Recent improvements of backpacks have effectively reduced the loads being applied to the user. However, currently there is no system that can reduce the total vertical force to the body. While the burden of the static force cannot be reduced, it may be possible to reduce the burden of the dynamic forces. Based on the concept of the springy-pole, a Dynamic Framesheet™ (DFS™) was developed to reduce the oscillatory forces applied to the user during walking. The system was tested against the Canadian Forces Clothe the Soldier (CIS) pack with the Load Carriage Simulator housed at Queen’s University and with human subjects in a controlled circuit of walking and obstacle tasks at three loads. The simulator testing involved displacement tracking of the pack and mannequin, localized pressure recording and hip reaction forces across three loads. For the human trials, acceleration profiles of the pack and person along with subjective responses to the packs were recorded. An adaptation of water wave analysis was used to identify local maximum and minimum values of displacement and acceleration. Power Spectral Density (PSD) plots, commonly used in ride quality analysis, were used to quantify the accelerations of the packs.

The results from the two packs differed, little however the DFS™ had some effect on the vertical motion of the load. There were a number of indications that the DFS™ did reduce the forces and pressures applied to the user. Overall, the CTS had more locations of excessive pressure than the DFS™. The results indicated that using the DFS™ results in a greater amount of force being applied to the body, however that force oscillates less. The magnitude of the primary frequency of the PSD curve was correlated with relative user acceptance. A potential design criterion using PSD plots was identified. The overall conclusion was that there may have been some effect due to the DFS™, however the matching of spring constants with load and control of non-vertical motions need to be improved.