Fictional robots are often presented as tough brutes that are capable of ripping apart or squeezing their enemies into submission. Yet in real life, beyond some military and heavy-duty industrial applications, “gentle touch” robots that can precisely manipulate fragile objects are potentially far more useful that their clunky counterparts.
Gentle touch robots promise to improve task performance, save time, and slash costs in applications ranging from food preparation to surgery. Yet before these goals can be achieved, a new generation of robotic manipulation technologies will have to be developed and perfected.
Several new research projects indicate that steady progress is already being made and that a new generation of gentler robots may not be too far away.
- Harvard University researchers are working on robots that are more sensitive and have greater dexterity than their predecessors.
- Soft robotics is the key to careful manipulation and gripping, but there’s room for improvement.
- Gentle touch robots could be useful in healthcare, undersea exploration, the food industry, and more.
Squishy at sea
Grasping delicate organisms from the sea floor requires a more gentle touch than even the most careful human diver can provide. After watching clumsy robotic manipulators attempt to collect fragile specimens of coral and sponges from the ocean floor, Robert Wood realized that a soft robotics approach would be perfect for the task.
Wood, a professor at the Harvard School of Engineering and Applied Science, and Kevin Galloway, a mechanical engineer at Harvard’s Wyss Institute, developed two manipulators to replace the powerful metal grippers used by many underwater remotely operated vehicles (ROVs).
Each of the new manipulators is capable of carefully recovering objects of different sizes and shapes. One type, inspired by the coiling action of a boa constrictor, is designed to reach into tight spaces and grasp small and irregularly shaped objects.
The other manipulator is a bellows-style unit that uses opposing pairs of bending actuators. The modular actuator technology is inexpensive and scalable, so it could be used for a wide range of commercial, biomedical, and industrial applications, according to Wood.
The biggest design challenge the researchers faced was a lack of precise target specifications. The team used an assortment of vegetables from a grocery store to approximate the size and shape of the specimens that would be collected by the manipulators. At the University of Rhode Island, the vegetables were lowered on a metal grate into a test tank.
Shortly thereafter, the gentle touch manipulators were operated in at ocean depths of more than 2,600 feet (see photo above).
Wood is now looking to enhance the technology. He would like to add tactile feedback to the manipulators, allowing operators to actually “feel” whatever the gripper is touching. This also has implications for prosthetics.
“This [could be] integrated with the human body in a way that you can actually sense the nerve stimuli and then can feed that into a micro-controller which there will be translated to a corresponding signal to activate the muscle,” he said. “You need to couple nerves with proper electrodes and combine that with the actuation of the muscles so you can create some integrated, biologically inspired actuation system for prostheses.”
Wood said he is also interested in experimenting with bilateral manipulation, rather than single-arm manipulation, to provide improved dexterity.
More on Robotic Manipulation:
- On Robot, OptoForce Get Investments for Cobot Grippers, Sensors
- Top 10 Robotics Startups at CES 2016
- Soft Robotics Raises $5 Million for Flexible Fingers
- Soft Robots Get a Grip on Fruit Picking
- SynTouch Gets $2.5 Million in Grants for New Machine Touch Applications
Totally tactile sensors for gentle touch
Wood may not have to wait long to realize his vision of gentle touch manipulators. Researchers at Harvard’s School of Engineering and Applied Sciences and the university’s Biorobotics Laboratory have created an inexpensive tactile sensor for robotic hands that could turn even the mightiest automation robot into a dexterous manipulator.
The new sensor uses TakkTile sensors from RightHand Robotics Inc. It takes an existing device — a tiny barometer — and encases it in a layer of vacuum-sealed rubber, which protects it from as much as 25 pounds of direct water pressure.
Leif Jentoft, a Harvard engineering graduate student, and Yaroslav Tenzer, a postdoctoral fellow, claim that the sensor can even survive a direct strike from a hammer. Yet the TakkTile is still sensitive enough to detect a very slight touch, they said.
The result, when added to a mechanical hand, is a robot that knows what it’s touching. According to the researchers, a TakkTile-equipped robot can gently pick up a balloon without popping it or snatch a key and use it to unlock a door without causing any damage to the key or door.
The researchers note that TakkTiles can be built using relatively simple equipment, including a vacuum chamber and standard printed circuit board fabricators. The tiny barometers are available and affordable because they are commonly used in mobile phones and GPS units to sense altitude, Jentoft and Tenzer said.
In my next article, we’ll look at how shaped-memory alloy and a new model can make robots more dexterous.