Design of Modular End-effector for Collaborative Robot based on Underactuated Mechanism

Author(s):  
Hyeonjun Park ◽  
Donghan Kim ◽  
Bumjoo Lee
Robotics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 14 ◽  
Author(s):  
Juan Sandoval ◽  
Med Amine Laribi ◽  
Saïd Zeghloul ◽  
Marc Arsicault ◽  
Jean-Michel Guilhem

This paper deals with a collaborative robot, i.e., cobot, coupled with a new prismatic compliant joint (PCJ) at its end-effector. The proposed collaborative solution is intended for Doppler sonography to prevent musculoskeletal disorders issues. On one hand, the Doppler sonographer’s postures are investigated based on motion capture use during the arteries examination. This study highlighted that configurations adopted by angiologists lead to the musculoskeletal disorder. On the other hand, the proposed PCJ with variable stiffness gives an intrinsic compliance to the cobot handling the probe. This feature allows preserving the human safety when both human and cobot share a common workspace. The effectiveness of the proposed solution is experimentally validated through a 7-DoF Franka Emika robot virtually coupled with the PCJ, during the execution of a trajectory performed during a Doppler ultrasound exam. The impact force criterion is considered as a safety performance.


Author(s):  
Mohammad H. FarzanehKaloorazi ◽  
Ilian A. Bonev

In this paper, the singularities of the typical 6R collaborative robot (such as the cobots made by Universal Robots) are analytically and geometrically described. Since the axes of the last three joints in such a cobot are not concurrent, the singularities are slightly different from those of the PUMA-style manipulator. It is shown that the determinant of the Jacobian matrix of the typical cobot splits into four factors, three of which can vanish. As in the typical PUMA-style manipulator, the three vanishing factors correspond to shoulder, elbow and wrist singularities. However, in a wrist singularity, the redundant motion associated with no end-effector movement is more complex.


2021 ◽  
Vol 11 (9) ◽  
pp. 4279
Author(s):  
Minhyo Kim ◽  
Youqiang Zhang ◽  
Sangrok Jin

This paper presents a control strategy that secures both precision and manipulation sensitivity of remote center motion with direct teaching for a surgical assistant robot. Remote center motion is an essential function of conventional laparoscopic surgery, and the most intuitive way a surgeon manipulates a robot is through direct teaching. The surgical assistant robot must maintain the position of the insertion port in three-dimensional space during the four-degree-of-freedom motions such as pan, tilt, spin, and forward/backward. In addition, the robot should move smoothly when controlling it with the hands during the surgery. In this study, a six-degree-of-freedom collaborative robot performs the cone-shaped trajectory with pan and tilt motion of an end-effector keeping the position of the remote center. Instead of the bulky mechanically constrained remote center motion mechanism, a conventional collaborative robot is used to mimic the wrist movement of a scrub nurse. A force/torque sensor that is attached between the robot and end-effector estimates the surgeon’s intention. A direct teaching control strategy based on position control is applied to guarantee precise remote center position maintenance performance. A motion generation algorithm is designed to generate motion by utilizing a force/torque sensor value. The parameters of the motion generation algorithm are optimized so that the robot can be operated with uniform sensitivity in all directions. The precision of remote center motion and the torque required for direct teaching are analyzed through pan and tilt motion experiments.


2019 ◽  
Vol 20 (1) ◽  
pp. 148-184
Author(s):  
Luis Gracia ◽  
J. Ernesto Solanes ◽  
Pau Muñoz-Benavent ◽  
Jaime Valls Miro ◽  
Carlos Perez-Vidal ◽  
...  

Abstract This paper presents a human-robot closely collaborative solution to cooperatively perform surface treatment tasks such as polishing, grinding, finishing, deburring, etc. The proposed scheme is based on task priority and non-conventional sliding mode control. Furthermore, the proposal includes two force sensors attached to the manipulator end-effector and tool: one sensor is used to properly accomplish the surface treatment task, while the second one is used by the operator to guide the robot tool. The applicability and feasibility of the proposed collaborative solution for robotic surface treatment are substantiated by experimental results using a redundant 7R manipulator: the Sawyer collaborative robot.


2021 ◽  
Vol 15 (2) ◽  
pp. 140-148
Author(s):  
Michele Gabrio Antonelli ◽  
◽  
Pierluigi Beomonte Zobel

The task of screwing is based on a set of actions with no added value, requiring precision, attention, and repeatability. These set of actions could consist of alienating and demanding activity for a human operator. Collaborative robotics can facilitate the performance of such tasks. This investigation focuses on the development of a smart station for the automated screwing of fittings in pneumatic manifolds. The collaborative robot Sawyer produced by Rethink Robotics is equipped with an appropriate end-effector and was utilized to receive the fittings from a vibrating feeder towards the end-effector. This facilitated centering of the fittings on the threaded holes, and the performance of the screwing task on a set of manifolds placed on a rotating station. The design of the end-effector and its prototype is described. In addition, the proposed automated process was experimentally tested and its effectiveness was validated.


ROBOT ◽  
2011 ◽  
Vol 33 (4) ◽  
pp. 434-439 ◽  
Author(s):  
Dangyang JIE ◽  
Fenglei NI ◽  
Yisong TAN ◽  
Hong LIU ◽  
Hegao CAI

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