Ergonomic Assessment of GMC Acadia SLT1 - Case Study Example

Ergonomic Assessment of GMC Acadia SLT An ergonomic assessment has been conducted for GMC Acadia SLT Workplace; visibility; display; display-control relationship; and the role of automation in human-machine interface have been assessed. Introduction The vehicle that has been used for the ergonomic assessment is GMC Acadia SLT-1 (see figure 1 below). Detailed features are available on the GMC and Yahoo website. In Saudi Arabia, vehicles are configured for Left Hand Drive for driving on the right side of the road. Figure 1. GMC Acadia SLT-11,2 Courtney and Wong have suggested that the use of anthropometric data allows consideration for relationship between pedals, steering wheel and seat, and seat adjustments. Details of the researcher conducting the usability test have been included in the table below. 1 Yahoo Autos, `2010 GMC Acadia,` Yahoo Autos website, accessed 5:15am, 7 May 2010, . 2 GMC, `The 2010 GMC Acadia,`GMC website, accessed 5:25am, 7 May 2010, . Table 1. Researcher Details Parameter Details Age Gender M Weight Year of receiving driving license Driving experience Annual driving mileage Approximate daily driving time 3 hours The Car as a Workspace Dimensions of the GMC Acadia SLT-1 have been included in table 2 below. Dimensions such as height, width, length, and wheelbase were measured for anthropometric assessment. Parsons has emphasized on the importance of standards for anthropometry in the design of products and services. The vehicle has been produced as per internationally accepted standards. Table 2. GMC Acadia SLT-1 Dimensions 1,2 Dimension Metre Height 1.775 Width 1.986 Length 5.098 Wheelbase 3.020 Cargo area dimensions with second and third row folded 3.31 Cargo area with second-row up and third row folded 1.95 Cargo area behind third row 0.61 Researcher anthropometric data has been included in table 3 below. The anthropometric information has been used for assessment of the vehicle. Data provided by Beardmore has been used for comparative reference with individual measurements. Table 3. Researcher Characteristics Dimension Metres Height 1.65 Eye 1.53 Shoulder Height 1.36 Elbow Height 1.03 Hip Height 0.9 Knuckle Height 0.7 Fingertip Height 0.61 Sitting Height 0.9 Sitting Shoulder 0.6 Sitting Elbow Height 0.2 Thigh Thickness 0.14 Buttock-Knee Length 0.56 Buttock-Poplietal Length 0.5 Knee Height 0.5 Shoulder Breadth-Deltoid 0.5 Shoulder Breadth-Acromoim 0.4 Hip Breadth Sitting 0.3 Chest Depth 0.2 Abdominal Depth 0.2 Shoulder-Elbow Length 0.4 Elbow Fingertip Length 0.5 Upper Limb Length 0.7 Shoulder Grip Length 0.6 Head Length 0.2 Head Breadth 0.15 Hand Length 0.2 Hand Breadth 0.08 Hand Breadth-over thumb 0.1 Foot Length 0.25 Foot Breadth 0.09 Span 1.7 Elbow Span 0.9 Vertical Reach 1.9 Vertical Reach (sit) 1.2 Forward Grip Reach (sit) 0.7 Forward pinch Reach (stand) 0.73 Postures including gender, stature, and weight were assessed against vehicle geometry including wheel position and seat position. Ingress to and egress from the driver`s seat were assessed. The seat position was adjusted one position to the forward, and the head rest was adjusted two positions for comfortable sitting position. The seatbelt is flexible and was easily adjusted for a comfortable position. Figure 2. Interior Layout1,2 The cargo area and ease of loading was examined. When the second and third rows are folded (see figure 2 above), the area is approximately 3.31 square metres. With the second-row up and third row folded, the cargo area is 1.95 square metres. The cargo area behind the third row is 0.61 square metres. This allows loading of bulky objects and the seat positions can be adjusted based on the requirements. A power liftgate is controlled by key fob controls. The liftgate can be controlled with a button inside the liftgate, or with a switch in the center console. There is a built-in safety sensor that stops the liftgate from opening or closing it if there is resistance. Detachable fixtures could be included for fastening objects and goods. The standard towing capacity is 2000 lbs, and the maximum towing capacity is 5200 lbs. The vehicle was tested for comfort and ride for short, medium and long distances. In Saudi Arabia, cities can be congested at certain hours and locations. Cities are connected by excellent highways that offer excellent driving conditions especially during the winter. The front passenger seat is 2-way power, and seats have 6-way power driver with manual recline and lumbar control. The seating is for 7 passengers with a 2-2-3 seating configuration and smart slide. They are made of leather and power reclining buckets. The vehicle was tested for all types of driving conditions. The vehicle is ideal for driving over medium and long distances. Visibility The vehicle has a rear-view mirror and camera system. A camera has been mounted near the license plate. While shifting into reverse the image from the camera is displayed in a portion of the rear-view mirror. The mirror can still be used. It reverts to normal full frame while shifting into drive or pack. Figure 3. Rear-view1,2 Lanes along the highway have been designated for overtaking, and the rear-view mirror is adequate when traffic rules are observed. A combination of mirrors with different curvatures could be used to eliminate blind spots. Figure 4. Head-up Display1,2 The view along the front has been illustrated in figure 4 above. A proper seating position allows unobstructed view. Display Characteristics of visual, auditory and other models of display have been listed. The development of multimodal displays reflects the use of technology for enhancing usability. Multimodal designs draw from theoretical models such as the Multiple Resource Theory extensively researched by Wickens. The theory has emerged over the past 50 years contributing to performance. According to the theory, human information processing is characterized by several separate channels or resources. This includes three dimensions: first dimension includes segregation of perceptual information into separate modalities such as visual and auditory; second dimension distinguishes stages of processing including perception, cognition and response; and the third dimension segregates information into separate spatial and verbal codes. Table 4. Displays Display Function Location Form Coding (S=Small; M=Medium; L=Large) Classification (C=Critical; I=Important; F=Functional) OnStar Remote ignition block; stolen vehicle assistance; hands-free calling; telematics system; navigation aid Dashboard Visual M C Theftlock Radio anti-theft Dashboard Visual S I StabiliTrak Vehicle stability control system Dashboard Visual M C AM FM Radio & Sound Controls Radio Dashboard Visual L F Tire Pressure Monitor Pressure monitor Dashboard Visual S I Compass Direction Dashboard Visual M I Digital Clock Time Dashboard Visual M F Voice Activated Controls Bluetooth enabled devices Dashboard Visual and Audio M I Instrument Cluster Navigation - speed; fuel indicator; battery indicator; Dashboard Visual L C Trip Computer System control Dashboard Visual M C Voice Activated Controls Phone operation Dashboard Audio M F Exterior Temperature Gauge Temperature Dashboard Visual S I Steering Wheel Mounted Control Vehicle control Dashboard Visual S I Cruise Control Speed control Dashboard Visual M I Multi-function remote Operates door lock unlock panic alarm; lift gate`; remote ignition Dashboard Visual M I Overhead console 3-function universal garage door opener Overhead Visual M F Displays have been listed in table 4. A system of coding has been developed based as suggested by Buck. Codes include small, medium, and large. Easterby has developed guidelines for tasks, processes and display design. Accordingly, a classification system has been developed. Classification of displays include critical, important, and functional. Figure 5. Dashboard1,2 Figure 6. Temperature Control1,2 Figure 7. Audio System1,2 Figure 8. Instrument Cluster1,2 Display Control Relationship According to Heaton, a theme for usability is definition and testing in a way that can lead to improvements in design. According to researchers including O`Hare, Sanders and McCormick, Spence and Driver, and Wickens, the primary mode of displaying information in the majority of systems is visual in the vehicle. Analog and digital forms of displays have been used for the systems. Analog form of display has been used for critical applications such as display of speed, fuel indicator, and battery indicator. The digital form of display has been used for not so critical applications such as temperature control or mileage achieved by the vehicle. A limited number of controls have auditory modality of interaction. However, the voice system requires training and has limited functional ability. Due to its limited ability, voice systems have been limited to non critical applications. Voice displays can be used for some systems such as navigation systems that can provide an additional way of displaying information. Simple commands such as start radio, start lights, etc can enhance the system. While driving, the driver has to interact with foot controls; hand controls; and visual and auditory controls. The maximum number of simultaneous manipulation include the foot; hands; and eyes and ears. The maximum interactions do not cause any discomfort. However, rapidly changing conditions requiring simultaneous manipulation can cause stress on the driver. For example, driving on an undivided street with vehicles plying on both directions and everybody rushing can cause a lot of stress. While driving long distances prolonged use of the foot on the throttle can cause stress on the legs and the muscles can become stiff. Environmental conditions such as rain or noisy street can render voice enabled systems ineffective. Pressure on the throttle pedal causes the moving vehicle to accelerate and the speedometer to rotate indicating the speed. The response is almost instantaneous giving the driver an indication of the vehicle speed, and react (push further or release) according to the speed limits. This form of display and control relationship has been traditional. Future systems have the promise of extensive use of sensors to control the driving. The air conditioning system uses a digital display of temperature. The user has the option to set air conditioning in terms of heating or cooling. There are controls for the direction of air inlets, and increasing or decreasing the temperature. The user can increase or decrease by pressing the switches. The system allows setting the indoor environment, avoiding thermal stress caused by extreme temperatures. This form of display and control relationship is adequate. In the future systems could have inbuilt settings that could automatically set parameters to adjust to human requirements. The power steering system allows the user to navigate the vehicle without the use of excessive force. When the user turns the steering to the right, the vehicle turns to the right and turning the steering to the left turns the vehicle to the left. The steering can also be used to turn the vehicle while it is moving in the reverse direction. A period of adjustment is required for using the steering. Some vehicles are equipped with an onboard navigation system that displays the movement. This form of display and control relationship is improvement over the previous lack of display and physical adjustment of the control, which posed a challenge for some forms of parking. Future systems are expected to enable precise co-ordinate movements and programming the move. Role of Automation in Human-machine Interface While driving the user has to physically use the throttle and brake and other manual controls such as steering, signal and lights; be alert visually and auditory; and use the voice enabled controls. Automation can greatly enhance the interaction. According to Agah performance of the human-machine systems depends on interaction between driver and car controls. One of the objectives is to make human interactions with the system effective and safe, besides being enjoyable and entertaining. Application, approach, system autonomy, interaction distance, and interaction media are important criteria. The displays have been located according to function. Johannsen has suggested that supervisory control of systems can be changed towards co-operative man-machine decision making. According to Crowley, a powerful tool for interaction between man and machine is computer vision. Computer vision coupled with video projection makes it possible to use digital input devices. In the Acadia the instrument cluster is located in front of the steering wheel, and the displays are analog and are connected to the electronic system. The operating system receives input from all the sensors, which could be used for controlling the vehicle. For example, cruise control allows a relaxed posture for long distance driving along the highway. Lenior et al. found that the aim of human-machine interaction in smart transportation is to realize effective, efficient and human-friendly transport. Adaptation to automation to human capabilities includes consideration of information uncertainty, operator trust and mutual man-machine adaptations. An ongoing trend in automation is changing role of human from controller to supervisor. Car systems should support, and sometimes take over critical parts of the driving task. As there is a lot of diversity in driver ability, driving context and dependence between driver and contextual factors, a personalized, adaptive and integrated support is desirable. Voice enabled systems can be developed based on systematic research. A thorough analysis is required for the process to be controlled and driver`s tasks and cognitive abilities to develop complex and supervision control systems. There is a need for further development in cognitive modelling and ergonomic task analysis in design practice. According to Girardin and Blat, there is a need to investigate appropriation of location-aware systems for in-car navigation systems. Technology allows the exploitation of pervasive geo-information. Co-evolution allows drivers to adapt to their in-car navigation systems, and adapt to needs. Alteration of learning process and technology appropriation allows reduction of stress rather than improve efficiency thereby creating implications for next-generation location-based services. References Agah, A., `Human interactions with intelligent systems: research taxonomy,` Computers & Electrical Engineering, 27(1), 2000, 71-107. Beardmore, R., `Anthropometric Data,` Roymech website, accessed 5:05am, 7 May 2010, . Buck, J., `Visual displays,` Human Factors: Understanding People-System Relationships, New York: Wiley, 1983, 195-231. Courtney, A. & Wong, M., `Anthropometry of the Hong Kong male and the design of bus driver cabs,` Applied Ergonomics, 16(4), 1985, 259-266. Crowley. J., `Vision for man-machine interaction,` Robotics and Autonomous Systems, 19(3-4), 1997, 347-358. Easterby, R., `Tasks, processes and display design,` Information Design, Chichester: Wiley., 1984, 19-36. Girardin, F. & Blat, J., `The co-evolution of taxi drivers and their in-car navigation systems, ` Pervasive and Mobile Computing, 2010, In Press. GMC, `The 2010 GMC Acadia,`GMC website, accessed 5:25am, 7 May 2010, . Heaton, N., `Defining usability,` Displays, 13(3), 1992, 147-150. Johannsen, G., Towards a new quality of automation in complex man-machine systems, Automatica, 28(2), 1992, 355-373. Lenior, D., Janssen, W., Neerincx, M. & Schreibers, K., `Human-factors engineering for smart transport: Decision support for car drivers and train traffic controllers,` Applied Ergonomics. 37(4), 2006, 479-490. O’Hare, J., `Perceptual integration,` Journal of the Washington Academy of Sciences, 81, 1991, 44-59. Parsons, K., `Ergonomics and international standards : Introduction, brief review of standards for anthropometry and control room design and useful information,` Applied Ergonomics, 26(4), August 1995, 239-247. Sanders, M. & McCormick, E., Human Factors in Engineering and Design (7th edn.), New York: McGraw-Hill, 1993. Spence, C. & Driver, J., Crossmodal space and crossmodal attention, Oxford: Oxford University Press, 2004. Wickens, C., Engineering Psychology and Human Performance (2nd edn.). New York: Harper Collins, 1992. Wickens, D., `Multiple Resources and Mental Workload,` Human Factors: The Journal of the Human Factors and Ergonomics Society, 50(3), 2008, 449-455. Yahoo Autos, `2010 GMC Acadia,` Yahoo Autos website, accessed 5:15am, 7 May 2010, . Read More