Effect of Object Size and Location on Contact Forces and Grasping Stability for an Underactuated Robotic Manipulator

This paper comprises a study of the grasping stability for an underactuated robotic manipulator under the condition of varying the position of different sizes cylindrical grasped objects. Grasping forces were calculated both theoretically and Via a CAD model for a 3-DOF underactuated robotic manipulator. The experimental part comprises the fabrication of the manipulator and performing the required tests on this manipulator by changing the position and size of the grasped object. Contact forces were observed experimentally by using the Force Sensing Resistors (FSR). Maps of stability and ejection for three different cylindrical object diameters (160, 200, 240) mm were presented. As a result, it was found that stable grasping is greatly affected by the size and location of the grasped object, where stable grasping is achieved for objects located near the actuator position.