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Article
Publication date: 23 August 2011

Ming Cong, Dong Liu, Yu Du, Haiying Wen and Yinghua Wu

The purpose of this paper is to build a seven‐degrees of freedom (DOF) parallel‐serial robot system which has the advantage of mechanical novelty and simplicity compared…

Abstract

Purpose

The purpose of this paper is to build a seven‐degrees of freedom (DOF) parallel‐serial robot system which has the advantage of mechanical novelty and simplicity compared with the existing platforms, and to share the experience of converting a popular motion base to an industrial robot for use in full‐mission tank training processes of three armored arms.

Design/methodology/approach

By studying the concept of the robot system, a novel parallel‐serial robot with seven DOF driven by electrical servo motors is built. And the transmission modules and Hooke joints are explored and designed in detail. Then the inverse kinematics based on coupling compensation and time‐jerk synthetic optimization methods for trajectory planning of the simulator are presented and further discussed in order to satisfy the requirements of high stability and perfect performance. In advance, the feasibility and applicability of this triune parallel‐serial robot system are verified.

Findings

A prototyped test shows that the performance of the system is of a satisfaction with real‐time tracking any trajectories given by the visual system smoothly. Finally, the characteristics of the robot system are realized and verified by experiments and an industrial application.

Practical implications

The triune full‐mission tank training simulator developed in this paper has been used in the military industry and it has a great potential application.

Originality/value

This successful usage of the novel and simple parallel robot system in the military industry expands the range of its applications in real‐life task more operators training. And the proposal methods of inverse kinematics based on coupling compensation and trajectory planning enhanced the theoretical research of the parallel robot.

Details

Industrial Robot: An International Journal, vol. 38 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 7 August 2007

Mathias Krefft, Philipp Last, Christoph Budde, Jochen Maass, Jürgen Hesselbach and Friedrich M. Wahl

This paper seeks to establish parallel robots with strong performance characteristics in handling and assembly processes.

Abstract

Purpose

This paper seeks to establish parallel robots with strong performance characteristics in handling and assembly processes.

Design/methodology/approach

The presented work introduces concepts and solutions related to the improvement of parallel kinematic mechanisms. Structural design topics and modeling approaches are as well considered as control schemes and new machine components particularly designed for high‐dynamic parallel robots. The results have been achieved by a unique interdisciplinary research group linking knowledge from mechanical engineering, electrical engineering and computer science.

Findings

The paper found numerous individually applicable methods leading to an improved efficiency of parallel robots. Several of the developments have been already implemented and validated by various self‐built machine prototypes and a new control system.

Originality/value

Owing to higher stiffness, accuracy and improved dynamic behavior parallel robots proved to be an efficient and suitable supplement to serial robots. By means of the various developments contributed in this paper, the promising potential of this class of robots is once more emphasized and further strengthened.

Details

Assembly Automation, vol. 27 no. 3
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 7 March 2008

Huapeng Wu, Heikki Handroos and Pekka Pessi

The purpose of this paper is to build up a parallel robot for assembling, machining and repairing of the vacuum vessel of the international thermonuclear experimental…

Abstract

Purpose

The purpose of this paper is to build up a parallel robot for assembling, machining and repairing of the vacuum vessel of the international thermonuclear experimental reactor (ITER).

Design/methodology/approach

The process of assembling and machining of the vacuum vessel need a special robot. By studying the structure of the vacuum vessel, a novel parallel robot is built, which has ten degrees of freedom driven by water hydraulic cylinders and electrical servo motors. Kinematic models for the redundant degree robot have been defined. A prototype has been built. Experiments for machine cutting and laser welding were carried out.

Findings

The parallel robot is capable of holding all necessary machining tools and welding end‐effectors in all positions accurately and stably inside the vacuum vessel sector. The kinematic models appeared to be complex because of the redundant structure of the robot, and an optimization algorithm ensuring the maximum stiffness during the robot motion helps to find the solution in the trajectory planning. The entire design and testing process of the robot appeared to be a very complex task due to the high specialization of the manufacturing technology needed in the ITER reactor, while the results demonstrate the applicability of the proposed solutions quite well.

Originality/value

Offers not only a device but also a methodology for the assembling and repairing of ITER by means of a parallel robot.

Details

Industrial Robot: An International Journal, vol. 35 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 16 January 2017

Yezhuo Li, Yan-An Yao, Junlin Cheng, Yaobin Tian and Ran Liu

The purpose of this paper is to propose an agile assistant robot to be used as a mobile partner with two rotational motions and one translational motion. This robot

Abstract

Purpose

The purpose of this paper is to propose an agile assistant robot to be used as a mobile partner with two rotational motions and one translational motion. This robot possesses the rolling function and three operating abilities to assistant human beings in the industrial environment.

Design/methodology/approach

The main body of the robot is a typical 4-RSR (where R denotes a revolute joint and S denotes a spherical joint) parallel mechanism. The mechanism can reach any position on the ground by two rolling modes (the equivalent Watt linkage rolling mode and the equivalent 6R linkage rolling mode), and the robot can work as a spotlight or a worktable in operating modes at the target location. The mobility, rolling modes, operating modes and kinematics are analyzed.

Findings

Based on the results of kinematics of this assistant robot, the upper platform of the 4-RSR rolling mechanism has two rotational motions and one translational motion which can be used in the industry. The proposed concept is verified by experiments on a physical prototype.

Practical implications

This paper also discusses the application to industrial cases where cooperation between workers and robots is required.

Originality/value

The work presented in this paper is a novel exploration to apply parallel mechanisms to the field of assistant rolling robots. It is also a new attempt to use the rolling mechanism in the field of mobile operating robots for industry tasks.

Details

Industrial Robot: An International Journal, vol. 44 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 13 May 2014

Mehdi Dehghani, Mahdi Ahmadi, Alireza Khayatian, Mohamad Eghtesad and Mehran Yazdi

The purpose of this paper is to present a vision-based method for the kinematic calibration of a six-degrees-of-freedom parallel robot named Hexa using only one Universal…

Abstract

Purpose

The purpose of this paper is to present a vision-based method for the kinematic calibration of a six-degrees-of-freedom parallel robot named Hexa using only one Universal Serial Bus (USB) camera and a chess pattern installed on the robot's mobile platform. Such an approach avoids using any internal sensors or complex three-dimensional measurement systems to obtain the pose (position/orientation) of the robot's end-effector or the joint coordinates.

Design/methodology/approach

The setup of the proposed method is very simple; only one USB camera connected to a laptop computer is needed and no contact with the robot is necessary during the calibration procedure. For camera modeling, a pinhole model is used; it is then modified by considering some distortion coefficients. Intrinsic and extrinsic parameters and the distortion coefficients are found by an offline minimization algorithm. The chess pattern makes image corner detection very straightforward; this detection leads to finding the camera and then the kinematic parameters. To carry out the calibration procedure, several trajectories are run (the results of two of them are presented here) and sufficient specifications of the poses (positions/orientations) are calculated to find the kinematic parameters of the robot. Experimental results obtained when applying the calibration procedure on a Hexa parallel robot show that vision-based kinematic calibration yields enhanced and efficient positioning accuracy. After successful calibration and addition of an appropriate control scheme, the robot has been considered as a color-painting prototype robot to serve in relevant industries.

Findings

Experimental results obtained when applying the calibration procedure on a Hexa parallel robot show that vision-based kinematic calibration yields enhanced and efficient positioning accuracy.

Originality/value

The enhanced results show the advantages of this method in comparison with the previous calibration methods.

Details

Industrial Robot: An International Journal, vol. 41 no. 3
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 28 August 2007

James A. Hunt

This paper aims to describe the topic of robot kinematics and provide a modern machine.

Abstract

Purpose

This paper aims to describe the topic of robot kinematics and provide a modern machine.

Design/methodology/approach

The paper examines, in brief, kinematics and robot kinematics, classes, constraints and chains to provide an introduction. An example shows how robot kinematics can benefit the design of advanced machines for industry.

Findings

Robot kinematics, in conjunction with mathematics and other disciplines, lead to a greater understanding of robotics design and control.

Originality/value

This paper discusses robot kinematics in brief as a robot design topic in its own right, as well as presenting the Gantry‐Tau robot as a new and interesting kinematic development. As such, the article should be of general interest to robotics engineers and designers.

Details

Industrial Robot: An International Journal, vol. 34 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 21 May 2018

Zhaotian Wang, Yezhuo Li and Yan-An Yao

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…

Abstract

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.

Details

Industrial Robot: An International Journal, vol. 45 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 20 April 2020

J. Guillermo Lopez-Lara, Mauro Eduardo Maya, Alejandro González, Antonio Cardenas and Liliana Felix

The purpose of this paper is to present a new vision-based control method, which enables delta-type parallel robots to track and manipulate objects moving in arbitrary…

Abstract

Purpose

The purpose of this paper is to present a new vision-based control method, which enables delta-type parallel robots to track and manipulate objects moving in arbitrary trajectories. This constitutes an enhanced variant of the linear camera model-camera space manipulation (LCM-CSM).

Design/methodology/approach

After obtaining the LCM-CSM view parameters, a moving target’s position and its velocity are estimated in camera space using Kalman filter. The robot is then commanded to reach the target. The proposed control strategy has been experimentally validated using a PARALLIX LKF-2040, an academic delta-type parallel platform and seven different target trajectories for which the positioning errors were recorded.

Findings

For objects that moved manually along a sawtooth, zigzag or increasing spiral trajectory with changing velocities, a maximum positioning error of 4.31 mm was found, whereas objects that moved on a conveyor belt at constant velocity ranging from 7 to 12 cm/s, average errors between 2.2-2.75 mm were obtained. For static objects, an average error of 1.48 mm was found. Without vision-based control, the experimental platform used has a static positioning accuracy of 3.17 mm.

Practical implications

The LCM-CSM method has a low computational cost and does not require calibration or computation of Jacobians. The new variant of LCM-CSM takes advantage of aforementioned characteristics and applies them to vision-based control of parallel robots interacting with moving objects.

Originality/value

A new variant of the LCM-CSM method, traditionally used only for static positioning of a robot’s end-effector, was applied to parallel robots enabling the manipulation of objects moving along unknown trajectories.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Content available
Article
Publication date: 2 December 2019

Yitao Pan, Yuan Chen and Lin Li

The purpose of this paper is to propose a two-degrees-of-freedom wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring, in order to improve the…

Abstract

Purpose

The purpose of this paper is to propose a two-degrees-of-freedom wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring, in order to improve the robot’s athletic ability, load capacity and rigidity, and to ensure the coordination of multi-modal motion.

Design/methodology/approach

First, based on the rotation transformation matrix and closed-loop constraint equation of the parallel trunk joint mechanism, the mathematical model of its inverse position solution is constructed. Then, the Jacobian matrix of velocity and acceleration is derived by time derivative method. On this basis, the stiffness matrix of the parallel trunk joint mechanism is derived on the basis of the principle of virtual work and combined with the deformation effect of the rope driving pair and the spring elastic restraint pair. Then, the eigenvalue distribution of the stiffness matrix and the global stiffness performance index are used as the stiffness evaluation index of the mechanism. In addition, the performance index of athletic dexterity is analyzed. Finally, the distribution map of kinematic dexterity and stiffness is drawn in the workspace by numerical simulation, and the influence of the introduced spring on the stiffness distribution of the parallel trunk joint mechanism is compared and analyzed. It is concluded that the stiffness in the specific direction of the parallel trunk joint mechanism can be improved, and the stiffness distribution can be improved by adjusting the spring elastic structure parameters of the rope-driven branch chain.

Findings

Studies have shown that the wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring has a great kinematic dexterity, load-carrying capacity and stiffness performance.

Research limitations/implications

The soft-mixed structure is not mature, and there are few new materials for the soft-mixed mixture; the rope and the rigid structure are driven together with a large amount of friction and hindrance factors, etc.

Practical implications

It ensures that the multi-motion mode hexapod mobile robot can meet the requirement of sufficient different stiffness for different motion postures through the parallel trunk joint mechanism, and it ensures that the multi-motion mode hexapod mobile robot in multi-motion mode can meet the performance requirement of global stiffness change at different pose points of different motion postures through the parallel trunk joint mechanism.

Social implications

The trunk structure is a very critical mechanism for animals. Animals in the movement to achieve smooth climbing, overturning and other different postures, such as centipede, starfish, giant salamander and other multi-legged animals, not only rely on the unique leg mechanism, but also must have a unique trunk joint mechanism. Based on the cooperation of these two mechanisms, the animal can achieve a stable, flexible and flexible variety of motion characteristics. Therefore, the trunk joint mechanism has an important significance for the coordinated movement of the whole body of the multi-sport mode mobile robot (Huang Hu-lin, 2016).

Originality/value

In this paper, based on the idea of combining rigid parallel mechanism with wire-driven mechanism, a trunk mechanism is designed, which is composed of four spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism in series. Its spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism can make the multi-motion mode mobile robot have better load capacity, mobility and stiffness performance (Qi-zhi et al., 2018; Cong-hao et al., 2018), thus improving the environmental adaptability and reliability of the multi-motion mode mobile robot.

Details

International Journal of Structural Integrity, vol. 10 no. 6
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 2 December 2019

Fei Guo, Shoukun Wang, Junzheng Wang and Huan Yu

In this research, the authors established a hierarchical motion planner for quadruped locomotion, which enables a parallel wheel-quadruped robot, the “BIT-NAZA” robot, to…

Abstract

Purpose

In this research, the authors established a hierarchical motion planner for quadruped locomotion, which enables a parallel wheel-quadruped robot, the “BIT-NAZA” robot, to traverse rough three-dimensional (3-D) terrain.

Design/methodology/approach

Presented is a novel wheel-quadruped mobile robot with parallel driving mechanisms and based on the Stewart six degrees of freedom (6-DOF) platform. The task for traversing rough terrain is decomposed into two prospects: one is the configuration selection in terms of a local foothold cost map, in which the kinematic feasibility of parallel mechanism and terrain features are satisfied in heuristic search planning, and the other one is a whole-body controller to complete smooth and continuous motion transitions.

Findings

A fan-shaped foot search region focuses on footholds with a strong possibility of becoming foot placement, simplifying computation complexity. A receding horizon avoids kinematic deadlock during the search process and improves robot adaptation.

Research limitations/implications

Both simulation and experimental results validated the proposed scenario available and appropriate for quadruped locomotion to traverse challenging 3-D terrains.

Originality/value

This paper analyzes kinematic workspace for a parallel robot with 6-DOF Stewart mechanism on both body and foot. A fan-shaped foot search region enhances computation efficiency. Receding horizon broadens the preview search to decrease the possibility of deadlock minima resulting from terrain variation.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

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