Case study on design of control panel
- 1. Case Study on Design of Control Panel Submitted by Jayant Gehlot Mohan Narayan Gupta
- 2. • Operator's role in industrial control centers is one of the most important determinants of whether an expected action is going to be successful or not. • In certain situations, due to the complex nature of the work, the existing interfaces and already prepared procedures do not meet the dynamic requirements of operator's cognitive demands, making the control tasks unnecessarily difficult
- 3. • This study was conducted to identify ergonomic issues with a specific industrial control panel, and redesign its layout and elements to enhance its usability
- 5. Sampling • Twenty control room operators took part in the study. • They were distributed across 5 comparable control desks, all located inside the main body of the selected industrial unit. • The participants were approximately 60th percentile males with mean height of 180 cm, mean age of 40 years, and fit for the duty over the study period. With a mean of 20 years of working in control room environments.
- 6. • All participants had more than one year of job experience in the same control room under analysis. • The majority of them had a background in either production (55%) or other instruments (40%). A much smaller percentage derived from other operational trades (5%).
- 7. Hierarchical Task Analysis (HTA) • Hierarchical task analysis (HTA) is a method of defining goals and tasks for a particular job using factors such as time, plan, sequence, and status and dividing each goal into sub-goals, each one with its plans, in order to produce the most effective method of achieving the final aim. • Firstly, all tasks to be evaluated were carefully defined within various scenarios. Then, 15–20-minute video recordings were obtained and time framed.
- 8. Link Analysis • The cost of each operation in the task is quantified by a link value, which can be a function of importance, frequency, difficulty, and other characteristics of the movements between two elements. • The goal of link analysis is therefore to minimize the overall cost, by rearranging the layout
- 9. • The existing control panel layout was gridded and all 97 elements (including press-buttons, switch-buttons, joy-sticks, and indicator lights) were allocated to matching cells (Table 1). • Two types of operator hand movement (transitions) were considered—back-and-forth motions between the origin (the hand position in the rest posture, at the bottom-left corner of the control panel) and the target element, as well as motions form one element to another.
- 11. Results • Link values are summarized in Table 2 where meaningful linkages are highlighted in red. Each value represents the relative weight of the movement; the direction of the movement can be seen by the location of the cell that is filled. Higher link values were observed between hand rest position and elements E17 and E28. Likewise, E30- E16, E28-E13, and E17-E2 showed robust linkages.
- 13. • In the improved layout, unusable components were omitted, and elements with inter-related functions were combined and referred to as similar codes. Moreover, indicator lights were integrated with the corresponding functional units.
- 15. Discussion • Control panel operation combines cognitive tasks, including visual search, recognition of items, and decision making, with bodily movements. • Besides physical and physiological considerations, psychological characteristics of the operator influence user experience and performance. • When the control interface is relatively large and physical movements are still required for operating, the accessibility of the control elements with respect to the operator's position or initial posture may play a more important role
- 16. • In the current study, through an effortless step, a considerable number of unusable elements were excluded, and the control panel shrunk in dimensions. • Furthermore, indicator lights were simply combined with corresponding components. This, in turn, allowed the panel surface to be allocated more effectively and efficiently.
- 17. Reference • S Raeisi, R Osqueizadeh, M Maghsoudipour, AS Jafarpisheh, Ergonomic Redesign of an Industrial Control Panel ,2016.