Study of Toe Joints to Enhance Locomotion of Humanoid Robots

Agarwal, Shlok; Popović, Marko B.

doi:10.1109/humanoids.2018.8625052

Cited by 7 publications

(2 citation statements)

References 27 publications

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“…The results indicated that at the beginning of the motion, specifically at 0.2 s, the foot with an active toe exhibited the strongest propulsion among the four types of feet, followed by the fixed toe, passive toe, and unrestricted toe, respectively. The strong propulsion might indicate the capability of enhancing the motion of the toe joint with the PIM ( Hughes et al, 1990 ; Agarwal and Popovic, 2018 ), transmitting the force from the upper leg to the phalanges, increasing its push-off force.…”

Section: Resultsmentioning

confidence: 99%

The experimental investigation of foot slip-turning motion of the musculoskeletal robot on toe joints

Nipatphonsakun,

Kawasetsu,

Hosoda

2023

Front. Robot. AI

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Owing to their complex structural design and control system, musculoskeletal robots struggle to execute complicated tasks such as turning with their limited range of motion. This study investigates the utilization of passive toe joints in the foot slip-turning motion of a musculoskeletal robot to turn on its toes with minimum movements to reach the desired angle while increasing the turning angle and its range of mobility. The different conditions of plantar intrinsic muscles (PIM) were also studied in the experiment to investigate the effect of actively controlling the stiffness of toe joints. The results show that the usage of toe joints reduced frictional torque and improved rotational angle. Meanwhile, the results of the toe-lifting angle show that the usage of PIM could contribute to preventing over-dorsiflexion of toes and possibly improving postural stability. Lastly, the results of ground reaction force show that the foot with different stiffness can affect the curve pattern. These findings contribute to the implementations of biological features and utilize them in bipedal robots to simplify their motions, and improve adaptability, regardless of their complex structure.

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Section: Resultsmentioning

confidence: 99%

The experimental investigation of foot slip-turning motion of the musculoskeletal robot on toe joints

Nipatphonsakun,

Kawasetsu,

Hosoda

2023

Front. Robot. AI

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“…The heel-to-toe rocking motion has proven to be associated with a reduced metabolic/energetic cost in human (Burnfield, 2010), robotic (Farizeh and Sadigh, 2014;Griffin et al, 2018), and prosthetic gaits (Kim and Collins, 2015). While numerous studies have focused on the effects of the toe link in human (Hughes et al, 1990;Kerrigan et al, 2000) and humanoid walking (Nishiwaki et al, 2002;Huang et al, 2012;Agarwal and Popovic, 2018;Sadedel et al, 2018;Hashimoto, 2020), most of the existing balance approaches are formulated under the flat-foot model assumption, in which the foot is modeled as a single rigid link in fixed contact with the ground. Few studies have addressed the important role of a refined foot-ground contact model in human postural control (Ivanenko et al, 1997;Nolan and Kerrigan, 2004).…”

Section: Introductionmentioning

confidence: 99%

State-Space Characterization of Balance Capabilities in Biped Systems with Segmented Feet

2021

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The human ability of keeping balance during various locomotion tasks is attributed to our capability of withstanding complex interactions with the environment and coordinating whole-body movements. Despite this, several stability analysis methods are limited by the use of overly simplified biped and foot structures and corresponding contact models. As a result, existing stability criteria tend to be overly restrictive and do not represent the full balance capabilities of complex biped systems. The proposed methodology allows for the characterization of the balance capabilities of general biped models (ranging from reduced-order to whole-body) with segmented feet. Limits of dynamic balance are evaluated by the Boundary of Balance (BoB) and the associated novel balance indicators, both formulated in the Center of Mass (COM) state space. Intermittent heel, flat, and toe contacts are enabled by a contact model that maps discrete contact modes into corresponding center of pressure constraints. For demonstration purposes, the BoB and balance indicators are evaluated for a whole-body biped model with segmented feet representative of the human-like standing posture in the sagittal plane. The BoB is numerically constructed as the set of maximum allowable COM perturbations that the biped can sustain along a prescribed direction. For each point of the BoB, a constrained trajectory optimization algorithm generates the biped’s whole-body trajectory as it recovers from extreme COM velocity perturbations in the anterior–posterior direction. Balance capabilities for the cases of flat and segmented feet are compared, demonstrating the functional role the foot model plays in the limits of postural balance. The state-space evaluation of the BoB and balance indicators allows for a direct comparison between the proposed balance benchmark and existing stability criteria based on reduced-order models [e.g., Linear Inverted Pendulum (LIP)] and their associated stability metrics [e.g., Margin of Stability (MOS)]. The proposed characterization of balance capabilities provides an important benchmarking framework for the stability of general biped/foot systems.

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Limits of Dynamic Postural Stability with a Segmented Foot Model

Mummolo

Vicentini

2020

Lecture Notes in Computational Vision and Biomechanics

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Study of Toe Joints to Enhance Locomotion of Humanoid Robots

Cited by 7 publications

References 27 publications

The experimental investigation of foot slip-turning motion of the musculoskeletal robot on toe joints

The experimental investigation of foot slip-turning motion of the musculoskeletal robot on toe joints

State-Space Characterization of Balance Capabilities in Biped Systems with Segmented Feet

Limits of Dynamic Postural Stability with a Segmented Foot Model

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