A Compact, Cost-Effective, and Highly Sensitive Optical Blocking Structure (OBS) Tactile Sensor for Enhanced Robotic Grasping

Haptic perception is essential for robotic grippers performing delicate handling tasks, yet designing a tactile sensor that is both low-cost and high-performance remains a challenge. This article addresses this issue by developing an optical blocking structure (OBS) sensor for tactile perception in robotic grippers. The OBS sensor is characterized by its ease of fabrication, cost-effectiveness (with a unit cost of $1.45), and high-performance metrics, including a maximum sensitivity of approximately 2.18 V/N, a wide pressure response range (>4 N), high resolution (0.009 N), a fast response time (15 ms), and a minimal dead zone (around 0.026 N). Experimental results demonstrate that a robotic gripper equipped with the OBS sensor can effectively detect object hardness, surface texture, and perform delicate force control tasks. Additionally, the OBS sensor exhibits high scalability. It can be configured into various array forms to enhance the gripper's sensing capabilities based on its structural characteristics. Validation experiments confirm that robotic grippers integrated with 2 × 2 and 1 × 6 array configurations of the OBS sensor can accurately detect multiple contact positions and forces. Consequently, the OBS sensor offers a straightforward and effective solution for enhancing tactile sensing in robotic grippers.