Team 5 - Gripper

Awab A., Borna M., Param O., Aman D.

EGR 557

Dr. Daniel Aukes

Biomechanics Background and Initial Speciﬁcations

Biomechanics:

1. G. M. Erickson, A. K. Lappin, T. Parker, and K. A. Vliet, “Comparison of bite‐force

performance between long‐term captive and Wild American alligators (alligator

mississippiensis),” Journal of Zoology, vol. 262, no. 1, pp. 21–28, Feb. 2006. *

This journal article discusses the bite forces of alligator jaws depending on the various

biological modiﬁcations, for example, jaw length, head shape, and body form, that occur

with different environments and conditions. It also discusses the different parameters

that can reveal conﬂicting results, such as the performance differences between wild

and captive alligators. From this journal, we are able to determine the ideal geometry for

a gripper to ensure the highest possible “bite force”.

2. A. Saber and A. Hassanin, “Some morphological studies on the jaw joint of the Australian

saltwater crocodile (Crocodylus porosus),” Journal of Veterinary Anatomy, vol. 7, no. 2,

pp. 55–74, 2014. *

This journal studies the biting forces exerted by the jaw of a saltwater crocodile. It

provides information about how the construction and anatomical structure of the jaw

joint lead to the forces it can exert. It looks at a variety of different skulls to properly

analyze the different parts, such as ligaments and muscles, that play a role in the force

exerted by the jaw.

3. A. Herrel, J. C. O’Reilly, and A. M. Richmond, “Evolution of bite performance in turtles,”

Journal of Evolutionary Biology, vol. 15, no. 6, pp. 1083–1094, Nov. 2002, doi:

10.1046/J.1420-9101.2002.00459.X.*

This paper empirically tests how the differences in body dimensions of several turtle

species are related to their bite performance. It determines how the bite force tends to

change in proportion to the jaw size as well. It relates the scaling laws and concludes

that changes in body size are associated with the design of the jaw apparatus. It also

explores the relationship between force and speed of closing of the jaw and the tradeoffs

associated with scaling the size of the jaw apparatus.

4. S. Burgess, “A review of linkage mechanisms in animal joints and related bioinspired

designs,” Bioinspiration & Biomimetics, vol. 16, no. 4, p. 041001, Jun. 2021, doi:

10.1088/1748-3190/ABF744.

5. M. Sakamoto, “Jaw biomechanics and the evolution of biting performance in theropod

dinosaurs,” Proceedings of the Royal Society B: Biological Sciences, vol. 277, no. 1698, pp.

3327–3333, Jun. 2010.

Bio-inspired:

1. Liu, C., Maiolino, P., Yang, Y., and You, Z. (2020). “Hybrid Soft-Rigid Deployable Structure

Inspired by Thick-Panel Origami”. Proceedings of the ASME 2020 International Design

Engineering Technical Conferences and Computers and Information in Engineering

Conference: 44th Mechanisms and Robotics Conference (MR). Virtual, Online, August

17–19, 2020, 10. doi:10.1115/detc2020-22246 *

This paper proposes a novel structure, inspired by thick-panel origami, with hybrid rigid

bodies and ﬂexible hinges. Able to be expanded, ﬂipped, and rotated, the waterbomb

origami pattern has been chosen to produce a large number of conﬁgurations. The

mechanism and motion analysis of a single unit and its basic assembly are conducted

theoretically and also simulated. An additive fabrication method based on 3D printing

makes it a one-step process to achieve a balance between rigidity and ﬂexibility in the

structure. Different conﬁgurations are demonstrated in three assemblies that exhibit

good transformability, reconﬁgurability, and scalability. With the expansion/packaging

ratio ranging from 0.11 to 7.2 in a modular unit, a mechanical metamaterial of negative

Poisson’s ratio can be obtained at any spatial size.

2. Joshua C. Triyonoputro, Weiwei Wan, Kantapon Akanesuvan, Kensuke Harada, "A

Double-jaw Hand that Mimics A Mouth of the Moray Eel", Robotics and Biomimetics

(ROBIO) 2018 IEEE International Conference on, pp. 1527-1532, 2018. *

In this paper, a moray eel’s jaw was used as a bio-inspiration and a gripper was designed

with two separate linked jaws like a moray eel which were pharyngeal jaw and oral jaw,

the pharyngeal jaw can move front or back and is able to grip different machines and

assemble and disassemble it parts, this improves the mobility and the grip strength can

be varied as needed.

3. K. C. Galloway et al., "Soft Robotic Grippers for Biological Sampling on Deep Reefs", Soft

Robot, vol. 3, no. 1, pp. 23-33, Mar 2016. *

In this paper, development of a 3-D printed soft robotic tri-gripper embedded with tactile

sensor array is presented. A facile fabrication strategy by 3D-printing thermoplastic

polyurethane (TPU) was employed to fabricate the soft tri-gripper consisting of 9

capacitive tactile sensor-laden phalanges. The 3D-printed TPU itself was used as a

sensory dielectric for the fabricated tri-gripper. The sensor and interconnect electrodes

have been designed to have minimum cross-sensor capacitive coupling with stretchable

interconnects to ensure robust integration. The designed sensors were patterned as

copper electrodes on top of ﬂexible polyimide ﬁlm and embedded within the gripper

during the 3D-printing process. The sensors were characterized and it exhibited a

maximum sensitivity of 2.87 %/kPa. The gripper was tested for up to 100 cycles of

compression and expansion. The developed sensory gripper ﬁnds application in

industrial and agricultural robotics

4. J. Gafford et al., "Shape deposition manufacturing of a soft atraumatic

deployable surgical grasper", Journal of Medical Devices, vol. 8, no. 3, 2014.

5. Zhang, W., He, Z., Sun, Y. et al. A Mathematical Modeling Method Elucidating the

Integrated Gripping Performance of Ant Mandibles and Bio-inspired Grippers. J Bionic

Eng 17, 732–746 (2020). https://doi.org/10.1007/s42235-020-0065-9 *

Saltwater

Crocodile

Panthera tigris

Alligator

Mississippiensis

Parrot ﬁsh

Weight

400 Ibs

200 - 600 Ibs

500 Ibs

45 lbs

Bite Force

3,700 PSI

1000 PSI

2900 PSI

530 PSI

Snout Length

62 inches

13 inches

78 inches

4 inches

Figure 1: Alligator Mississippiensis Bite Force vs Snout Length

Figure 2: Parrot ﬁsh jaw demonstrated in 4 bar linkage

Engineering Drawing

Figure 3: Rigid body diagram showing linkages inspired by the parrot ﬁsh. The yellow links are

rigid and the blue shaded area demonstrates the end effector.

Figure 5: Location of springs, actuators, and connection to the rigid links

Discussion

Discuss your rationale for the size animal you selected in terms of your ability to replicate key

features remotely with limited material selection.

We decided to choose a parrot ﬁsh due to it’s high bite force and small size. In the scope

of this project, it is more realistic to replicate a smaller animal than a large animal, such

as an alligator, due to the limited material selection and time. With affordable yet reliable

actuators, replicating a parrot ﬁsh is possible for this project

Find a motor and battery that can supply the mechanical power needs obtained above. Consider

that motor eﬃciencies may be as high as 95%, but if you can’t ﬁnd it listed, assume you ﬁnd a

more affordable motor at 50-70% eﬃciency. Compare the mechanical watts/kg for the

necessary motor and battery vs the animal’s mechanical power/mass above? Which one is

more energy dense?

Motor: BETU 2Pack 25KG High Torque RC Servo

Battery: ABENIC DC 12V 2A (24W) 4000mAh Super Rechargeable Portable Li-ion Lithium

Battery DC12400 Blue

Mechanical watts/kg: 12/0.2 = 60 Watts/kg

Parrot ﬁsh power/mass: 610626.050146222/20= 30531.3025073 kg/cm^2*kg

The parrot ﬁsh is more energy dense.