Design and Implementation of a Magnetic Coupling Based Segmented Bend Angle Sensor for a Soft Robotic Gripper

The design and implementation of a sensor for accurate measurement of the bend angle of a soft robotic gripper are described in this article. The proposed sensor employs two planar coils on flexible printed circuit boards (PCBs). Three such pairs are introduced in separate regions of a finger of the soft gripper. The angle by which a finger bends is measured in terms of the change of mutual inductance between the coils due to bending. A prototype soft gripper, with the sensors embedded, has been fabricated in-house. Experiments with the gripper performing pinch and enveloping grasps of different types of objects are described. The results from the prototype showed that the proposed segmented angle sensor can provide information about the shape of the object that is grasped.