Imperial College London

Dr Nicolas Rojas

Faculty of EngineeringDyson School of Design Engineering

Lecturer
 
 
 
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Contact

 

n.rojas

 
 
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Location

 

Dyson BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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46 results found

N Rojas, F Thomas, 2013, The closure condition of the double banana and its application to robot position analysis, 2013 IEEE International Conference on Robotics and Automation, Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 4641-4646, ISSN: 1050-4729

A double banana is defined as the bar-and-joint assembly of two bipyramids joined by their apexes. Clearly, the bar lengths of this kind of assembly are not independent as we cannot assign arbitrary values to them. This dependency can be algebraically expressed as a closure condition fully expressed in terms of bar lengths. This paper is devoted to its derivation and to show how its use simplifies the position analysis of many well-known serial and parallel robots thus providing a unifying treatment to apparently disparate problems. This approach permits deriving the univariate polynomials, needed for the closed-form solution of these position analysis problems, without relying on trigonometric substitutions or difficult variable eliminations.

CONFERENCE PAPER

Rojas N, Mohan R, Sosa R, 2013, Reconfiguration in linkages by variable allocation of joint positions: a modular design approach, 3rd IFToMM International Symposium on Robotics and Mechatronics, Pages: 587-596

CONFERENCE PAPER

Mohan RE, Rojas N, Seah S, Sosa Ret al., 2013, Design principles for robot inclusive spaces, 19th International Conference on Engineering Design (ICED13)

CONFERENCE PAPER

Rojas N, Thomas F, 2013, The Univariate Closure Conditions of All Fully Parallel Planar Robots Derived From a Single Polynomial, IEEE Transactions on Robotics, Vol: 29, Pages: 758-765, ISSN: 1552-3098

JOURNAL ARTICLE

Rojas N, Thomas F, 2013, Application of Distance Geometry to Tracing Coupler Curves of Pin-Jointed Linkages 1, Journal of Mechanisms and Robotics, Vol: 5, Pages: 021001-021001, ISSN: 1942-4302

JOURNAL ARTICLE

M R Elara, N Rojas, R Sosa, J Kaisneret al., 2013, Robot Inclusive Space challenge: A design initiative, 2013 6th IEEE Conference on Robotics, Automation and Mechatronics (RAM), Pages: 73-78, ISSN: 2158-2181

CONFERENCE PAPER

S Nansai, N Rojas, M R Elara, R Sosaet al., 2013, Exploration of adaptive gait patterns with a reconfigurable linkage mechanism, 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems, Pages: 4661-4668, ISSN: 2153-0858

CONFERENCE PAPER

Rojas N, Thomas F, 2012, Formulating Assur kinematic chains as projective extensions of Baranov trusses, Mechanism and Machine Theory, Vol: 56, Pages: 16-27, ISSN: 0094-114X

JOURNAL ARTICLE

Rojas N, Thomas F, 2012, On closed-form solutions to the position analysis of Baranov trusses, Mechanism and Machine Theory, Vol: 50, Pages: 179-196, ISSN: 0094-114X

JOURNAL ARTICLE

N Rojas, J Borràs, F Thomas, 2012, The octahedral manipulator revisited, 2012 IEEE International Conference on Robotics and Automation, Pages: 2293-2298, ISSN: 1050-4729

CONFERENCE PAPER

Rojas N, Thomas F, 2011, A Coordinate-Free Approach to Tracing the Coupler Curves of Pin-Jointed Linkages, ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Pages: 417-426

In general, high-order coupler curves of plane mechanisms cannot be properly traced by standard predictor-corrector algorithms due to drifting problems and the presence of singularities. Instead of focusing on finding better algorithms for tracing curves, a simple coordinate-free method that first traces these curves in a distance space and then maps them onto the mechanism workspace is proposed. Tracing a coupler curve in the proposed distance space is much simpler because (a) the equation of this curve in this space can be straightforwardly obtained from a sequence of bilaterations; and (b) the curve in this space naturally decomposes into branches in which the signs of the oriented areas of the triangles involved in the aforementioned bilaterations remain constant. A surjective mapping permits to map the thus traced curves onto the workspace of the mechanism. The advantages of this two-step method are exemplified by tracing the coupler curves of a double butterfly linkage, curves that can reach order 48.

CONFERENCE PAPER

Rojas N, Thomas F, 2011, The Forward Kinematics of 3-R$\underline{P}$R Planar Robots: A Review and a Distance-Based Formulation, IEEE Transactions on Robotics, Vol: 27, Pages: 143-150, ISSN: 1552-3098

JOURNAL ARTICLE

Rojas N, Thomas F, 2011, Distance-based position analysis of the three seven-link Assur kinematic chains, Mechanism and Machine Theory, Vol: 46, Pages: 112-126, ISSN: 0094-114X

JOURNAL ARTICLE

Rojas N, Thomas F, 2011, Closed-Form Solution to the Position Analysis of Watt–Baranov Trusses Using the Bilateration Method, Journal of Mechanisms and Robotics, Vol: 3, Pages: 031001-031001, ISSN: 1942-4302

JOURNAL ARTICLE

Rojas N, Borràs J, Thomas F, 2010, A distance-based formulation of the octahedral manipulator kinematics, IFToMM Symposium on Mechanism Design for Robotics 2010, Pages: 1-12

CONFERENCE PAPER

Rojas N, Thomas F, 2010, A Robust Forward Kinematics Analysis of 3-RPR Planar Platforms, Advances in Robot Kinematics: Motion in Man and Machine, Editors: Lenarcic, Stanisic, Dordrecht, Publisher: Springer Netherlands, Pages: 23-32, ISBN: 978-90-481-9262-5

BOOK CHAPTER

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