Design, Modeling, and Manufacturing of a Variable Lateral Stiffness Arm via Shape Morphing Mechanisms

Abstract In this paper, we present a continuously tunable stiffness arm for safe physical human-robot interactions. Compliant joints and compliant links are two typical solutions to address safety issues for physical human-robot interactions via introducing mechanical compliance to robotic systems. While extensive studies explore variable stiffness joints/actuators, variable stiffness links for safe physical human-robot interactions are much less studied. This paper details the design and modeling of a compliant robotic arm whose stiffness can be continuously tuned via cable-driven mechanisms actuated by a single servo motor. Specifically, a 3D printed compliant robotic arm is prototyped and tested by static experiments, and an analytical model of the variable stiffness arm is derived and validated by testing. The results show that the lateral stiffness of the robot arm can achieve a variety of 221.26 % given a morphing angle of 90°. The variable stiffness arm design developed in this study could be a promising approach to address safety concerns for safe physical human-robot interactions.

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A Continuously Tunable Stiffness Arm With Cable-Driven Mechanisms for Safe Physical Human-Robot Interaction

Volume 10: 44th Mechanisms and Robotics Conference (MR) ◽

10.1115/detc2020-22035 ◽

2020 ◽

Author(s):

Yu She ◽

Zhaoyuan Gu ◽

Siyang Song ◽

Hai-Jun Su ◽

Junmin Wang

Keyword(s):

Variable Stiffness ◽

Human Robot Interaction ◽

Robotic Arm ◽

Robot Arm ◽

Robot Interaction ◽

Safety Issues ◽

Compliant Joints ◽

Mechanical Compliance ◽

3D Printed ◽

Tunable Stiffness

Abstract In this paper, we present a continuously tunable stiffness arm for safe physical human-robot interactions. Compliant joints and compliant links are two typical solutions to address safety issues for physical human-robot interaction via introducing mechanical compliance to robotic systems. While extensive studies explore variable stiffness joints/actuators, variable stiffness links for safe physical human-robot interactions are much less studied. This paper details the design and modeling of a compliant robotic arm whose stiffness can be continuously tuned via cable-driven mechanisms actuated by a single servo motor. Specifically, a 3D printed compliant robotic arm is prototyped and tested by static experiments, and an analytical model of the variable stiffness arm is derived and validated by testing. The results show that the lateral stiffness of the robot arm can achieve a variety of 221.26% given a morphing angle of 90°. The study demonstrates that the compliant link design could be a promising approach to address safety concerns for safe physical human-robot interactions.

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A Novel Variable Stiffness Compliant Robotic Gripper Based on Layer Jamming

Volume 5B: 43rd Mechanisms and Robotics Conference ◽

10.1115/detc2019-98294 ◽

2019 ◽

Author(s):

Yuan Gao ◽

Xiguang Huang ◽

Ishan Singh Mann ◽

Hai-Jun Su

Keyword(s):

Load Capacity ◽

Variable Stiffness ◽

Fold Increase ◽

Structural Stiffness ◽

Working Process ◽

Shape Morphing ◽

Individual Finger ◽

Low Load ◽

3D Printed ◽

Stiffness Variation

Abstract In this paper, we present a novel compliant robotic gripper with three variable stiffness fingers. While the shape morphing of the grippers is cable-driven, the stiffness variation is enabled by layer jamming. The inherent flexibility makes compliant grippers suitable for tasks such as grasping soft and irregular objects. However, their relatively low load capacity due to low structural stiffness limits their applications. Variable stiffness robotic grippers have the potential to address this challenge as their stiffness can be tuned on demand based on the needs of tasks. Layer jamming is an emerging method for variable stiffness due to its advantages of light weight, simple and quick actuation. In our design, the compliant backbone of the fingers is made of 3d printed PLA material. Four thin film materials are attached to each side of the skeleton. The working process of the robotic gripper follows two basic steps. First, the compliant skeleton is bent to a desired shape by actuating a tension cable via a servo motor. Second, upon application of a negative pressure by a vacuum pump, the finger is stiffened up owing to the increasing of the friction between contact surfaces of layers preventing their relative movement. Since the structural stiffness of the fingers is increased, their load capacity will be increased proportionally. When the air pressure is sufficiently large, the morphed shape can even be locked (no slipping). Test for stiffness of individual finger and load capacity of the robotic gripper are conducted to validate capability of the design. The results showed a 69-fold increase in stiffness of individual finger and a 30-fold increase in gripper’s load capacity.

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A Novel Variable Stiffness Compliant Robotic Gripper Based on Layer Jamming

Journal of Mechanisms and Robotics ◽

10.1115/1.4047156 ◽

2020 ◽

Vol 12 (5) ◽

Author(s):

Yuan Gao ◽

Xiguang Huang ◽

Ishan Singh Mann ◽

Hai-Jun Su

Keyword(s):

Load Capacity ◽

Variable Stiffness ◽

Fold Increase ◽

Servo Motor ◽

Shape Morphing ◽

On Demand ◽

Individual Finger ◽

Low Load ◽

3D Printed ◽

Stiffness Variation

Abstract In this paper, we present a novel compliant robotic gripper with three variable stiffness fingers. While the shape morphing of the fingers is cable-driven, the stiffness variation is enabled by layer jamming. The inherent flexibility makes compliant gripper suitable for tasks such as grasping soft and irregular objects. However, their relatively low load capacity due to intrinsic compliance limits their applications. Variable stiffness robotic grippers have the potential to address this challenge as their stiffness can be tuned on demand of tasks. In our design, the compliant backbone of finger is made of 3D-printed PLA materials sandwiched between thin film materials. The workflow of the robotic gripper follows two basic steps. First, the compliant skeleton is driven by a servo motor via a tension cable and bend to a desired shape. Second, upon application of a negative pressure, the finger is stiffened up because friction between contact surfaces of layers that prevents their relative movement increases. As a result, their load capacity will be increased proportionally. Tests for stiffness of individual finger and load capacity of the robotic gripper are conducted to validate capability of the design. The results showed a 180-fold increase in stiffness of individual finger and a 30-fold increase in gripper’s load capacity.

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Industrial part localization and grasping using a robotic arm guided by 2D monocular vision

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-06-2018-0128 ◽

2018 ◽

Vol 45 (6) ◽

pp. 794-804 ◽

Cited By ~ 3

Author(s):

Zhaohui Zheng ◽

Yong Ma ◽

Hong Zheng ◽

Yu Gu ◽

Mingyu Lin

Keyword(s):

Camera Calibration ◽

High Precision ◽

Calibration Method ◽

Monocular Vision ◽

Robotic Arm ◽

Robot Arm ◽

Content Type ◽

Calibration Algorithm ◽

Target Locating ◽

Practical Implications

Purpose The welding areas of the workpiece must be consistent with high precision to ensure the welding success during the welding of automobile parts. The purpose of this paper is to design an automatic high-precision locating and grasping system for robotic arm guided by 2D monocular vision to meet the requirements of automatic operation and high-precision welding. Design/methodology/approach A nonlinear multi-parallel surface calibration method based on adaptive k-segment master curve algorithm is proposed, which improves the efficiency of the traditional single camera calibration algorithm and accuracy of calibration. At the same time, the multi-dimension feature of target based on k-mean clustering constraint is proposed to improve the robustness and precision of registration. Findings A method of automatic locating and grasping based on 2D monocular vision is provided for robot arm, which includes camera calibration method and target locating method. Practical implications The system has been integrated into the welding robot of an automobile company in China. Originality/value A method of automatic locating and grasping based on 2D monocular vision is proposed, which makes the robot arm have automatic grasping function, and improves the efficiency and precision of automatic grasp of robot arm.

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Improved Artificial Potential Field Method Manipulator Inverse Kinematics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.273.119 ◽

2013 ◽

Vol 273 ◽

pp. 119-123

Author(s):

Ding Jin Huang ◽

Teng Liu

Keyword(s):

Potential Field ◽

Inverse Kinematics ◽

Search Space ◽

Field Method ◽

Robotic Arm ◽

Artificial Potential Field ◽

Robot Arm ◽

Potential Field Method ◽

Inverse Kinematics Problem ◽

Artificial Potential Field Method

The use of traditional analytical method for manipulator inverse kinematics is able to get a display solution with the limitations of the application, only when the robotic arm has a specific structure. In view of the insufficient, this paper presents an improved artificial potential field method to solve the inverse kinematics problem of the manipulator which does not have a special structure. Firstly, establish the standard DH model for the robot arm. Then the strategy that improves search space of artificial potential field method and motion control standard is presented by combining artificial potential field method with the manipulator. Finally, the simulation results show that the proposed method is effective.

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Towards Adaptive Prosthetic Sockets using 3D-printed Variable-stiffness Shape-memory Structures

2019 2nd IEEE International Conference on Soft Robotics (RoboSoft) ◽

10.1109/robosoft.2019.8722811 ◽

2019 ◽

Author(s):

Afonso Pourfarzaneh ◽

Majid Taghavi ◽

Tim Helps ◽

Jonathan Rossiter

Keyword(s):

Shape Memory ◽

Variable Stiffness ◽

3D Printed ◽

Memory Structures

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Design of a Tunable Stiffness Composite Leg for Dynamic Locomotion

Volume 7: 33rd Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2009-86847 ◽

2009 ◽

Cited By ~ 16

Author(s):

Kevin C. Galloway ◽

Jonathan E. Clark ◽

Daniel E. Koditschek

Keyword(s):

Variable Stiffness ◽

Legged Robots ◽

Simulation Studies ◽

Dynamic Coupling ◽

High Speeds ◽

Leg Stiffness ◽

Passive Compliance ◽

Leg Design ◽

Tunable Stiffness ◽

Running Robots

Passively compliant legs have been instrumental in the development of dynamically running legged robots. Having properly tuned leg springs is essential for stable, robust and energetically efficient running at high speeds. Recent simulation studies indicate that having variable stiffness legs, as animals do, can significantly improve the speed and stability of these robots in changing environmental conditions. However, to date, the mechanical complexities of designing usefully robust tunable passive compliance into legs has precluded their implementation on practical running robots. This paper describes a new design of a “structurally controlled variable stiffness” leg for a hexapedal running robot. This new leg improves on previous designs’ performance and enables runtime modification of leg stiffness in a small, lightweight, and rugged package. Modeling and leg test experiments are presented that characterize the improvement in stiffness range, energy storage, and dynamic coupling properties of these legs. We conclude that this variable stiffness leg design is now ready for implementation and testing on a dynamical running robot.

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DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

ASEAN Engineering Journal ◽

10.11113/aej.v11.17865 ◽

2021 ◽

Vol 11 (4) ◽

pp. 70-79

Author(s):

Dino Dominic Forte Ligutan ◽

Argel Alejandro Bandala ◽

Jason Limon Española ◽

Richard Josiah Calayag Tan Ai ◽

Ryan Rhay Ponce Vicerra ◽

...

Keyword(s):

3D Printing ◽

Polylactic Acid ◽

Grip Force ◽

Thermoplastic Polyurethane ◽

Robotic Arm ◽

End Effector ◽

Design Considerations ◽

3D Printed ◽

Materials Used ◽

Metal Work

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

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An integrated system design interface for operating 8-DoF robotic arm

10.31224/osf.io/m7rtg ◽

2022 ◽

Author(s):

Madhav Rao

Keyword(s):

Upper Limb ◽

System Integration ◽

Integrated System ◽

Microsoft Kinect ◽

Robotic Arm ◽

Robot Arm ◽

Game Engine ◽

Kinematic Modeling ◽

Articulated Robot ◽

Integrated System Design

This study examines the system integration of a game engine with robotics middleware to drive an 8 degree offreedom (DoF) robotic upper limb to generate human-like motion for telerobotic applications. The developed architectureencompasses a pipeline execution design using Blender Game Engine (BGE) including the acquisition of real humanmovements via the Microsoft Kinect V2, interfaced with a modeled virtual arm, and replication of similar arm movements on the physical robotic arm. In particular, this study emphasizes the integration of a human “pilot” with ways to drive such a robotic arm through simulation and later, into a finished system. Additionally, using motion capture technology, a human upper limb action was recorded and applied onto the robot arm using the proposed architecture flow. Also, we showcase the robotic arm’s actions which include reaching, picking, holding, and dropping an object. This paper presentsa simple and intuitive kinematic modeling and 3D simulation process, which is validated using 8-DoF articulated robot to demonstrate methods for animation, and simulation using the designed interface.

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