Development and evaluation of a symbolic modelling tool for serial manipulators with any number of degrees of freedom

2016 ◽  
Author(s):  
Parham M. Kebria ◽  
Hamid Abdi ◽  
Saeid Nahavandi
Keyword(s):  
Degrees Of Freedom ◽  
Serial Manipulators ◽  
Symbolic Modelling

Distributed Operational Space Formulation of Serial Manipulators

2013 ◽  
Vol 9 (2) ◽  
Author(s):  
Kishor D. Bhalerao ◽  
James Critchley ◽  
Denny Oetomo ◽  
Roy Featherstone ◽  
Oussama Khatib
Keyword(s):  
Parallel Algorithms ◽  
Time Complexity ◽  
Degrees Of Freedom ◽  
Null Space ◽  
Divide And Conquer ◽  
Serial Manipulators ◽  
Divide And Conquer Algorithm ◽  
Operational Space ◽  
Space Formulation ◽  
Space Dynamics

This paper presents a new parallel algorithm for the operational space dynamics of unconstrained serial manipulators, which outperforms contemporary sequential and parallel algorithms in the presence of two or more processors. The method employs a hybrid divide and conquer algorithm (DCA) multibody methodology which brings together the best features of the DCA and fast sequential techniques. The method achieves a logarithmic time complexity (O(log(n)) in the number of degrees of freedom (n) for computing the operational space inertia (Λe) of a serial manipulator in presence of O(n) processors. The paper also addresses the efficient sequential and parallel computation of the dynamically consistent generalized inverse (J¯e) of the task Jacobian, the associated null space projection matrix (Ne), and the joint actuator forces (τnull) which only affect the manipulator posture. The sequential algorithms for computing J¯e, Ne, and τnull are of O(n), O(n2), and O(n) computational complexity, respectively, while the corresponding parallel algorithms are of O(log(n)), O(n), and O(log(n)) time complexity in the presence of O(n) processors.

Compensation of geometric and elastic errors in large manipulators with an application to a high accuracy medical system

Robotica ◽  
2002 ◽  
Vol 20 (3) ◽  
pp. 341-352 ◽  
Author(s):  
Ph. Drouet ◽  
S. Dubowsky ◽  
S. Zeghloul ◽  
C. Mavroidis
Keyword(s):  
Degrees Of Freedom ◽  
High Accuracy ◽  
Medical Robot ◽  
Serial Manipulators ◽  
High Position ◽  
Six Degrees Of Freedom ◽  
Position Accuracy ◽  
End Point ◽  
Compensation Process ◽  
Very High

A method is presented that compensates for manipulator end-point errors in order to achieve very high position accuracy. The measured end-point error is decomposed into generalized geometric and elastic error parameters that are used in an analytical model to calibrate the system as a function of its configuration and the task loads, including any payload weight. The method exploits the fundamental mechanics of serial manipulators to yield a non-iterative compensation process that only requires the identification of parameters that are function only of one variable. The resulting method is computationally simple and requires far less measured data than might be expected. The method is applied to a six degrees-of-freedom (DOF) medical robot that positions patients for cancer proton therapy to enable it to achieve very high accuracy. Experimental results show the effectiveness of the method.

scholarly journals Design and Kinematic Analysis of a Novel 2-DoF Closed-Loop Mechanism for the Actuation of Machining Robots

2021 ◽  
Author(s):  
Angelica Ginnante ◽  
François Leborne ◽  
Stéphane Caro ◽  
Enrico Simetti ◽  
Giuseppe Casalino
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parallel Mechanisms ◽  
Serial Manipulators ◽  
Hard Materials ◽  
Serial Robots ◽  
Revolute Joints ◽  
Machining Robot ◽  
Kinematic Models ◽  
Kinematic Performance

Abstract The essential characteristics of machining robots are their stiffness and their accuracy. For machining tasks, serial robots have many advantages such as large workspace to footprint ratio, but they often lack the stiffness required for accurately milling hard materials. One way to increase the stiffness of serial manipulators is to make their joints using closed-loop or parallel mechanisms instead of using classical prismatic and revolute joints. This increases the accuracy of a manipulator without reducing its workspace. This paper introduces an innovative two degrees of freedom closed-loop mechanism and shows how it can be used to build serial robots featuring both high stiffness and large workspace. The design of this mechanism is described through its geometric and kinematic models. Then, the kinematic performance of the mechanism is analyzed, and a serial arrangement of several such mechanisms is proposed to obtain a potential design of a machining robot.

scholarly journals Kinematic Synthesis and Analysis of the RoboMech Class Parallel Manipulator with Two Grippers

Robotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 99
Author(s):  
Zhumadil Baigunchekov ◽  
Med Amine Laribi ◽  
Azamat Mustafa ◽  
Abzal Kassinov
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Geometric Parameters ◽  
Geometric Constraints ◽  
Least Square ◽  
Kinematic Synthesis ◽  
Serial Manipulators ◽  
Kinematic Chains ◽  
End Effectors ◽  
Cold Stamping

In this paper, methods of kinematic synthesis and analysis of the RoboMech class parallel manipulator (PM) with two grippers (end effectors) are presented. This PM is formed by connecting two output objects (grippers) with a base using two passive and one negative closing kinematic chains (CKCs). A PM with two end effectors can be used for reloading operations of stamped products between two adjacent main technologies in a cold stamping line. Passive CKCs represent two serial manipulators with two degrees of freedom, and negative CKC is a three-joined link with three negative degrees of freedom. A negative CKC imposes three geometric constraints on the movements of the two output objects. Geometric parameters of the negative CKC are determined on the basis of the problems of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the PM with two end effectors have been solved.

DeltaBot: A New Cable-Based Ultra High Speed Robot

2003 ◽  
Author(s):  
Saeed Behzadipour ◽  
Robert Dekker ◽  
Amir Khajepour ◽  
Edmon Chan
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Manufacturing Industry ◽  
Design Procedure ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Manufacturing Cost ◽  
End Effector ◽  
Serial Manipulators

The growing needs for high speed positioning devices in the automated manufacturing industry have been challenged by robotic science for more than two decades. Parallel manipulators have been widely used for this purpose due to their advantage of lower moving inertia over the conventional serial manipulators. Cable actuated parallel robots were introduced in 1980’s to reduce the moving inertia even further. In this work, a new cable-based parallel robot is introduced. For this robot, the cables are used not only to actuate the end-effector but also to apply the necessary kinematic constraints to provide three pure translational degrees of freedom. In order to maintain tension in the cables, a passive air cylinder is used to push the end-effector against the stationary platform. In addition to low moving inertia, the new design benefits from simplicity and low manufacturing cost by eliminating joints from the robot’s mechanism. The design procedure and the results of experiments will be discussed in the following.

Geometry and Position Analysis of a Novel Class of Hybrid Manipulators

1994 ◽  
Author(s):  
Change-de Zhang ◽  
Shin-Min Song
Keyword(s):  
Closed Form ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Parallel Mechanisms ◽  
Serial Manipulators ◽  
Closed Form Solutions ◽  
Position Analysis ◽  
Hybrid Manipulator ◽  
Load Carrying ◽  
Inverse Position Analysis

Abstract This paper presents a novel class of hybrid manipulators composed of two serially connected parallel mechanisms, each of which has three degrees of freedom. The lower and upper platforms respectively control the position and orientation of the end-effector. The advantages of this type of hybrid manipulator are larger workspace (as compared with parallel manipulators) and better rigidity and higher load-carrying capability (as compared with serial manipulators). The closed-form solutions of the forward and inverse position analyses are discussed. For forward position analysis, it is shown that the resultant equation for the positional mechanism is an 8-th order, a 6-th order, a 4-th order, or a 2-nd order polynomial, depending on the geometry and joint types of the passive subchain, while for the orientational mechanism, it is an 8-th order, or a 2-nd polynomial depending on the geometry. For inverse position analysis, it is demonstrated that the positional and orientational mechanisms both possess analytical closed-form solutions.

Feasible Motion Solutions for Serial Manipulators at Singular Configurations

2003 ◽  
Vol 125 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Yuefa Fang ◽  
Lung-Wen Tsai
Keyword(s):  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Full Rank ◽  
Joint Space ◽  
Serial Manipulators ◽  
First Order ◽  
Singular Configurations ◽  
Cartesian Space ◽  
Novel Approach ◽  
Singular Configuration

When a serial manipulator is at a singular configuration, the Jacobian matrix will lose its full rank causing the manipulator to lose one or more degrees of freedom. This paper presents a novel approach to model the manipulator kinematics and solve for feasible motions of a manipulator at singular configurations such that the precise path tracking of a manipulator at such configurations is possible. The joint screw linear dependency is determined by using known line varieties so that not only the singular configurations of a manipulator can be identified but also the dependent joint screws can be determined. Feasible motions in Cartesian space are identified by using the theory of reciprocal screws and the resulting equations of constraint. The manipulator first-order kinematics is then modeled by isolating the linearly dependent columns and rows of the Jacobian matrix such that the mapping between the feasible motions in Cartesian space and the joint space motions can be uniquely determined. Finally, a numerical example is used to demonstrate the feasibility of the approach. The simulation results show that a PUMA-type robot can successfully track a path that is singular at all times.

scholarly journals Minimization of dynamic joint reaction forces of the 2-DOF serial manipulators based on interpolating polynomials and counterweights

2015 ◽  
Vol 42 (4) ◽  
pp. 249-260 ◽  
Author(s):  
Slavisa Salinic ◽  
Marina Boskovic ◽  
Radovan Bulatovic
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Lagrange Equations ◽  
Symbolic Form ◽  
Serial Manipulators ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Inertia Forces ◽  
Joint Reaction ◽  
Selection Of

This paper presents two ways for the minimization of joint reaction forces due to inertia forces (dynamic joint reaction forces) in a two degrees of freedom (2-DOF) planar serial manipulator. The first way is based on the optimal selection of the angular rotations laws of the manipulator links and the second one is by attaching counterweights to the manipulator links. The influence of the payload carrying by the manipulator on the dynamic joint reaction forces is also considered. The expressions for the joint reaction forces are obtained in a symbolic form by means of the Lagrange equations of motion. The inertial properties of the manipulator links are represented by dynamical equivalent systems of two point masses. The weighted sum of the root mean squares of the magnitudes of the dynamic joint reactions is used as an objective function. The effectiveness of the two ways mentioned is discussed.

KINEMATIC INVERSION OF FUNCTIONALLY-REDUNDANT SERIAL MANIPULATORS: APPLICATION TO ARC-WELDING

2005 ◽  
Vol 29 (4) ◽  
pp. 679-690 ◽  
Author(s):  
Liguo Huo ◽  
Luc Baron
Keyword(s):  
Arc Welding ◽  
Degrees Of Freedom ◽  
Null Space ◽  
Computationally Efficient ◽  
Secondary Tasks ◽  
Serial Manipulators ◽  
Six Degrees Of Freedom ◽  
Kinematic Inversion ◽  
Resolution Scheme ◽  
Robotic Tasks

This paper introduces the concept of functional redundancy of serial manipulators, and presents a new resolution scheme to solve such redundant robotic tasks requiring less than six degrees-of-freedom. Instead of projecting the secondary task onto the null space of the Jacobian matrix in order to take advantage of the redundancy, the twist of end-effector is directly decomposes into two orthogonal subspaces where the main and secondary tasks lie, respectively. The algorithm has shown to be computationally efficient and well suited to solve functionally-redundant robotic tasks, such as arc-welding.

scholarly journals A Novel Kinematic Directional Index for Industrial Serial Manipulators

2020 ◽  
Vol 10 (17) ◽  
pp. 5953 ◽  
Author(s):  
Giovanni Boschetti
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Maximum Speed ◽  
Robot Arm ◽  
Serial Manipulators ◽  
Six Degrees Of Freedom ◽  
Serial Robot ◽  
Novel Method ◽  
Points Of View ◽  
Articulated Robot

In the last forty years, performance evaluations have been conducted to evaluate the behavior of industrial manipulators throughout the workspace. The information gathered from these evaluations describes the performances of robots from different points of view. In this paper, a novel method is proposed for evaluating the maximum speed that a serial robot can reach with respect to both the position of the robot and its direction of motion. This approach, called Kinematic Directional Index (KDI), was applied to a Selective Compliance Assembly Robot Arm (SCARA) robot and an articulated robot with six degrees of freedom to outline their performances. The results of the experimental tests performed on these manipulators prove the effectiveness of the proposed index.

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