Hopping control for the musculoskeletal bipedal robot: BioBiped

Sharbafi, Maziar Ahmad; Radkhah, Katayon; Stryk, Oskar von; Seyfarth, André

doi:10.1109/iros.2014.6943254

Cited by 15 publications

(14 citation statements)

References 23 publications

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“…In this approach, stance leg control goal is developing joint torques to yield spring-like behavior of the virtual leg. In Section 4, we explain how this method is used in different applications: (1) Mimicking human-like leg elastic behavior with a robot (Sharbafi et al, 2014 ; Oehlke et al, 2016 ) e.g., implemented by VMC (Virual model control) (2) energy management through ankle torque and biarticular muscles (Sharbafi et al, 2014 , 2016 ). There are also Extended SLIP models, like ESLIP (Ludwig et al, 2012 ) or the variable leg spring (VLS) model (Riese et al, 2013 ), describing leg spring adjustments (stiffness, rest length) during the stance phase.…”

Section: Locomotor Sub-function Concept and Template Modelsmentioning

confidence: 99%

“…Regarding swing leg control, we follow two approaches: The first approach is an improvement of the Raibert leg adjustment approach (Raibert, 1986 ) using the CoM velocity to find the desired leg angle. This VBLA (velocity based leg adjustment) method (Sharbafi and Seyfarth, 2016 ) provides a stabilizing control strategy for different gaits (Sharbafi et al, 2013b , 2014 ; Sharbafi and Seyfarth, 2015 ) and also nicely describes human perturbation recovery for hopping in place (Sharbafi and Seyfarth, 2013 ). Although this can be employed to control the swing leg as one of the locomotor sub-functions, it is not at the focus of this paper because of lack of template model describing the control concept.…”

Section: Locomotor Sub-function Concept and Template Modelsmentioning

confidence: 99%

“…In this paper we explain how understanding bipedal locomotion using the concept of three locomotor sub-functions can be employed to design and control assistive wearable robots. In that respect, first, we survey our previous studies on combinations of the control concepts of three locomotor sub-functions to achieve stable gaits (Sharbafi et al, 2013b , 2014 , 2016 , 2017 ; Mohammadinejad et al, 2014 ; Oehlke et al, 2016 ; Sharbafi and Seyfarth, 2017 ; Zhao et al, 2017 ). Then, we show that considering such an architecture to control a wearable robot, an actuator can be designed with optimal performance for a range of motions required for different locomotor sub-functions.…”

Section: Introductionmentioning

confidence: 99%

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Locomotor Sub-functions for Control of Assistive Wearable Robots

2017

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A primary goal of comparative biomechanics is to understand the fundamental physics of locomotion within an evolutionary context. Such an understanding of legged locomotion results in a transition from copying nature to borrowing strategies for interacting with the physical world regarding design and control of bio-inspired legged robots or robotic assistive devices. Inspired from nature, legged locomotion can be composed of three locomotor sub-functions, which are intrinsically interrelated: Stance: redirecting the center of mass by exerting forces on the ground. Swing: cycling the legs between ground contacts. Balance: maintaining body posture. With these three sub-functions, one can understand, design and control legged locomotory systems with formulating them in simpler separated tasks. Coordination between locomotor sub-functions in a harmonized manner appears then as an additional problem when considering legged locomotion. However, biological locomotion shows that appropriate design and control of each sub-function simplifies coordination. It means that only limited exchange of sensory information between the different locomotor sub-function controllers is required enabling the envisioned modular architecture of the locomotion control system. In this paper, we present different studies on implementing different locomotor sub-function controllers on models, robots, and an exoskeleton in addition to demonstrating their abilities in explaining humans' control strategies.

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Section: Locomotor Sub-function Concept and Template Modelsmentioning

confidence: 99%

Section: Locomotor Sub-function Concept and Template Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Locomotor Sub-functions for Control of Assistive Wearable Robots

2017

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“…Inspired by simulation results [41], a simulation model of the BioBiped robot used biarticular thigh actuators to generate an appropriate leg swing motion for forward hopping [117,153]. For this, a pre-tension of the elastic element in the SEA (during late stance) resulted in a passive response of the spring realizing the leg swing motion [117].…”

Section: Biarticular Structures In Legged Robotsmentioning

confidence: 99%

“…Many of these advantages have been introduced several decades ago [12,83,84,92,[94][95][96]104,175]. Potential implementations may enable simplified swing leg control for foot placement (as predicted in [117,153]) or reactive balance control [110]. Still, some of the features of biarticular actuators are still unexploited in robotics and await their proof-of-concept in hardware systems.…”

Section: Applicationsmentioning

confidence: 99%

Biarticular muscles in light of template models, experiments and robotics: a review

Schumacher

Sharbafi

Seyfarth

et al. 2020

J. R. Soc. Interface.

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Leg morphology is an important outcome of evolution. A remarkable morphological leg feature is the existence of biarticular muscles that span adjacent joints. Diverse studies from different fields of research suggest a less coherent understanding of the muscles' functionality in cyclic, sagittal plane locomotion. We structured this review of biarticular muscle function by reflecting biomechanical template models, human experiments and robotic system designs. Within these approaches, we surveyed the contribution of biarticular muscles to the locomotor subfunctions (stance, balance and swing). While mono-and biarticular muscles do not show physiological differences, the reviewed studies provide evidence for complementary and locomotor subfunction-specific contributions of mono-and biarticular muscles. In stance, biarticular muscles coordinate joint movements, improve economy (e.g. by transferring energy) and secure the zig-zag configuration of the leg against joint overextension. These commonly known functions are extended by an explicit role of biarticular muscles in controlling the angular momentum for balance and swing. Human-like leg arrangement and intrinsic (compliant) properties of biarticular structures improve the controllability and energy efficiency of legged robots and assistive devices. Future interdisciplinary research on biarticular muscles should address their role for sensing and control as well as non-cyclic and/or non-sagittal motions, and non-static moment arms. royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 17: 20180413 royalsocietypublishing.org/journal/rsif J. R. Soc. Interface 17: 20180413

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