Online regeneration of bipedal walking gait pattern optimizing footstep placement and timing

Kryczka, Przemyslaw; Kormushev, Petar; Tsagarakis, Nikos G.; Caldwell, Darwin G.

doi:10.1109/iros.2015.7353844

Cited by 52 publications

(50 citation statements)

References 10 publications

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“…During the control loop, a portion of the trajectory is sent to the Inverse Kinematics solver, which computes the correspondent portion of joint displacement to be sent to the robot. Modules related to manipulation tasks uses a WholeBody Inverse Kinematics library by Rocchi et al (2015), while the module related to walking uses a different strategy and Inverse Kinematics inspired by Kryczka et al (2015). Indeed, we decide to give freedom to the control module developers, so that they could use the control laws and IK approaches that they were more familiar with.…”

Section: Control Modulesmentioning

confidence: 99%

The Walk-Man Robot Software Architecture

et al. 2016

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A software and control architecture for a humanoid robot is a complex and large project, which involves a team of developers/researchers to be coordinated and requires many hard design choices. If such project has to be done in a very limited time, i.e., less than 1 year, more constraints are added and concepts, such as modular design, code reusability, and API definition, need to be used as much as possible. In this work, we describe the software architecture developed for Walk-Man, a robot participant at the Darpa Robotics Challenge. The challenge required the robot to execute many different tasks, such as walking, driving a car, and manipulating objects. These tasks need to be solved by robotics specialists in their corresponding research field, such as humanoid walking, motion planning, or object manipulation. The proposed architecture was developed in 10 months, provided boilerplate code for most of the functionalities required to control a humanoid robot and allowed robotics researchers to produce their control modules for DRC tasks in a short time. Additional capabilities of the architecture include firmware and hardware management, mixing of different middlewares, unreliable network management, and operator control station GUI. All the source code related to the architecture and some control modules have been released as open source projects.

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Section: Control Modulesmentioning

confidence: 99%

The Walk-Man Robot Software Architecture

et al. 2016

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“…However, the underlying simple template models (like LIP) require inverse dynamics or ZMP controllers to use ankles for a better tracking. Therefore, a combination of stepping and CoP modulation strategies is usually used Faraji et al (2014); Kryczka et al (2015); Feng et al (2013) for humanoid walking. Intuitive attack angle adjustment rules which capture the extra CoM velocity in hopping Raibert (1986) are extended to walking conditions too through capturability framework Koolen et al (2012).…”

Section: Control Approachmentioning

confidence: 99%

Bipedal walking and push recovery with a stepping strategy based on time-projection control

Faraji

Razavi

Ijspeert

2019

The International Journal of Robotics Research

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In this paper, we present a simple control framework for on-line push recovery with dynamic stepping properties. Due to relatively heavy legs in our robot, we need to take swing dynamics into account and thus use a linear model called 3LP which is composed of three pendulums to simulate swing and torso dynamics. Based on 3LP equations, we formulate discrete LQR controllers and use a particular time-projection method to adjust the next footstep location on-line during the motion continuously. This adjustment, which is found based on both pelvis and swing foot tracking errors, naturally takes the swing dynamics into account. Suggested adjustments are added to the Cartesian 3LP gaits and converted to joint-space trajectories through inverse kinematics. Fixed and adaptive foot lift strategies also ensure enough ground clearance in perturbed walking conditions. The proposed structure is robust, yet uses very simple state estimation and basic position tracking. We rely on the physical series elastic actuators to absorb impacts while introducing simple laws to compensate their tracking bias. Extensive experiments demonstrate the functionality of different control blocks and prove the effectiveness of time-projection in extreme push recovery scenarios. We also show self-produced and emergent walking gaits when the robot is subject to continuous dragging forces. These gaits feature dynamic walking robustness due to relatively soft springs in the ankles and avoiding any Zero Moment Point (ZMP) control in our proposed architecture.

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“…This generally involves updating the footstep plan, which can be performed using a lower dimensional model, or by directly incorporating the footstep locations in the optimisation process [6]. Kryczka et al [7] presented a ZMP-based method for incorporating, amongst other things, some level of timing feedback into the optimisation process. Their approach also requires measurement of the ZMP, and optimises a gait pattern depending on the Linear Inverted Pendulum Model (LIPM).…”

Section: Related Workmentioning

confidence: 99%

Omnidirectional bipedal walking with direct fused angle feedback mechanisms

Allgeuer

Behnke

2016

2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids)

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An omnidirectional closed-loop gait based on the direct feedback of orientation deviation estimates is presented in this paper. At the core of the gait is an open-loop central pattern generator. The orientation feedback is derived from a 3D nonlinear attitude estimator, and split into the relevant angular deviations in the sagittal and lateral planes using the concept of fused angles. These angular deviations from expected are used by a number of independent feedback mechanisms, including one that controls timing, to perform stabilising corrective actions. The tuning of the feedback mechanisms is discussed, including an LQR-based approach for tuning the transient sagittal response. The actuator control scheme and robot pose representations in use are also addressed. Experimental results on an igus Humanoid Open Platform demonstrate the core concept of this paper, that if the sensor management and feedback chains are carefully constructed, comparatively simple model-free and robot-agnostic feedback mechanisms can successfully stabilise a generic bipedal gait.

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Online regeneration of bipedal walking gait pattern optimizing footstep placement and timing

Cited by 52 publications

References 10 publications

The Walk-Man Robot Software Architecture

The Walk-Man Robot Software Architecture

Bipedal walking and push recovery with a stepping strategy based on time-projection control

Omnidirectional bipedal walking with direct fused angle feedback mechanisms

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