Universities Robotics: Hands and Multi-fingered Grasps

Without the capability to hold, touch, lift, gesticulate, clean or use the hands and fingers, humans would only function partially in any living environment. So too, would robots if they cannot master such simple human activities. One of the technical challenges researchers face today is developing near-human-like robotic hands or multi-fingered – parallel mechanisms and articulated movements – grasps, which must not only be robust, but also contain a large dexterity to carry out difficult tasks in radioactive environments, extreme temperatures and polluted air as well as enable safe human interactions.

To undertake such tasks, robots require accurate and sophisticated sense of touch. Some of the universities advancing such functionalities include Virginia Tech, Laval University in Canada, the University of the West of England and the research collaboration between Cornell University, the University of Chicago and iRobot.

RAPHaEL – Robotic Air Powered Hand with Elastic Ligaments is a fully articulated robotic hand powered by a compressor tank, an accordion-like tube actuator with a microcontroller operating and coordinating its fingers. According to Dennis Hong, director of the Robotics and Mechanisms Laboratory (RoMeLa) and faculty adviser at Virginia Tech, the “air-powered design is what makes the hand unique, as it does not require the use of any motors or other actuators, the grasping force and compliance can be easily adjusted by simply changing the air pressure.” Through the adjusting of air pressures, the hand can be commanded to make a lighter or a sturdier grip. “There would be great market potential for this hand, such as for robotic prosthetics, due to the previously described benefits, as well as low cost, safety and simplicity,” Hong added. Visit the online exhibition stand of RoMeLa on EXPO21XX to see more projects at Virginia Tech.

Source: Laboratoire de robotique, Laval University

The need for a robotic hand actuated with less than two motors led to the development of SARAH – Self Adaptive Robotic Auxiliary Hand, in collaboration with the Canadian Space Agency and the Laboratoire de robotique at Laval University. SARAH might not carry out your trash, but it will undertake heavy duty tasks like cleaning up nuclear sites, retrieving radio-active waste from old storing sites in order to package and store it in safer conditions. SARAH was originally designed for use in space. In order to satisfy the requirements of the waste retrieval tasks, several components were redesigned. Among others, the new gripper which is slightly smaller and actuated by two motors and weighs less than half of its 12-DOF predecessor (MARS Hand). However, the level of mobility remains the same.

Source: University of the West of England

The Bristol Robotics Lab is one of 5 institutes researching on CHRIS (Cooperative Human Robots Interaction Systems), a robotic system that has the potential of behaving autonomously in an intelligent way. The project aims to discover ways, based on adaptive control algorithm, for humans and service robots to perform co-operatives tasks in co-located spaces, for example, in the kitchen where one stirs the soup and the other adds the cream. For such cooperative tasks to succeed, the robot must be programmed to understand the shared goals for example, communicate cognitively to accomplish different task while cause minimal harm to humans.

A completely different approach is the “universal gripper” from a team of researchers from Cornell University, the University of Chicago and iRobot. They have created a universal gripper that uses the jamming of particulate material inside an elastic bag to hold on to objects.  The gripper uses the same phenomenon that makes a vacuum packed bag of ground coffee so firm; in fact, ground coffee worked very well in the device. But the researchers found a new use for this everyday phenomenon: They placed the elastic bag against a surface and then removed the air from the bag, solidifying the ground coffee inside and forming a tight grip. When air is returned to the bag, the grip relaxes.

These are exciting technological developments and there is every chance that the next generation of grasps with improved functional abilities will soon be announced.