3D-printed optoelectronic tactile sensor for soft robotic applications

Abstract

As we approach the Fourth Industrial Revolution, more companies are shifting from utilizing human resources to utilizing robots in performing tasks with faster, higher performances and low rates of error. This is especially true for highly repetitive tasks that require great concentration such as mass production. In recent years, soft robotic grippers have been a topic of interest for research due to their exceptional potential compared to conventional hard robots. Soft robotic grippers are made from soft materials which allow them to conform to the object of interest, gripping and manipulating them without causing any damage.

This report proposes a soft gripper structure with extrinsic tactile sensing properties based on optical waveguide transmission methods. The 3D printed gripper consists of an opaque shutter supported by elastic bridges, which obstructs the light traveling in the waveguide with applied external force. The effect of thickness and rigidity of the waveguide bridge on the linearity, sensitivity, range, maximum force, recovery time, and repeatability are investigated in this work. Finally, a two-jaw gripper was used to test its practical usage as a gripper to grasp various objects, observing the changes in light intensity with the force applied. The test confirms that the designed structure can provide accurate feedback of the force to grip an apple and a grape, working as an effective optical tactile sensor.