Self-Adaptive Compensation Method on the Tool Position of Roller Gear Cam Surface

2010 ◽  
Vol 154-155 ◽  
pp. 396-400
Author(s):  
Rong Yu Ge ◽  
Qing Song Wang ◽  
Xu Qiang Shang
Keyword(s):  
Rotation Angle ◽  
Optimization Method ◽  
Compensation Method ◽  
Adaptive Compensation ◽  
Machining Error ◽  
Flexible Compensation ◽  
Tool Position ◽  
Tool Diameter ◽  
Adaptive Tool ◽  
Self Adaptive

The roller gear cam surface is often machined by the unequal diameter manufacture method, which means the tool diameter is smaller than that of the roller and the tool position compensation method is most used. For tool position of roller gear cam, it is important to confirm the compensation vector for the tool position compensation method, including compensation value and direction. In the paper, a new self-adaptive tool position optimization method is proposed, which make minimizing the normal machining error as the object function and make two compensation factors as the optimization variables. This algorithm can find out the best compensation direction and value by the tool position optimization for any cam rotation angle and make the tool position self-adaptive and flexible compensation according to the machining error. A numerical calculation example shows that the optimization algorithm can feasibly reduce the machining error. At last a conclusion has been drawn that the radius difference between the tool and the roller is the best compensation value and the best compensation direction is not fixed.

An Error Compensation Method for Rectangular Window Based on NURBS Reconstruction Theory

2018 ◽  
Vol 917 ◽  
pp. 284-288
Author(s):  
Dong Xia Li ◽  
Ai Min Wang ◽  
Peng Hao Ren
Keyword(s):  
Software Development ◽  
Error Compensation ◽  
Tool Path ◽  
Measured Data ◽  
Compensation Method ◽  
Adaptive Compensation ◽  
Machining Error ◽  
Rectangular Window ◽  
B Splines ◽  
Error Calculation

Aiming at the error compensation problem for rectangular window, this paper presents a method of compensation for rectangular window based on NURBS (Non-Uniform Rational B-Splines) reconstruction. In the method, the machining surface is digitally obtained by means of on-machine measurement. The measured data are divided into four regions and different error compensation schemes are used for different regions. The adaptive compensation of the machining error calculated based on NURBS reconstruction theory is achieved by modifying the coordinates of the tool point in the cutter location file. The automation of error calculation and compensation is implemented by software development based on Visual Studio 2012. At the end of the paper, a compensating tool path is emulated in VERICUT. The results show our method is feasible.

Nonlinear Self-Adaptive Compensation of Screw down System of Tandem Cold Mill

2010 ◽  
Vol 139-141 ◽  
pp. 1883-1888
Author(s):  
Bao Quan Liu ◽  
Zi Dong Wang ◽  
Hong Zhang ◽  
Jun Sheng Wang ◽  
Yan Zhang
Keyword(s):  
Control System ◽  
Dynamic Performance ◽  
Compensation Method ◽  
Servo Control ◽  
Adaptive Compensation ◽  
Parameter Uncertainties ◽  
Servo Control System ◽  
Highly Nonlinear ◽  
Hydraulic Servo ◽  
Self Adaptive

The Screw Down System (SDS) is a typical hydraulic servo control system. It is the key actuator of cold rolling mill. The dynamic performance of SDS has a significant effect on the accuracy of thickness. Hydraulic servo control system is not always optimal and stable due to highly nonlinear and parameter uncertainties. In this paper, the most important nonlinear relating flow and pressure is analyzed. A nonlinear self-adaptive compensation method is designed. Modeling and simulating the hydraulic servo control system of SDS using this method, the numerical simulation results show that the maximum overshoot and static error of the compensated system are more less than that of without nonlinear compensation. The overshoot of the compensated system is less than 10% when the cold strip is rolling. So the thickness tolerance of the cold strip can be guaranteed easily. This self- adaptive compensation method can be used to other hydraulic servo control systems.

On-line first-order machining error compensation for thin-walled parts considering time-varying cutting condition

2021 ◽  
pp. 1-16
Author(s):  
Xiong Zhao ◽  
Lianyu Zheng ◽  
Yuehong Zhang
Keyword(s):  
Error Compensation ◽  
Compensation Method ◽  
Cutting Condition ◽  
Time Varying ◽  
Machining Error ◽  
Process Step ◽  
Compensation Model ◽  
First Order ◽  
On Line ◽  
Thin Walled

Abstract Mirror error compensation is usually employed to improve the machining precision of thin-walled parts. However, this zero-order method may result in inadequate error compensation, due to the time-varying cutting condition of thin-walled parts. To cope with this problem, an on-line first-order error compensation method is proposed for thin-walled parts. With this context, firstly, the time-varying cutting condition of thin-walled parts is defined with its in-process geometric and physical characteristics. Based on it, a first-order machining error compensation model is constructed. Then, during the process planning, the theory geometric and physical characteristic of thin-walled parts are respectively obtained with CAM software and structure dynamic modification method. After process performing, the real geometric characteristic of thin-walled parts is measured, and it is used to calculate the dimension error of thin-walled parts. Next, the error compensated value is evaluated based on the compensation model, from which, an error compensation plane is constructed to modify the tool center points for next process step. Finally, the machining error is compensated by performing the next process step. A milling test of thin-walled part is employed to verify the proposed method, and the experiment results shown that the proposed method can significantly improve the error compensation effect for low-stiffness structure, and thickness precision of thin-walled parts is improved by 71.4 % compared with the mirror error compensation method after machining.

scholarly journals Design, Optimization, and Experiment on a Bioinspired Jumping Robot with a Six-Bar Leg Mechanism Based on Jumping Stability

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Ziqiang Zhang ◽  
Bin Chang ◽  
Jing Zhao ◽  
Qi Yang ◽  
Xingkun Liu
Keyword(s):  
Dynamic Models ◽  
Rotation Angle ◽  
High Sensitivity ◽  
Optimization Method ◽  
Small Range ◽  
Configuration Optimization ◽  
Inertia Moment ◽  
Object A ◽  
Reduced Mechanism ◽  
Optimization Parameters

A jumping leg with one degree of freedom (DOF) is characterized by high rigidity and simple control. However, robots are prone to motion failure because they might tip over during the jumping process due to reduced mechanism flexibility. Mechanism design, configuration optimization, and experimentation were conducted in this study to achieve jumping stability for a bioinspired robot. With locusts as the imitated object, a one-DOF jumping leg mechanism was designed taking Stephenson-type six-bar mechanism as reference, and kinematic and dynamic models were established. The rotation angle of the trunk and the total inertia moment were used as stability criteria, and the sensitivity of different links to the target was analyzed in detail. With high-sensitivity link lengths as the optimization parameters, a configuration optimization method based on the particle swarm optimization algorithm was proposed in consideration of the different constraint conditions of the jumping leg mechanism. Optimization results show that this method can considerably improve optimization efficiency. A prototype of the robot was developed, and the experiment showed that the optimized trunk rotation angle and total inertia moment were within a small range and can thus meet the requirements of jumping stability. This work provides a reference for the design of jumping and legged robots.

A robotic boring system for intersection holes in aircraft assembly

2018 ◽  
Vol 45 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Yingjie Guo ◽  
HuiYue Dong ◽  
Guifeng Wang ◽  
Yinglin Ke
Keyword(s):  
Optimization Method ◽  
Northwest China ◽  
Compensation Method ◽  
Practical Case ◽  
Content Type ◽  
Aircraft Assembly ◽  
Position Accuracy ◽  
Position And Orientation ◽  
Robot Stiffness ◽  
Robotic Boring

Purpose The purpose of this paper is to introduce a robotic boring system for intersection holes in aircraft assembly. The system is designed to improve the boring quality and position accuracy of the intersection holes. Design/methodology/approach To improve the boring quality of intersection holes, a robot posture optimization model is established. The target of the model is to maximize the robot stiffness and the variate is location of the robot on the guideway. The model is solved by the iterative IKP algorithm based on the Jacobian matrix. To improve the position accuracy of intersection holes, a robot positioning accuracy compensation method is introduced. In the method, a laser tracker is used to measure the actual position and orientation of the boring bar. Combined with the desired position and orientation, the error can be obtained and compensated. Findings In practical case of the robotic boring system, the robot stiffness is effectively improved and the surface roughness of intersection holes achieves a grade of Ra0.8. Besides, the robot end achieves a position accuracy of 0.05 mm and an orientation accuracy of 0.05°. Practical implications The robotic boring system has been applied successfully in one of the aircraft assembly projects in northwest China. Originality/value The robotic boring system can be applied for machining intersection holes in an aircraft assembly. With the robot posture optimization method and accuracy compensation method, the boring quality and position accuracy of the intersection holes can be guaranteed.

Calculation and Optimization of Cutter Position for Flank Milling Spatial Cam Based on NURBS

2008 ◽  
Vol 375-376 ◽  
pp. 578-582
Author(s):  
Rong Yu Ge ◽  
Xian Ying Feng ◽  
Xian Chun Song
Keyword(s):  
Tool Path ◽  
Optimization Method ◽  
Least Square ◽  
Flank Milling ◽  
Normal Vector ◽  
Machining Error ◽  
Cam Mechanism ◽  
Tool Axis ◽  
Milling Method ◽  
Tool Axis Vector

In some cases the spatial cam is manufactured with a cutter whose diameter is smaller than that of the roller of cam mechanism, which is defined as nonequivalent manufacture method in the paper. By the analysis for manufacture of contact lines between the cam and the roller, it is indicated that errors caused by the different directions of normal vector are unavoidable for the nonequivalent manufacture method. In order to find the best tool axis vector to minimize the machining error, this paper realized the nonequivalent machining of spatial cam surfaces using the NC flank milling method and proposed a new generation algorithm of the tool path based on NURBS. The NURBS ruled surface of tool axis trajectory is confirmed based on the least square optimization method and the machining error model is given. At last, a numerical calculation and simulation example is described to verify the effectiveness of the algorithm proposed in the paper.

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