Performance-Oriented Design of Inverse Kinematics Algorithms: Extended Jacobian Approximation of the Jacobian Pseudo-Inverse

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Joanna Karpińska ◽  
Krzysztof Tchoń
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Ritz Method ◽  
Approximation Error ◽  
Robotic Manipulators ◽  
Error Functional ◽  
Free Representation ◽  
Pseudo Inverse ◽  
Jacobian Inverse ◽  
Jacobian Algorithm

For redundant robotic manipulators, we study the design problem of Jacobian inverse kinematics algorithms of desired performance. A specific instance of the problem is addressed, namely the optimal approximation of the Jacobian pseudo-inverse algorithm by the extended Jacobian algorithm. The approximation error functional is derived for the coordinate-free representation of the manipulator’s kinematics. A variational formulation of the problem is employed, and the approximation error is minimized by means of the Ritz method. The optimal extended Jacobian algorithm is designed for the 7 degrees of freedom (dof) POLYCRANK manipulator. It is concluded that the coordinate-free kinematics representation results in more accurate approximation than the coordinate expression of the kinematics.

scholarly journals Design of inverse kinematics algorithms: extended Jacobian approximation of the dynamically consistent Jacobian inverse

2015 ◽  
Vol 25 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Joanna Ratajczak
Keyword(s):  
Inverse Kinematics ◽  
Ritz Method ◽  
Approximation Error ◽  
Approximation Problem ◽  
Cholesky Decomposition ◽  
Redundant Manipulators ◽  
Jacobian Inverse

Abstract The paper presents the approximation problem of the inverse kinematics algorithms for the redundant manipulators. We introduce the approximation of the dynamically consistent Jacobian by the extended Jacobian. In order to do that, we formulate the approximation problem and suitably defined approximation error. By the minimization of this error over a certain region we can design an extended Jacobian inverse which will be close to the dynamically consistent Jacobian inverse. To solve the approximation problem we use the Cholesky decomposition and the Ritz method. The computational example illustrates the theory.

A complete analytical solution to the inverse kinematics of the Pioneer 2 robotic arm

Robotica ◽  
2005 ◽  
Vol 23 (1) ◽  
pp. 123-129 ◽  
Author(s):  
John Q. Gan ◽  
Eimei Oyama ◽  
Eric M. Rosales ◽  
Huosheng Hu
Keyword(s):  
Analytical Solution ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Robotic Manipulators ◽  
Robotic Arm ◽  
Effective Solution ◽  
Robotic Arms ◽  
Unstructured Environment ◽  
Inverse Kinematics Problem

For robotic manipulators that are redundant or with high degrees of freedom (dof), an analytical solution to the inverse kinematics is very difficult or impossible. Pioneer 2 robotic arm (P2Arm) is a recently developed and widely used 5-dof manipulator. There is no effective solution to its inverse kinematics to date. This paper presents a first complete analytical solution to the inverse kinematics of the P2Arm, which makes it possible to control the arm to any reachable position in an unstructured environment. The strategies developed in this paper could also be useful for solving the inverse kinematics problem of other types of robotic arms.

Inverse Kinematics Solutions for General Spatial Linkages

1987 ◽  
Author(s):  
M. Tucker ◽  
N. D. Perreira
Keyword(s):  
Inverse Kinematics ◽  
Robot Control ◽  
Degrees Of Freedom ◽  
General Purpose ◽  
Inverse Solution ◽  
Six Degrees Of Freedom ◽  
Inverse Kinematics Problem ◽  
Spatial Linkages ◽  
Pseudo Inverse ◽  
Solution Techniques

Abstract A procedure for obtaining solutions to the general inverse kinematics problem for both position and velocity is presented. Solutions to this problem are required for improved robot control and linkage synthesis. The procedure requires obtaining the inverse of the actual robot linkage Jacobian. A procedure to detect the presence of singularities in the Jacobians and their causes are given. Inverse solution techniques applicable to robots with less than, equal to, or greater than six degrees of freedom and their implementation to robots with various types of singularities is outlined. For each case, the implementation of both the complete Moore-Penrose inverse and a robot specific pseudo inverse are included. Although it is not necessary to use the complete Moore-Penrose inverse on any particular robot, it can be used to obtain generic inverse routines for general purpose applications.

A modified firefly algorithm for the inverse kinematics solutions of robotic manipulators

2021 ◽  
Vol 28 (3) ◽  
pp. 257-275
Author(s):  
Jesus Hernandez-Barragan ◽  
Carlos Lopez-Franco ◽  
Nancy Arana-Daniel ◽  
Alma Y. Alanis ◽  
Adriana Lopez-Franco
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Firefly Algorithm ◽  
Statistical Tests ◽  
Robotic Manipulators ◽  
Optimization Techniques ◽  
Multimodal Optimization ◽  
End Effector ◽  
Prismatic Joints ◽  
Joint Limits

The inverse kinematics of robotic manipulators consists of finding a joint configuration to reach a desired end-effector pose. Since inverse kinematics is a complex non-linear problem with redundant solutions, sophisticated optimization techniques are often required to solve this problem; a possible solution can be found in metaheuristic algorithms. In this work, a modified version of the firefly algorithm for multimodal optimization is proposed to solve the inverse kinematics. This modified version can provide multiple joint configurations leading to the same end-effector pose, improving the classic firefly algorithm performance. Moreover, the proposed approach avoids singularities because it does not require any Jacobian matrix inversion, which is the main problem of conventional approaches. The proposed approach can be implemented in robotic manipulators composed of revolute or prismatic joints of n degrees of freedom considering joint limits constrains. Simulations with different robotic manipulators show the accuracy and robustness of the proposed approach. Additionally, non-parametric statistical tests are included to show that the proposed method has a statistically significant improvement over other multimodal optimization algorithms. Finally, real-time experiments on five degrees of freedom robotic manipulator illustrate the applicability of this approach.

A Jacobian-based algorithm for planning the motion of an underactuated rigid body undergoing forward and reverse rotations

Robotica ◽  
2009 ◽  
Vol 28 (5) ◽  
pp. 747-757 ◽  
Author(s):  
Sung K. Koh
Keyword(s):  
Rigid Body ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Practical Importance ◽  
The Body ◽  
Coordinate Frame ◽  
Torque Generation ◽  
Generation Mechanisms ◽  
Jacobian Algorithm ◽  
Null Matrix

SUMMARYA Jacobian-based algorithm that is useful for planning the motion of a floating rigid body operated using two input torques is addressed in this paper. The rigid body undergoes a four-rotation fully reversed (FR) sequence of rotations which consists of two initial rotations about the axes of a coordinate frame attached to the body and two subsequent rotations that undo the preceding rotations. Although a Jacobian-based algorithm has been useful in exploring the inverse kinematics of conventional robot manipulators, it is not apparent how a correct FR sequence for a desired orientation could be found because the Jacobian of FR sequences is singular as well as being a null matrix at the identity. To discover the FR sequences that can synthesize the desired orientation circumventing these difficulties, the Jacobian algorithm is reformulated and implemented from arbitrary orientations where the Jacobian is not singular. Due to the insufficient degrees-of-freedom of four-rotation FR sequences required to achieve all possible orientations, the rigid body cannot achieve certain orientations in the configuration space. To best approximate these infeasible orientations, the Jacobian-based algorithm is implemented in the sense of least squares. As some orientations can never be attained by a single four-rotation FR sequence, two different four-rotation FR sequences are exploited alternately to ensure the convergence of the proposed algorithm. Assuming the orientation is supposed to be manipulated using three input torques, the switching Jacobian algorithm proposed in this paper has significant practical importance in planning paths for aerospace and underwater vehicles which are maneuvered using only two input torques due to the failure of one of the torque-generation mechanisms.

Effects of Dynamic Model Errors in Task-Priority Operational Space Control

Robotica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Paolo Di Lillo ◽  
Gianluca Antonelli ◽  
Ciro Natale
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Null Space ◽  
Control Algorithms ◽  
Model Errors ◽  
Operational Space ◽  
Dynamic Level ◽  
Concurrent Tasks ◽  
Modeling Errors

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.

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.

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