Robot Inverse Kinematics Research Articles

Forward Kinematics of Six-DOF Parallel Robot Based on Adaptive Differential Evolution

Parallel robot inverse kinematics solution is relatively easier to obtain than forward kinematics forward, this paper assumes that the forward kinematics of six-DOF parallel robot is given then using the kinematics inverse solution to approximate the forward solution. To improve efficiency and stability of the approximation, an adaptive parameters differential evolution algorithm is proposed and applied to the forward kinematics problem. The experimental results show that the modified algorithm can gain the forward kinematics of parallel robot efficiently.

Real-time Control of 7R Manipulator Based on Motion Capture

In consideration of the delaying control caused by the complexity of inverse kinematics of 7-DOF redundant robots, a new control method of human-robot interaction is presented. A method to transfer data between motion capture system and Robai manipulator system in real time is designed. Under Windows 7, the corresponding server and client can be set up by using VC of Microsoft Visual Studio and the data among different systems can be exchanged and transported in real time through data processing algorithm. Compared with the traditional solution of inverse kinematics of robot, a comprehensive method is adopted to use the information of different human arm positions in the motion capture system to calculate the manipulator's joint angle and analysis solution is derived. It can reduce the amount of calculation of the controlling system and the real-time control of the manipulator is realized, so that it meets the need of synchronization of the experimenter and Robai manipulator in real time. The validity of the method is verified and the satisfactory results are achieved through the experiments.

Kinematics Analysis of Four-Legged Walking Robots for Grabbing Object

Development of integrated hand-foot function is the inevitable choice for the practical application of multi-legged robots. In this paper, a new type of robot which has the structure of four-legged walking robot based on hand-foot-integration is introduced. The image system is installed in the body of the robot, which is used to direct the robot to complete grabbing object. Kinematics relations of grasping states of robot are described. The inverse kinematic is analyzed in details. Firstly, the structure of the robot is introduced. Secondly, the kinematics relation of serial manipulator with grasping function is researched. Finally, the inverse kinematics of robot in grasping object is obtained. The relevant formula is deduced in this paper, and the formula expression is given. The analysis process is last verified through a numerical example. The model can be used for motion control of robot.

Simulation of Vision-Based Royal Jelly Collecting Robot

A new method to collect royal jelly is proposed according to the view of industrial robot. A three-dimensional model of royal jelly collecting robot with a monocular camera is built. Detecting the particular shapes via Fourier Descriptors and finding the corresponding target points though the image shot by the camera. The vision-based process and the 3-D simulation are performed alternately to simulate picking up queen bee larvae according to robotic forward kinematics and inverse kinematics.

Modeling and Adaptive Tracking Control of a Quadrotor UAV

The dynamics of UAV’s have special features that can complicate the process of designing a trajectory tracking controller. In this paper, after modelling the quadrotor as a VTOL UAV, a nonlinear adaptive controller is designed to solve trajectory tracking problem in the presence of parametric and nonparametric uncertainties. This controller doesn’t need knowing any physical parameters of the quadrotor, and there isn’t need to retune the controller for various payloads. In this approach, the control of a quadrotor is performed by using decentralized adaptive controllers in the inner (attitude control) and outer (translational movement control) loops. The outer loop generates the instantaneous desired angles for inner loop. The inner loop stabilizes the orientation of the vehicle. Inverse kinematic of robot is used to convert outputs of the outer loop to inputs of the inner loop. The controller needs some unknown physical parameter to generate control signals. A robust parameter identifier estimates the required parameters for the outer control loops. Simulations are carried out to illustrate the robustness and tracking performance of the controllers.

Virtual Robot Kinematic Learning System: A New Teaching Approach

Computer assisted learning systems for robotics can assist students to understand topics on robot modeling, direct and inverse kinematics, join motions, trajectories, and also workspace limitations. This paper presents a virtual robotic kinematic learning system as a new teaching approach of robotics class which will assist and promote better students’ understanding of robotics. From the virtual system’s interface, basic structure and movement of Cartesian, Cylindrical, Spherical and Articulated robot can be visualized. The transformation matrix exercises allow students to write down the formula of translation and rotation matrix and then see the movements of the virtual robot based on the input. In this virtual system, a Lynxmotion Arm Robot was used to teach kinematics for the manipulator movement using Denavit Hartenberg representation. The system is developed using Unity 3D for the animation and for the calculation of robot kinematic, C-Sharp and Java script programming language were used. The system will be evaluated with the students to determine its effectiveness in providing a new teaching approach.

Kinematics Research of 6R Arc Welding Robot Based on Radial Basis Function Neural Network

Take serial robot with six DOF for example. On the basis of analyzing the characteristics of RBF neural network, inverse kinematics calculation of arc welding robot was achieved by RBF of six-input and single output. The forward and inverse kinematics could be seen as a nonlinear mapping between the joint space and the operation space of the robot. Take the algorithm based on RBF. Acquire RBF centers by the nearest neighbor clustering algorithm. The inverse kinematics of robot was solved. Through learning the training samples of the positive solutions to determine weight coefficient of neural network, the robots pose could be accurately solved. The example shows that the algorithm has the characteristics of simple calculation and effective solution, etc. The cumbersome derivation of traditional methods is avoided. It can be seen as kinematics trajectory tracking controller of serial mechanism system.

Kinect-based Robot Teleoperation by Velocities Control in the Joint/Cartesian Frames

Abstract In this paper we present a new concept of robot teleoperation by tracking the pose of the human operator's body with the Kinect motion capture sensor. Instead of controlling robot joint positions, positions of operator's hands and legs are used to control robot velocities. In the first method operator's movements control velocities of individual robot joints, while in the second, velocities of a robot tool in the Cartesian space are controlled in the same manner. In the latter case the joint coordinates are obtained directly from robot's inverse kinematics equations. The methods were demonstrated on a five degrees of freedom (5-DOF) articulated robot arm Mitsubishi Movemaster EX.

Trajectory Planning of Free-floating Space Robot with Avoidance of Dynamic Singularity

Aiming at the dynamic singularity of generalized Jacobian matrix caused by non-holonomic constraints in free-floating space robots,an approach of indirectly solving robot inverse kinematics is presented.With the decomposed kinematics equation and the constructed iterative function,the approach transforms the dynamic singularity into kinematic singularity,avoids directly solving inverse generalized Jacobian matrix,and resolves the dynamic parameter relativity problem caused by generalized Jacobian matrix singularity.Numerical simulations demonstrate that the approach achieves the non-holonomic trajectory planning of free floating space robot with avoidance of dynamic singularity effectively.

Control Desacoplado de Plataforma Neumática de 3-GDL utilizada como Simulador de Movimiento

In this paper the kinematics analysis and decoupled control scheme in joint space is development of a three degree of freedom parallel robot actuated by pneumatic actuators; the robot is used as motion simulator. A brief description of robot is done and after that the set of equations based on vectorial formulation is obtained in order to describe the inverse kinematics of robot. The analytic kinematics relations are validated by simulation combining Matlab with Adams package software. The decoupled control scheme is proposed for each actuated joints, where the desired joints positions are computed by the inverse kinematics equations. The control loops in joint space are implemented in three degree of freedom parallel robot in application of position control. Finally, the experimental results are shown to probe the effectiveness of kinematics control scheme in terms of system performance.

A novel hybrid electromagnetism‐like algorithm for solving the inverse kinematics of robot

PurposeThis paper aims to develop a new real‐time effective method for solving the inverse kinematics (IK) problem, especially for those manipulators with high‐dimensional nonlinear kinematic equations.Design/methodology/approachThe paper transforms the IKs problem into a minimization problem. Then, a novel meta‐heuristic algorithm, called the electromagnetism‐like method (EM), is used to solve this equivalent problem. Moreover, in order to further improve the computational efficiency and accuracy of EM, a hybrid method which combines EM with the Davidon‐Fletcher‐Powell (DFP) method is proposed.FindingsThe results showed that EM is a powerful yet easy algorithm for solving the IKs problem of robot manipulators. Its complexity is independent on the characteristics of the kinematic equations involving dimensionality and the degree of nonlinearity. Moreover, EM can be used as an accompanying algorithm for DFP method to get better precision at a lower iteration number.Originality/valueThe method developed in this paper is a generalized approach that is efficient enough to obtain IK solutions independent of robot geometry and the number of degrees of freedom.

Fuzzy Adaptive Algorithm for Biped Robot Inverse Kinematics

An improved inverse kinematics control scheme for biped robot is presented to solve the problems of the Jacobian matrix singularity and fixed-parameters in the numerical solution.The Jacobian inversion is replaced with the approximate solution of differential motion equation.Combined with the adaptive fuzzy control to reduce the tracking error,it can regulate adaptive parameters in order to arbitrarily approach the exact solution by approximate solution.An extremely accurate and strong robust fuzzy adaptive algorithm can be obtained.Results of simulation on a biped robot show the effectiveness of the scheme.The total computation time of the presented algorithm is about 0.35 ms,so it can satisfy the requirements of real-time control of the actual biped robot.

A new method to solve robot inverse kinematics using Assur virtual chains

SUMMARYThis paper describes a numerical algorithm to solve the inverse kinematics of parallel robots based on numerical integration. Inverse kinematics algorithms based on numerical integration involve the drift phenomena of the solution; as a consequence, errors are generated when the end-effector location differs from that desired. The proposed algorithm associates a novel method to describe the differential kinematics with a simple numerical integration method. The methodology is presented in this paper and its exponential stability is proved. A numerical example and a real application are presented to outline its advantages.

Vision-Based Robotic Motion Control for Non-autonomous Environment

A visual servo control system with SOPC structure is implemented on a retrofitted Mitsubishi RV-M2 robotic system. The hardware circuit has the functions of quadrature encoder decoding, limit switch detecting, pulse width modulation (PWM) generating and CMOS image signal capturing. The software embedded in Nios II micro processor has the functions of using UART to communicate with PC, robotic inverse kinematics calculation, robotic motion control schemes, digital image processing algorithm and gobang game AI algorithm. A CMOS color image sensor is used to catch the environment time-varying change for robotic vision-based servo control. A gobang game is planned to investigate the implementation problem of the visual servo robotic motion control in non-autonomous environment. A model-free intelligent self-organizing fuzzy control (SOFC) strategy is employed to design the robotic joint controller. A vision based trajectory planning algorithm is designed to calculate the desired angular positions or trajectory of each robotic joint. The experimental results show that this visual servo control robot has reliable control actions.

Damped least square based genetic algorithm with Ggaussian distribution of damping factor for singularity-robust inverse kinematics

Robot inverse kinematics based on Jacobian inversion encounters critical issues of kinematic singularities. In this paper, several techniques based on damped least squares are proposed to lead robot pass through kinematic singularities without excessive joint velocities. Unlike other work in which the same damping factor is used for all singular vectors, this paper proposes a different damping coefficient for each singular vector based on corresponding singular value of the Jacobian. Moreover, a continuous distribution of damping factor following Gaussian function guarantees the continuous in joint velocities. A genetic algorithm is utilized to search for the best maximum damping factor and singular region, which used to require ad hoc searching in other works. As a result, end effector tracking error, which is inherited from damped least squares by introducing damping factors, is minimized. The effectiveness of our approach is compared with other methods in both non-redundant robot and redundant robot.

Robot inverse kinematics via neural and neurofuzzy networks: architectural and computational aspects for improved performance

Neural networks are universal nonlinear-function approximators and have for long time been used to implement various practical nonlinear inverse mappings. The choice of network type and structure depends on the mapping type and the degree of generalization required. The use of neural networks for solving the inverse robot kinematics has been extensively studied by many workers, but still some problems related to the complexity and strong nonlinearity of the inverse kinematics process need suitable heuristic and adhoc techniques and simplifications. The aim of this paper is exactly to contribute towards filling this gap by investigating a number of computational and architectural issues so as to improve the performance of the implementation of the inverse kinematics process. These issues include the generation and preprocessing of training data, the data scaling, the treatment of multiple solutions, the reduction of the approximation error, and the speeding-up of the training process. A generic neural network architecture is proposed which employs multiple radial-basis function (RBF) network elements and the “mixture of local experts” principle. An algorithm is presented for the training data preprocessing which greatly reduces the training time and overall system error. Two fuzzy-logic solutions are provided and discussed; one employing a fuzzy associative memory (FAM), and the other a neurofuzzy cell architecture proposed by the authors. In all cases no knowledge is assumed about the inverse kinematics of the robot at hand, as long as its forward kinematics is known. Some indicative simulation results are included and discussed.

Flexible design, analysis and programming methodology of robotic welding cells for multiple configuration products

This paper presents the way in which constraint-based parametric solid modelling can support flexible programming of robotic welding cells for widely varying configurations of the same product family. The key to flexibility is parametric definition of the robot environment i.e., product configuration, product parts, work-holding devices etc., and of the path itself. Robot inverse kinematics is implicitly employed through constrained motions of the robot links defined in the CAD system. 3D exact simulation models are generated by embedding motion interpolators for each motion defined. Possible collisions or other undesirable states in robotic task implementation are discovered through the solid modeller. A production cell, where security doors are manufactured, is used as a case study where two industrial robots perform seam and spot welding, respectively.

Application of neural networks augmenting Taguchi's orthogonal arrays for simulating kinematics problems of robotics

This research focuses on integrating back propagation with the concepts of Taguchi's orthogonal arrays to map both robot forward kinematics and robot inverse kinematics. Traditionally, end users were required to have some experience with robot kinematics training programs in order to analyse the kinematics and train the robots. When the type of robot changes, end users must again analyse the robot kinematics and solve extensive mathematical equations in order to control the new robot. An alternative approach for developing robot manipulator models is to use the concepts of neural networks to approximate robot kinematics to overcome the drawbacks of the existing methods. Moreover, an additional benefit is derived from the use of Taguchi's orthogonal arrays. This study shows that using orthogonal arrays for data collection can reduce the amount of data required to map robot kinematics, although some accuracy is lost with solving the inverse kinematics problems. The simulations used to verify the model developed have been conducted on the Jumbo Drilling robot.

Forward and Inverse Kinematics of the Cardio-Surgical Robot with Non-Coincident Axis of the Wrist

The paper shows the analyses of Polish cardio-surgical robot RobIn-Heart© in order to create the kinematical model. The direct kinematical model is created basing on Denavit-Hartenberg method. For deriving the inverse kinematical model the inverse transform of transition between the base of the robot and the effector: the effector has been immobilized and the base has been released. Thanks to that, the equations of the model became relatively plain.

Hierarchical kinematic analysis of robots

According to their kinematic structure, serial robot manipulators present singularities, which are defined as the configurations where the mobility of the manipulator is reduced. Singularities introduce problems in the robot operations that need to be avoided. This is usually done by detecting a singular configuration and then deviating from it. The usual methods for singularity avoidance, most of them based on the determinant of the Jacobian matrix, implicitly consider all singularities equally disastrous to the robot kinematics. This paper introduces a new analysis method, the hierarchical kinematic analysis, based on the fact that the robot kinematic singularities are not equally important to the behaviour of the manipulator. Singularities are ranked according to their influence on the robot inverse kinematics. Moreover, this method provides a recursive algorithm to solve the inverse kinematics problem of serial robots faster, and more accurately. The method, based on a graphical interpretation of the Jacobian matrix, is summarised in an algorithm. To illustrate its usefulness, this algorithm is applied in detail to a SCARA and a PUMA robot. Finally, the algorithm is applied to a robot without a spherical wrist, the T 3 robot. The results are interpreted and, even in classical examples, some new facts can be extracted by using the hierarchical kinematic analysis.