Reducing knee joint load is a well-established approach in the conservative management of knee osteoarthritis (KOA), and the use of joint-unloading exoskeletons offers a promising means to achieve this goal. In response to this need, this study presents a novel adaptive passive body-weight-support knee exoskeleton. First, to address the misalignment between the exoskeleton axis and the biological knee joint axis, a design method for an adaptive exoskeleton mechanism is proposed from the perspective of knee-exoskeleton (K-E) closed-loop compatibility. Inspired by the natural human walking gait, a gait-based principle for passive body weight support is introduced. Combined with the proposed adaptive mechanism, an adaptive passive weight-supporting exoskeleton was developed. A kinematic model of the K-E closed-loop mechanism was established, and the mechanical design and structural principles of the exoskeleton were elaborated in detail. Compatibility simulations and gait simulations demonstrate the exoskeleton’s ability to accommodate knee motion and its mechanical interaction with the human body. Experimental results on movement compatibility confirm that the exoskeleton does not interfere with basic human motions, with parasitic force amplitudes remaining below 25 N, exhibiting favorable biomechanical compatibility. Gait experiments further verify the exoskeleton’s capacity to support body weight, and its effects on gait patterns are discussed. The outdoor experiments verified that the exoskeleton effectively reduces plantar pressure, thereby providing indirect evidence of its efficacy in offloading the knee joint.
Guo et al. (2026) studied this question.