INVERSE KINEMATICS FOR A 6 DOF MANIPULATOR BASED ON NEURAL NETWORK

运用神经网络求解机器人运动学位姿逆解，突破了文献局限于研究位置逆解的状况，首次实现自组织神经网络求解机器人姿态逆解。通过深入分析基于Ｋｏｈｏｎｅｎ网络原理和Ｖｉｄｒｏｗ－Ｈｏｆ误差修正的Ｍ．Ｒ．Ｓ．自组织神经网络及机器人运动学特性，创新了自组织神经网络训练算法并建立了一类工业机器人位姿逆解的神经网络方法。对ＰＵＭＡ５６０机器人的计算机仿真结果表明，本算法在自组织能力和定位控制精度方面大幅度提高。

Two optimization algorithms for solving robotics inverse kinematics with redundancy

The kinematic redundancy in a robot leads to an infinite number of solutions for inverse kinematics, which implies the possibility to select a 'best' solution according to an optimization criterion. In this paper, two optimization objective functions are proposed, aiming at either minimizing extra degrees of freedom (DOFs) or minimizing the total potential energy of a multilink redundant robot. Physical constraints of either equality or inequality types are taken into consideration in the objective functions. Since the closed-form solutions do not exist in general for highly nonlinear and constrained optimization problems, we adopt and develop two numerical methods, which are verified to be effective and precise in solving the two optimization problems associated with the redundant inverse kinematics. We first verify that the well established trajectory following method can precisely solve the two optimization problems, but is computation intensive. To reduce the computation time, a sequential approach that combines the sequential quadratic programming and iterative Newton-Raphson algorithm is developed. A 4-DOF Fujitsu Hoap-1 humanoid robot arm is used as a prototype to validate the effectiveness of the proposed optimization solutions.

An Analysis of the Inverse Kinematics for a 5-DOF Manipulator

This paper proposes an analytical solution for a 5-DOF manipulator to follow a given trajectory while keeping the orientation of one axis in the end-effector frame. The forward kinematics and inverse kinematics for a 5-DOF manipulator are analyzed systematically. The singular problem is discussed after the forward kinematics is provided. For any given reachable position and orientation of the end-effector, the derived inverse kinematics will provide an accurate solution. In other words, there exists no singular problem for the 5-DOF manipulator, which has wide application areas such as welding, spraying, and painting. Experiment results verify the effectiveness of the methods developed in this paper. Keywords Inverse kinematics - modeling and control - 5-DOF manipulator This work was supported by the National High Technology Research and Development Program of China (No. 2002AA422160), and the National Key Fundamental Research and Development Project of China (973, No.2002CB312200)De Xu graduated from Shandong University of Technology (SUT), China in 1985. He received a Masters degree from SUT in 1990, and a Ph.D. degree from Zhejiang University, China in 2001. He has been with the Institute of Automation, at the Chinese Academy of Sciences (CASIA) since 2001. He is an associate professor with the Laboratory of Complex Systems and Intelligence Science, CASIA. He worked as on academic visitor in the Department of Computer Science, at the University of Essex from May to August 2004. He is a member of the IEEE. His research interests include robotics and automation, especially the control of robots such as visual and intelligent control.Carlos Antonio Acosta Calderon received a B.S. degree in Computer Science Engineering from Pachuca Institute of Technology, Mexico in 2000, and a M.Sc. degree in Computer Science (Robotics and Intelligent Machines) from the University of Essex, UK in 2001. He is currently pursuing a Ph.D degree in Computer Science at the University of Essex, UK. His research interests have focused on mobile robots, in particular, the coordination of multi-robot systems, mobile manipulators, and learning by imitation. He is a member of IEEE.John Q. Gan received a B.Sc. degree in electronic engineering from Northwestern Polytechnic University, China in 1982, a M.Eng. degree in automatic control and a Ph.D degree in biomedical electronics from Southeast University, China in 1985 and 1991, respectively. He is a Senior Lecturer in the Department of Computer Science at the University of Essex, UK. He has co-authored a book, and published over 100 research papers. His research interests are in robotics and intelligent systems, brain-computer interfaces, pattern recognition, signal processing, data fusion, and neurofuzzy computation.Huosheng Hu is a Professor in the Department of Computer Science, at the University of Essex, and head of the Human Centered Robotics Group. His research interests include autonomous mobile robots, human-robot interaction, evolutionary robotics, multi-robot collaboration, embedded systems, pervasive computing, sensor integration, RoboCup, intelligent control, and networked robotics. He has published over 200 papers in journals, books, and conferences, and received two best paper awards. He is a founding member of the IEEE Society of Robotics and Automation Technical Committee of Internet and Online Robots, and a member of the IASTED Technical Committee on “Robotics” for 2001–2004. He was a Conference Chairman for the 1st European Embedded Systems Conference in Paris, 1996, and has been a member of the Program Committees for many international conferences such as IROS (2005–2006), IASTED Robotics and Applications Conferences (2000-present), and RoboCup Symposiums (2000–2004). Dr. Hu is a Chartered Engineer, a senior member of IEEE, and a member of IEE, AAAI, ACM, IASTED and IAS.Min Tan graduated from Tsing Hua University, China in 1986. He received a Ph.D. degree in 1990 from CASIA. He is a professor with the Laboratory of Complex Systems and Intelligence Science, CASIA. He has published over 100 papers in journals, books, and conferences. His research interests include robotics and complex system theory.

Inverse Kinematics Analysis of a 7-DOF Space Manipulator for Trajectory Design

To solve the inverse kinematics problem for redundant degrees of freedom（DOFs）manipulators has been and still continues to be quite challenging in the field of robotics.Aiming at trajectory planning for a 7-DOF space manipulator system,joint rotation trajectories are obtained from predetermined motion trajectories and poses of the end effector in Cartesian space based on the proposed generalized inverse kinematics method.A minimum norm method is employed to choose the best trajectory among available trajectories.Numerical simulations with the7-DOF manipulator show that the proposed method can achieve the planned trajectory and pose under the circumstances of minimum angular velocities.Moreover,trajectory results from the proposed kinematics model and inverse kinematics method has the advantages of simple modelling,low computation cost,easy to solve and plan trajectory conveniently.The smooth and continuous joint rotation functions obtained from the proposed method are suitable for practical engineering applications.

Study on general inverse kinematics of rotating/tilting positioner for robotic arc welding off-line programming

Off line programming provides an essential link between CAD and CAM, whose development will result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is one of the most typical workcells. The inverse kinematics of robot and positioner is the foundation of the off line programming system. The previous researchers only focused on a special solution of the positioner inverse kinematics, which is the solution at down hand welding position. In this paper, we introduce a method for representing welding position. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented, and an approach to find the unique solution of the inverse kinematics is discussed. The simulation experiment results show that the general algorithm can improve the ability of robotic arc welding off line programming system to program all types of welding positions.

Inverse kinematics and welding experiments of the intersecting pipe welding robot

A robot used for multi-pass welding of the piping branch junctions and nozzle attachments to main pressure vessels is 4-DOF serial mechanism, two mobile joints and two rotary joints are adopted in design. The kinematic model was established with DH parameters, the inverse kinematics was solved. According to the forward and inverse kinematics equations, the robot kinematics was simulated in Matlab, the simulations indicate that the solution for inverse kinematics can satisfy the welding requirements well. As there are size errors, processing errors and welding deformation, the path of welding is forecasted according to the previous welding situation, and then, the path is taught at desired via-points, which plays an important role in submerged-arc welding. The submerged-arc welding experiments indicate that the robot and the welding methods are preferable to ensure welding quality.

Inverse kinematics of a heavy duty manipulator with 6-DOF based on dual quaternion

An iterative method is introduced successfully to solve the inverse kinematics of a 6-DOF manipulator of a tunnel drilling rig based on dual quaternion, which is difficult to get the solution by Denavit-Hartenberg(D-H) based methods. By the intuitive expression of dual quaternion to the orientation of rigid body, the coordinate frames assigned to each joint are established all in the same orientation, which does not need to use the D-H procedure. The compact and simple form of kinematic equations, consisting of position equations and orientation equations, is also the consequence of dual quaternion calculations. The iterative process is basically of two steps which are related to solving the position equations and orientation equations correspondingly. First, assume an initial value of the iterative variable; then, the position equations can be solved because of the reduced number of unknown variables in the position equations and the orientation equations can be solved by applying the solution from the position equations, which obtains an updated value for the iterative variable; finally, repeat the procedure by using the updated iterative variable to the position equations till the prescribed accuracy is obtained. The method proposed has a clear geometric meaning, and the algorithm is simple and direct. Simulation for 100 poses of the end frame shows that the average running time of inverse kinematics calculation for each demanded pose of end-effector is 7.2 ms on an ordinary laptop, which is good enough for practical use. The iteration counts 2-4 cycles generally, which is a quick convergence. The method proposed here has been successfully used in the project of automating a hydraulic rig.

Wavelet network solution for the inverse kinematics problem in robotic manipulator

Wavelet network, a class of neural network consisting of wavelets, is proposed to solve the inverse kinematics problem in robotic manipulator. A wavelet network suitable for dealing with multi-input and multi-output system is constructed. The network is optimized by reducing the number of wavelets handling large dimension problem according to the sample data. The algorithms for sparseness analysis of input data and fitting wavelets to the output data with orthogonal method are introduced. Then Levenberg-Marquardt algorithm is used to train the network. Simulation results showed that this method is capable of solving the inverse kinematics problem for PUMA560.

Inverse kinematics and error analysis of cooperative welding robot with multiple manipulators

Precise welding of the T-joints between aircraft hyperbolic panels and stringers is required. Therefore, a method of solving inverse kinematics equations for a cooperative welding robot with multiple manipulators based on neural networks was investigated. To build an effective Denavit-Hartenberg(DH)model for this robot, sample data was obtained considering the movement ranges of the robot joints.Based on back propagation(BP) and radial basis function(RBF) neural networks, 18 joint sub-spaces were mapped to the workspaces of three manipulators. The high-dimensional and nonlinear inverse kinematics problem was transformed into a multi-input and multi-output prediction model. The results revealed that the prediction model of solving the cooperative welding robot kinematics equations was quite accurate. Moreover, compared with the BP-based model, the calculation process of the RBF-based prediction model was slower, but yielded more accurate predictions.

Inverse Kinematics Analysis of Weld Inspection Manipulator at Pipe Joint in Nuclear Industry

A redundant manipulator that can online clamp pipe was developed to track along a cylinder intersection curve. With an ultrasonic transducer mounted on its end-effector, the manipulator can perform welding seam inspection at pipe joint in nuclear industry. An inverse kinematics solution expressed in joint space was solved based on the combination of geometric method and D-H matrix transformation. Expression about joints variables was obtained based on the scanning parameters of pipeline. The analysis method and results can be widely applied for online trajectory planning of intersection curve scanning manipulators.

Inverse kinematics analysis of tubular joint welding robot

A rail type mobile robot introduced in this paper is used to carry out automatic welding on the T, Y and K-joints in offshore platform jackets. This robotic system is composed of a mobile platform and a serial manipulator. The structure of manipulator was designed according to the mathematical modeling of single brace tubular joint ; some improvements of the robot mechanism were considered to improve the flexibility＂ of manipulator and increase the workspace. The inverse kinematics analysis was solved through two steps calculation. The collision avoidance strategy used in the K-joint automatic welding was discussed. Moreover, the simulation results were presented to demonstrate the feasibility of the robot mechanism used in tubular joint welding and the validity of the joint value calculation method.

Robot inverse kinematics based on FCM and fuzzy-neural network

Presents a fast and effective method proposed by combining the fuzzy C means (FCM) and the fuzzy neural network for solving robot inverse kinematics, and its successful application to the robot inverse kinematics and concludes from simulation results that this new method not only has high efficiency and accuracy, but also good generalization, and it also overcomes the "dimension disaster" of fuzzy set in a fuzzy neural network fairly well.

Simulation of proton–neutron collisions in inverse kinematics and its possible application

Neutrons have played a vital role in many nuclear physics fields.In some cases,the inverse kinematics of neutrons colliding with other nuclei are also worth studying.In this study,the inverse kinematics of thermal neutrons colliding with high-energy protons is simulated by using the Monte Carlo method.Thermal neutrons are taken as target particles,whereas protons are incident particles.The simulation implies that,after collision,the energy of the output neutron at 0°equals the energy of the incident proton.A possible application of the result is proposed that might yield single-energy neutrons.Some key parameters of the conceptual design were evaluated,demonstrating that the design may reach high-neutron-energy resolution.

On the Kinematics for the Closed Planar Homothetic Inverse Motions in Complex Plane

In this paper, the Steiner area formula and the polar moment of inertia were expressed during one-parameter closed planar homothetic inverse motions in complex plane. The Steiner point was defined when the rotation number was different zero and it was called the Steiner normal when the rotation number was equal to zero. The fixed pole point was given with its components and its relation between Steiner point or Steiner normal was explained. The sagittal motion of a telescopic crane was considered as an example. This motion was described by a double hinge consisting of the fixed control panel of the telescopic crane and the moving arm of the telescopic crane. The theoretical concepts and results were applied for this motion.

Inverse kinematics of redundant robot based on VC++

This paper uses a 7-degree-of-freedom(7-DOF)manipulator end-effector to research inverse kinematics solution,Three methods are used and compared,including fixing an angle method,the iteration method and the neutral network method.By comparison,the iteration method is much better because of its high accuracy,fast speed and stabilization,and it does not require calculation of the pseudoinverse of the Jacobian.Thus,this control scheme is well suited for real-time implementation,which is essential if the end-effector trajectory is continuously modified based on sensor's feedback.Finally,using VC++and Microsoft foundation classes(MFC)to achieve the main machine interface.Through verification,the precision meets the requirements of general control system in real-time implementation.

The Inverse Kinematics Analysis of Six-DOF Robots

The kinematics of robots mainly analyses the transformational relation between links and the end-actuator position and orientation of robots,its two kinds of topics mainly include:direct kinematics topic and inverse kinematics topic[1].This paper mainly researched the inverse kinematics of Six-DOF robots,built Six-DOF robots inverse kinematics model with D-H parameter model,and worked out the robot’s homogeneous transformation matrix[2].Now we will build the model and study to the inverse kinematics of RBT-6SO3S which from Jiang Su Hui-Bo Robots Company.

Probing Nuclei with High-Energy Hadronic Probes at Inverse Kinematics

Proton knockout reactions are a widely used tool to study nuclear ground-state distributions. While the interpretation of traditional experiments in direct kinematics has to account for initial and final state interactions, experiments in inverse kinematics can overcome such limitations. We discuss results of an experiment at the BM@N setup at JINR using a 12C beam at 48 GeV/c to study quasi-elastic scattering reactions, single proton distributions, and short-range correlated nucleon-nucleon pairs. The inverse kinematics allows for the direct measurement of the nucleon-nucleon pair center-of-mass motion and provides first experimental evidence for scale separation of such pairs. Based on these results, we will in the future study neutron-rich nuclei in inverse kinematics in the context of short-range correlations and neutron stars.

A Mixed Real-time Algorithm for the Forward Kinematics of Stewart Parallel Manipulator

Aimed at the real-time forward kinematics solving problem of Stewart parallel manipulator in the control course, a mixed algorithm combining immune evolutionary algorithm and numerical iterative scheme is proposed. Firstly taking advantage of simpleness of inverse kinematics, the forward kinematics is transformed to an optimal problem. Immune evolutionary algorithm is employed to find approximate solution of this optimal problem in manipulator＇s workspace. Then using above solution as iterative initialization, a speedy numerical iterative scheme is proposed to get more precise solution. In the manipulator running course, the iteration initialization can be selected as the last period position and orientation. Because the initialization is closed to correct solution, solving precision is high and speed is rapid enough to satisfy real-time requirement. This mixed forward kinematics algorithm is applied to real Stewart parallel manipulator in the real-time control course. The examination result shows that the algorithm is very efficient and practical.

Inverse Kinematic Solution for Robot Manipulator Based on Electromagnetism-like and Modified DFP Algorithms

为计算数字解决方案到机器的操纵者的反的 kinematics 问题的一个新方法在这份报纸被开发。与联合限制，像电磁的方法(他们) 利用吸引力排斥机制很快向最佳答案移动样品点。基于他们给的这个近似答案，一个修改 Davidon-Fletcher-Powell (DFP ) 算法被开发在需要的精确解决这个问题。不同于传统的算法，这个修改 DFP (MDFP ) 算法随机选择在 0 和 1 之间的搜索步尺寸。因此，计算复杂性极大地被减少。试验性的结果基于十个将军测试功能和这个新在真实附近的时间混血儿方法能最好生产的美洲狮 560 机器人表演性能。