Removal of singularities in the inverse dynamics of parallel robots

Özdemir, Mustafa

doi:10.1016/j.mechmachtheory.2016.09.009

Cited by 16 publications

(12 citation statements)

References 19 publications

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“…Recently, a complete set of necessary conditions have been derived for enabling parallel robots to pass through type II singular configurations while maintaining stable motion [28]. This contribution increases the potential applicability of the approach proposed in this paper.…”

Section: Remarkmentioning

confidence: 91%

A new terminal converging adaptive control for 6-degree-of-freedom parallel robotic manipulators with bounded control inputs

Zhao

Spurgeon

Liang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part I:

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A new terminal converging adaptive control for 6-degree-of-freedom parallel robotic manipulators with bounded control inputs. Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 231 (4). pp. 271-281. ISSN 0959-6518 Available from: http://eprints.uwe.ac.uk/31842We recommend you cite the published version. The publisher's URL is: http://dx.doi.org/10.1177/0959651817698333Refereed: Yes (no note) Disclaimer UWE has obtained warranties from all depositors as to their title in the material deposited and as to their right to deposit such material. UWE makes no representation or warranties of commercial utility, title, or fitness for a particular purpose or any other warranty, express or implied in respect of any material deposited. UWE makes no representation that the use of the materials will not infringe any patent, copyright, trademark or other property or proprietary rights. UWE accepts no liability for any infringement of intellectual property rights in any material deposited but will remove such material from public view pending investigation in the event of an allegation of any such infringement. PLEASE SCROLL DOWN FOR TEXT. A New Terminal Converging AbstractIn this study, a new terminal converging adaptive control approach with bounded control inputs is developed for the 6 degree of freedom (DOF) parallel robot manipulator. The non-smooth feedback control principle is combined with particular bounded functions to define both the control input and associated adaptive law. TheLyapunov method is used to present a stability analysis in order to prove that the error trajectories are semi-globally asymptotically stable. Numerical simulation results relating to a 6 DOF parallel robot are presented to validate the effectiveness of the proposed approach and to compare the performance obtained with other candidate control schemes. It is shown that the proposed scheme achieves more rapid error convergence and exhibits improved robustness whilst guaranteeing that the control signal remains within known bounds.Keywords: Non-smooth control, Saturation control, Robot manipulator, Parallel robot IntroductionThe 6 DOF parallel robot manipulator has some superior properties when compared with its serial counterpart such as higher accuracy, higher stiffness and higher load-carrying capacity [1,2]. By virtue of these merits, they can be used as actuators for high precision operation of heavy payload such as a flight simulator, an astronomical telescope or machine-tools [3,4]. Such applications require high performance control, which means the designed control algorithm should achieve high precision and a fast convergence speed.From the point of view of systems and control, the 6 DOF parallel robot manipulator is a typical multi-input multi-output (MIMO), strongly coupled nonlinear system. Due to the complex dynamics and application environment, modeling error cannot be avoided. It is very challenging to design high performance control algorithms and this has attracted extens...

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Section: Remarkmentioning

confidence: 91%

A new terminal converging adaptive control for 6-degree-of-freedom parallel robotic manipulators with bounded control inputs

Zhao

Spurgeon

Liang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part I:

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“…It is important to note, however, that singularity-crossing motions can safely be executed if the kinodynamic constraints of the robot are respected [4], [5], [6], [7]. This is a key finding, because the motion capabilities of the robot can be greatly enlarged if such motions are allowed.…”

Section: Imentioning

confidence: 99%

A Singularity-Robust LQR Controller for Parallel Robots

Bordalba

Porta

Ros

2018

2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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Parallel robots exhibit the so-called forward singularities, which complicate substantially the planning and control of their motions. Often, such complications are circumvented by restricting the motions to singularity-free regions of the workspace. However, this comes at the expense of reducing the motion range of the robot substantially. It is for this reason that, recently, efforts are underway to control singularitycrossing trajectories. This paper proposes a reliable controller to stabilize such kind of trajectories. The controller is based on the classical theory of linear quadratic regulators, which we adapt appropriately to the case of parallel robots. As opposed to traditional computed-torque methods, the obtained controller does not rely on expensive inverse dynamics computations. Instead, it uses an optimal control law that is easy to evaluate, and does not generate instabilities at forward singularities. The performance of the controller is exemplified on a five-bar parallel robot accomplishing two tasks that require the traversal of singularities.

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“…13-20 ile verilen f fonksiyonu (0,t f ) aralığında azalmayan bir fonksiyondur (Eş. [25][26][27][28]. …”

Section: T T T T T T F T T T T T F T T T F T T T T T Tunclassified

“…Seçilen bu değerler için f fonksiyonuna ait polinom katsayıları şöyledir: a 3 =−140,1022, a 4 =675,7155, a 5 =−1045,9, a 6 =512,5554, a 7 =118,3645 ve a 8 =−119,5911. Paralel robotların tekil konumlardan geçebilmelerini mümkün kılmak için tutarlılık koşuluna ek olarak sağlanması gereken diğer koşullar Özdemir [25] tarafından verilmiştir. Bu örnek özelinde söz konusu ek koşul, tekillik anında H matrisinin determinantının zamana göre birinci türevinin sıfırdan farklı bir değere sahip olmasıdır.…”

Section:  unclassified

“…Tutarlı hareket planlamasına alternatif olarak geliştirilmiş tekilliklere karşı gürbüz dengeleme [22] ve tekilliklerde tutarlılığa sahip yükleme [23,24] yöntemleri de mevcuttur. Paralel robotların tekil konumlardan geçebilmesi için tutarlılık koşuluna ek olarak sağlanması gereken diğer koşullar Özdemir [25] tarafından sunulmuştur. Bu çalışmaya da konu olan tutarlı hareket planlaması yöntemi, sözü edilen problemin çözümüne dair önemli bir adım olmakla beraber bir dezavantaja da sahiptir.…”

Section: Gi̇ri̇ş (Introduction)unclassified

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