Skin wrinkles and folds enable asymmetric stretch in the elephant trunk

Schulz, Andrew; Boyle, Madeline; Boyle, Colin; Sordilla, Sophia; Rincon, Catalina; Hooper, Scott L.; Aubuchon, Catie; Reidenberg, Joy S.; Hu, David L.

doi:10.1073/pnas.2122563119

Cited by 35 publications

(45 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the proximal base, the cross-section is dominated by radial muscle, marked “radial,” the light-colored muscle close to the nasal cavities. A large amount of radial muscle is presumably to help with lifting as the base does not stretch much longitudinally ( Figure 4e ) [12]. The longitudinal muscle marked “L,” is darker red and lies between the radial muscle and the skin of the trunk.…”

Section: Resultsmentioning

confidence: 99%

“…Generally, such robots are covered in smooth skin. The addition of wrinkles[12] may improve grip without increasing the squeezing force and risk damaging fragile objects. The wrinkles may also improve the devices’ reach by enabling the skin to stretch.…”

Section: Discussionmentioning

confidence: 99%

“…To estimate the contact area of the trunk and the barbell, we measure the frequency ω and amplitude A of the trunk wrinkles at 80 positions, including eight axial positions along the frozen elephant trunk and 10 azimuthal positions for each axial position. Previous work showed that the trunk tip is nearly inextensible: the distal 30 cm of the trunk stretches less than 10% strain, which is small compared to the stretch mid-distally, which is 25 percent[12]. We thus assume that the wrinkle geometry of the frozen trunk matches the live elephant.…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…To estimate the contact area of the trunk and the barbell, we measure the frequency ω and amplitude A of the trunk wrinkles at eight positions along the frozen elephant trunk with 10 different azimuthal positional measurement around the ventral section taken at each position. Previous measurements of strain during extension shows that the tip of the trunk, defined as the last 30 cm, stretches less than 10% strain, which is small compared to stretch mid-distally, which is 25 percent(Schulz et al, 2022). We thus assume that the wrinkle geometry of the un-extended frozen trunk matches the live elephant.…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…Due to their quick movement through the dense canopy, there are few measurements of tail prehension [11]. Instead of a smooth friction pad as in capuchins, elephants have had a wrinkled ventral section in their trunk [12]. In this study, we consider how wrinkles may improve the surface area of the grip.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Elephant trunks use an adaptable prehensile grip

Schulz¹,

Reidenberg

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Although it is well-known that elephants use their trunk in a prehensile fashion, little is known about the mechanics of their grip. In this study, we show that an African elephant recruits greater length of its trunk with increasing weight lifted. We measure the wrinkle and trunk geometry from a frozen elephant trunk at the Smithsonian and challenge a female African elephant at Zoo Atlanta to lift various barbell weights using only its trunk. The elephant lifts a 60-kg weight at a speed of 1 m/s, employing 450 watts of power. Increasing weights cause the trunk's contact area with the weight to increases six-fold. Our findings may inspire the design of more adaptable soft robotic grippers.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Mathematical Modelingmentioning

confidence: 99%

Section: Mathematical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Elephant trunks use an adaptable prehensile grip

Schulz¹,

Reidenberg

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Bioinspired Continuum Robots with Programmable Stiffness by Harnessing Phase Change Materials

Zhang¹,

Wang²,

Chen³

et al. 2023

Adv Materials Technologies

View full text Add to dashboard Cite

are referred to as continuum robots. [1] Compared with traditional robots composed of rigid links and joints, continuum robots featured with both softness and compliance exhibit reduced complexity in interactions with the environment in application scenarios, such as minimally invasive surgery, [2] environment exploration, [3] and safe human-robot interaction. [4] As a promising candidate for constructing safe human-centered robots, continuum robots are shifting the mechanical design of intelligent machines from the sole use of rigid materials toward the use of compliant materials. [5] However, these robots are challenged by the inherent contradiction between softness and load-bearing capacity when dealing with stress application scenarios, since the carrying capacity of compliant materials is much worse than that of rigid materials. [6] Aiming at this inherent challenge in existing continuum robots, a hybrid robotic system that combines both soft and rigid materials may figure out the contradiction between the structural stiffness and shape adaption capability. [7] Tensegrity structures, created by Fuller, may provide a novel paradigm for the continuum robotic design. [8] The combination of rigid components and high softness endows this structure with desirable characteristics found in both classically rigid and Continuum robots offer significant advantages over traditional ones in some specific scenarios, such as urban search and rescue, minimally invasive surgery, and inspection of cluttered environments. However, motions and/or operations of existing continuum robots always suffer from those limitations in varying curvature interaction scenarios because of the homogeneity and singleness of the structural stiffness. Herein, inspired by the mechanism of an elephant trunk for regulating local stiffness, a three-segment continuum robot constructed by tensegrity structure, which relies on a stiffness tunable material, with its Young's modulus switchable between 1.79 and 271.62 MPa to achieve the robotic stiffness programmable characteristics, is proposed. For predicting the robotic configuration with varying stiffness distribution, a mechanical model based on the framework of the finite element method is derived. Theoretical predictions reveal that the curvature of each segment can be regulated by programming stiffness of the smart materials; therefore, the customizable design can offer an effective route for real-time robotic interactions. By evaluating motion characteristics, stiffness performance, and conformal interaction capability, the experimental results demonstrate that the robot can freely regulate the configuration on-demand, which may provide a foundation for the application of continuum robots with programmable stiffness for interacting with unstructured environments.

show abstract

Of tusks and trunks: A review of craniofacial evolutionary anatomy in elephants and extinct Proboscidea

Nabavizadeh

2024

The Anatomical Record

View full text Add to dashboard Cite

While being the largest living terrestrial mammals, elephants are best known for their highly modified and uniquely elaborate craniofacial anatomy—most notably with respect to their often‐massive tusks and intricately muscular, multifunctional proboscis (i.e., trunk). For over a century, studies of extinct proboscidean relatives of today's elephants have presented hypotheses regarding the evolutionary history of the crania and tusks of these animals and their bearing on the evolution of the proboscis. Herein, I explore major functional characteristics of the proboscidean head. I give a brief review of the anatomy of tusks and dentition, the feeding apparatus, and proboscis in extant elephants and explore their overall bearing in elephant feeding behavior as well as other aspects of their ecology. I also review the evolution of the proboscidean head, with a synthetic analysis of studies and further speculation exploring the interconnected evolutionary roles of tusk morphology and use, feeding anatomy and functional implications thereof, and proboscis anatomy and use in the ancestry of elephants. Notable emphasis is given to the evolutionary role of initial elongation of the mandibular symphysis in the development of the proboscis in many proboscideans. Subsequent secondary shortening of the symphysis and elevation of the temporal region and occiput allowed for a pendulous trunk and proal feeding in living elephants and other proboscidean groups with highly lophodont dentition.

show abstract

Skin wrinkles and folds enable asymmetric stretch in the elephant trunk

Cited by 35 publications

References 46 publications

Elephant trunks use an adaptable prehensile grip

Elephant trunks use an adaptable prehensile grip

Bioinspired Continuum Robots with Programmable Stiffness by Harnessing Phase Change Materials

Of tusks and trunks: A review of craniofacial evolutionary anatomy in elephants and extinct Proboscidea

Contact Info

Product

Resources

About