D Bipedal Walking through Linear MPC with 3D Capturability

Cited by 13 publications

References 20 publications

Instantaneous Capture Input for Balancing the Variable Height Inverted Pendulum

Instantaneous Capture Input for Balancing the Variable Height Inverted Pendulum

Humanoid Robots in Aircraft Manufacturing: The Airbus Use Cases

Towards Safe Locomotion Navigation in Partially Observable Environments with Uneven Terrain

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