Curved layer path planning on a 5-axis 3D printer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Joao Duarte ◽  
Isabel Espírito Santo ◽  
M. Teresa T. Monteiro ◽  
A. Ismael F. Vaz
Keyword(s):  
Path Planning ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Inner Core ◽  
Cubic Splines ◽  
3D Printer ◽  
Content Type ◽  
Planning Strategy ◽  
Supporting Structure ◽  
Shell Type

Purpose This paper aims to provide an approach to print shell-type objects using a 5-axis printer. The proposed approach takes advantage of the two additional printer degrees of freedom to provide a curved layer path planning strategy. Design/methodology/approach This paper addresses curved layer path planning on a 5-axis printer. This printer considers movements along the three usual axes together with two additional axes at the printing table (rotation and tilt), allowing to build more complex and reliable objects. Curved layer path planning is considered where polygons obtained from the slicing stage are approximated by linear and cubic splines. The proposed printing strategy consists in building an inner core supporting structure followed by outer curved layers. Findings The curved layer path planning strategy is validated for shell-type objects by considering a 5-axis printer simulator. An example with an aeronautic object is presented to illustrate the proposed approach. Originality/value The paper presents an approach to curved layer path planning on a 5-axis printer, for shell-type objects.

Motion and force control method of 7-DOF cable-driven rehabilitation exoskeleton robot

2018 ◽  
Vol 38 (5) ◽  
pp. 595-605 ◽  
Author(s):  
Wencheng Ni ◽  
Hui Li ◽  
Zhihong Jiang ◽  
Bainan Zhang ◽  
Qiang Huang
Keyword(s):  
Design Methodology ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Body Measurements ◽  
Joint Movement ◽  
Content Type ◽  
Rehabilitation Training ◽  
Exoskeleton Robot ◽  
Training Mode ◽  
Active Rehabilitation

Purpose The purpose of this paper is to design an exoskeleton robot and present a corresponding rehabilitation training method for patients in different rehabilitation stages. Design/methodology/approach This paper presents a lightweight seven-degrees-of-freedom (DOF) cable-driven exoskeleton robot that is wearable and adjustable. After decoupling joint movement caused by a cable-driven mechanism, active rehabilitation training mode and passive rehabilitation training mode are proposed to improve the effect of rehabilitation training. Findings Simulations and experiments have been carried out, and the results validated the feasibility of the proposed mechanism and methods by a fine rehabilitative effect with different persons. Originality/value This paper designed a 7-DOF cable-driven exoskeleton robot that is suitable for patients of different body measurements and proposed the active rehabilitation training mode and passive rehabilitation training mode based on the cable-driven exoskeleton robot.

An efficient reformulation of a multiscale method for the eddy current problem

2017 ◽  
Vol 36 (5) ◽  
pp. 1421-1429
Author(s):  
Markus Schöbinger ◽  
Karl Hollaus ◽  
Joachim Schöberl
Keyword(s):  
Eddy Current ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Current Problem ◽  
Multiscale Method ◽  
Content Type ◽  
Eddy Current Problem ◽  
Laminate Thickness ◽  
The Cost ◽  
Laminated Material

Purpose This paper aims to improve the efficiency of a numerical method to treat the eddy current problem on a laminated material, where using a mesh that resolves each individual laminate would be too computationally expensive. Design/methodology/approach The domain is modeled using a coarse mesh that treats the laminated material as a bulk with averaged properties. The fine-structured behavior is recovered by introducing micro-shape functions in the ansatz space. One such method is analyzed to find further model restrictions. Findings By using a special reformulation, it is possible to eliminate the additional degrees of freedom introduced by the multiscale ansatz at the cost of an additional modeling error that decreases with the laminate thickness. Originality/value The paper gives a computationally more efficient approximate variant to a known multiscale method.

General inverse solution of six-degrees-of-freedom serial robots based on the product of exponentials model

2018 ◽  
Vol 38 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Haixia Wang ◽  
Xiao Lu ◽  
Wei Cui ◽  
Zhiguo Zhang ◽  
Yuxia Li ◽  
...  
Keyword(s):  
Design Methodology ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Complex Problem ◽  
Content Type ◽  
Geometrical Properties ◽  
Closed Form Solutions ◽  
Six Degrees Of Freedom ◽  
Serial Robots ◽  
Six Dof

Purpose Developing general closed-form solutions for six-degrees-of-freedom (DOF) serial robots is a significant challenge. This paper thus aims to present a general solution for six-DOF robots based on the product of exponentials model, which adapts to a class of robots satisfying the Pieper criterion with two parallel or intersecting axes among its first three axes. Design/methodology/approach The proposed solution can be represented as uniform expressions by using geometrical properties and a modified Paden–Kahan sub-problem, which mainly adopts the screw theory. Findings A simulation and experiments validated the correctness and effectiveness of the proposed method (general resolution for six-DOF robots based on the product of exponentials model). Originality/value The Rodrigues rotation formula is additionally used to turn the complex problem into a solvable trigonometric function and uniformly express six solutions using two formulas.

scholarly journals Robotic additive manufacturing system for dynamic build orientations

2020 ◽  
Vol 26 (4) ◽  
pp. 659-667
Author(s):  
Nicholas R. Fry ◽  
Robert C. Richardson ◽  
Jordan H. Boyle
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Manufacturing System ◽  
Print Quality ◽  
Orientation Relationships ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Build Orientation

Purpose This paper aims to present a multi-axis additive robot manufacturing system (ARMS) and demonstrate its beneficial capabilities. Design/methodology/approach ARMS was constructed around two robot arms and a fused filament fabrication (FFF) extruder. Quantitative experiments are conducted to investigate the effect of printing at different orientations with respect to gravity, the effect of dynamically changing build orientation with respect to the build tray when printing overhanging features, the effect of printing curved parts using curved, conformal layers. These capabilities are combined to print an integrated demonstrator showing potential practical benefits of the system. Findings Orientation with respect to gravity has no effect on print quality; dynamically changing build orientation allows overhangs up to 90° to be cleanly printed without support structures; printing an arch with conformal layers significantly increases its strength compared to conventional printing. Research limitations/implications The challenge of automatic slicing algorithms has not been addressed for multi-axis printing. It is shown that ARMS could eventually enable printing of fully-functional prototypes with embedded components. Originality/value This work is the first to prove that the surface roughness of an FFF part is independent of print orientation with respect to gravity. The use of two arms creates a novel system with more degrees of freedom than existing multi-axis printers, enabling studies on printing orientation relationships and printing around inserts. It also adds to the emerging body of multi-axis literature by verifying that curved layers improve the strength of an arch which is steeply curved and printed with the nozzle remaining normal to the curvature.

From Manhattan to Tenochtitlán: identifying ethical commercial norms

2018 ◽  
Vol 24 (4) ◽  
pp. 435-456 ◽  
Author(s):  
Jason Good ◽  
Paloma Vargas Montes ◽  
Bryan W. Husted ◽  
Blanca López de Mariscal
Keyword(s):  
Sixteenth Century ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Business Models ◽  
Business Practices ◽  
Content Type ◽  
Environmentally Sustainable ◽  
Historical Texts ◽  
Ethical Norms ◽  
Met Expectations

Purpose This paper aims to examine the sixteenth-century Nahua society of central Mexico to answer the question, what commercial ethical norms operated in the sixteenth-century Nahua society? After decades of trying, Western business models and managerial theories have not met expectations in terms of fostering a socially and environmentally sustainable future. Qualitatively different approaches are needed, and one way to find them is to look at business models, norms and practices that operated in societies that were isolated from Western influences. Design/methodology/approach This paper contributes to efforts to find and analyze historical texts that include business practices. In particular, this study uses grounded theory techniques to examine the presence of ethical commercial norms in one of history’s foundational ethnographic texts, The Florentine Codex, a sixteenth-century study of Nahua society. Findings This study identified six commercial ethical norms that structured Nahua commerce: “care for others,” “exercise prudence,” “tell the truth,” “be respectful of others,” “show reverence to the gods” and “be humble.” Confidence in these findings was enhanced by their “qualitative degrees of freedom,” whereby these norms were found to operate in other sectors of Nahua society. Originality/value This study contributes to the literature by demonstrating ethical norms of commerce that can emerge in isolation from Western cultures; providing a rigorous and novel methodology for deriving norms from historical texts; and expanding knowledge of business practices beyond modern Western contexts.

A novel hybrid electromagnetism‐like algorithm for solving the inverse kinematics of robot

2011 ◽  
Vol 38 (4) ◽  
pp. 429-440 ◽  
Author(s):  
Feng Yin ◽  
Yaonan Wang ◽  
Shuning Wei
Keyword(s):  
Heuristic Algorithm ◽  
Hybrid Method ◽  
Minimization Problem ◽  
Inverse Kinematics ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
High Dimensional ◽  
Equivalent Problem ◽  
Content Type ◽  
Iteration Number

PurposeThis paper aims to develop a new real‐time effective method for solving the inverse kinematics (IK) problem, especially for those manipulators with high‐dimensional nonlinear kinematic equations.Design/methodology/approachThe paper transforms the IKs problem into a minimization problem. Then, a novel meta‐heuristic algorithm, called the electromagnetism‐like method (EM), is used to solve this equivalent problem. Moreover, in order to further improve the computational efficiency and accuracy of EM, a hybrid method which combines EM with the Davidon‐Fletcher‐Powell (DFP) method is proposed.FindingsThe results showed that EM is a powerful yet easy algorithm for solving the IKs problem of robot manipulators. Its complexity is independent on the characteristics of the kinematic equations involving dimensionality and the degree of nonlinearity. Moreover, EM can be used as an accompanying algorithm for DFP method to get better precision at a lower iteration number.Originality/valueThe method developed in this paper is a generalized approach that is efficient enough to obtain IK solutions independent of robot geometry and the number of degrees of freedom.

Automatic disassembly navigation for accurate virtual assembly path planning

2014 ◽  
Vol 34 (3) ◽  
pp. 244-254 ◽  
Author(s):  
Wanbin Pan ◽  
Yigang Wang ◽  
Peng Du
Keyword(s):  
Virtual Reality ◽  
Path Planning ◽  
Virtual Environment ◽  
Design Methodology ◽  
Virtual Assembly ◽  
New Method ◽  
Virtual Reality System ◽  
New Approach ◽  
Content Type ◽  
Human Interactions

Purpose – The purpose of this paper is to develop an automatic disassembly navigation approach for human interactions in the virtual environment to achieve accurate and effective virtual assembly path planning (VAPP). Design/methodology/approach – First, to avoid the error-prone human interactions, a constraint-based disassembly method is presented. Second, to automatically provide the next operable part(s), a disassembly navigation mechanism is adopted. Finally, the accurate assembly path planning can be obtained effectively and automatically by inversing the ordered accurate disassembly paths, which are obtained interactively in the virtual environment aided with the disassembly navigation matrix. Findings – The applications present that our approach can effectively avoid the error-prone interactive results and generate accurate and effective VAPP. Research limitations/implications – There are several works that could be conducted to make our approach more general in the future: to further study the basic disassembly direction deducing rules to make the process of determining disassembly direction totally automatic, to consider the hierarchy of the parts in virtual reality system and to consider the space for assembly/disassembly tools or operators. Originality/value – The approach has the following characteristics: a new approach to avoid the error-prone human interactions for accurate assembly path planning obtaining, a new constraint deducing method for determining the disassembly semantics automatically or semi-automatically is put forward and a new method for automatically identifying operable parts in VAPP is set forward.

A flexible self-adaptive underactuated hand with series passive joints

2018 ◽  
Vol 45 (4) ◽  
pp. 516-525 ◽  
Author(s):  
Chao Luo ◽  
Wenzeng Zhang
Keyword(s):  
Design Methodology ◽  
Degrees Of Freedom ◽  
Industrial Sector ◽  
Initial Position ◽  
Kinematics And Dynamics ◽  
Force Distribution ◽  
Content Type ◽  
Robot Hands ◽  
Dynamics Analyses ◽  
Soft Finger

Purpose This paper aims to propose a novel hand to bridge the gap between the traditional rigid robot hands and the soft hands to obtain a better grasping performance. Design/methodology/approach The proposed hand consists of three fingers. Each finger has 15 degrees of freedom and three phalanxes, which can bend in one direction when load is applied, but they are rigid toward the opposite direction at the initial position. The grasping process and simulations of the fingers are discussed in this paper. Both kinematic and dynamics analyses are performed to predict the performance of the hand. Subsequently, a prototype of the hand is developed for experiments. Findings Both kinematics and dynamics analyses indicate good grasping performance of the hand. Simulations and experiments confirm the feasibility of the finger design. The hand can execute hybrid grasping modes with more uniform force distribution and a larger workspace than traditional rigid fingers. The proposed hand has much potential in the industrial sector. Originality/value A new method to obtain better grasping performance and to bridge the gap between the rigid finger and the soft finger has been presented and verified. The hand combines the advantages of both the rigid phalanxes and the soft fingers. Compared with some traditional rigid fingers, the proposed design has a more uniform force distribution and a bigger workspace.

Motion and path planning of a novel multi-mode mobile parallel robot based on chessboard-shaped grid division

2018 ◽  
Vol 45 (3) ◽  
pp. 390-400 ◽  
Author(s):  
Zhaotian Wang ◽  
Yezhuo Li ◽  
Yan-An Yao
Keyword(s):  
Path Planning ◽  
Parallel Robot ◽  
Content Type ◽  
Planning Strategy ◽  
Planning Algorithm ◽  
Rolling Mode ◽  
Path Planning Algorithm ◽  
Grid Division ◽  
Multi Mode ◽  
Motion Strategy

Purpose The purpose of this paper is to put forward a rolling assistant robot with two rolling modes, and the multi-mode rolling motion strategy with path planning algorithm, which is suitable to this multi-mode mobile robot, is proposed based on chessboard-shaped grid division (CGD). Design/methodology/approach Based on the kinematic analysis and motion properties of the mobile parallel robot, the motion strategy based on CGD path planning algorithm of a mobile robot with two rolling modes moving to a target position is divided into two parts, which are local self-motion planning and global path planning. In the first part, the mobile parallel robot can move by switching and combining the two rolling modes; and in the second part, the specific algorithm of the global path planning is proposed according to the CGD of the moving ground. Findings The assistant robot, which is a novel 4-RSR mobile parallel robot (where R denotes a revolute joint and S denotes a spherical joint) integrating operation and rolling locomotion (Watt linkage rolling mode and 6R linkage rolling mode), can work as a moving spotlight or worktable. A series of simulation and prototype experiment results are presented to verify the CGD path planning strategy of the robot, and the performance of the path planning experiments in simulations and practices shows the validation of the path planning analysis. Originality/value The work presented in this paper is a further exploration to apply parallel mechanisms with two rolling modes to the field of assistant rolling robots by proposing the CGD path planning strategy. It is also a new attempt to use the specific path planning algorithm in the field of mobile robots for operating tasks.

Validation of design and materials for additive manufacturing of endocavitary mechanical distractor

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jose Manuel Sierra ◽  
Maria del Rocio Fernandez ◽  
Jose Ignacio Ignacio Rodriguez Garcia ◽  
Jose Luis Cortizo ◽  
Marta María Villazon
Keyword(s):  
Additive Manufacturing ◽  
Low Income ◽  
High Performance ◽  
Design Methodology ◽  
Three Dimensional ◽  
3D Printer ◽  
Validation Process ◽  
Content Type ◽  
Endoscopic Microsurgery ◽  
Optimal Material

Purpose This paper describes the evolution of the design of a mechanical distractor fabricated using additive manufacturing (AM) technology for use in surgical procedures, such as transanal endoscopic microsurgery (TEM). The functionality of the final device was analysed and the suitability of different materials was determined. Design/methodology/approach Solid modelling and finite element modelling software were used in the design and validation process to allow the fabrication of the device by AM. Several prototypes were manufactured and tested in this study. Findings A new design was developed to greatly simplify the existing devices used in TEM surgery. The new design is easy to use, more economical and does not require pneumorectum. Different AM materials were investigated with regard to their mechanical properties, orientation of parts in the three-dimensional (3D) printer and cytotoxicity to select the optimal material for the design. Social implications The device designed by AM can be printed anywhere in the world, provided that a 3D printer is available; the 3D printer does not have to be a high-performance printer. This makes surgery more accessible, particularly in low-income regions. Moreover, patient recovery is improved and pneumorectum is not required. Originality/value A suitable mechanical distractor was designed for TEM, and different materials were validated for fabrication by AM.

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