Final Year Project Presentation - Identification of Basic Elements for Car Seat Design

Identification of Basic Elements for Car Seat Design

Final Year Project Presentation

Acknowledgment

Agenda for the Day

Special thanks to the following personnel / organizations:

• Assistant Professor Qu Xingda for his kind patience, support, invaluable and selfless guidance, as well as his encouragement over the course of the project.

• To Daimler South East Asia Pte Ltd; Mr. Dennis Tan, Mr. Fwu Ming Teck and Mr. Liaw Swee Chong for their technical support and kind sponsorship of equipment.

• To Mr. Ho Songyu Ben for his assistance, coordination and support over the course of the project.

• To School of Mechanical and Aerospace Engineering for providing this opportunity and facilitates that facilitates the progression of the Final Year Project.

Focus Group Discussion Summary

Features Affecting Driver Fatigue

Introduction

• Project Information
• Project Objectives

Literature Review

• Concept of Driver Fatigue
• Factors leading to Driver Fatigue
• How Car Seat Design Influence Driver Fatigue

Focus Group Discussion Methodology

• Participant Recruitment and Demographics

Focus Group Discussion Results

• Seats Comparison
• Static Display Contours and Features Discussion
• Static Display Material Discussion
• Car Seat Positioning
• Car Seat Inclination and Seating Angles

Focus Group Discussion Summary

• Features Affecting Driver Fatigue

Post Experimental Comparison

Conclusion

Design factors that may affect driver fatigue.

Introduction

Project Information

Seat position and posture that may affect driver fatigue.

Table 3

Fatigue generally described as a condition resulting from previous stress, causing reversible damage of performance and functions.

Focus Group Discussion Results

Car Seat Positioning

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Table 4

Other factors that may affect driver fatigue.

Fatigue is generally followed by a decline in alertness and raised sensation of strain

Question: Views and opinions on how positioning of car seats affects driver fatigue ?

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By Mr. Rahul (TUM Create)

• Car seats position with respect to height of steering wheels and distance from the foot pedal plays a part in drivers' fatigue.
• Improper positioning results in, driver's thigh not fully supported, deviation of pressure point on the seats, resulting in driver feeling uncomfortable.

Table 5

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Human spend tremendous amount of time in seated postures

Question: Views and opinions on how positioning of car seats affects driver fatigue ?

Past Studies / Experiments Conducted

• Driver's comfort not only relate to pleasure sensation, it is also closely related to health and safety.
• Comfort, health and safety are important for the musculoskeletal disorders which a correct seat and driving posture can avoid.
• Low back pain is an example of the implications arising from a bad position when seated, where such implications will lead to driver discomfort and fatigue (By: Giuseppe).

Features that may affect or increase drivers fatigue (Top 5)

Question: Views and opinions on how positioning of car seats affects driver fatigue ?

Past Studies / Experiments Conducted

• Results show that car seat must be able to fulfill the following features namely;
• Assuring a correct and good bio-mechanical alignment of body posture.
• Reaching of control levers, steering wheel, and pedals must be assured.
• Able to support and evenly distribute body weight.

• Fundamental differences between driving posture and sitting postures can be defined using the following points;
• When seated in driving posture, the feet do not have a supporting function.
• Body balance and control assured by the seat, thus a high and inclined backrest is essential.
• Headrest and antisubmarine system contributes to the overall safety requirement of the seat structure.
• Visibility and reach-ability of the control levers and buttons must be established and assured when seated in the driving posture.

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Constrained sitting postures may lead to discomfort, health disorder and driver fatigue

Post Experimental Comparison

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Table 6

Car-seat manufacturers compelled to actively address seat ergonomics to gain a competitive edge

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Question

Views and opinions on how positioning of car seats affects driver fatigue ?

Introduction

Project Objective

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Slide 1

Better understanding on fatigue - car seat design interaction

Focus Group Discussion Results

Static Display Material Discussion

Objective 1

Objective 2

To develop taxonomy for describing the identified car seat design elements for the selected car seats through the focus group approach.

To determine the relationships between car seat design elements and driver fatigue, as well as how age related differences will affect this relationship.

Question

What is your views and opinions on the material used for the car seats on display?

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Question: What is your views and opinions on the material used for the car seats on display?

By Mr. Rahul (TUM Create)

• Bucket seats (Uncomfortable) vs Car seats on display (Comfortable).
• Due to the amount of cushion used.

• Hardness of cushion affects amount of body support received.

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Slide 2

Literature Review

Concept of Driver Fatigue

• Lack of an agreed definition of fatigue.

Recommendation & Conclusion

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Focus Group Discussion Results

Static Display Contours and Features Discussion

• Researchers may refer it as a phenomenon or a theoretical entity.

Question: What is your views and opinions on the contours and the features of the car seats on display?

Past Studies / Experiments Conducted

• Lumbar support statistically help reduce spinal flexion relative to the flat lumbar support (By: Matthew and Lawrence)
• Small reduction in flexion will produce large reductions in tissue stress and helps in reducing fatigue related discomfort.
• Use of the lumbar support results in a more upright alignment (By: Andersson).
• Improve in cervical spine posture = Improve in individuals' cervical spine health and for longer term degenerative changes.

By Mr. Liaw (Daimler S.E.A - Mercedes Benz Singapore)

• Side areas of backrest stabilize the driver's back posture in an upright fixed position.
• However, design posed certain restriction to the body movement as mentioned above.
• Additional features like lumbar area added in recent years, to provide additional comfort and back support required.

• Different theories of fatigue have been proposed, which includes the neural models and arousal theories

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Question

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Focus Group Discussion Results

Seats Comparison

What is your views and opinions on the contours and the features of the car seats on display?

Question

• Arousal theories links the concept of attention and fatigue, as well as allowing the psychological and psychological measures of fatigue.

Slide 11

What is your views and opinions on the sitting experience between a European and Japanese car seats?

Question: What is your views and opinions on the contours and the features of the car seats on display?

Thank You

Past Studies / Experiments Conducted

• Majority of the vibrations experienced by drivers enters the body through the seat. (By: Van Niekerka)
• Mainly vertical vibrations, has the largest impact on the body. (By: Falou)

• Natural frequency for human trunk = Between 4 to 8 Hz. (By: Ofori)
• Rough terrain and heavy-duty vehicles = Whole-body vibration of forest equipment operators exceeding recommended vibration limits. (By: Fai)

By Mr. Rahul (TUM Create)

• Contours and design of car seats greatly depends on the types of car driven, and the driving condition.

• Larger side area of seat cushion and back rest = High level of safety.
• Arms and hand movement of Asian driver affected and restricted by the sides area. European (Larger built) fits the seats nicely with their body tuck in comfortably between the side areas, and their arms and hand outside the side areas.

Focus Group Discussion Methodology

Participant Recruitment and Demographics

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Question: What is your views and opinions on the sitting experience between a European and Japanese car seats?

By Mr. Rahul (TUM Create)

• European cars sold internationally, therefore Asian body structure and dimensions taken into consideration.
• Such consideration may not be tailor-made to Asian context but it certainly satisfies the requirements of the 95 percentile driver.

By Mr. Liaw (Daimler S.E.A - Mercedes Benz Singapore)

• Japanese car seats more comfortable than European ones.
• Japanese car seats (Spacious).
• European car seats (Side area of backrest cause restriction to body movement BUT provides 'hugging' effect to retain driver initial position).

Participants includes; Automotive Industry Representatives, Research and Development Center Representatives and End-Users

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Slide 8

Question: What is your views and opinions on the sitting experience between a European and Japanese car seats?

Literature Review

Factors leading to Driver Fatigue

Past Studies / Experiments Conducted

• Pilot evaluation and experimental study (By: Coelho and Dahlman) prove that, side area supports aggravates the problem of designing a seat to fit every human being in the range of accommodation targeted in the seat's design, posing discomfort that leads to fatigue.

Slide 9

• Vibration influence the level of comfort experienced.

• Increase in intervertebral disk pressure due to flatten lumbar spine from prolonged seating.

Table 1

Literature Review

How Car Seat Design Influence Driver Fatigue

Seat design will determine the following;

Discomfort Level Rise

Table 2

Driver Fatigue

• Amount of postural musculature recruited
• Effect of static seating
• Amount of vibration received

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