## 3 Results and Discussion
### Scientific Mapping
#### 3.2.2 Hardware  
Because virtual reality is a complex technology that combines interactive media, sensors, displays, human-machine interactions, simulations, computer graphics, and artificial intelligence technologies to expand human perception, virtual reality systems frequently require the use of multiple devices [56]. Depending on the application, virtual reality hardware may range from a basic computer to specific display devices, motion capture equipment, and interactive gadgets, such as wearable devices, cameras, head-mounted displays (HMD), and so on. Table 5 lists the hardware, gadgets, and apparatuses referenced in the evaluated publications. We found a vast variety of technologies, both in terms of the devices and the models employed in each category. Some studies did not specify which model was used. We discovered that the most frequently utilized hardware may be classified into seven basic categories: (1) head-mounted displays (HMD), (2) motion capture systems, (3) cockpits, (4) sensors, (5) automatic virtual environments (CAVEs), (6) interaction devices, and (7) glasses. These categories are not mutually exclusive, and the arrangement is often built by combining various technologies. \begin{table}
\begin{tabular}{c c} \hline \hline
**Ref.** & **Number of Participants** \\ \hline
[20,48,53,55] & 11 to 20 \\ \hline
[43,46] & 21 to 30 \\ \hline
[52] & 31 to 40 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Number of participants. Both visualization and tracking technologies are required in a virtual-reality environment. Head-mounted displays and projection-based systems are the most frequently utilized virtual reality visualization technologies in the industrial sector. Head-mounted displays are devices that are affixed to the head of a virtual reality user and generally feature one or two screens as the image source, as well as a collimating lens between the eyes and the display [62]. Projection virtual-reality systems, on the other hand, include single or multiple projector-based powerwalls, as well as surrounding, walk-in installations based on numerous projection screens (e.g., CAVEs). The authors of [56] noted that the usage of CAVEs and head-mounted displays is unusual in industry, which they attribute to high costs. However, since head-mounted displays were the most widely used devices in the research we considered, we discovered a \begin{table}
\begin{tabular}{c c c} \hline \hline
**Ref.** & **Hardware** & **Category** \\ \hline
[15, 16, 19, 20, 45, 51, 52, 53, 55] & HTC Vive & HMD \\ \hline
[46] & Oculus Rift & \\ \hline
[43, 50] & Microsoft Kinect & \\ \hline
[54] & Vicon & Motion Capture \\ \hline
[51] & Motion Capture (model unspecified) & \\ \hline
[54] & New Holland T5.120 tractor & \\  & model cabin & \\ \hline
[46] & Driver’s seat, steering wheel, & \\  & three pedals and the center & \\  & console of an Audi A4 & Cockpit \\ \hline
[48] & 1:1 physical model 2018 & \\  & Mercedes-Benz E200L & \\ \hline
[48] & Steering wheel kit Logitech G29 & \\ \hline
[54] & Zephyr BioHarness to record & \\  & human physiological data & \\ \hline
[54] & IX500 pressure mat (to collect & \\  & seat pressure data (used only for & \\  & cabin design) & Sensors \\ \hline
[51] & ECG/GSR (for Real-time & \\  & analysis of user’s emotion) & \\ \hline
[41] & Three-walled room (two walls & \\  & and a floor) & \\ \hline
[44] & four-wall room & \\ \hline
[40] & Power wall projection setup & \\ \hline
[41] & Nintendo Wii Remote & \\ \hline
[20] & Xbox controller & \\ \hline
[44] & Flystick & \\ \hline
[46, 52] & Optical tracking Leap Motion & \\ \hline
[54] & Tobii Pro & \\ \hline
[40] & Active shutter glasses (model & \\  & unspecified) & Glasses \\ \hline
[41] & Stereo glasses (model & \\  & unspecified) & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Hardware, equipment, gadgets, and apparatuses utilized in the examined research. distinct situation. One likely reason is that, until recently, the use of head-mounted displays was restricted due to their high cost and technological restrictions.