Mathematical Model and Error Analysis of Coordinate Measuring Arm with Revo Revolving Body

2011 ◽  
Vol 52-54 ◽  
pp. 156-161 ◽  
Author(s):  
Lei Zhao ◽  
Shu Gui Liu
Keyword(s):  
Mathematical Model ◽  
Measurement Accuracy ◽  
System Model ◽  
Error Sources ◽  
Spherical Domain ◽  
New Type ◽  
Space Coordinate ◽  
Improving Accuracy ◽  
Revolving Body ◽  
The Mathematical Model

A new type of coordinate measuring arm with a Revo revolving body which can realize quick measuring in spherical domain has high stability, fast measuring speed and high accuracy compared with common coordinate measuring arm. We use the method of space coordinate transformation to solve the problem that the transformation matrix can’t be got from Revo body to test head by DH method, and apply DH theory to build the mathematical model of system. The system model is verified right by sketching. The error model is built and the effect of measurement accuracy from all error sources is deeply analyzed. It presents a theory foundation for further researching on improving accuracy of this new type of coordinate measuring arm.

scholarly journals An Improved Capacitive Sensor for Detecting the Micro-Clearance of Spherical Joints

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2694 ◽  
Author(s):  
Wen Wang ◽  
Wenjun Qiu ◽  
He Yang ◽  
Haimei Wu ◽  
Guang Shi ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Real Time ◽  
Measurement Accuracy ◽  
Detection Method ◽  
Capacitive Sensor ◽  
Parallel Manipulators ◽  
Differential Capacitance ◽  
Industrial Robots ◽  
The Mathematical Model ◽  
Fringe Effect

Due to the flexible and compact structures, spherical joints are widely used in parallel manipulators and industrial robots. Real-time detection of the clearance between the ball and the socket in spherical joints is beneficial to compensate motion errors of mechanical systems and improve their transmission accuracy. This work proposes an improved capacitive sensor for detecting the micro-clearance of spherical joints. First, the structure of the capacitive sensor is proposed. Then, the mathematical model for the differential capacitance of the sensor and the eccentric micro-displacement of the ball is deduced. Finally, the capacitance values of the capacitive sensor are simulated with Ansoft Maxwell. The simulated values of the differential capacitances at different eccentric displacements agree well with the theoretical ones, indicating the feasibility of the proposed detection method. In addition, the simulated results show that the proposed capacitive sensor could effectively reduce the capacitive fringe effect, improving the measurement accuracy.

Theoretical and Experimental Study of the Dynamics of the Tripod-Ball Sliding Joint With Clearance

2001 ◽  
Author(s):  
Jia Xiaohong ◽  
Ji Linhong ◽  
Jin Dewen ◽  
Zhang Jichuan
Keyword(s):  
Mathematical Model ◽  
Equations Of Motion ◽  
Experimental Studies ◽  
Active System ◽  
New Concepts ◽  
Sliding Joint ◽  
New Type ◽  
Set Up ◽  
The Mathematical Model ◽  
Kane Method

Abstract Clearance is inevitable in the kinematic joints of mechanisms. In this paper the dynamic behavior of a crank-slider mechanism with clearance in its tripod-ball sliding joint is investigated theoretically and experimentally. The mathematical model of this new-type joint is established, and the new concepts of basal system and active system are put forward. Based on the mode-change criterion established in this paper, the consistent equations of motion in full-scale are derived by using Kane method. The experimental rig was set up to measure the effects of the clearance on the dynamic response. Corresponding experimental studies verify the theoretical results satisfactorily. In addition, due to the nonlinear elements in the improved mathematical model of the joint with clearance, the chaotic responses are found in numerical simulation.

Valve Gear Refinement

2000 ◽  
Vol 124 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Jurij Avsec ◽  
Milan Marcic ◽  
Maks Oblak
Keyword(s):  
Mathematical Model ◽  
Cam Design ◽  
Cam Follower ◽  
New Type ◽  
Cam Profile ◽  
Profile Design ◽  
Comparison Of The Results ◽  
The Mathematical Model ◽  
Valve Gear ◽  
Lubrication Properties

This paper describes a new type of valve gear cam—MULTICAM—which consists of seven curves and allows an optimum cam profile design. In order to calculate the cinematic and dynamic values and to assess the minimum oil film thickness in the valve gear, the mathematical model of an ideal valve gear was used. In addition, the comparison of the results between the polysine cam and the new MULTICAM cam design was made. By means of the new cam design the Hertz pressures were reduced at the point of contact between the cam and the cam follower and the lubrication properties at the top of the cam improved.

Error Model and Calibration Analysis of the Flexible Coordinate Measuring Machine

2011 ◽  
Vol 121-126 ◽  
pp. 3273-3277 ◽  
Author(s):  
Fang Li ◽  
Shu Gui Liu ◽  
Lei Zhao
Keyword(s):  
Mathematical Model ◽  
Coordinate Measuring Machine ◽  
Least Square Method ◽  
Coefficient Matrix ◽  
Error Model ◽  
Least Square ◽  
Parameter Calibration ◽  
Measuring Machine ◽  
Improving Accuracy ◽  
The Mathematical Model

A new 5-DOF flexible coordinate measuring machine (CMM) is introduced in this paper, which uses REVO system produced by Renishaw. According to the D-H method, the mathematical model is built, and then the error model of the flexible CMM is derived. The parameter calibration based on the nonlinear least square method is analyzed theoretically. Due to the disadvantages of Gauss-Newton method, LM method is researched, which improved the singularity of the coefficient matrix. The calibration analysis is a basis for improving accuracy of the flexible CMM.

Stability of Velocity-Loop-Based Hydraulic Control Loading System

2012 ◽  
Vol 619 ◽  
pp. 472-475
Author(s):  
Pan Guo Qi ◽  
Li Wei Zhao ◽  
Pei Chao Cong ◽  
Hui Wang
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
System Model ◽  
Flight Simulator ◽  
Stability Conditions ◽  
Hydraulic Control ◽  
Function Block ◽  
Loading System ◽  
The Stability ◽  
The Mathematical Model

A hydraulic Control Loading System (CLS) based on velocity-loop was developed and installed on our flight simulator earlier days, but the CLS cannot keep stable in some conditions. This problem is discussed in this paper. The mathematical model of velocity-loop-based CLS is firstly developed with the method of transfer function block diagram. Then, system’s stability conditions are put forward using Roth criterion based on the system model developed. At last, the experiments proves the stability

scholarly journals Machine Directional Register System Modeling for Shaft-Less Drive Gravure Printing Machines

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Shanhui Liu ◽  
Xuesong Mei ◽  
Jian Li ◽  
Li'e Ma
Keyword(s):  
Mathematical Model ◽  
System Modeling ◽  
System Model ◽  
Experimental Setup ◽  
Gravure Printing ◽  
Servo Motor ◽  
Definition Of ◽  
The Mathematical Model ◽  
Register Error ◽  
Control Accuracy

In the latest type of gravure printing machines referred to as the shaft-less drive system, each gravure printing roller is driven by an individual servo motor, and all motors are electrically synchronized. The register error is regulated by a speed difference between the adjacent printing rollers. In order to improve the control accuracy of register system, an accurate mathematical model of the register system should be investigated for the latest machines. Therefore, the mathematical model of the machine directional register (MDR) system is studied for the multicolor gravure printing machines in this paper. According to the definition of the MDR error, the model is derived, and then it is validated by the numerical simulation and experiments carried out in the experimental setup of the four-color gravure printing machines. The results show that the established MDR system model is accurate and reliable.

Analysis of Mechanical Error’s Effect on the Measurement Accuracy of the Six-Axis Force Sensor

2014 ◽  
Vol 627 ◽  
pp. 177-181
Author(s):  
Ru Nan Liang
Keyword(s):  
Mathematical Model ◽  
Monte Carlo ◽  
Theoretical Basis ◽  
Measurement Accuracy ◽  
Force Sensor ◽  
Stewart Platform ◽  
System Structure ◽  
The Monte Carlo Method ◽  
Six Degree Of Freedom ◽  
The Mathematical Model

Force sensor based on the six degree of freedom (6-DoF) Stewart platform is universal for wide applications. Mechanism errors are significant for its measuring accuracy. However, because of the multi-variables and the complicated forms, it is difficult to solve the expression directly. The Monte Carlo method is proposed based on the analysis of the system structure and the mathematical model. The effect of mechanism errors on the measurement accuracy was assessed. With this method, a complex accuracy expression of the sensor could be avoided. It also provided a theoretical basis for designing the sensor of the Stewart platform.

Dynamics and Stability of Non-Planar Rigid Rotor Equipped with Two Ball-Spring Autobalancers

2019 ◽  
Vol 19 (02) ◽  
pp. 1950001 ◽  
Author(s):  
Mousa Rezaee ◽  
Mir Mohammad Ettefagh ◽  
Reza Fathi
Keyword(s):  
Mathematical Model ◽  
Nonlinear Equations ◽  
Equations Of Motion ◽  
Rigid Rotor ◽  
Out Of Plane ◽  
New Type ◽  
Nonlinear Equations Of Motion ◽  
The Mathematical Model ◽  
System Time

Recently, a new type of automatic ball balancer (ABB), called the ball-spring autobalancer (AB), has been proposed, which substantially eliminates the drawbacks of the traditional ABBs. In previous studies, the dynamics of the Jeffcott planar rotor equipped with ball-spring AB has been investigated. In the Jeffcott model, it is assumed that the ABB is located on the plane of the unbalance disk. However, for the non-planar rigid rotor with distributed imbalances, out-of-plane motions may occur, and the Jeffcott model becomes unreliable as the tilting motion cannot be explained. To this end, the aim of this paper is to analyze the capability of the ball-spring AB in balancing non-planar rotors and to reconfirm its pre-claimed advantages over the traditional ABBs for balancing non-planar rotors. To start, the mathematical model of the rigid rotor with two ball-spring ABs is established, based on which the nonlinear equations of motion are derived. Then, the system time responses are computed numerically and the balanced stable regions are acquired by the Lyapunov’s first method. The results of this study show that the ball-spring ABs can balance the non-planar rotors and the tilting motion does not impair the pre-claimed advantages of the ball-spring AB.

The Pre-Travel Error Study of Electrical Trigger Probe in On-Machine Measurement

2016 ◽  
Vol 693 ◽  
pp. 1466-1473 ◽  
Author(s):  
Yong Lin Cai ◽  
Ning Ning Cui ◽  
Xiang Mo ◽  
Xiang Kai Yao ◽  
Wei Qing Sun
Keyword(s):  
Mathematical Model ◽  
Machine Tool ◽  
Measurement Accuracy ◽  
Nc Machining ◽  
Efficient Measure ◽  
High Efficient ◽  
Probe Angle ◽  
Moving Direction ◽  
The Mathematical Model ◽  
Error Study

On-machine measurement is a high-efficient measure method in NC machining, and there are pre-travel errors during measurement. What is more, these errors tend to present anisotropy, and affect the measurement accuracy. This paper aimed at measuring the anisotropy of probe’s pre-travel error. First, the standard ball is measured by changing the probe angle with the same machine tool moving direction, and the pre-travel errors with different probe angles under the same machine tool errors are obtained. Then, the machine tool backlash errors are measured and compensated, and the pre-travel errors with different probe angle are obtained. Finally, the mathematical model of pre-travel error is established. The method proposed in this paper can be used to determine probe’s pre-travel error with anisotropy.

Fixture Optimization for Robotic Belt Grinding System

2011 ◽  
Vol 121-126 ◽  
pp. 2030-2034
Author(s):  
Dong Zhang ◽  
Chao Yun ◽  
Ling Zhang
Keyword(s):  
Mathematical Model ◽  
Optimization Methods ◽  
Belt Grinding ◽  
Robotic Grinding ◽  
The Monte Carlo Method ◽  
New Type ◽  
Set Up ◽  
Robotic Belt Grinding ◽  
The Mathematical Model ◽  
Grinding System

The precision is impacted when the robotic grinding path is discontinuous and the gripper needs to be replaced during manufacturing. In order to solve this problem, a new type PPPRRR grinding robot was proposed. The mathematical model for the robotic grinding paths was set up. The factors including the pose of the workpiece respect to the end joint and the position of contact wheel respect to the robot base frame {O}were analyzed to influence the grinding ability of the system. Base on the Monte Carlo method the posture and position factors above had been optimized, and the grinding ability of the system was increased. The optimization methods were proved right and workable by grinding golf head experiment.

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