scholarly journals Inverse modeling of the stewart foot

2021 ◽  
Vol 12 (9) ◽  
pp. s774-s793
Author(s):  
Adriana Comanescu ◽  
Alexandra Rotaru ◽  
Liviu Marian Ungureanu ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Inverse Modeling ◽  
Inverse Kinematics ◽  
Robotic Systems ◽  
Kinematic Modeling ◽  
Kinematic Parameters ◽  
End Effector ◽  
Kinematic Chains ◽  
Special Character ◽  
Logical Functions

The Stewart's leg is used today in the majority of parallel robotic systems, such as the Stewart platform, but also in many other types of mechanisms and kinematic chains, in order to operate them or to transmit motion. A special character in the study of robots is the study of inverse kinematics, with the help of which the map of the motor kinematic parameters necessary to obtain the trajectories imposed on the effector can be made. For this reason, in the proposed mechanism, we will present reverse kinematic modeling in this paper. The kinematic output parameters, ie the parameters of the foot and practically of the end effector, ie those of the point marked with T, will be determined for initiating the working algorithm with the help of logical functions, "If log(ical)", with the observation that here they play the role of input parameters; it is positioned as already specified in the inverse kinematics when the output is considered as input and the input as output. The logical functions used, as well as the entire calculation program used, were written in Math Cad.

scholarly journals Positional modeling of the 2T6R robot mechanism

2021 ◽  
Vol 12 (9) ◽  
pp. s902-s921
Author(s):  
Adriana Comanescu ◽  
Alexandra Rotaru ◽  
Liviu Marian Ungureanu ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Inverse Kinematics ◽  
Simple Algorithm ◽  
Logical Function ◽  
End Effector ◽  
Logical Functions

The positional modeling of the 2T6R robot mechanism is done for inverse kinematics, i.e. when the imposed positions of the end effector T, imposed, belonging to the final element 3, are known and the necessary positions and speeds of the two input motors, the two leading elements, are determined, 1 and 6. It is proposed to solve a simple algorithm in the program MathCad 2000, which uses for initiation the logical function If Log. The kinematic output parameters, i.e. the parameters of the foot and practically of the final effector, i.e. those of the point marked with T, will be determined for initiating the working algorithm using the logical functions, "If log (ical)", with the observation that here plays the role of parameters input; is positioned as already specified in reverse kinematics when the output is considered as input and input as output. The logical functions used, as well as the entire calculation program used, were written in Math Cad 2000.

scholarly journals Inverse and Forward Kinematic Analysis of a 6-DOF Parallel Manipulator Utilizing a Circular Guide

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Alexey Fomin ◽  
Anton Antonov ◽  
Victor Glazunov ◽  
Yuri Rodionov
Keyword(s):  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Forward Kinematics ◽  
Rotational Angle ◽  
End Effector ◽  
Kinematic Chains ◽  
Position And Orientation ◽  
Manipulator Design ◽  
Forward Kinematic

The proposed study focuses on the inverse and forward kinematic analysis of a novel 6-DOF parallel manipulator with a circular guide. In comparison with the known schemes of such manipulators, the structure of the proposed one excludes the collision of carriages when they move along the circular guide. This is achieved by using cranks (links that provide an unlimited rotational angle) in the manipulator kinematic chains. In this case, all drives stay fixed on the base. The kinematic analysis provides analytical relationships between the end-effector coordinates and six controlled movements in drives (driven coordinates). Examples demonstrate the implementation of the suggested algorithms. For the inverse kinematics, the solution is found given the position and orientation of the end-effector. For the forward kinematics, various assembly modes of the manipulator are obtained for the same given values of the driven coordinates. The study also discusses how to choose the links lengths to maximize the rotational capabilities of the end-effector and provides a calculation of such capabilities for the chosen manipulator design.

Kinematic Modeling and Hardware Development of 5-DoF Robot Manipulator

2014 ◽  
Vol 612 ◽  
pp. 51-58
Author(s):  
Kumar Patel Dharmendra ◽  
K. Ramachandra ◽  
Singh Sartaj
Keyword(s):  
Analytical Method ◽  
Inverse Kinematics ◽  
Robot Manipulator ◽  
Robot Arm ◽  
Trigonometric Functions ◽  
Kinematic Modeling ◽  
Positional Accuracy ◽  
End Effector ◽  
Hardware Development ◽  
Articulated Robot

This paper presents a 5-DoF articulated robot manipulator and proposes a strategy for solving its inverse kinematics. The Denavit – Hartenberg (D-H) parameterization has been used to model the kinematics of the manipulator. As degree of freedom of manipulator increases, the geometrical solution for inverse kinematics becomes difficult; hence an analytical method for the same is presented. Novelty in the method presented is that no approximations of trigonometric functions are used resulting in a theoretical positional accuracy of 10-10mm of the end-effector. The articulated robotic manipulator developed makes use of integrated actuators and rapid prototyping technology enabling easy replication for educational purposes. The robot arm has been used for manipulation tasks in its workspace successfully.

Kropotkin

2016 ◽  
Author(s):  
Ruth Kinna
Keyword(s):  
Political Theory ◽  
Human Nature ◽  
Political Change ◽  
Direct Action ◽  
The State ◽  
Social Analysis ◽  
Mutual Aid ◽  
Special Character ◽  
Revolutionary Politics

This book is designed to remove Peter Kropotkin from the framework of classical anarchism. By focusing attention on his theory of mutual aid, it argues that the classical framing distorts Kropotkin's political theory by associating it with a narrowly positivistic conception of science, a naively optimistic idea of human nature and a millenarian idea of revolution. Kropotkin's abiding concern with Russian revolutionary politics is the lens for this analysis. The argument is that his engagement with nihilism shaped his conception of science and that his expeditions in Siberia underpinned an approach to social analysis that was rooted in geography. Looking at Kropotkin's relationship with Elisée Reclus and Erico Malatesta and examining his critical appreciation of P-J. Proudhon, Michael Bakunin and Max Stirner, the study shows how he understood anarchist traditions and reveals the special character of his anarchist communism. His idea of the state as a colonising process and his contention that exploitation and oppression operate in global contexts is a key feature of this. Kropotkin's views about the role of theory in revolutionary practice show how he developed this critique of the state and capitalism to advance an idea of political change that combined the building of non-state alternatives through direct action and wilful disobedience. Against critics who argue that Kropotkin betrayed these principles in 1914, the book suggests that this controversial decision was consistent with his anarchism and that it reflected his judgment about the prospects of anarchistic revolution in Russia.

scholarly journals Preliminary Analysis of a Lightweight and Deployable Soft Robot for Space Applications

2021 ◽  
Vol 11 (6) ◽  
pp. 2558
Author(s):  
Mario Troise ◽  
Matteo Gaidano ◽  
Pierpaolo Palmieri ◽  
Stefano Mauro
Keyword(s):  
Preliminary Analysis ◽  
Inverse Kinematics ◽  
Control Algorithm ◽  
Dynamic Models ◽  
Robotic Systems ◽  
Inflation Pressure ◽  
Space Applications ◽  
Space Industry ◽  
Rigid Body Model ◽  
Soft Manipulator

The rising interest in soft robotics, combined to the increasing applications in the space industry, leads to the development of novel lightweight and deployable robotic systems, that could be easily contained in a relatively small package to be deployed when required. The main challenges for soft robotic systems are the low force exertion and the control complexity. In this manuscript, a soft manipulator concept, having inflatable links, is introduced to face these issues. A prototype of the inflatable link is manufactured and statically characterized using a pseudo-rigid body model on varying inflation pressure. Moreover, the full robot model and algorithms for the load and pose estimation are presented. Finally, a control strategy, using inverse kinematics and an elastostatic approach, is developed. Experimental results provide input data for the control algorithm, and its validity domain is discussed on the basis of a simulation model. This preliminary analysis puts the basis of future advancements in building the robot prototype and developing dynamic models and robust control.

Kinematic Analysis and Optimization of a Novel Robot for Surgical Tool Manipulation

2008 ◽  
Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Robotic Systems ◽  
Small Space ◽  
Surgical Robots ◽  
Tool Positioning ◽  
Rotation Axes ◽  
Surgical Tool ◽  
Linear Nature

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.

scholarly journals Finite-Horizon Kinetic Energy Optimization of a Redundant Space Manipulator

2021 ◽  
Vol 11 (5) ◽  
pp. 2346
Author(s):  
Alessandro Tringali ◽  
Silvio Cocuzza
Keyword(s):  
Kinetic Energy ◽  
Real Time ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Computational Time ◽  
Redundant Manipulators ◽  
Space Robotics ◽  
Optimal Method ◽  
End Effector ◽  
Global Optimal

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.

A Hybrid Self-Stressed Cable-Driven Mechanism

2008 ◽  
Author(s):  
Saeed Behzadipour
Keyword(s):  
Static Loading ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Tensile Force ◽  
Cable System ◽  
End Effector ◽  
Stiffness Analysis ◽  
Cable Length ◽  
Cable Drive ◽  
Forward And Inverse Kinematics

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.

Kinematics of a Fully-Decoupled Remote Center-of-Motion Parallel Manipulator for Minimally Invasive Surgery

2012 ◽  
Vol 6 (2) ◽  
Author(s):  
Chin-Hsing Kuo ◽  
Jian S. Dai
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Surgical Instruments ◽  
End Effector ◽  
Minimally Invasive Surgical ◽  
Inverse Kinematics Problem

A crucial design challenge in minimally invasive surgical (MIS) robots is the provision of a fully decoupled four degrees-of-freedom (4-DOF) remote center-of-motion (RCM) for surgical instruments. In this paper, we present a new parallel manipulator that can generate a 4-DOF RCM over its end-effector and these four DOFs are fully decoupled, i.e., each of them can be independently controlled by one corresponding actuated joint. First, we revisit the remote center-of-motion for MIS robots and introduce a projective displacement representation for coping with this special kinematics. Next, we present the proposed new parallel manipulator structure and study its geometry and motion decouplebility. Accordingly, we solve the inverse kinematics problem by taking the advantage of motion decouplebility. Then, via the screw system approach, we carry out the Jacobian analysis for the manipulator, by which the singular configurations are identified. Finally, we analyze the reachable and collision-free workspaces of the proposed manipulator and conclude the feasibility of this manipulator for the application in minimally invasive surgery.

PERANCANGAN ARSITEKTUR RUANG LIMINAL ANTARA SEBUAH DUALISME (BERTANI DAN MELAUT)

2021 ◽  
Vol 3 (1) ◽  
pp. 1087
Author(s):  
Michael Gideon Josian ◽  
Maria Veronica Gandha
Keyword(s):  
General Public ◽  
Point Of View ◽  
Common Space ◽  
Special Character ◽  
Ideal System ◽  
The World ◽  
The Future ◽  
Letting Go

The future of dwelling has a very board context and will continue to be discussed, it is possible that the discussions about “dwelling” is come from the environment of farming and fishing. Things that are not much cared for but still have a role in the survival of the world. Therefore this matter will be discussed using the role of architecture as space, to be able to create an ideal system by paying attention to the quality of farming and fishing for the future, and leaving a trace or memory to be able to carry messages for the future. Talking about the future of an interaction that occurs between the general public and farmers and fishermen, especially considering that farmers and fishermen themselves can be compared to two different poles, a liminal space is needed, which may already exist indirectly in the environment. By letting go of individual egos and emphasizing ego to the point of view of farmers and fishermen. To present a common space, or a place that contains a special character of a city that contains a message for the future. Keywords:  dualism; hope; liminal; trace;  Abstrak Masa depan cara berhuni memiliki konteks yang sangat luas dan akan terus diperbincangkan. Tidak menutup kemungkinan datang dari pembahasan mengenai cara berhuni dengan bertani dan melaut. Hal yang tidak banyak dipedulikan tetapi tetap memiliki peran dalam kelangsungan dunia. Oleh karena itu, masa depan berhuni ini akan dibahas dengan menggunakan peran arsitektur sebagai ruang, untuk dapat menciptakan sistem yang ideal dengan memperhatikan kualitas bertani dan melaut bagi masa depan, dan meninggalkan sebuah jejak atau kenangan untuk dapat membawa pesan bagi masa depan. Berbicara mengenai masa depan dari sebuah interaksi yang terjadi antara masyarakat umum dengan para petani dan nelayan, apalagi mengingat para petani dan nelayan itu sendiri dapat diibaratkan berada pada kedua kutub yang berbeda, maka dibutuhkanlah sebuah ruang liminal, yang mungkin sudah hadir secara tidak langsung pada lingkungan masyarakat. Dengan cara melepaskan ego individual dan menekankan ego kepada sudut pandang para petani dan nelayan. Untuk menghadirkan sebuah ruang bersama, atau sebuah tempat yang mengandung sebuah karakter tersendiri dari sebuah kota yang berisi pesan bagi masa depan.

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