Academic Journal of Science and Technology 
ISSN: 2771-3032 | Vol. 5, No. 1, 2023 

 

179 

The	Design	of	LabVIEW‐based	Measurement	&	Control	
System	of	Automatic	Straightening	Machine	
Qigeng Liu1, Kuosheng Jiang2, *, Chuanshuai Wang3 

1, 2, 3 School of Mechanical Engineering, Anhui University of Science and Technology, Anhui, 232001, China 
2 Anhui Key Laboratory of Mine Intelligent Equipment and Technology, Anhui University of Science and Technology, Huainan, 232001, 
China  
1, 2, 3 State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and 
Technology, Huainan, 232001, China  
2 Shanqi Automobile Huainan Special Purpose Vehicle Co., Ltd, Huainan, 232001, China  
*Corresponding author 

 

Abstract: With the development of the machinery industry and the popularization of shaft parts, the bending and deformation 
problems of shaft parts in the machining process have become particularly prominent. In order to reduce the bending deformation 
and improve the yield of parts, shaft straightening machines have become a necessary choice. According to the development 
status of straightening machines at home and abroad, and based on the consideration of improving the automation and intelligence 
level of domestic straightening machines, a fully automatic straightening machine measurement and control system has been 
proposed and developed in this paper based on the LabVIEW platform. It has been proved that the straightening machine can 
realize parallel operation of data in the working process, with high straightening accuracy and good operation stability. 

Keywords: Straightening machine, LabVIEW, FPGA, Measurement and Control system. 
 

1. Introduction 
With the development of the machinery industry, shaft 

parts are put to an increasingly wide use in the machinery 
industry, and the bending and deformation of shaft parts in 
machining not only affects the subsequent processes of 
machining and manufacturing, but also brings a heavy burden 
to enterprises. In order to reduce the bending deformation in 
an effort to improve the yield of parts, shaft straightening 
machines have become a necessary choice[1] [2] [3]. There 
are many companies and scientific research institutions 
abroad specializing in the research and development of 
straightening machines, with the more famous companies as 
follows: MAE in Germany, Galdabini in Italy, TAA 
TRANDING in the United States, Towa Seiki Co., Ltd. of 
Japan and International Measuring Co., Ltd. and so on. Their 
straightening machines have relatively high measurement 
accuracy, automation and intelligence[3] [4 [5] [6] [7] [8] [9] . 
In China, the development of straightening machines is still 
at a low level in terms of intelligence and automation and the 
measurement accuracy. Based on the consideration of 
improving the automation and intelligence level of domestic 

ones, a fully automatic straightening machine measurement 
and control system based on the LabVIEW platform is 
proposed and developed in this paper to flexibly detect and 
straighten shaft workpieces.   

2. Overall Design Scheme of 
Measurement and Control System  

The circular bounce detection and straightening correction 
of the workpiece is one of the main problems to be solved by 
this design. It can be seen from the straightening diagram of 
the measurement and control system in Figure 1 that the 
measurement and control system of the automatic 
straightening machine mainly includes four parts: data 
acquisition, data processing, positioning and straightening, 
and FPGA controller. The first part includes the displacement 
sensor of differential variable voltage, data acquisition card, 
and photoelectric encoder. The second part is mainly 
completed by the industrial control computer. The third 
includes motion control card, stepper motor, servo motor, and 
servo drive; The FPGA controller uses AX-7035 development 
board of the black gold.  

 

 
Figure 1. Calibration Schematic of Measurement and Control System 

 



 

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The core of the automatic measurement and control system 

of the straightening machine designed in this paper is the 
industrial computer processing and FPGA control, which 
realizes the functions of data acquisition, data processing, 
workpiece detection, positioning and straightening, 
monitoring of the operating status of the control system, data 
statistics and query. Based on the versatility of the 
straightening measurement and control system of shaft parts, 
the automatic measurement and control system of the 
straightening machine designed in this paper mainly has the 
following five functions: 1) The collected data is transmitted 
to the industrial computer for analysis and processing through 
Gigabit Ethernet, with the processing results returned to the 
FPGA; 2) With the adoption of distributed assembly operation, 
different shaft parts are straightened to meet different needs; 
3) The measurement and control system uses multi-channel 
displacement sensors to collect data, arrange them in different 

measurement positions, and detect the workpiece according 
to what is needed; 4) On the basis of the complexity of 
detecting shaft parts, adjust the number of displacement 
sensors and the installation angle of the encoder are adjusted 
to achieve a good detection effect; 5) with the identification 
and judge of whether the workpiece is qualified, the 
straightened and corrected unqualified workpiece and the 
qualified one is put into the corresponding storage silo or 
different assembly lines to record and query the detection 
process and results of the workpiece. Therefore, the overall 
structure of the measurement and control system of the 
automatic straightening machine is shown in Figure 2, which 
mainly includes automatic loading and unloading, data 
collection, data processing, positioning and straightening, 
qualification determination, data recording and other parts of 
the workpiece.  

 

 
Figure 2. The Overall Structure Diagram of Measurement & Control system 

 

3. The Hardware System of 
Measurement and Control System  

Through the analysis of the working principle and overall 
architecture of the measurement and control system of the 
automatic straightening machine, its hardware system is 
mainly composed of industrial computer, FPGA, 
displacement sensor, photoelectric encoder, data acquisition 
card, motion control card, servo motor and servo drive, 
solenoid valve components, with the specific relationship 
between each component shown in Figure 3. Among them, 
the industrial computer is selected as a domestic IPC610 
working equipment and control system with 14 slots, 
supporting PCI and ISA bus, the industrial computer has high 
stability and reliability, with a strong anti-interference ability 
to operate in various complex environments. The FPGA 
module is selected from the FPGA development board 
developed by Xilinx XC7A35T-2FGG484I, which is 

equipped with a DDR3 data cache module with a capacity of 
256MB, and the clock frequency of 400MHz can increase the 
FPGA development bandwidth to 12.8GB/s. The sensor is 
selected from the high-precision displacement sensor of 
German VOLFA. The data acquisition card is selected by 
Advantech's PCI-1716, which has a maximum bandwidth of 
250KS, automatic analog input scanning, and provides 8 
analog gradient inputs, with a good noise reduction effect; 
The role of motion control card is mainly used to control 
servo motor, so the motion control card selected in this paper 
is of DMC5410A with multiple general I/O, continuous 
interpolation cache I/O, external CAN bus I/O expansion to 
meet the needs of various control I/O, and the various pulse 
signals and switching signals connected to the control card are 
shown in Figure 4. The servo motor is selected from MINAS 
A5 family AC servo of Panasonic, with the controller of a 
feed-forward function to increase the stability of the 
straightening control system operation and improve the 
accuracy of detecting workpieces. 

 



 

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Figure 3. System hardware system diagram 

 

 
Figure 4. The Interface Schematic of the Motion Control Card 

 

4. The Software System 
As for the traditional application system development of 

FPGA, VHDL or Verilog text programming language is used 

to write code, with a large workload, and high difficulty of 
development. An icon program instead of a text program is 
used in the LabVIEW FPGA tool, which is less difficult to 
develop and easy to learn and use, so LabVIEW FPGA tool is 



 

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applied in this paper as the development platform of the 
system.   

4.1. The Workflow of Automatic Straightening 
Machine 

The workflow of automatic straightening machine is 
mainly divided into seven steps, as shown in Figure 5, i.e., 1) 
power supply and system initialization to confirm the status 
of relevant indicators. Dial the "hand/self-transfer switch" to 
the "automatic" position, with the "automatic mode" in the 
straightening manipulator control system selected, and press 
the "automatic start" and "manipulator start" buttons of the 
main interface of the host operation at the same time to start 
automatic operation; 2) The automatic feeding manipulator 
takes out the workpiece from the process storage position, 
transports it to the straightening workbench, and starts the 
automatic straightening process; 3) the pneumatic unit of 
FPGA control solenoid valve control drives top clamping 
workpiece; At the same time, control the servo motor to drive 

the workpiece to rotate; 4) During the rotation of the 
workpiece, the three-way displacement sensor and 
photoelectric encoder measure the circular runout of the 
workpiece and the rotation angle of the motor, and the FPGA 
control data acquisition card collects the measured data to 
transmit it to the industrial computer through the serial port 
after signal processing; 5) The industrial computer analyzes 
the obtained data, calculates the circular runout of the three 
channels, and finds the maximum bending amount and 
direction angle of the workpiece; 6) If straightening is 
required, the industrial computer presses down the workpiece 
through the FPGA control servo motor drives the indenter of 
the workbench, and feedback the amount of pressure to the 
industrial computer. If it cannot be straightened, the 
manipulator will take out the workpiece and put it into the 
unqualified belt; 7) If all measuring points are qualified, the 
straightening is completed and the next straightening begins. 
If any measuring points are unqualified, repeat (6) and 
subsequent steps within the given number of straightening 
times and time until all measuring points are qualified.   

 

 
Figure 5. The workflow of the automatic straightening machine 

 
The inspection system is shown in Figure 6. Displacement 

sensors collect data once for every 1 degree of shaft rotation, 
and 360 times per sensor after one rotation of the shaft. The 

data collected by the acquisition card is processed by the 
industrial computer to obtain the maximum bending 
deformation and direction of the workpiece at the position of 



 

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the displacement sensor.   
 

Figure 6. Basic Schematic Diagram of the Detection System 
 

4.2. The Theory & Method of Data Acquisition 
and Processing   

Data collection, processing and storage of straightening 
machine measurement and control system are inseparable, of 
which data acquisition is the premise of control. In this paper, 
PCI-1716 data acquisition card is used to collect relevant data 
of each sensor. Data processing is the basis of the application, 
and the data of this system mainly has three processing 
processes: 1) F/V filter conversion of the sensor output signal; 
2) Digital filtering, nonlinear compensation and signal scaling 
are used to process the data once; 3) Through the calculation 
and analysis of the data, discover the signal law, determine 
the nature of the object, generate the necessary control signal, 
and study the control effect after the control and the secondary 
processing of the control program before control. The random 
error is mainly processed by remote point detection and 
digital filter, with the singularity point eliminated by 
prediction and the collected data smoothed by digital filters 
such as sequencing filtering, RM filtering, weighted filtering, 
reference filtering, debugging filtering and single filtering, 
eliminating or reducing various noises and improving the 
signal-to-noise ratio. For the systematic error, the methods of 

lookup table, curve comparison and interpolation are in place 
to eliminate the nonlinear error of the sensor, and the models 
of temperature error and the dynamic characteristic curve 
change is applied to correct the error of the temperature 
characteristic of the sensor and the error of the dynamic 
characteristics of the system.   

4.3. The Interface of Measurement & Control 
System of the Straightening Machine  

The interface of the Automatic straightening machine’s 
measurement and control system designed by LabVIEW t 
shown in Figure 7, includes six modules: main interface 
operation, sensor test, debugging panel, parameter setting, 
data query and statistics. The first is shown in Figure 8, with 
a total of 6 functional areas, the top of which is the actual 
value area of the differential, the middle is the runout quantity 
display area and the bending direction display area measured 
by the displacement sensor, the bottom is the manipulator 
operation area, the left side is the function menu area, and the 
right side is the working status display area and the correction 
quantity display area.   

 

 
Figure 7. The interface of the Automatic straightening machine’s measurement and control system 

 



 

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Figure 8. The Main Interface of Measurement & Control System 
 

Figure 9 is the interface of sensor test, which displays the 
measurements (in microns) collected by each channel in real 
time. The abscissa is the measurement channel number 
(expandable to six channels, and Figure 8 shows the case 
where three channels are enabled), and the ordinate is the 

current sensor value of each channel. The interface enables 
intuitive determination of the appropriate installation position 
of the sensor and real-time dynamic monitoring of the entire 
measurement process.   

 

 
Figure 9. Sensor Test Interface 

 
Figure 10 shows the debug window interface of the system, 

which is mainly used to monitor the function setting of the 
system, and can be accessed through the shortcut key of F4.   

 



 

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Figure 10. The Debug Window Interface 

 
Figure 11 is the parameter setting interface, including four 

modules: workpiece setting, correction quantity parameter 
setting, reverse correction parameter setting and weighted 

parameter setting. In the manual state, the user can set and 
modify the straightening parameters of workpiece through 
this interface.   

 

 
Figure 11. Parameter Setting Interface 

 



 

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Figure 12. Communication Program between FPGA and IPC 

 

4.4. Part of the Program of Measurement & 
Control System of Straightening Machine 

Figure 12 is the communication program between FPGA 
and IPC, which is used to realize communication between IPC 
and FPGA.   

Figure 13 is the monitoring program of equipment 
condition, which is used to monitor the operation of 
displacement sensors and encoders in real time during the 
straightening process, and if there is an abnormality, it is fed 
back to the industrial computer through the FPGA to make an 
alarm signal.   

 

 

 
Figure 13. Equipment condition monitoring procedure. 

 

5. Summary 
Based on the consideration of improving the automation 

and intelligence level of domestic straightening machine, this 
paper constructs the hardware part of the measurement and 
control system of straightening machine with the FPGA 
controller as the core, with LabVIEW platform applied to 
develop the software part of the measurement and control 
system. It has proved that the straightening machine designed 
in this paper can realize parallel operation of data during the 
working process, with high straightening accuracy and good 
operation stability. However, there is also the problem of slow 
speed of the data interaction and the straightening accuracy 
needs to be further improved.   

Acknowledgment 

This work was supported by the National Natural Science 

Foundation Project in China (51705003 and 51979261), 
Anhui University Natural Science Research Project 
(KJ2017A081), Anhui Science and Technology Major Project 
(1808085QE130), Anhui University of Technology Youth 
Fund (12867), and Anhui Provincial Education Department 
Fund (11673), Graduate Innovation Fund (2019CX2030). 

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