Smart Living Products
ISDN2001/2002: Second Year Design Project
How can basic ergonomic principles improve the physical and psychological comfort of an elderly lower-limb training device?
Introduction
This independent study focuses on the role of ergonomics in the design of our final product, E-Pillow, a soft lower-limb training device for elderly users. At the beginning of the study, I mainly wanted to investigate how to design the best leg angle and choose suitable materials for the product. Since the device requires users to push with their lower limbs, I first thought that the most important design decision was to find an ideal angle that could reduce pressure on the knee and ankle while still allowing effective exercise.
However, during the research process, I found that it was difficult to define one fixed “best” leg angle. Different users may have different body sizes, flexibility, muscle strength, joint conditions, and recovery needs. Elderly users are also not a single group with the same physical ability. Because of this, the ideal angle and material softness can be highly dependent on the user, their age, and their physical condition. This made me realize that the physical design could not be solved only by simple mechanical reasoning or general online research. The leg angle and material choice were still important, but I started to understand that they should be considered together with how the user feels when using the product.
Research Journal and Change of Direction
My research direction developed gradually during the study. Instead of suddenly changing from a physical topic to a psychological topic, the study slowly expanded from body posture and material comfort to the overall comfort experience of the user. The process can be summarized as follows:
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Original focus: I first planned to study the best angle for leg placement and the material choice for the cushion.
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Problem found: I could not find sufficient data to support one universal angle for all elderly users.
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Reason: The comfortable angle is strongly dependent on different people, age groups, body conditions, muscle strength, and rehabilitation needs.
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Consultation: After chatting with a physical therapist, I understood that comfort in rehabilitation products is not only about whether the posture is mechanically correct. It is also related to whether the user feels safe, confident, and willing to move.
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Transition of focus: Therefore, my study moved from a purely physical focus, such as angle and material, to a wider ergonomic focus that also considers the user’s feeling during interaction.
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New focus: I started to study motion comfort and psychological comfort, including smooth resistance, low starting force, soft appearance, clear guidance, and a sense of control.
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Final direction: Instead of trying to prove one perfect angle, I focused on how the product can feel smoother, safer, softer, and less intimidating for elderly users.
This transition made the research more useful for our final product, because E-Pillow is not only a mechanical training device. It is also a product that elderly users need to trust and feel comfortable using. The final direction still includes physical comfort, but it also explains why the product should look friendly, feel controlled, and reduce fear during use.
Ergonomic Understanding
Through this short research journey, I learned that ergonomics should be considered from both physical and psychological perspectives.
Physical / Motion Comfort
Motion comfort is about how the user feels when pushing the device. For elderly users, the first push should not feel too heavy or sudden, because a high starting resistance may create pressure on the knee and ankle. A smoother and more controlled motion can make the training experience feel safer and more natural.
Important design points include:
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The movement should feel smooth and controlled, not stiff or mechanical.
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Low starting resistance can reduce the initial load on the knee and ankle.
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A softer resistance system can make the first movement easier for weaker users.
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Springs and pneumatic cushioning can create a gradual force response.
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The device should support the user’s movement instead of making the user feel like they are fighting against a rigid machine.
Psychological Comfort
Psychological comfort is about how the user feels before and during use. For elderly users, a product may be rejected if it looks too medical, hard, dangerous, or difficult to control. Therefore, the appearance and interaction should help the user feel safe and confident.
Important design points include:
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The device should look stable, friendly, and approachable.
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A soft pillow-like appearance can reduce fear and make the product feel familiar.
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Clear foot placement helps the user understand how to use the device correctly.
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Simple controls and visible safe-range indicators can improve the sense of control.
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Easy-release features and gentle feedback can make users feel safer during exercise.
How the Research Affected Our Final Product
This research directly influenced the final design direction of E-Pillow. Instead of designing the product only as a mechanical pushing device, the final product was developed as a soft, friendly, and comfortable training object.
The influence on the final product can be seen in several areas:
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Pillow appearance: The final product uses a pillow-like shape to make the device look soft, familiar, and less intimidating for elderly users.
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Soft material direction: The soft outer form supports the idea of psychological comfort and makes the product feel less like a medical machine.
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Pneumatic cushion system: The inner air cushion helps create a softer pushing feeling and avoids a rigid mechanical response.
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Spring return system: The spring system helps the cushion rebound after being pressed, supporting repeated training movement.
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Controlled resistance: The air system and valve can help control pressure release, making the motion smoother and more comfortable.
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Angled structure: Although the research did not define one perfect angle, the final structure still uses an angled setup to guide lower-limb movement in a more ergonomic and controlled position.
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User-centered direction: The design moved from “finding the correct mechanical angle” to “creating a comfortable overall experience” for elderly users.
Conclusion and How It Supports Our Project
Overall, this independent study helped me understand that ergonomic design is not only about measurements, angles, or materials. At first, I expected the research to give a clear answer about the best leg angle and cushion material. However, after reviewing the limitations of general data and chatting with a physical therapist, I realized that physical comfort is closely connected to the user’s body condition, age, strength, confidence, and sense of safety. Therefore, the study naturally expanded from pure physical design to a more complete understanding of comfort as a user experience.
Through the study, I learned that motion comfort and psychological comfort should work together. From the motion side, smooth movement, low starting resistance, pneumatic cushioning, and spring return can reduce pressure on the knee and ankle and make the device feel less rigid. From the psychological side, a soft pillow appearance, stable form, clear foot placement, simple interaction, and safe feeling can help elderly users feel more confident and willing to use the product.
Therefore, this research supports our final product by explaining why E-Pillow should be soft, approachable, and controlled in movement. The final product is not only designed to provide lower-limb training, but also to make elderly users feel safe, supported, and comfortable during use. Although this was only a short and basic study of ergonomics, it helped guide the design direction of our final product and showed that small design decisions can strongly affect the user’s overall comfort experience.