A flexible swallowing gripper for harvesting apples and its grasping force sensing model

•A flexible swallowing gripper was developed to harvest apples.•Building the grasping force sensing model related to bending angle based on the CBCM.•The grasping force can be perceived in real-time without the force sensor.•Force sensing was most accurate (error of 5.65%) at the middle of the finger.•The maximum contact force, 5.72 N, was generated at the bottom of the finger.