Proximity-Tactile Dual-Modal Sensing Using Flexible Opto-Electric Dome Array for Precise Grasping

In precision grasping tasks, proximity and tactile sensors play a crucial role in improving grasping quality and protecting target objects. However, existing research indicates that these sensors are often influenced by factors such as the color, material, and conductivity of the target objects, leading to decreased sensor accuracy. This reduction in accuracy negatively impacts grasping quality and hinders the automation of critical stages in precision grasping. In this study, a novel optoelectronic proximity and tactile bimodal sensing system based on a flexible opto-electric dome array is proposed. The system features a large proximity range with fixed proximity and contact markers that are unaffected by the target objects, enabling full automation of essential stages in precision grasping and eliminating unstable factors associated with target objects. In addition, the system facilitates automated self-calibration of the transfer function, leading to improved precision grasping efficiency in specific environments. The development of the physical model for this sensor is detailed, the stability of the proximity and contact markers is validated, and the role of these markers in enabling automated self-calibration and improving accuracy is described. Finally, by leveraging the advantages of the sensing system, a fully automated precision grasping control method is designed. Experimental results with various target objects demonstrate that vibrations and slippage during the grasping process are reduced, and soft objects are grasped nondestructively. Furthermore, online experiments are conducted to assess sensor wear and ambient light interference, with results demonstrating that this sensing scheme has a wide range of application scenarios and provides a solution for automatic precision grasping.