To facilitate the study of how passive leg stiffness
influences locomotion dynamics and performance, we have
developed an affordable and accessible 400 g quadruped robot
driven by tunable compliant laminate legs, whose series and
parallel stiffness can be easily adjusted; fabrication only takes
2.5 hours for all four legs. The robot can trot at 0.52 m/s or 4.4
body lengths per second with a 3.2 cost of transport (COT).
Through locomotion experiments in both the real world and
simulation we demonstrate that legs with different stiffness
have an obvious impact on the robot’s average speed, COT,
and pronking height. When the robot is trotting at 4 Hz in
the real world, changing the leg stiffness yields a maximum
improvement of 37.1% in speed and 62.0% in COT, showing
its great potential for future research on locomotion controller
designs and leg stiffness optimizations.
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Feedback Control of the Locomotion of a Tailed Quadruped Robot
The traditional locomotion paradigm of quadruped robots is to use dexterous (multi degrees of freedom) legs and dynamically optimized footholds to balance the body and achieve stable locomotion. With the introduction of a robotic tail, a new locomotion paradigm becomes possible as the balancing is achieved by the tail and the legs are only responsible for propulsion. Since the burden on the leg is reduced, leg complexity can be also reduced. This paper explores this new paradigm by tackling the dynamic locomotion control problem of a reduced complexity quadruped (RCQ) with a pendulum tail. For this specific control task, a new control strategy is proposed in a manner that the legs are planned to execute the open-loop gait motion in advance, while the tail is controlled in a closed-loop to prepare the quadruped body in the desired orientation. With these two parts working cooperatively, the quadruped achieves dynamic locomotion. Partial feedback linearization (PFL) controller is used for the closed-loop tail control. Pronking, bounding, and maneuvering are tested to evaluate the controller’s performance. The results validate the proposed controller and demonstrate the feasibility and potential of the new locomotion paradigm.
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- Award ID(s):
- 1906727
- PAR ID:
- 10326665
- Date Published:
- Journal Name:
- ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 45TH MECHANISMS AND ROBOTICS CONFERENCE (MR)
- Volume:
- Volume 8B
- Issue:
- V08BT08A009
- Page Range / eLocation ID:
- 1-8
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1115/DETC2021-71611
