Combat backpack

Context

A national defence R&D project, run under the Civil-Military Technology Cooperation programme and managed by KRIT, to develop a lightweight, modular backpack system for Korean special forces. NH Co., Ltd. led the project and the system integration; UNIST was responsible for the frame and the weight-distribution system, and for usability evaluation.

Challenge

Special-forces operators carry heavy loads for long periods, and packs that do not transfer weight to the pelvis put them at constant risk of back injury. There was also no device or protocol to measure objectively how well a backpack distributes its load.

My role

• Requirements from research. I reviewed the literature on load carriage and injuries (61 papers collected by March 2022), studied female-specific needs, and benchmarked military and outdoor packs to draft the design requirements.
• Frame concepts. I developed frame concepts in SolidWorks — elastic suspension, a pivot point in the upper lumbar area and a one-point hip-belt connection — that informed the final carbon-fibre frame.
• Testing. Later I contributed to the weight-distribution measurement device and its tests, and to a usability study with 60 participants, where I helped design the experiment, facilitated about half of the sessions and prepared the heart-rate and questionnaire data.

Process

Literature to requirements. The review covered load distribution, load-carriage systems, backpack design, ergonomics and context of use, and fed directly into the requirement list.

Frame ideation. I moved from sketches to CAD concepts: a frame that pivots in the upper lumbar area so the pack follows the body during walking, and a one-point hip-belt connection. The team's concepts were reviewed with NH against durability, comfort and load distribution, and the final curved carbon-fibre frame was developed from this stage.

Measuring weight distribution. The team built a torso mannequin with four load cells that measures how much of a pack's load reaches the shoulders and how much the pelvis. In the published test with a 35.1 kg pack, adjusting the straps moved the pelvis share from 63.6% to 97.6%.

Deliverables

• Design requirements from the literature and benchmarking
• Frame concepts and CAD models that informed the final frame
• Contributions to the measurement device, its test protocol and the usability study

The work led to a registered design and two patent filings (co-inventor), including a measurement system for evaluating how a backpack distributes load across the body.