Optimizing Commercial Vehicle Seat Design: A Proposal

Significance

Drivers are the lead roles of the transportation systems and if there performance degrades then the passengers also have to suffer. There is a possibility of fatigue or even accident. Today, the driving experience is not at all good for them. Poor designed of the seats imposes a great amount of stress on them. Long term injuries such as low back pain and whiplash are common. This research proposes some 6-degree solutions by the variation of certain parameters such as H-points, R-points, inclination angles and many more. Optimization techniques have been discussed. 

As per [1], the driver’s seat is an important part of the commercial vehicle. If not properly taken care of, it can cause fatigue. Before a seat is devised, many issue are taken into consideration. Many musculoskeletal problems have been identified and researches also trying to combat them. Different approaches have been made in the areas of safety and comfort. Some are pressure, mechanical, vibratory, ergonomic [2]. When the risk is reduced, the performance of the drivers will increase. There are primarily two types of injuries- Whiplash and low back pain. The seat has to be constructed using the body contour [3]. In order to achieve the required comfort level, anthropometric and ergonomic conditions have to be applied at same time [4]. The driver feels uneasy then his performance will be degraded. For optimisation, anthropometric and technical aspects have to be taken into consideration [5]. The two organisations namely, the Society of Automobile Engineers (SAE) and automotive industry standards (AIS) have proposed various ranges of specifications and 6-degree solutions for commercial vehicle seats and the placement of the control units with respect to the H-point. Low back pain is a very common issue found in the drivers that drive for long distances. This has to be reduced. Many measures have been taken to grant lumbar assistance, side help and many more. Headrest has also been provided, rubber mat. These helped to reduce the lower back pain considerably [6]. Whiplash injuries due to rear end of the neck affects the head more than the neck [7]. Neck injuries cannot take a life but their long-term. 

Volvo Whiplash Protection Story (WHIPS) devised some guidelines and methods to reduce these injuries of the neck. It included backrest. All the tests are covered in [8]. Muscle fatigue is another type of injury in which the forces on the joint and muscle is exerted on the driver. [9] Revealed that long- distance travelling causes fatigue and many submission methods were used to model this phenomena. There are two types of foods namely static and dynamic comfort [10]. In order to increase the comfort level, supports have to be provided. The headrest should be changed its position as shown in [11]. Articulation was done so that the injury due to whiplash is prevented [12]. Ergonomic process helps in defining the driver posture along with the specifications of the seat, the parameters such as seat, head and back rest angles. When the seats inclination angle is perpendicular without any lumbar support, it a very low comfortable level. But when this angle is 120° without any lumbar support, it provides a greater level of comfortable [11]. The type of home that is used in the seat rest also affects the level of comfortable. The static liberal position changes with the different type of foam used. This affects H point location [13]. There are many characteristics of 6-degree solutions that are defined by the Automobile industry of India such as H-point, torso angle R-point and many more. H-point and R-point are very important parameters that are used industrially [14]. 

• Can the adjustments of seat back, and seat head rest angles help in the reduction of discomfort of the driver?
• Is it possible that the change in the material of the foam reduce the injuries caused to the driver?
• How can H-points and R-points improve the design characteristics of the driver’s seat?

Literature Review

The seat is a very important issue today because with the growing populations. Long driving results in many health issues and therefore strategies mentioned in this proposal can be implemented. The need of the customers for a better and safe solution in the area of driving safety is continuously increasing [15]. The need is increasing and therefore the manufacturers have to respond fast and provide them quality solutions and products. Not only this market is fruitful today, but also in the future because the demand for cars is a never ending process. 

As per [16], the back rest, head and the seat rest angle need to be altered to provide a better experience to the driver while reducing his discomfort. The angle of inclination should be around 120 degrees with no lumbar support to maximise the comfort. The back angle of the seat should be adjusted in such a way that it at 25 degrees in relation to rearward inclination from the torso line. My aim is to propose an arrangement in which the pressure is distributed more efficiently between the neck and the head rest [11]. An articulation could be done 43.5 cm such that it above the H-point and the mean sitting height of 88cm. This will help the driver to sit in his normal Position. This addresses my research question number 1. 

Next challenge is the reduction in the number of injuries, the type of foam can be changed so that maximum comforting item is used in the seat back and seat bottom. This can help to find the equilibrium of the driver’s siting position. [14] The location of the H-point will also change using different foam type. My aim is to make use of this variation in H-point and choose that foam that gives the least discomfort and prevents the injuries. This addresses my research question number 2. 

Finally, various parameters that are declared as important, playing key roles in reducing the inconvenience. 3DH machines can calculate H-point and torso angle that determine the optimised seating for commercial vehicles. The height of the head restraint should be more than 750mm and this value need to be found out between the cases of lowest and highest adjustments [7]. My aim is to provide the head support properly, keeping the retrained area more than 85cm on both side to improve the design characteristics further. This addresses my research question number 3. 

Research Questions

This research reveals that a common product for all the clients is not a good option. Each person has a different body shape, contour and physical features and therefore custom ergonomically built seats for the drivers in commercial vehicles is mandatory. The safety always comes first over any other thing and hence driving safety is to be followed. Earlier methods and techniques resulted in injuries, long term back pains, neck-pains and even headaches. This degraded the performances of the drivers to a significant level and hence that of the passengers. Head and neck are one of the important parts of our body.  Therefore, there protection is a must. These injuries may become serious some day or result in the accidents. Driving safety is a very serious issue and if the methods mentioned in this proposal are followed and developed further then surely the scenario will be much better to that what is now. Moreover, the global market of seat comfort is increasing day by day and is likely to increase in the future as well [15]. This market is a very good opportunity for the investors and manufacturers because continuous research and development is going on.

References:

[1]  Onamumi, A. Samuel, Lucas, E. BAbaj de, “Ergonomic investigation of occupational drivers and seat design of taxi cabs in Nigeria”, ARPN Journal of science and technology, Nigeria, April 2012, vol. 2, pp. 214- 220.

[2]  T.C Fai, F. Delbressine and M. Rauterberg, “Vehicle seat design: state of the art and recent development”, Proceedings world engineering congress, Penang Malaysia, 2007, pp. 51-61.

[3]  Irene Kamp, “The influence of car-seat design on its character experience”, Applied Ergonomics, 2012, vol.43, pp. 329-335.

[4]  Mike Kolich, “Automobile seat comfort: occupant preferences vs. anthropometric accommodation” Applied Ergonomics, 2003, vol.34, pp. 177–184.

[5]  C.R. Mehta, L.P. Gite and S.C. Pharade, “Review of anthropometric considerations for tractor seat design”, International Journal of Industrial Ergonomics, science direct, 2008, vol. 38, pp. 546–554.

[6]  Hirochi udo, Takaoki Tajmi and shinichi uda, “Low back load in two car driver seats”, International journal of industrial ergonomics, Elsevier, 1997, vol. 20, pp. 215-222.

[7]  Mats Y. Svensson, per lovesund and Yngve haland, “The influence of seat-back and head restraint Properties on the head-neck Motion during rear-impact”, A&d. Anal., 1996, Vol. 28, pp. 22l-227.

[8]  Bjorn Lundell, Lotta Jackobsonn and Bo Alfredson, “The whips seat –A car seat for improved protection against neck injuries in rear end impact”, Auto liv, Sweden, Paper Number 98-S7-O-08, Unpublished.

[9]  M. Grujicic, B. Pandurangan and X. Xie, “Musculoskeletal computational analysis of the influence of car-seat design/adjustments on long-distance driving fatigue”, International Journal of Industrial Ergonomics, Elsevier, 2010, vol. 40, pp. 345-355.

[10]  A. Siefert, S. Pankoke, and H.P. Wolfel, “Virtual optimisation of car passenger seats: Simulation of static and dynamic effects on drivers’ seating comfort”, International Journal of Industrial Ergonomics, Elsevier, 2008, vol. 38, pp. 410–424.

[11]  M. Franz, A. Durt , R. Zenk and P.M.A. Desmet, “Comfort effects of a new car headrest with neck support”, Applied Ergonomics, 2012, vol. 43, pp. 336-343.

[12]  Denis Alves Coelho and Sven Dahlman, “Articulation at shoulder level – A pilot experimental study on car seat comfort”, Applied Ergonomics, 2012, vol. 43, pp. 27-37.

[13]  R.K Ippili, P. Davies and A.K. Bajaj, “Nonlinear multi-body dynamic modelling of seat occupant system with polyurethane seat and H-point prediction”, International Journal of Industrial Ergonomics, 2008, Vol. 38, pp. 368-383.

[14]  Indian Automobile Industry standards (AIS-097), “Procedure for determining the “H” point and the torso angle for 50th percentile adult male in Seating positions of motor vehicles”, 2007, Printed by the automotive research association of India, Pune, Publication No. 832.

[15] Attwood, D. A.; Deeb, J. M.; Danz-Reece, M. E. Ergonomic Solutions for the Process Industries. Elsevier Inc., 2004.

[16]  Giuseppe Andreoni, Giorgio C. Santambrogio and Marco Rabuffetti, “Method for analysis of posture and interface pressure of car drivers”, Applied ergonomics, 2002, vol. 33, pp. 511-522.