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Page 6 of 31 Songthumjitti et al. Intell Robot 2023;3(3):306-36 I http://dx.doi.org/10.20517/ir.2023.20

Table 4. Horizontal axis linear slider specification
Horizontal axis linear slider
Manufacture NSK
Model MCH10105H20D
Nominal Stroke 1050 mm
Ball Screw Lead 20 mm
Mass 33 kg

Table 5. Vertical axis linear slider specification
Vertical axis linear slider
Manufacture NSK
Model MCH10100H20K
Nominal Stroke 1110 mm
Ball Screw Lead 20 mm
Mass 27 kg

Table 6. Laser distance sensor specification
Laser distance sensor
Manufacture Panasonic
Model HG-C1030
Output Type NPN output
Measurement Center Distance 30 mm
Measurement Range ±5 mm

Table 7. Acceleration sensor specification
Acceleration sensor
Manufacture Kionix
Model KXR94-2050
Measurement Range ±2G
Sensitivity 660mV/G
Frequency Range 800Hz (-3dB)

specification of the horizontal axis linear slider is shown in Table 4, and the specification of the vertical axis
linear slider is shown in Table 5.

3.1.4. Laser distance sensor
For spectrum analysis, structure displacement must be measured. Therefore, a laser distance sensor is placed
in the system to be used to measure structure displacement that results from oscillation, and its specifications
can be found in Table 6.

3.1.5. Acceleration sensor
In subsequent sections, we use the acceleration of the structure of the robot as feedback to the control system,
so an acceleration sensor is attached to the frame. Its specifications are listed in Table 7.

3.2. Modeling
3.2.1. Actuator system transfer function
Theactuatorsystemisrequiredtomovetherobottothedesiredcoordinate. Itconsistsofservopacks,ACservo
motors, and linear sliders, where each component has its own characteristics. In this study, we will represent
the characteristic of all these components with one transfer function, , which consists of a second-order
low-pass filter and a time delay, which come from an experiment and will be further explained in the section
on spectrum analysis. To facilitate stability analysis, the time delay from the transfer function Equation (2) is
approximated using the Pade approximation method.