Adaptive Robot Combined with Hybrid Electrostatic and Gecko-inspired Gripping Pads to Manipulate Bulky, Non-smooth Items in the Most Effort-saving Way

Scholars from Stanford Biomimetics and Dexterous Manipulation Lab (BDML) recently published their research and development on a hybrid electrostatic and gecko-inspired gripping pad for manipulating bulky, non-smooth items. The gripping pad largely increases the real contact area and adhesion upon objects, especially those with non-smooth surfaces, and helps the robot to carry heavy items by low internal forces, broadening the applications in retail and household environments.

Capacities of the hybrid gripping pads have been fully tested by manipulation experiments using Flexiv’s adaptive robot, Rizon 4.

The content below is summarized and authorized from Hybrid electrostatic and gecko-inspired gripping pads for manipulating bulky, non-smooth items, which was published on Smart Materials and Structures by the Stanford research team.

The research of flexible and versatile gripping tools is always active in the robotics-related study field, some outcomes of which such as the suction gripper, the electrostatic gripper, and the gecko-inspired adhesive gripper have been widely applied, however, they are not suitable for small robots to handle bulky items under household and retail environments, like grocery bags and cardboard cartons. Since not all these items are equipped with handles, and some of them are heavy, easily deformed or crushed, humans usually try to wrap their fingers around the bottom corners to grasp or hold them, which needs fine squeezing force control. Besides, items like cardboards own rough surfaces, requiring high on the adhesion of gripping tools.

To break the limits of existing plans, researchers from BDML combine the technology of electrostatic grippers and gecko-inspired dry adhesives to make a hybrid type of gripping pad. The pad mainly consists of three parts: biomaterial adhesives composed of PDMS layer and CCTO-doped silicone rubber, electroadhesive pad composed of electrodes and BOPP film, and a compliant foam that helps conform to macroscopic surface undulations.

The test indicates the hybrid gripping pad enables larger contact area on objects and 7x higher adhesion than features cast in single-material process, which also works well on rough surfaces; moreover, it produces higher adhesive shear stress values than grippers with previous adhesives, assisting robots to lift a variety of bulky items with low internal forces in comparison to their weight.

With the capacity of fine force control and dual-arm cooperation, the adaptive robot Rizon is used for hybrid adhesive gripper tests under different circumstances. During the human-robot collaborative grasping, the applied internal force of the robot can be reduced by a factor of two with voltage, from 2.25N at 0V to 1N(the resolution of the measured forces is 0.05N); during the robot-robot collaborative grasping, Rizon 4 picks up various objects(such as cardboard boxes, plastic bins, soccer balls, stainless steel water bottles, etc.) with low internal forces, meanwhile, it is proved to be versatile enough to lift or carry diverse heavy, bulky, and non-smooth items.

Future work will be focusing on the durability of hybrid adhesives under practical applications, says the research team. As a general-purpose robotics company that develops and applies the best human-inspired robotics and AI technologies, Flexiv insists on the importance of advanced technology and would like to devote to its R&D and commercialization to finally realize the vision of making people’s work and life more creative and enjoyable with human-centered technology.

Reference

Han, A.K., Hajj-Ahmad, A., and Cutkosky, M.R., “Hybrid electrostatic and gecko-inspired gripping pads for manipulating bulky, non-smooth items,” Smart Materials and Structures (2020)