A coupled and indirectly self-adaptive under-actuated hand with double-linkage-slider mechanism

2019 ◽  
Vol 46 (5) ◽  
pp. 660-671 ◽  
Author(s):  
Siyun Liu ◽  
Wenzeng Zhang ◽  
Jie Sun
Keyword(s):  
Kinematic Analysis ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
High Reliability ◽  
Robotic Hand ◽  
Force Analysis ◽  
Content Type ◽  
High Flexibility ◽  
Two Stages ◽  
Self Adaptive

Purpose Underactuated fingers are adapted to generate several grasping modes for different tasks, and coupled fingers and self-adaptive fingers are two important types of them. Aiming to expand the application and increase adaptability of robotic hand, this paper aims to propose a novel grasping model, called coupled and indirectly self-adaptive (CISA) grasping model, which is the combination of coupled finger and indirectly self-adaptive finger. Design/methodology/approach CISA grasping process includes two stages: first, coupled and then indirectly self-adaptive grasping; thus, it is not only integrated with the good pinching ability of coupled finger but also characterized with the high flexibility of indirectly self-adaptive finger. Furthermore, a CISA hand with linkage-slider, called CISA-LS hand, is designed based on the CISA grasping model, consisting of 1 palm, 5 CISA-LS fingers and 14 degrees of freedom. Findings To research the grasping behavior of CISA-LS hand, kinematic analysis, dynamic analysis and force analysis of 2-joint CISA-LS finger are performed. Results of grasping experiments for different objects demonstrate the high reliability and stability of CISA-LS hand. Originality/value CISA fingers integrate two grasping modes, coupled grasping and indirectly self-adaptive grasping, into one finger. And a double-linkage-slider mechanism is designed as the switch device.

Analysis and Optimization of a New Differentially Driven Cable Parallel Robot

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Hamed Khakpour ◽  
Lionel Birglen ◽  
Souheil-Antoine Tahan
Keyword(s):  
Kinematic Analysis ◽  
Design Methodology ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Cable Robot ◽  
Proper Design ◽  
Two Indices ◽  
Three Degrees Of Freedom ◽  
Cable Robots

In this paper, a new three degrees of freedom (DOF) differentially actuated cable parallel robot is proposed. This mechanism is driven by a prismatic actuator and three cable differentials. Through this design, the idea of using differentials in the structure of a spatial cable robot is investigated. Considering their particular properties, the kinematic analysis of the robot is presented. Then, two indices are defined to evaluate the workspaces of the robot. Using these indices, the robot is subsequently optimized. Finally, the performance of the optimized differentially driven robot is compared with fully actuated mechanisms. The results show that through a proper design methodology, the robot can have a larger workspace and better performance using differentials than the fully driven cable robots using the same number of actuators.

Take-off control and characteristics of FanWing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lin Meng ◽  
Yang Gao ◽  
Yangyang Liu ◽  
Shengfang Lu
Keyword(s):  
Control System ◽  
Control Systems ◽  
Design Methodology ◽  
Control System Design ◽  
Control Methods ◽  
Force Analysis ◽  
Close Attention ◽  
Content Type ◽  
Vehicle Load ◽  
Practical Implications

Purpose As a short take-off and landing aircraft, FanWing has the capability of being driven under power a short distance from a parking space to the take-off area. The purpose of this paper is to design the take-off control system of FanWing and study the factors that influence the short take-off performance under control. Design/methodology/approach The force analysis of FanWing is studied in the take-off phase. Two take-off control methods are researched, and several factors that influence the short take-off performance are studied under control. Findings The elevator and fan wing control systems are designed. Although the vehicle load increases under the fan wing control, the fan wing control is not a recommended practice in the take-off phase for its sensitivity to the pitch angle command. The additional pitch-down moment has a significant influence on the control system and the short take-off performance that the barycenter variation of FanWing should be considered carefully. Practical implications The presented efforts provide a reference for the location of the center of gravity in designing FanWing. The traditional elevator control is more recommended than the fan wing control in the take-off phase. Originality/value This paper offers a valuable reference on the control system design of FanWing. It also proves that there is an additional pith-down moment that needs to be paid close attention to. Four factors that influence the short take-off performance are compared under control.

Design and vibration analysis of a self-adaptive piston in a novel nanoimprint system

2017 ◽  
Vol 69 (4) ◽  
pp. 591-597
Author(s):  
Chaoran Liu ◽  
Yufeng Su ◽  
Jinzhao Yue ◽  
Junjie Wang ◽  
Weiwei Xia ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Vibration Analysis ◽  
Design Methodology ◽  
The Self ◽  
Ball Screw ◽  
Piston Rings ◽  
Content Type ◽  
Simulation Results ◽  
The One ◽  
Self Adaptive

Purpose A self-adaptive piston is designed for the compressional gas cushion press nanoimprint lithography system. It avoids the lube pollution and high wear of traditional piston. Design/methodology/approach The self-adaptive piston device consists of symmetrical piston bodies, piston rings and other parts. The two piston bodies are linked by a ball-screw. The locking nut adjusts the distance between two piston bodies to avoid the piston rings from being stuck. The piston rings are placed between two piston bodies. Findings The simulation results based on COMSOL indicate that cylinder vibration caused by self-adaptive piston is 15.9 times smaller than the one caused by a traditional piston. Originality/value The self-adaptive piston is superior to the traditional piston in decreasing cylinder vibration.

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.

Optimal grasp force for robotic grasping and in-hand manipulation with impedance control

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaoqing Li ◽  
Ziyu Chen ◽  
Chao Ma
Keyword(s):  
Degrees Of Freedom ◽  
Impedance Control ◽  
Difficult Problem ◽  
Contact Forces ◽  
Design Parameters ◽  
Robotic Hand ◽  
Content Type ◽  
Cone Constraint ◽  
Grasp Force ◽  
Grasp Quality

Purpose The purpose of this paper is to achieve stable grasping and dexterous in-hand manipulation, the control of the multi-fingered robotic hand is a difficult problem as the hand has many degrees of freedom with various grasp configurations. Design/methodology/approach To achieve this goal, a novel object-level impedance control framework with optimized grasp force and grasp quality is proposed for multi-fingered robotic hand grasping and in-hand manipulation. The minimal grasp force optimization aims to achieve stable grasping satisfying friction cone constraint while keeping appropriate contact forces without damage to the object. With the optimized grasp quality function, optimal grasp quality can be obtained by dynamically sliding on the object from initial grasp configuration to final grasp configuration. By the proposed controller, the in-hand manipulation of the grasped object can be achieved with compliance to the environment force. The control performance of the closed-loop robotic system is guaranteed by appropriately choosing the design parameters as proved by a Lyapunove function. Findings Simulations are conducted to validate the efficiency and performance of the proposed controller with a three-fingered robotic hand. Originality/value This paper presents a method for robotic optimal grasping and in-hand manipulation with a compliant controller. It may inspire other related researchers and has great potential for practical usage in a widespread of robot applications.

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.

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