(Nanowerk News) While gripping objects is a relatively easy task for us humans, there is a lot of mechanics involved in this simple task. Grabbing an object requires fine control of the fingers, their position, and the pressure each finger exerts, which in turn requires complex sensing abilities. It is not surprising that robotic grip and manipulation are very active areas of research in robotics.
Today, industrial robot hands have replaced humans in a variety of complex and dangerous activities, including in restaurants, farms, factories and factories. In general, soft robotic grippers are better suited for tasks where the object being picked up is fragile, such as fruit and vegetables. However, while soft robots hold promise as harvesting tools, they usually share a common drawback: their price. Most soft robotic gripper designs require complex assembly of several parts. This drives up development and maintenance costs.
Fortunately, a research team from the Japan Advanced Institute of Technology (JAIST), led by Associate Professor Van Anh Ho, has come up with an innovative solution to this problem. Taking a leaf from nature, they have developed an innovative soft robotic gripper called ‘ROSE,’ which stands for ‘Rotation-Based Squeezing Gripper.’ Details about the ROSE design, as well as their latest study results, were presented at the event Robotics: Science and Systems 2023 (RSS2023) conference (“ROSE: Rotation-based Squeezing Robotic Gripper towards Universal Handling of Objects”).
What makes ROSE so impressive is its design. The soft handle part is in the form of a funnel or cylindrical sleeve and is connected to a hard round base, which in turn is attached to the actuator shaft. The funnel should be placed over the object to be picked up, covering most of its surface. Then, the actuator rotates the base, which causes the flexible funnel skin to tightly wrap around the object, as shown in the video below. This mechanism is loosely inspired by the changing shape of the rose, which blooms during the day and closes at night.
ROSE offers substantial advantages over more conventional grippers. First, it is much cheaper to manufacture. All the hard parts can be 3D printed, while the funnel itself can be easily produced using molds and liquid silicone rubber. This ensures that the design is easily scalable and suitable for mass production.
Second, ROSE can easily pick up various objects without complicated control and sensing mechanisms. Unlike grippers which rely on finger-like structures, ROSE arms apply gentler, more uniform pressure. This makes ROSE more suitable for handling fragile products, such as strawberries and pears, as well as smooth objects. Weighing less than 200 grams, the gripper can achieve an impressive payload-to-weight ratio of 6812%.
Third, ROSE is very durable and sturdy. The team demonstrated that they could continue to retrieve objects successfully even after 400,000 trials. In addition, the funnel will still function properly if there are significant cracks or cuts. “The proposed gripper excels in demanding scenarios, as evidenced by its ability to withstand tough tests in which we cut the funnel into four separate, full-height sections,” says Assoc. Prof. Ho, “These tests underscore the gripper’s outstanding durability and optimal performance in challenging conditions.”
Finally, ROSE can be endowed with sensing capabilities. The researchers achieved this by placing multiple cameras on a circular base, pointing toward the inside of the funnel, which is covered in markers, whose position the camera can capture and analyze through image processing algorithms. This promising approach allows estimation of the size and shape of the object being held.
The research team noted that ROSE could be an attractive option for a variety of applications, including harvesting and sorting operations in factories. It can also find a home in messy environments such as farms, professional kitchens, and warehouses. “The ROSE gripper has significant potential to revolutionize gripping applications and gain wide acceptance in various fields,” concludes Assoc. Prof. Ho, “Its straightforward yet robust and dependable design is set to inspire researchers and manufacturers to embrace it for a variety of thrilling tasks in the near future.”