Error Analysis of a Manipulators

2014 ◽  
Vol 933 ◽  
pp. 395-398
Author(s):  
Li Wen Chen ◽  
Bing Yan Cui ◽  
Guang Hao Zhang
Keyword(s):  
Error Analysis ◽  
Degrees Of Freedom ◽  
Theoretical Foundation ◽  
Initial Position ◽  
Error Model ◽  
Error Evaluation ◽  
Spherical Parallel Mechanism ◽  
Model Technique ◽  
Three Degrees Of Freedom ◽  
Theory Error

The forearm is a typical ball and socket joint which have three degrees of freedom rotation. In this case the study of a 3-DOF manipulators is very interesting. In this paper, a novel manipulators based on 3-DOF orthogonal spherical parallel mechanism is proposed. Error analysis play an important role on the design and applications of the manipulators. The error model is derived in closed forms by using differential theory. Error evaluation index is defined. Terminal platform error distribution is analyzed and discussed in detail by using the error model technique. The analytic results indicate error value is smallest in initial position of the manipulators,the bigger value of error distributes in the workspace edge. So, this paper could provide a theoretical foundation for design and application of the manipulators.

FEM Based Numerical Simulation of Delta Parallel Mechanism

2013 ◽  
Vol 690-693 ◽  
pp. 2978-2981 ◽  
Author(s):  
Jian Zhong Zhang ◽  
Xin Peng Xie ◽  
Chuan Jin Li ◽  
Ying Ying Xin ◽  
Zhao Ming He
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Theoretical Foundation ◽  
Future Research ◽  
Element Analysis ◽  
Pick And Place ◽  
Integral Structure ◽  
Inverse Dynamics Analysis ◽  
Three Degrees Of Freedom

This paper describes a parallel three degrees of freedom delta mechanism used for pick-and-place. It has the advantages of simple integral structure, strong bearing capacityhigh precisionkinematics and dynamics performance. According to this mechanism wide development prospect, the company study on the inverse kinematics inverse dynamics analysis and the static analysis by using ANSYS finite element analysis Software of Delta. These analyses have laid a good theoretical foundation for future research. These researches provide possible for widely used in foodpackingautomated assembly line occasions of small and medium-sized enterprises.

Performance Analysis of 3-URU Spherical Parallel Mechanism Designed Based on Velocity Transmission and Force Constraint Indices

2015 ◽  
Vol 758 ◽  
pp. 71-76
Author(s):  
Syamsul Huda ◽  
Syafri ◽  
Mulyadi Bur
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Output Link ◽  
Kinematic Synthesis ◽  
Platform Motion ◽  
Spherical Parallel Mechanism ◽  
Velocity Transmission ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Spherical Motion

In this paper was observed performances of developed three degrees of freedom (dof) parallel mechanism named 3-URU spherical parallel mechanism. The mechanism is composed of three identical limbs mounted symmetrically to base (fixed link) and platform (output link). The limb is constructed by universal-revolute and universal joints. The kinematic constants of mechanism consisting of link lengths, radius of platform, radius of base, mounting angle of limb and platform to base and platform were determined with consideration of velocity transmission and force constraint indices. To evaluate performance of mechanism, it was manufactured a prototype of mechanism designed base on these two mentioned indices. There are three steps proposed to realize the mechanism, (i) kinematic synthesis to determine of kinematic constants, (ii) design of mechanical components to define shape and dimension of links and joints by considering collision in wokingspace and static analysis, (iii) evaluation of mechanism performances consisting of workingspace, controllability of platform motion and static payload. Based on obtained results, it can be clarified that, the mechanism can produce spherical motion of platform which rotates on steady point recognized as center of platform rotation. The platform can achieve maximum inclination angle, 80 degree and at this posture occurs translational error, 0.0102 mm. On the other hand, the mechanism can support payload ten times of weight of moving parts.

Static error model of a three-floated gyroscope with a rotor supported on gas-lubricated bearings

2017 ◽  
Vol 232 (16) ◽  
pp. 2850-2860 ◽  
Author(s):  
Yan Li ◽  
Fuhai Duan ◽  
Liang Fan ◽  
Ying Yan
Keyword(s):  
Regression Analysis ◽  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Axial Direction ◽  
Error Model ◽  
Specific Force ◽  
Static Error ◽  
Rapid Prediction ◽  
Bearing Force ◽  
Three Degrees Of Freedom

Three-floated gyroscope with the advantages of high accuracy has been widely used in platform inertial navigation system. To investigate the influence of specific force on the measured angular velocity of a gyroscope with a rotor supported on gas-lubricated bearings, a static error model considering three-degrees-of-freedom displacement of the rotor is proposed through numerical computation. Firstly, the conical Reynolds equation incorporated with the Fukui and Kaneko’s slip model is adopted and solved by the finite difference method, and the bearing force, caused by specific force, are obtained for each rotor displacement. Secondly, the error of gyroscope measured angular velocity is calculated from bearing force and rotor displacement. Finally, the relationship between the error and specific force is obtained by regression analysis, and the static error model of the gyroscope is proposed. To simplify the ternary regression analysis to binary, two intermediate parameters, radial interference torque and circumferential angle between interference torque and specific force, are introduced. Numerical results show that interference torque is approximately π/2 ahead of specific force in circumferential direction with fz > 0, and π/2 behind specific force with fz < 0, and that a large interference torque is produced when the specific force in radial and axial direction are both large. The error model provides a rapid prediction of the error caused by rotor displacement by three-degrees-of-freedom specific force.

scholarly journals A Sensor Based on a Spherical Parallel Mechanism for the Measurement of Fluid Velocity: Physical Modelling and Computational Analysis

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2867 ◽  
Author(s):  
Roque Saltarén ◽  
Gerardo Portilla ◽  
Alejandro Barroso ◽  
Juan Cely
Keyword(s):  
Parallel Mechanism ◽  
Inertial Measurement Unit ◽  
Degrees Of Freedom ◽  
Fluid Velocity ◽  
Physical Modelling ◽  
Measurement Unit ◽  
Adams Software ◽  
Spherical Parallel Mechanism ◽  
The Impact ◽  
Three Degrees Of Freedom

In this article, a new method was developed to measure the velocity of a fluid using a sensor, based on the use of a spherical parallel mechanism with three degrees-of-freedom (DOF). This sensor transforms the kinetic energy of the fluid into potential energy by deforming the parallel mechanism. This deformation is due to the impact of the fluid on a sphere attached to the platform of the parallel mechanism. Through the acquisition of data from a sensor using an inertial measurement unit (IMU) in the sphere, an algorithm calculates the velocity and direction of the fluid. In this article, a mathematical model of the mechanism and an algorithm for correctly measuring the velocity and direction of the fluid is developed; this algorithm is tested through a simulation in the Adams software, and the MATLAB software is used to execute the algorithm. The results show that the algorithm calculates the velocity and the direction of the fluid correctly, demonstrating the technical feasibility of the sensor.

Kinematics Analysis of a 3-RRR Spherical Parallel Mechanism with Coaxial Input Shafts

2013 ◽  
Vol 404 ◽  
pp. 237-243
Author(s):  
Yu Lei Hou ◽  
Xin Zhe Hu ◽  
Da Xing Zeng
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Inverse Solution ◽  
Kinematics Analysis ◽  
Motion Feature ◽  
Displacement Problem ◽  
Spherical Parallel Mechanism ◽  
Three Degrees Of Freedom

As an important mechanism with special and extensive application, the three degrees of freedom spherical parallel mechanism is always a research hot in the mechanical fields. In this paper, the feature of the 3-RRR spherical parallel mechanism with coaxial input shafts is introduced, and its motion feature is analyzed based on the screw theory. The mobility of the spherical parallel mechanism is calculated by using the Modified Kutzbach-Grübler criterion, and the inverse displacement problem of the mechanism is solved. Then the expression of the Jacobian matrix is deduced based on the kinematics equation and its inverse solution. The contents of this paper should be useful for the further application of the spherical parallel mechanism.

scholarly journals Active Disturbance Rejection for a Three Degrees of Freedom Gyroscope

2018 ◽  
Vol 51 (13) ◽  
pp. 372-377 ◽  
Author(s):  
Juan E. Andrade García ◽  
Alejandra Ferreira de Loza ◽  
Luis T. Aguilar ◽  
Ramón I. Verdés
Keyword(s):  
Disturbance Rejection ◽  
Degrees Of Freedom ◽  
Active Disturbance Rejection ◽  
Three Degrees Of Freedom
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