Detection of the Architecture Singularity of a 6-DOF Parallel Manipulator Based on Artificial Neural Network Algorithm (original) (raw)
Related papers
Journal of Intelligent and Robotic Systems, 2003
A three degree-of-freedom planar parallel manipulator, intended for high-speed, highprecision wire-bonding and electronic-component placement tasks, has been developed in our laboratory. In this paper, the work related to the kinematic manipulator-architecture selection is presented. The reachable workspace and "effective base area" metrics of the parallel manipulator were utilized for selecting the best possible architecture amongst six potential configurations. Constant platformorientation regions, within the reachable workspace of the selected manipulator, were identified based on the manipulator task requirements. Simulation results for the workspace analyses (reachable workspace, effective base areas, and constant-orientation regions) are presented in this paper. Once the optimal-workspace architecture was selected, both workspace-boundary and internal singularities were further investigated in order to have a clear view of the set of uncontrollable poses of the manipulator. Singularity analyses examples are also included herein.
Latin American Journal of Solids and Structures, 2016
The effects of distinctive parameters such as revolute joint angle or spherical joint location of mobile platform in a 6-DOF 6-RUS parallel manipulators on workspace, kinematic, and dynamic indices are investigated in this study to select proper structure commensurate with performance. Intelligent multi-objective optimization method is used to design the manipulator. Considering distinctive parameters, relevant relations for developing inverse kinematic and Jacobin matrix are obtained. In order to study dynamic properties, mass matrix is obtained from calculating the total kinetic energy of the manipulator. After modifying multi-objective Bees algorithm, it used to optimize the manipulator structure considering all geometrical parameters with proper constraints. In addition of comparison of three well known 6-RUS manipulators' types, variation diagram of workspace, local and global dynamics and kinematics performance indices have been drawn with respect to structural parameters variation and limitation of these parameters with proper value are determined. Moreover, considering all dimensional parameters, Pareto front line of multi objective optimization of structure is presented based on dynamic and kinematic performance in predetermined workspace. Based on the results, a fairly comparison among various types of 6-RUS manipulators can be conducted and the most appropriate set of dimensional parameters are selected based on specific demand.
Analytic formulation of the 6-3 fully-parallel manipulator's singularity determination
Robotica, 2001
When a parallel manipulator reaches a singular configuration (singularity), the end effect (platform) pose cannot be controlled any longer, and infinite active forces must be applied in the actuated joints to balance the loads exerted on the platform. Therefore, these singularities must be avoided during motion. The first step to avoid them is to locate all the platform poses (singularity locus) making the manipulator singular. Hence, the availability of a singularity locus equation, explicitly relating the manipulator geometric parameters to the singular platform poses, greatly facilitates the design process of the manipulator. The problem of determining the platform poses, that make the 6-3 fully-parallel manipulator (6-3 FPM) singular, will be addressed. A simple singularity condition will be written. This singularity condition consists in equating to zero the mixed product of three vectors, that are easy to be identified on the manipulator, and it is geometrically interpretable....
Kinematic Synthesis of Parallel Manipulator via Neural Network Approach
In this research, Artificial Neural Networks (ANNs) have been used as a powerful tool to solve the inverse kinematic equations of a parallel robot. For this purpose, we have developed the kinematic equations of a Tricept parallel kinematic mechanism with two rotational and one translational degrees of freedom (DoF). Using the analytical method, the inverse kinematic equations are solved for specific trajectory, and used as inputs for the applied ANNs. The results of both applied networks (Multi-Layer Perceptron and Redial Basis Function) satisfied the required performance in solving complex inverse kinematics with proper accuracy and speed.
Singularity analysis of planar parallel manipulators
Mechanism and Machine Theory, 1995
With regard to planar parallel-manipulators, a general classification of singularities into three groups is introduced. The classification scheme relies on the properties of the Jacobian matrices of the manipulator at hand. The Jacobian matrices of two classes of planar parallel manipulators are derived and the three types of singularities are identified for them. The first class contains 20 manipulators constructed with three different combinations of legs of the PRR, PPR, RRR and RPR types, P and R representing prismatic and revolute pairs, respectively. The second class consists of 4 manipulators constructed with three legs of the PRP and RRP types. Finally, one example for each class is included. Contrary to earlier claims, we show that the third type of singularity is not necessarily architecturedependent.
Neural network algorithm for workspace analysis of a parallel mechanism
Aircraft Engineering and Aerospace Technology, 2007
Purpose-This paper aims to combine and further develop different mathematical models of the workspace representation of 6 degrees of freedom parallel mechanisms and to bring a new point of view to existing workspace analysis methods through using neural networks (NN). Design/methodology/approach-For the orientation workspace of the 6-3 SPM, discretization method is used which is based on Euler angles and the NN algorithm is applied. Findings-The workspace analysis is carried out in the direction perpendicular to the moving platform which is the most workable direction of 6-3 Stewart platform mechanisms and NN algorithm has decreased processing time. Originality/value-The determination of the point, on that direction, at which the workspace is maximum, is outlined. It is the first time that the NN is used for classification of workspace of a parallel manipulator.
Modelling and simulation of 3DOF parallel manipulator using artificial neural network
IOP Conference Series: Materials Science and Engineering, 2019
Parallel Robot (PR) has shown its ability to be precise in its movement. Actuators move simultaneously to achieve the required target, on top of that its payload is much greater than what a serial robot can withstand. To determine workspace of the robot with known angles Forward kinematics has to be introduced which, bring a lot of difficulty as it requires the solution of multiple coupled nonlinear algebraic equations. Those equations bring multiple valid solutions. Those solutions could lead to different locations. As it is not going to make the pick and place for PR will be easier. This paper will discuss a numerical method that calculates the Forward Kinematics for PR. This method uses Artificial Neural Network which relay on training with a certain number of iterations. The set of data to be used in the training can be obtained from PR simulation. This method will serve to know workspace around PR as it will help it to pick the target object.
IEEE Access, 2021
This article introduces a new kinematic modeling method used to analyze coupled rigid multibody movements. The method was applied to the study of a 5R planar parallel mechanism's kinematics and consists of analyzing two fixed configurations of the mechanism to systematize the rotational relationships between the two structures. Mathematical models were developed using complex numbers. The inverse kinematic problem was modeled as a system of eight nonlinear equations and eight unknowns, which was solved with Newton-Raphson's method. Subsequently, with the inverse problem model, a numerical database related to the mechanism configurations, including singular positions, was generated to train a multilayer neural network. The Levenberg-Marquardt algorithm was used for network training. Finally, an interpolated linear path was used to understand the efficiency of the trained network. INDEX TERMS Parallel robots, artificial neural networks, complex numbers, kinematics, Newton-Raphson. I. INTRODUCTION Parallel manipulators have been studied by several researchers over the past two decades, because they have competitive advantages over open-chain robots, for example, greater accuracy, increased load capacity, more rigidity, among others [1]. These features are essential in industrial applications, such as simulators, machine tools, and CNCs, among others [2]. Due to their special characteristics, parallel robots are currently studied by various authors [3]-[8]. Parallel robots are used in several applications where high levels of accuracy and precision are required: for example, in spray paint operations [9] and machining operations [10]. To gain control of robots, the kinematic models that govern their movements are needed. These models are classified into inverse kinematics and direct kinematics. Various mathematical tools have been used to model the kinematics of parallel robots, such as homogeneous matrices [11], complex The associate editor coordinating the review of this manuscript and approving it for publication was Yongming Li .
Design Optimization of a Parallel Manipulator Based on Evolutionary Algorithms
2009
Parallel manipulators are well known for their high dynamic performances and low positioning errors. In the last few years parallel manipulators have attracted great attention from researchers involved in different areas, including highprecision robotics, machine-tools, simulators and haptic devices. Generally speaking, the performance of a robotic manipulator is highly dependent on its structural configuration. Thus, after its choice, the mechanical structure must be defined, i.e., the set of parameters defining the structure must be dimensioned. At this stage some performance criteria may be utilized. In this paper the kinematic design of a 6-dof parallel robotic manipulator for maximum dexterity is analyzed. First, the condition number of the inverse kinematic jacobian is used as a measure of dexterity and a genetic algorithm is utilized to solve the optimization problem. Afterwards, a neuro-genetic formulation is developed and tested. It is shown that the neuro-genetic algorithm...
Design of a Parallel Robotic Manipulator using Evolutionary Computing
International Journal of Advanced Robotic Systems, 2012
In this paper the kinematic design of a 6-dof parallel robotic manipulator is analysed. Firstly, the condition number of the inverse kinematic jacobian is considered as the objective function, measuring the manipulator's dexterity and a genetic algorithm is used to solve the optimization problem. In a second approach, a neural network model of the analytical objective function is developed and subsequently used as the objective function in the genetic algorithm optimization search process. It is shown that the neuro-genetic algorithm can find close to optimal solutions for maximum dexterity, significantly reducing the computational burden. The sensitivity of the condition number in the robot's workspace is analysed and used to guide the designer in choosing the best structural configuration. Finally, a global optimization problem is also addressed.