Bioinspired Soft Robotic Gripper

A gripper for general purposes with grasping and holding capabilities enabled by a simple control scheme. The gripper is a combination of soft materials, underactuated mechanisms, and a bioinspired design. The actuation mechanism is based on the control of a single cable tension, which enables a grasping adaptable to objects of different shape.

The BioRobotics Institute

Specifications

Overall dimensions40 · 55 · 135 mm3
Weight 110 g (excluding the DC motor)
Tip to tip distance40 mm (@rest position)
Tip to tip distance200 mm (@ max opening)
Maximum grasping force3 N
Vertical resistive force25 N
Horizontal resistive force8.05 N

Overview

The actuation mechanism is based on the control of a single cable tension, which enables a grasping adaptable to objects of different shape.

The soft robotic gripper is made of three identical soft fingers that are connected to a rigid frame and are controlled by a DC motor through a cable based mechanism. The gripper doesn't hasve a rigid skeleton. The finger design is based on the biological
dimensions of a human finger. Each element is made of three phalanges, each of which is separated by triangular cuts with an angle of 45 degrees. The  length of each finger is 135mm.

The gripper has an actuation mechanism based on a single cable and a rotary DC motor with a magnetic incremental encoder and coupled with a planetary gearhead. The cable path is inside the phalanges’ body using dedicated holes without interfering with the grasped object. To reduce the friction between the cable and the fingers, silicone tubes have been inserted into the channels.
Both ends of the cable are anchored on a spool, which is fixed to the motor shaft and located at the base of the gripper. When the motor is actuated, the cable ends are wound on the spool, and as a consequence, the reduced length of the cable produces bending in the finger.

References

Describes the project via an introduction, and has a soft gripper description and fabrication section. Goes into the manufacturing process, and experimental tests.

Mariangela Manti, Taimoor Hassan, Giovanni Passetti, Nicolo` D’Elia, Cecilia Laschi, and Matteo Cianchetti. Finally discusses he results and has a discussion section.

Wevolver 2023