Modeling and Synchronous Control of Dual Mechanically Coupled Linear Servo System

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
Wu-Sung Yao
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Dynamic Stiffness ◽  
System Modeling ◽  
Coupled System ◽  
Mechanical Coupling ◽  
Synchronous Control ◽  
Linear Motors ◽  
Operation Speed ◽  
Control Scheme

This paper presents a system modeling technique for a high-speed gantry-type machine tool driven by linear motors. One feed axis of the investigated machine tool is driven by the joint thrust from two parallel linear motors. These two parallel motors are coupled mechanically to form the Y-axis while another standalone motor fixed to a support forms the X-axis. The components in the X-axis, which is treated as the mechanical coupling, are carried by the slides of the Y-axis motors. This configuration is applied to improve the dynamic stiffness of the system and operation speed/acceleration. However, the precise synchronous control of the two parallel and coupled motors would be the major challenge. To overcome this challenge, a multivariable system identification method is developed in this paper. This method is used to construct an accurate system mathematical model for the target coupled system. A synchronous control scheme is then applied to the model obtained using the proposed technique. The performance of the system is experimentally verified with a high-speed S-curve motion profile. The results substantiate the constructed system model and demonstrate the effectiveness of the control scheme.

scholarly journals Nonlinear Synchronous Control for H-Type Gantry Stage Used in Electric VehiclesManufacturing

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2305
Author(s):  
Ran Chen ◽  
Zongxia Jiao ◽  
Liang Yan ◽  
Yaoxing Shang ◽  
Shuai Wu
Keyword(s):  
Tracking Error ◽  
Tracking Performance ◽  
System Model ◽  
Lyapunov Analysis ◽  
End Effector ◽  
Mechanical Coupling ◽  
Synchronous Control ◽  
Linear Motors ◽  
Proposed Model ◽  
Synchronous Error

The H-type gantry stage (HGS) is widely used in electric vehicle manufacturing and other fields. However, resulting from the existence of mechanical coupling, the synchronous control problem of HGS always troubles many engineers. Most synchronization schemes were either engaged in improving each motor’s tracking performance or committed to pure motion synchronization only. However, tracking and synchronous performance are interconnected, because of the mechanical coupling. In this paper, a rigid assumed system model of HGS, concerning the effects of mid-beam rotary inertia, mid-beam stiffness, and end-effector movement, is presented. Based on the proposed model, an adaptive robust synchronous control based on a rigid assumed model (ARSCR) is proposed to improve both synchronous and tracking performance of the HGS. From the Lyapunov analysis, the proposed ARSCR can achieve the convergence of synchronous error and tracking error, simultaneously. An HGS driven by dual linear motors is built and used to perform the experimental verification. The experimental results indicate the effectiveness of the proposed method.

Desired Compensation Adaptive Robust Contouring Control of an Industrial Biaxial Precision Gantry Subject to Cogging Forces

2009 ◽  
Author(s):  
Chuxiong Hu ◽  
Bin Yao ◽  
Qingfeng Wang
Keyword(s):  
High Speed ◽  
Parametric Uncertainties ◽  
Control Performance ◽  
Linear Motors ◽  
Output Tracking ◽  
Control Scheme ◽  
Contouring Control ◽  
Contouring Accuracy ◽  
Sinusoidal Functions ◽  
Force Ripple

To obtain a higher level of contouring motion control performance for linear-motor-driven multi-axes mechanical systems subject to significant nonlinear cogging forces, both coordinated control of multi-axes motions and effective compensation of cogging forces are necessary. In addition, the effect of unavoidable velocity measurement noises needs to be carefully examined and sufficiently attenuated. To solve these problems simultaneously, in this paper, a discontinuous projection based desired compensation adaptive robust contouring controller is developed by explicitly taking into account the specific characteristics of cogging forces in the controller designs and employing the task coordinate formulation for coordinated motion controls. Specifically, based on the largely periodic nature of cogging forces with respect to position, design models consisting of known sinusoidal functions of positions corresponding to the main harmonics of the force ripple waveforms with unknown weights are used to approximate the unknown cogging forces. Theoretically, the resulting controller achieves a guaranteed transient performance and final contouring accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. In addition, the controller also achieves asymptotic output tracking when there are parametric uncertainties only. Comparative experimental results obtained on a high-speed industrial biaxial precision gantry driven by linear motors are presented to verify the excellent contouring performance of the proposed control scheme and the effectiveness of the cogging force compensations.

Optimization of Thermal Performance of Hybrid Journal Bearings for High Speed Machine Tool Spindle with Small Diameter

2010 ◽  
Vol 139-141 ◽  
pp. 731-738 ◽  
Author(s):  
Xue Bing Yang ◽  
Wan Li Xiong ◽  
Zhi Quan Hou ◽  
Ju Long Yuan
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Load Capacity ◽  
Dynamic Stiffness ◽  
Small Diameter ◽  
Journal Bearings ◽  
Oil Film ◽  
Machine Tool Spindle ◽  
High Efficient ◽  
Operation Parameters

Multi-array hole-entry hybrid journal bearings have been widely applied to support the high speed precision machine tool spindle with small diameter used in high efficient inner grinding, due to their prominent properties of high rotation accuracy, high dynamic stiffness, high vibration damping and long life. But the imperfection of the hybrid bearing is the significant temperature rising in the oil film on the condition of high speed operation, which brings about the sharp decreasing of load capacity and the larger thermal deformation of the bushing that cause the bearing failure immediately. In this paper, CFD analysis of the temperature fields of the multi-array hole-entry hybrid journal bearing with various bearing construction parameters and operation parameters are presented. According to the simulation results, the temperature rising in the oil film can be controlled efficiently by optimizing the matching of the bearing construction parameters and operation parameters and excellent characteristics of load capacity and static stiffness have been obtained simultaneously.

scholarly journals Two-Degree-Of-Freedom Dynamic Model-Based Terminal Sliding Mode Control with Observer for Dual-Driving Feed Stage

Symmetry ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 488 ◽  
Author(s):  
Wei Fan ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Yongquan Zhang ◽  
Rong Zeng ◽  
...  
Keyword(s):  
Sliding Mode Control ◽  
Dynamic Model ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mechanical Coupling ◽  
Synchronous Control ◽  
Model Based ◽  
Control Scheme ◽  
Two Degree Of Freedom

The position synchronous control of multi-axis gantry-type feed stage is crucial in precision machine tools. Industrial position control which aims to widen the bandwidth and improve disturbance rejection of single axis is not enough to achieve precise synchronization in a dual-driving feed stage. The characteristics diversity, transmission-mechanism deformation, and mechanical coupling effect between dual axes will degrade the control accuracy. Hence, the novel two-degree-of-freedom (2-DOF) dynamic model-based terminal sliding mode control (TSMC) with disturbance and state observer is proposed in this paper for the synchronous control of a 2-DOF dual-driving feed stage. The 2-DOF dynamic model, based on Lagrange equation, is established along with the parameters identification method. The predictive natural frequencies and vibration modes frequencies by the proposed dynamic model are compared by a modal experiment. Then, the 2-DOF dynamic model-based TSMC is provided to satisfy the tracking and synchronization control. In order to reduce the chattering and to increase the robustness against the mechanical coupling, the disturbance and state observer is designed. Moreover, Lyapunov stability criterion is used to analyze the stability of the proposed control scheme. Finally, an industrial application of 2-DOF dual-driving feed stage is utilized to validate the effectiveness of the proposed control scheme. The proposed 2-DOF dynamic model-based TSMC with observer has been effectively demonstrated to improve synchronous performance and tracking accuracy.

Study on an Open CNC System of 3-Axis Micro Milling Machine Tool

2009 ◽  
Vol 69-70 ◽  
pp. 369-373 ◽  
Author(s):  
Liang Huang ◽  
Ning He ◽  
Liang Li
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Special Functions ◽  
Fast Response ◽  
Micro Milling ◽  
Milling Machine ◽  
Cnc System ◽  
Linear Motors ◽  
Open Cnc ◽  
Open Cnc System

The traditional CNC system is established on conventional machine tool mainly using ball screws. This could not suitable for micro mechanical machining with linear motor which could provide high speed, high precision, fast response and zero backlash. In this paper, a 3-axis micro milling machine tool with an open CNC system has been developed based on motion controller and linear motors. Considering the requirements of micro milling several special functions just like micro cutting tool setting are provided in exploited control software. The system dynamic characteristics are evaluated through experiments with servo parameters adjustments. In the following machining experiments, the whole system is proved economically and effectively.

Control of Linear Motors for Machine Tool Feed Drives: Design and Implementation of H∞ Optimal Feedback Control

1996 ◽  
Vol 118 (4) ◽  
pp. 649-656 ◽  
Author(s):  
D. M. Alter ◽  
Tsu-Chin Tsao
Keyword(s):  
Machine Tool ◽  
Closed Loop ◽  
Force Feedback ◽  
Dynamic Stiffness ◽  
Tracking Performance ◽  
Optimal Feedback Control ◽  
Optimal Position ◽  
Linear Motors ◽  
Feed Drives ◽  
Position Feedback

Direct drive linear motors have good potential for use as next generation machine tool feed drives since they can increase machining rates and improve servo accuracy by eliminating gear related mechanical problems. To exploit the high speed and high response direct drives for machining, the servo control must achieve as high as possible tracking performance while at the same time establishing as much as possible the dynamic stiffness in order to maintain machining stability and reduce the effect of machining disturbance forces on the tool position. This paper investigates the use of optimal H∞ control to design for large stiffness and closed-loop tracking performance. Position feedback alone is first considered, with cutting force feedback later added to augment closed loop stiffness. Optimal position feedback is experimentally seen to achieve up to a 46 percent stiffness improvement over that achievable with proportional-derivative control. The addition of force feedback to the servo-loop resulted in a further 70 to 100 percent stiffness improvement over the position feedback alone values.

scholarly journals Analysis of the dynamic characteristics of downsized aerostatic thrust bearings with different pressure equalizing grooves at high or ultra-high speed

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110180
Author(s):  
Ruzhong Yan ◽  
Haojie Zhang
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Rotation Speed ◽  
Dynamic Stiffness ◽  
Simulation Method ◽  
Perturbation Amplitude ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Ultra High Speed ◽  
Air Film

This study adopts the DMT(dynamic mesh technology) and UDF(user defined functions) co-simulation method to study the dynamic characteristics of aerostatic thrust bearings with equalizing grooves and compare with the bearing without equalizing groove under high speed or ultra high speed for the first time. The effects of air film thicness, supply pressure, rotation speed, perturbation amplitude, perturbation frequency, and cross section of the groove on performance characteristics of aerostatic thrust bearing are thoroughly investigated. The results show that the dynamic stiffiness and damping coefficient of the bearing with triangular or trapezoidal groove have obvious advantages by comparing with that of the bearing without groove or with rectangular groove for the most range of air film thickness, supply pressure, rotation speed, perturbation amplitude, especially in the case of high frequency, which may be due to the superposition of secondary throttling effect and air compressible effect. While the growth range of dynamic stiffness decreases in the case of high or ultra-high rotation speed, which may be because the Bernoulli effect started to appear. The perturbation amplitude only has little influence on the dynamic characteristic when it is small, but with the increase of perturbation amplitude, the influence becomes more obvious and complex, especially for downsized aerostatic bearing.

Dynamic Analysis of Helical Milling Unit Based on Virtual Machine Tool

2011 ◽  
Vol 188 ◽  
pp. 463-468 ◽  
Author(s):  
Xu Da Qin ◽  
Qi Wang ◽  
H.Y. Wang ◽  
Song Hua
Keyword(s):  
Machine Tool ◽  
Virtual Machine ◽  
Dynamic Stiffness ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Helical Milling ◽  
Response Analysis ◽  
Computer Simulation Model ◽  
Element Analysis ◽  
Virtual Machine Tool

The virtual prototype is a computer simulation model of the physical product that can be analyzed like a real machine. This paper studies the helical milling unit based on the virtual machine tool. The helical milling unit is first designed according to the kinematics of the helical milling. The main parts of the equipment include rotating mechanism, orbital agency and radial offset organization. Based on the feasibility analysis of the structure, the three-dimensional geometrical model is built in the Solidworks software. The key parts in the model are separated from the device and introduced into the finite element analysis (FEA) software, according to the cutting loads tested from experiment, static and dynamic modal analysis and harmonic response analysis are carried out for the key parts of this device. The results show that the static and dynamic stiffness can meet design requirement.

Multiple CMOS Intersection Measuring System Modeling and Analysis

2012 ◽  
Vol 614-615 ◽  
pp. 1299-1302
Author(s):  
Ming Jing Li ◽  
Yu Bing Dong ◽  
Guang Liang Cheng
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
System Modeling ◽  
Position Effect ◽  
Field Of View ◽  
Measuring System ◽  
Price Ratio ◽  
Matlab Simulation ◽  
Modeling And Analysis

Multiple high speed CMOS cameras composing intersection system to splice large effect field of view(EFV). The key problem of system is how to locate multiple CMOS cameras in suitable position. Effect field of view was determined according to size, quantity and dispersion area of objects, so to determine camera position located on below, both sides and ahead to moving targets. This paper analyzes effect splicing field of view, operating range etc through establishing mathematical model and MATLAB simulation. Location method of system has advantage of flexibility splicing, convenient adjustment, high reliability and high performance-price ratio.

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