**2. Material and methods**

#### **2.1 Subjects**

Eight university students participated in the study. None of the participants suffered from any vestibular and visual dysfunction and were not taking any medication during the experiments. The mean age was 21.7 years old (aged 19-23 years). Prior to the experiment, informed consent was obtained about the nature of the experiment and the objectives of the experiment as well as participant rights were fully explained. Participants were tested individually during the entire experiment session and received payment for their participation. Ishihara plates for Pseudo Isochromatic test were used to test normal visual of a subject. The test for colour blindness was adapted from Courtney (1986).

#### **2.2 Apparatus**

#### **2.2.1 Virtual stimulus**

The virtual stimulus system used is a virtual robot manufacturing system (from here onwards to be referred only as the virtual environment (VE)). This Virtual Environment

or designing visual display unit (VDU) equipment and systems**.** When Menozzi, M., *et al* (1999) conducted studies comparing cathode ray tube (CRT) display and liquid crystal display (LCD) for their suitability in visual tasks in VDU, it was found that LCD provided better viewing conditions compared to CRT display. Nichols, S. (1999) investigated the design of VR equipment in respect to the physical ergonomics such as head mounted display (HMD) and hand-held input devices and the problems associated with it. Shieh and Lin (2000) investigated the effect of screen type, ambient lighting and colour combination on VDT to visual performance and found that those factors do affect VDT performance. Lin (2003) studied the effects of contrast ratio and text colour on visual performance using TFT-LCD and found that contrast ratio significantly affects visual performance. In 2007, after being approved by ANSI on 14th November, the Human Factor Engineering Society published the new national standard for human factor engineering of computer workstation (ANSI/HFES100), which eventually becomes the comprehensive ergonomics guideline in

Ergonomics research related to virtual environment has been conducted in the past, but the focus of the research is only on the use of VE as a tool in ergonomics analysis (Shaikh,I., *et al*, 2004; Colombo and Cugini, 2005; Pappas, M., *et al*, 2005; Dukic, T., *et al,* 2007; Hu, B, *et al*, 2011). Shaikh,I., *et al*, (2004) studied on participatory ergonomics using VR and found that VR system will help towards designing better workplaces. Colombo and Cugini (2005) researched on virtual humans and prototypes, evaluating ergonomics and safety. While Pappas, M. *et al* (2005) investigated on ergonomic evaluation of virtual assembly tasks. Other researchers such as Dukic, T *et al* (2007) researched on the evaluation of ergonomics in a virtual manufacturing process and Hu, B. *et al* (2011) presented preliminary experimental results on the relationship between ergonomic measurements in VE and RE for some typical

It has been noted that no research on ergonomics design criteria for designing a virtual environment has been reported. Thus, the objective of this study in identifying the

Eight university students participated in the study. None of the participants suffered from any vestibular and visual dysfunction and were not taking any medication during the experiments. The mean age was 21.7 years old (aged 19-23 years). Prior to the experiment, informed consent was obtained about the nature of the experiment and the objectives of the experiment as well as participant rights were fully explained. Participants were tested individually during the entire experiment session and received payment for their participation. Ishihara plates for Pseudo Isochromatic test were used to test normal visual of

The virtual stimulus system used is a virtual robot manufacturing system (from here onwards to be referred only as the virtual environment (VE)). This Virtual Environment

ergonomics design criteria for designing a Virtual Environment is imperative.

a subject. The test for colour blindness was adapted from Courtney (1986).

the design of a VDT.

"drilling" tasks.

**2.1 Subjects** 

**2.2 Apparatus** 

**2.2.1 Virtual stimulus** 

**2. Material and methods** 

presents a virtual robot activity for storage loading and unloading (SLU) process (shown in Figure 1). It was developed using direct X and Dark Basic Professional. The Autodesk 3DS Max software was used to build the virtual object. The VE was displayed through a projector on a wide screen. The projector was connected via cable to a laptop controlled by a keyboard and mouse. This wide screen allows the projection of stereoscopic images where each eye will see the slightly shifted images.

Fig. 1. Snap shot of Virtual Robot Manufacturing System
