Direct and Inverse Kinematics for Coordinated Motion Tasks of a Two-Manipulator System

1996 ◽  
Vol 118 (4) ◽  
pp. 691-697 ◽  
Author(s):  
P. Chiacchio ◽  
S. Chiaverini ◽  
B. Siciliano

A new formulation for direct kinematics of a system of two manipulators is presented This allows a straightforward description of general coordinated motion tasks in terms of meaningful absolute and relative variables An effective inverse kinematics algorithm is devised which exploits the above formulation where the task Jacobians are expressed in terms of the Jacobians of the single manipulators The scheme is extended to handle the presence of redundant degrees of freedom in the system Different types of grasp between the end effectors and a commonly held object are treated with minimum reformulation effort. Case studies are developed throughout the paper for a system of two PUMA 560 manipulators which illustrate the capabilities of the scheme.

2011 ◽  
Vol 383-390 ◽  
pp. 2350-2355
Author(s):  
Dong Guo ◽  
Min Xu ◽  
Shi Lu Chen ◽  
Yu Qian

The purpose of this study is to produce a modeling capability for integrated flight dynamics of flexible aircraft that can better predict some of the complex behaviors in flight due to multi-physics coupling. Based on the studying of the exiting modeling approaches, the author put forward a new modeling method, and developed a new formulation integrating nonlinear rigid-body flight mechanics and linear aeroelastic dynamics for fully elastic aircrafts using Lagrangian mechanics. The new equations of motion overcome the disadvantages of the exiting methods, and include automatically all six rigid-body degrees of freedom and elastic information, the seamless integration is achieved by using the same reference frame and the same variables to describe the aircraft motions and the forces acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft.


Robotica ◽  
2018 ◽  
Vol 37 (4) ◽  
pp. 675-690 ◽  
Author(s):  
Pavel Laryushkin ◽  
Victor Glazunov ◽  
Ksenia Erastova

SummaryAn approach for calculating the maximum possible absolute values of joint velocities or generalized reactions in a leg of a parallel mechanism has been considered in this paper. The Jacobian analysis and the Screw theory-based methods have been used to acquire the result. These values are calculated for the “worst” directions of the external load or end-effector’s velocity for each leg. The feasibility of using these parameters as the measures of closeness to different types of parallel mechanism singularity is discussed. Further, how this approach is related to the state-of-the-art methods has been illustrated. The key aspect of the discussed approach is that the normalization of vectors or screws is carried out separately for angular and linear components. One possible advantage of such an approach is that it deals only with the kinematic and statics of the mechanism while still providing physically meaningful and practically applicable measures. Case studies of a 3-Degrees Of Freedom translational parallel mechanism and a planar parallel mechanism are presented for illustration and comparison.


Author(s):  
فتحي بن جمعة أحمد

ملخص البحث تعدّ هذه المحاولة في دراسة مجالات التفسير الموضوعي ومنهجية البحث فيه  مفتاحا لبعض القضايا المتعلقة بالموضوع، ومدخلا لدراسة التفسير الموضوعي يسهل على طلاب العلم والباحثين فهم كلام الله، وتدبر معانيه، والاهتداء به، والقيام ببحوث تطبيقية في مجالات التفسير الموضوعي. فقد بينت أن مجالات البحث في التفسير الموضوعي أربعة وهي البحث في المصطلح، والموضوع، والمحاور، والوحدة الموضوعيّة في السورة القرآنيّة. وقد أكدت أن البحث في محاور القرآن الكريم من مجالات البحث في التفسير الموضوعي التي لم تحظَ باهتمام الباحثين، ثم توسعت في سوق الأدلة والبراهين الدالة على أن الوحدة الموضوعية للسورة القرآنيّة مجال أساس من مجالات البحث في التفسير الموضوعي الذي لا ينبغي إغفاله، وإهمال شأنه. ثم بحثت في موضوع منهجيّة البحث في التفسير الموضوعي، ونظراً للخلط أوالاضطراب الذي بدا لدى بعض الباحثين في هذا الصدد، وضحت المقدمات المنهجيّة العامة الضرورية للبحث في التفسير الموضوعي ثم حاولت رسم الإطار التصوري والمنهجي العام والضوابط الأساسية التي يجب أن يتبعها الباحث إذا أراد الكتابة في التفسير الموضوعي. ثم بيّنت الخطوات الأساسيّة للبحث في التفسير الموضوعي ومنها حرية الباحث في اختيار موضوع بحثه والاطلاع على أكبر عدد ممكن من التفاسير بمختلف أنواعها مع الاستفادة من التراث البشري في حقول المعرفة المتنوعة على أن تكون الهيمنة للقرآن أولا وأخيرا على الكتب الأخرى والنظريات البشرية. الكلمات الرئيسة: القرآن، تفسير، موضوعي، مجالات، منهج. Abstract This article is an attempt to address the issue of the scopes and research methodology in the thematic commentary of the Holy Qur’Én. It could be considered as an introductory work for students and researchers who are interested in this field of research which will help them develop a good understanding of the meanings and teachings of the Qur’Én and its application to the real life. It may also help them undertake case studies and research in the field of thematic commentary of the Qur’Én. It has been explained in the article that the scope of the thematic commentary of the Qur’Én includes four areas; i.e. the concept, the topic, the central themes and the thematic unity of the SËrah/Chapter. The article gives a special emphasis on the study of the Qur’Énic central themes as it was overlooked by some researchers. It also provides a systematic investigation on the thematic unity of the SËrah/Chapter and considers it a significant area of research in the thematic commentary of the Qur’Én. The article also addresses the issue of the research methodology in the field of the thematic commentary of the Qur’Én. In this regard, the author highlights the principles, conditions and framework for undertaking research projects in this field of study and explains the major steps that should be followed in the execution of the research. These steps include freedom of choosing the research topic, freedom of benefitting from different types of tafsÊr (interpretation of the Qur’Én) works and schools and benefitting from the human heritage in different fields of knowledge, provided that the Qur’Én should have controlling power on other books and human theories.   Key Words: The Qur’Én, TafsÊr, Thematic, Scopes, Methodology. Abstrak Artikel ini ialah satu percubaan menangani isu  skop dan metodologi penyelidikan dalam tafsiran Al-Qur’Én Holy mengikut tema. Ia boleh dianggap sebagai satu kajian permulaan untuk pelajar-pelajar dan sarjana-sarjana yang meminati bidang ini penyelidikan yang akan membantu mereka merangka satu pemahaman yang baik tentang makna-makna dan ajaran-ajaran Qur’Én dan perlaksanaannya dalam kehidupan sebenar. Ia mungkin juga  dapat membantu mereka menjalankan kajian kes dalam bidang penyelidikan tafsiran Al-Qur’Én mengikut tema. Artikel ini akan menjelaskan  skop tafsiran Al-Qur’Én mengikut  tema ini merangkumi empat bidang:  konsep tafsiran mengikut tema, topiknya, tema-tema kecil dan tema umum Surah Al-Qur’Én. Artikel ini memberi satu penekanan khas pada kajian tafsiran Al-Qur’Én mengikut  tema kerana ia agak kurang mendapat perhatian beberapa penyelidik. Ia juga menampilkan satu kajian sistematik pada pemahaman tema Surah dalam Al-Qur’Én dan menganggapnya satu bidang penyelidikan penting dalam kajian tafsiran Al-Qur’Én mengikut tema. Artikel juga memberikan perhatian kepada bidang metodologi penyelidikan terhadap usaha tafsiran Al-Qur’Én secara bertema. Dalam hal ini, pengkaji akan menonjolkan prinsip-prinsip, syarat-syarat dan rangka kerja untuk projek-projek projek penyelidikan dalam lapangan ini dan menerangkan langkah-langkah utama yang harus diikuti dalam pelaksanaan penyelidikan yang berkenaan. Lang-langkah ini termasuk kebebasan memilih tajuk penyelidikan, kebebasan dalam mengambil  manfaat daripada jenis-jenis tafsiran Qur’Én yang berbeza serta sekolah-sekolah pemikiran yang berbeza dalam aliran tafsir serta rangka bagaimana memanfaatkan warisan tamadun manusia berlandaskan ajaran Al-Qur’Én. Kata Kunci: Al-Qur’Én, TafsÊr, Tema, Bidang-bidang, Metodologi.


Robotica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Paolo Di Lillo ◽  
Gianluca Antonelli ◽  
Ciro Natale

SUMMARY Control algorithms of many Degrees-of-Freedom (DOFs) systems based on Inverse Kinematics (IK) or Inverse Dynamics (ID) approaches are two well-known topics of research in robotics. The large number of DOFs allows the design of many concurrent tasks arranged in priorities, that can be solved either at kinematic or dynamic level. This paper investigates the effects of modeling errors in operational space control algorithms with respect to uncertainties affecting knowledge of the dynamic parameters. The effects on the null-space projections and the sources of steady-state errors are investigated. Numerical simulations with on-purpose injected errors are used to validate the thoughts.


Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson

The size and limited dexterity of current surgical robotic systems are factors which limit their usefulness. To improve the level of assimilation of surgical robots in minimally invasive surgery (MIS), a compact, lightweight surgical robotic positioning mechanism with four degrees of freedom (DOF) (three rotational DOF and one translation DOF) is proposed in this paper. This spatial mechanism based on a bevel-gear wrist is remotely driven with three rotation axes intersecting at a remote rotation center (the MIS entry port). Forward and inverse kinematics are derived, and these are used for optimizing the mechanism structure given workspace requirements. By evaluating different spherical geared configurations with various link angles and pitch angles, an optimal design is achieved which performs surgical tool positioning throughout the desired kinematic workspace while occupying a small space bounded by a hemisphere of radius 13.7 cm. This optimized workspace conservatively accounts for collision avoidance between patient and robot or internally between the robot links. This resultant mechanism is highly compact and yet has the dexterity to cover the extended workspace typically required in telesurgery. It can also be used for tool tracking and skills assessment. Due to the linear nature of the gearing relationships, it may also be well suited for implementing force feedback for telesurgery.


2021 ◽  
Vol 11 (13) ◽  
pp. 6209
Author(s):  
Iwona Pajak ◽  
Grzegorz Pajak

This paper presents the usage of holonomic mobile humanoid manipulators to carry out autonomous tasks in industrial environments, according to the smart factory concept and the Industry 4.0 philosophy. The problem of transporting lengthy objects, taking into account mechanical limitations, the conditions for avoiding collisions, as well as the dexterity of the manipulator arms was considered. The primary problem was divided into three phases, leading to three different types of robotic tasks. In the proposed approach, the pseudoinverse Jacobian method at the acceleration level to solve each of the tasks was used. The redundant degrees of freedom were used to satisfy secondary objectives such as robot kinetic energy, the maximization of the manipulability measure, and the fulfillment mechanical and collision-avoidance limitations. A computer example involving a mobile humanoid manipulator, operating in an industrial environment, illustrated the effectiveness of the proposed method.


2021 ◽  
Vol 11 (5) ◽  
pp. 2346
Author(s):  
Alessandro Tringali ◽  
Silvio Cocuzza

The minimization of energy consumption is of the utmost importance in space robotics. For redundant manipulators tracking a desired end-effector trajectory, most of the proposed solutions are based on locally optimal inverse kinematics methods. On the one hand, these methods are suitable for real-time implementation; nevertheless, on the other hand, they often provide solutions quite far from the globally optimal one and, moreover, are prone to singularities. In this paper, a novel inverse kinematics method for redundant manipulators is presented, which overcomes the above mentioned issues and is suitable for real-time implementation. The proposed method is based on the optimization of the kinetic energy integral on a limited subset of future end-effector path points, making the manipulator joints to move in the direction of minimum kinetic energy. The proposed method is tested by simulation of a three degrees of freedom (DOF) planar manipulator in a number of test cases, and its performance is compared to the classical pseudoinverse solution and to a global optimal method. The proposed method outperforms the pseudoinverse-based one and proves to be able to avoid singularities. Furthermore, it provides a solution very close to the global optimal one with a much lower computational time, which is compatible for real-time implementation.


2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi

Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.


Author(s):  
Saeed Behzadipour

A new hybrid cable-driven manipulator is introduced. The manipulator is composed of a Cartesian mechanism to provide three translational degrees of freedom and a cable system to drive the mechanism. The end-effector is driven by three rotational motors through the cables. The cable drive system in this mechanism is self-stressed meaning that the pre-tension of the cables which keep them taut is provided internally. In other words, no redundant actuator or external force is required to maintain the tensile force in the cables. This simplifies the operation of the mechanism by reducing the number of actuators and also avoids their continuous static loading. It also eliminates the redundant work of the actuators which is usually present in cable-driven mechanisms. Forward and inverse kinematics problems are solved and shown to have explicit solutions. Static and stiffness analysis are also performed. The effects of the cable’s compliance on the stiffness of the mechanism is modeled and presented by a characteristic cable length. The characteristic cable length is calculated and analyzed in representative locations of the workspace.


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