On process modeling method of manipulator object grasping based on optimization problem and pressure force control

Abstract

The work addresses the problem of simulating grasping an object of a specific shape by a robotic manipulator. The robot under consideration is similar to the human hand in terms of kinematic configuration. The modeling mechanism includes several stages: positioning the robotic hand over the object, placing the manipulator’s fingers relative to the shape of the object grasped, calculating the contact force required to grasp the object, and moving the hand holding the object. The first and last phases are conducted by changing the coordinates of the robotic manipulator’s kinematic center. The finger positioning stage is reduced to solving the inverse kinematics problem through an evolutionary optimization method, i.e. a genetic algorithm. The grasping phase defines the relevant contact force based on resolving the tracking issue for a set value, which is a predetermined touch force. The amount of the assigned touch force is reliant on the required friction force between fingers and the object that ensures a firm grasp. The authors approximate the finger dynamics to second-order dynamics. The simulation findings reveal the applicability of the proposed method to the problem of object grasping using a robotic manipulator.