Session: 03-13-01: Multifunctional Electronics and Energy Devices

Paper Number: 95199

95199 - Dry Adhesion Based Pneumatic Grippers Programmed by Low Pressure 

Controlling adhesion at interfaces on demand is essential for many industrial processes. Although many studies have utilized external stimuli such as magnetic field, electric current, temperature or air pressure to switch the adhesion at interfaces between high and low adhesive states, these approaches often require bulky supporting equipment that provides the stimuli and thus render the adhesive surfaces difficult to integrate in robotic systems. Specifically, for pneumatically-controlled adhesive surfaces, an internal pressure higher than 50 kPa is usually required to realize a 10-fold change of adhesion. Therefore, there is a strong need for new pneumatic grippers that can be activated with low pressure and thus be more easily integrated with existing robotic systems.

In this talk, we report a dry adhesion-based soft gripper that can achieve more than 10-fold change of adhesion forces using positive and negative internal pneumatic pressures as low as ~10 kPa. Due to the perpendicular position between the air passage and the working surface, the soft gripper can be easily connected to a syringe or a hand-pinching inflator, allowing for pressure modulation simply by hand. We further demonstrate that pressure can be controlled through the linear motion of an actuator, evidencing convenient integrability of the gripper into existing robotic systems. The working mechanism of the soft gripper with pressure-tunable adhesion is elastic deformation of the contacting membrane and the side wall under positive or negative pressure, which alters the stress distribution at the interfaces and facilitates crack initiation and propagation at the contact interface. Through adhesion in a mechanical testing system, we quantify the effective adhesion strength of the gripper in contact with a glass substrate as a function of internal pressure. Image analysis of the contacting interface suggests that a positive pressure facilitates crack initiation on the edge, while negative pressure facilitates crack initiation in the center of the contacting interface.

We perform finite element modeling to investigate the adhesion of the soft grippers as a function of pressure, both positive and negative. Cohesive elements are used to simulate the adhesive interactions on the contact interface. Interfacial crack initiation mechanisms that are consistent with the experimental observations are observed in the simulations, confirming the underlying mechanism for adhesion changes with pressure modulation. These results show that pneumatics powered dry adhesives can be potentially portable and energy efficient. We expect that our results will help facilitate design and adoption of soft grippers in transfer printing and assembly of advanced electronics and precision devices, as well as in design of other soft robotic mechanisms such as those for locomotion.

Presenting Author: Guangchao Wan Syracuse University

Presenting Author Biography: Guangchao Wan obtained his PhD at Dartmouth College, under the supervision of Prof. Zi Chen. He is now a postdoc at Syracuse Univeristy, under the supervision of Prof. Wanliang Shan and Prof. Teng Zhang.

Authors:

Guangchao Wan Syracuse University
Yanbing Tang Syracuse University
Kevin Turner University of Pennsylvania
Wanliang Shan Syracuse University