A Variable-Impedance Control Strategy for Suspended Backpacks to Reduce Dynamic Load and Prevent End-Stop Impacts*

Suspended backpacks have been verified to effectively reduce the energy consumption of the human body when carrying heavy loads. However, during vigorous movements, there is a risk of end-stop impacts between the load frame and the back frame due to the low suspension stiffness. In this work, a variable-impedance control strategy is proposed for suspended backpacks, which can automatically adjust the suspension stiffness and damping to reduce dynamic load and prevent end-stop impacts. A variable impedance suspended backpack (VIB) is developed to validate the proposed control strategy. Experimental results on the VIB suspended backpack demonstrate that the proposed strategy reduces load acceleration by 0.365 m/s², decreases energy consumption by 13.41%, and minimizes relative displacement by 29.42%.