Measurement Configuration Optimization and Kinematic Calibration of a Parallel Robot

2021 ◽  
pp. 1-11
Author(s):  
Chenhui Huang ◽  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Qizhi Meng

Abstract This paper presents the kinematic calibration of a 4-DOF high-speed parallel robot. In order to improve the calibration effect by decreasing the influence of the unobservable disturbance variables introduced by error measurement, a measurement configuration optimization method is proposed. Configurations are iteratively selected inside the workspace by a searching algorithm, then the selection results are evaluated through an index associated with the condition number of the identification Jacobian matrix, finally the number of optimized configurations are determined. Since the searching algorithm has been shown to be sensitive to local minima, a meta-heuristic method has been applied to decrease this sensibility. To verify the effectiveness of the algorithm and kinematic calibration, computation validations, pose error estimations and experiments are performed. The results show that the identification accuracy and calibration effect can be significantly improved by using the optimized configurations.

Author(s):  
Mansour Abtahi ◽  
Hodjat Pendar ◽  
Aria Alasty ◽  
Gholamreza Vossoughi

In the past few years, parallel manipulators have become increasingly popular in industry, especially, in the field of machine tools. Hexaglide is a 6 DOF parallel manipulator that can be used as a high speed milling machine. In this paper, the kinematics and singularity of Hexaglide parallel manipulator are studied systematically. At first, this robot has been modeled and its inverse and forward kinematic problems have been solved. Then, formulas for solving inverse velocity are derived and Jacobian matrix is obtained. After that, three different types of singularity for this type of robot have been investigated. Finally a numerical example is presented.


2016 ◽  
Vol 8 (6) ◽  
Author(s):  
Tian Huang ◽  
Pujun Bai ◽  
Jiangping Mei ◽  
Derek G. Chetwynd

This paper presents a comprehensive methodology for ensuring the geometric pose accuracy of a 4DOF high-speed pick-and-place parallel robot having an articulated traveling plate. The process is implemented by four steps: (1) formulation of the error model containing all possible geometric source errors; (2) tolerance design of the source errors affecting the uncompensatable pose accuracy via sensitivity analysis; (3) identification of the source errors affecting the compensatable pose accuracy via a simplified model and distance measurements; and (4) development of a linearized error compensator for real-time implementation. Experimental results show that a tilt angular accuracy of 0.1/100 and a volumetric/rotational accuracy of 0.5 mm/±0.8 deg of the end-effector can be achieved over the cylindrical task workspace.


2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Gang Han ◽  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Qizhi Meng ◽  
Sai Zhang

Abstract Parameters optimization is complicated by various parameters and nonlinear design problems. In this paper, the interaction mechanism of motion/force transmissibility and various parameters on normalized motor torque and speed of a four degrees-of-freedom (4-DOF) high-speed parallel robot is analyzed. Based on this interaction mechanism, evaluation indices of acceleration capacity, speed ability, and adept cycle time are proposed. Through combining these indices with task requirements and technical criteria of driving systems, the technology-oriented constraints are set up and a parameter optimization method is proposed. With this method, the dimensional parameters, driving system specifications, and work pose of the robot have been synchronously optimized to ensure low driving torque and high pick-and-place frequency. This synchronous optimal design method is general and can be further applied to parameter optimization for different types of parallel robots.


Author(s):  
Saeed Varziri ◽  
Leila Notash

In this article kinematic calibration of the central linkage of a wire-actuated parallel robot, which has a parallelogram mechanism in its structure, is discussed. It is shown that the dependency between the parallelogram joint angles affect the conditioning of the identification Jacobian matrix. Through a sensitivity analysis, it is presented that some of the parallelogram link lengths are not identifiable. Two nonlinear calibration approaches, Gauss-Newton and Levenberg-Marquardt, have also been explained and their difference especially when the identification Jacobian matrix is ill-conditioned, are pointed out.


Author(s):  
Ki-Sang Song ◽  
Arun K. Somani

From the 1994 CAIS Conference: The Information Industry in Transition McGill University, Montreal, Quebec. May 25 - 27, 1994.Broadband integrated services digital network (B-ISDN) based on the asynchronous transmission mode (ATM) is becoming reality to provide high speed, multi bit rate multimedia communications. Multimedia communication network has to support voice, video and data traffics that have different traffic characteristics, delay sensitive or loss sensitive features have to be accounted for designing high speed multimedia information networks. In this paper, we formulate the network design problem by considering the multimedia communication requirements. A high speed multimedia information network design alogrithm is developed using a stochastic optimization method to find good solutions which meet the Quality of Service (QoS) requirement of each traffic class with minimum cost.


Author(s):  
Zijian Guo ◽  
Tanghong Liu ◽  
Wenhui Li ◽  
Yutao Xia

The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].


Author(s):  
Deqi Yu ◽  
Xiaojun Zhang ◽  
Jiandao Yang ◽  
Kai Cheng ◽  
Weilin Shu ◽  
...  

Fir-tree root and groove profiles are widely used in gas turbine and steam turbine. Normally, the fir-tree root and groove are characterized with straight line, arc or even elliptic fillet and splines, then the parameters of these features were defined as design variables to perform root profile optimization. In ultra-long blades of CCPP and nuclear steam turbines and high-speed blades of industrial steam turbine blades, both the root and groove strength are the key challenges during the design process. Especially, in industrial steam turbines, the geometry of blade is very small but the operation velocity is very high and the blade suffers stress concentration severely. In this paper, two methods for geometry configuration and relevant optimization programs are described. The first one is feature-based using straight lines and arcs to configure the fir-tree root and groove geometry and genetic algorithm for optimization. This method is quite fit for wholly new root and groove design. And the second local optimization method is based on B-splines to configure the geometry where the local stress concentration occurs and the relevant optimization algorithm is used for optimization. Also, several cases are studied as comparison by using the optimization design platform. It can be used not only in steam turbines but also in gas turbines.


2009 ◽  
Vol 69-70 ◽  
pp. 580-584 ◽  
Author(s):  
D.F. Zhang ◽  
Feng Gao

A novel 6-(P-2P-S) parallel robot is put forward. With the characters of some movement decoupling on the orthogonal pose, the robot can be used as the macro manipulator of the macro/micro dual driven robots. The macro manipulator as a high-precision positioning device, it is significant for the practical application and drive train design to research statics. First, the force Jacobian matrix is deduced, which is related to the orientation parameters. Then based on the Jacobian matrix singular value decomposed characteristic, the static force transmission evaluation indicators Kf and Km are defined. Finally, considering structure constraints and parameters, the distribution of evaluation indicators in the orientation workspace is drawn, which provide the theoretical base for the design and applications of the robot. Because of the characters of simple structure, high carrying capacity, less motion inertia, good manufacturability, the 6-(P-2P-S) parallel macro manipulator has been designed.


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