scholarly journals Design and Implementation of a Multi-Function Gripper for Grasping General Objects

2019 ◽  
Vol 9 (24) ◽  
pp. 5266 ◽  
Author(s):  
Long Kang ◽  
Jong-Tae Seo ◽  
Sang-Hwa Kim ◽  
Wan-Ju Kim ◽  
Byung-Ju Yi
Keyword(s):  
Degrees Of Freedom ◽  
Manual Labor ◽  
Cluttered Environments ◽  
Industrial Robotics ◽  
Design And Implementation ◽  
Suction Cup ◽  
Working Environments ◽  
Wide Range ◽  
Pick And Place ◽  
Three Degrees Of Freedom

The development of a reliable pick-and-place system for industrial robotics is facing an urgent demand because many manual-labor works, such as piece-picking in warehouses and fulfillment centers tend toward automation. This paper presents an integrated gripper that combines a linkage-driven underactuated gripper with a suction gripping system for picking up a variety of objects in different working environments. The underactuated gripper consists of two fingers, and each finger has three degrees of freedom that are obtained by stacking one five-bar mechanism over one double parallelogram. Furthermore, each finger is actuated by two motors, both of which can be installed at the base owing to the special architecture of the proposed robotic finger. A suction cup is used to grasp objects in narrow spaces and cluttered environments. The combination of the suction and traditional linkage-driven grippers allows stable and reliable grasping under different working environments. Finally, practical experiments using a wide range of objects and under different grasping scenarios are performed to demonstrate the grasping capability of the integrated gripper.

scholarly journals Analysis of Upper-Limb and Trunk Kinematic Variability: Accuracy and Reliability of an RGB-D Sensor

2020 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Alessandro Scano ◽  
Robert Mihai Mira ◽  
Pietro Cerveri ◽  
Lorenzo Molinari Tosatti ◽  
Marco Sacco
Keyword(s):  
Upper Limb ◽  
Gold Standard ◽  
Degrees Of Freedom ◽  
Cost Effective ◽  
Human Motion ◽  
Working Environments ◽  
Wide Range ◽  
Upper Limb Movements ◽  
Clinical Environments ◽  
Point To Point

In the field of motion analysis, the gold standard devices are marker-based tracking systems. Despite being very accurate, their cost, stringent working environments, and long preparation time make them unsuitable for small clinics as well as for other scenarios such as industrial application. Since human-centered approaches have been promoted even outside clinical environments, the need for easy-to-use solutions to track human motion is topical. In this context, cost-effective devices, such as RGB-Depth (RBG-D) cameras have been proposed, aiming at a user-centered evaluation in rehabilitation or of workers in industry environment. In this paper, we aimed at comparing marker-based systems and RGB-D cameras for tracking human motion. We used a Vicon system (Vicon Motion Systems, Oxford, UK) as a gold standard for the analysis of accuracy and reliability of the Kinect V2 (Microsoft, Redmond, WA, USA) in a variety of gestures in the upper limb workspace—targeting rehabilitation and working applications. The comparison was performed on a group of 15 adult healthy subjects. Each subject had to perform two types of upper-limb movements (point-to-point and exploration) in three workspace sectors (central, right, and left) that might be explored in rehabilitation and industrial working scenarios. The protocol was conceived to test a wide range of the field of view of the RGB-D device. Our results, detailed in the paper, suggest that RGB-D sensors are adequate to track the upper limb for biomechanical assessments, even though relevant limitations can be found in the assessment and reliability of some specific degrees of freedom and gestures with respect to marker-based systems.

Analysis and Validation of a Flexible Planar Two Degrees-of-Freedom Parallel Manipulator With Structural Passive Compliance

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Genliang Chen ◽  
Zhuang Zhang ◽  
Lingyu Kong ◽  
Hao Wang
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Interaction Force ◽  
Flexible Manipulator ◽  
End Effector ◽  
Flexible Links ◽  
Wide Range ◽  
Pick And Place ◽  
Passive Compliance ◽  
Large Deflection Problem

Abstract Passive compliance plays an important role in robot pick-and-place manipulation where large interaction force will be produced in response to small misalignments. In this paper, the authors report on compliance analysis and validation of a novel planar pick-and-place parallel manipulator consisting of a flexible limb. In the proposed manipulator, a planar flexible parallelogram linkage, which is coupled with a rigid one, is introduced to connect the moving and the base platforms. Since the flexible parallelogram linkage is capable of producing large deformation in both the horizontal and the vertical directions, the end effector of the manipulator can generate wide-range motions because of the flexible links. An efficient approach to the large deflection problem of flexible links is used to precisely predict the kinetostatics of the manipulator. Then, a compensation algorithm to the structural deflection of the links can be developed to actively control the position of the parallel manipulator’s end effector. The merit of the proposed flexible manipulator is its intrinsic passive compliance while performing pick-and-place tasks. A prototype is fabricated to conduct experiments for the validation of the proposed idea. The results show that the prototype has acceptable positioning accuracy, even when a large external load is exerted on its end effector. The compliance properties of the proposed flexible manipulator have also been verified in both the horizontal and the vertical directions.

Dynamic Trajectory Planning for a Three Degrees-of-Freedom Cable-Driven Parallel Robot Using Quintic B-Splines

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Sen Qian ◽  
Kunlong Bao ◽  
Bin Zi ◽  
W. D. Zhu
Keyword(s):  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Planning Method ◽  
End Effector ◽  
B Spline ◽  
B Splines ◽  
Pick And Place ◽  
Two Factors ◽  
Three Degrees Of Freedom

Abstract This paper presents a new trajectory planning method based on the improved quintic B-splines curves for a three degrees-of-freedom (3-DOF) cable-driven parallel robot (CDPR). First, the conditions of positive cables’ tension are expressed in terms of the position and acceleration constraints of the end-effector. Then, an improved B-spline curve is introduced, which is employed for generating a pick-and-place path by interpolating a set of given via-points. Meanwhile, by expressing the position and acceleration of the end-effector in terms of the first and second derivatives of the improved B-spline, the cable tension constraints are described in the form of B-spline parameters. According to the properties of the defined pick-and-place path, the proposed motion profile is dominated by two factors: the time taken for the end-effector to pass through all the via-points and the ratio between the nodes of B-spline. The two factors are determined through multi-objective optimization based on the efficiency coefficient method. Finally, experimental results on a 3-DOF CDPR show that the improved B-spline exhibits overall superior behavior in terms of velocity, acceleration, and cables force compared with the traditional B-spline. The validity of the proposed trajectory planning method is proved through the experiments.

scholarly journals Robotic pick-and-place of novel objects in clutter with multi-affordance grasping and cross-domain image matching

2019 ◽  
pp. 027836491986801 ◽  
Author(s):  
Andy Zeng ◽  
Shuran Song ◽  
Kuan-Ting Yu ◽  
Elliott Donlon ◽  
Francois R. Hogan ◽  
...  
Keyword(s):  
Recognition Algorithm ◽  
Training Data ◽  
Success Rates ◽  
Cluttered Environments ◽  
Cross Domain ◽  
Classification Framework ◽  
Wide Range ◽  
Pick And Place ◽  
Additional Data Collection ◽  
Novel Objects

This article presents a robotic pick-and-place system that is capable of grasping and recognizing both known and novel objects in cluttered environments. The key new feature of the system is that it handles a wide range of object categories without needing any task-specific training data for novel objects. To achieve this, it first uses an object-agnostic grasping framework to map from visual observations to actions: inferring dense pixel-wise probability maps of the affordances for four different grasping primitive actions. It then executes the action with the highest affordance and recognizes picked objects with a cross-domain image classification framework that matches observed images to product images. Since product images are readily available for a wide range of objects (e.g., from the web), the system works out-of-the-box for novel objects without requiring any additional data collection or re-training. Exhaustive experimental results demonstrate that our multi-affordance grasping achieves high success rates for a wide variety of objects in clutter, and our recognition algorithm achieves high accuracy for both known and novel grasped objects. The approach was part of the MIT–Princeton Team system that took first place in the stowing task at the 2017 Amazon Robotics Challenge. All code, datasets, and pre-trained models are available online at http://arc.cs.princeton.edu/

FEM Based Numerical Simulation of Delta Parallel Mechanism

2013 ◽  
Vol 690-693 ◽  
pp. 2978-2981 ◽  
Author(s):  
Jian Zhong Zhang ◽  
Xin Peng Xie ◽  
Chuan Jin Li ◽  
Ying Ying Xin ◽  
Zhao Ming He
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Theoretical Foundation ◽  
Future Research ◽  
Element Analysis ◽  
Pick And Place ◽  
Integral Structure ◽  
Inverse Dynamics Analysis ◽  
Three Degrees Of Freedom

This paper describes a parallel three degrees of freedom delta mechanism used for pick-and-place. It has the advantages of simple integral structure, strong bearing capacityhigh precisionkinematics and dynamics performance. According to this mechanism wide development prospect, the company study on the inverse kinematics inverse dynamics analysis and the static analysis by using ANSYS finite element analysis Software of Delta. These analyses have laid a good theoretical foundation for future research. These researches provide possible for widely used in foodpackingautomated assembly line occasions of small and medium-sized enterprises.

Design and Implementation of a Binary Redundant Manipulator With Cascaded Modules1

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Emmanouil Tzorakoleftherakis ◽  
Anastasia Mavrommati ◽  
Anthony Tzes
Keyword(s):  
Computational Complexity ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Redundant Manipulator ◽  
Stable States ◽  
Design And Implementation ◽  
Serial Robot ◽  
The Subject ◽  
Forward And Inverse Kinematics ◽  
Three Degrees Of Freedom

The subject of this paper is the design and implementation of a prototype snakelike redundant manipulator. The manipulator consists of cascaded modules eventually forming a macroscopically serial robot and is powered by shape memory alloy (SMA) wires. The SMAs (NiTi) act as binary actuators with two stable states and as a result, the repeatability of the manipulator's movement is ensured, alleviating the need for complex feedback sensing. Each module is composed of a customized spring and three SMA wires which form a tripod with three degrees of freedom (DOFs). Embedded microcontrollers networked with the I2C protocol activate the actuators of each module individually. In addition, we discuss certain design aspects and propose a solution that deals with the limited absolute stroke achieved by SMA wires. The forward and inverse kinematics of the binary manipulator are also presented and the tradeoff between maneuverability and computational complexity is specifically addressed. Finally, the functionality and maneuverability of this design are verified in simulation and experimentally.

Design and Implementation of an Articulated Robotic Arm for Precise Positioning

2011 ◽  
Vol 201-203 ◽  
pp. 1972-1977
Author(s):  
Enaiyat Ghani Ovy ◽  
Shah Muhammad Ferdous ◽  
Mohammad Rokonuzzaman ◽  
Nurul Absar Chowdhury
Keyword(s):  
Spot Welding ◽  
Degrees Of Freedom ◽  
Material Handling ◽  
Mechanical Design ◽  
Industrial Applications ◽  
Robotic Arm ◽  
Analytic Description ◽  
Precise Positioning ◽  
Design And Implementation ◽  
Three Degrees Of Freedom

This project is intended to design an articulated robotic arm which could locate a point in space with its given coordinates at three degrees of freedom. The basic three rotary movements are base rotation, first and second arm swivel. With different payload capability and design, the robot can be employed in various industrial applications including spot welding, assembling, cutting, material handling and many more. The mechanical structure is designed and a physical setup is developed for which a microcontroller based control circuit is designed for the purpose of control. This paper is focused mainly on the mechanical design of the structure. An elaborate analytic description of the components and tools is presented with necessary specifications. This structure is very flexible and has the ability to reach over obstructions. It can achieve different positions and orientations with in the working envelop.

Vibration Attenuation of an Electromechanical System Coupled with Plate Springs Damped by an Impact Element

2015 ◽  
Vol 07 (03) ◽  
pp. 1550043 ◽  
Author(s):  
Marek Lampart ◽  
Jaroslav Zapoměl
Keyword(s):  
Differential Equations ◽  
Degrees Of Freedom ◽  
Electromechanical System ◽  
Force Balance ◽  
Wide Range ◽  
Vibration Attenuation ◽  
Impact Element ◽  
The Impact ◽  
System Movement ◽  
Three Degrees Of Freedom

The main aim of this paper is focused on vibration attenuation of the electromechanical system flexibly coupled with a baseplate and damped by an impact element. The model is constructed with three degrees of freedom in the mechanical oscillating part, two translational and one rotational. The system movement is described by three mutually coupled second-order ordinary differential equations, derived by the force balance method. Here, the most important nonlinearities are: stiffness of the support spring elements and internal impacts. The main results show the impact damping device attenuates vibrations of the rotor frame in a wide range of the excitation frequencies, that is wider then in the case when the impact element works only as an inertia damper without occurrence of any impacts.

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