M.S. (Master of Science)
Department of Mechanical Engineering
Robots are specially designed to do our needs in every field, mainly in manufacturing, automation, pharmaceuticals, and aerospace. Typically, robots are equipped with a gripper to grasp objects easily. While they function well, they can be very complex and require extensive linkages and computational power for them to operate with ease. Handling an object without a gripper is known as non-prehensile manipulation. Among non-prehensile manipulation methods, throwing, presumably followed by catching, can be used to transport objects at higher heights or longer distances than is achievable for manipulator arm with a traditional grasping manipulation method. In this thesis, throwing, catching, and balancing of an object by using a two-link planar manipulator is presented. Given a goal position, required release position and velocity are determined for throwing. The throwing non-prehensile manipulation is proposed in consideration with the hand-object dynamics between the ready and release motions to achieve the release position and velocity. The interaction between the hand and object is studied to design a desired trajectory of the arm. Catching control is achieved by using the object position as the target to the end effector of the manipulator in X directional motion while keeping the motion in Y-direction as a constant. Balancing control is then implemented to the disk-shaped end effector to prevent the object from falling after catching. The vision system is used to track the object. As a preliminary work, motor modeling was performed to find the motor's parameters and test the motors as joint actuators while object tracking is done through a vision system. The inverse dynamics control law is used to find the command torque at each joint motor. In this work, throwing, catching, and balancing are executed together in sequence to achieve the objective of this work. The proposed approaches are simulated in MATLAB and then implemented on an experimental setup for verification. Finally, experimental results are provided and compared with the simulation results.
Erumalla, Sandeep Reddy, "Throwing, catching, and balancing of a disk with a disk-shaped end effector by using a two-link manipulator" (2018). Graduate Research Theses & Dissertations. 6465.
Northern Illinois University
Rights Statement 2