Passive knee joint power-assisted exoskeleton

The passive knee joint power-assisted exoskeleton comprises a shank rod, an inner side plate, an outer side plate, a Bowden cable, a roller, a tension spring, an upper connecting rod, a lower connecting rod, a ratchet and pawl mechanism and a forward locking mechanism. The shank rod is located between the inner side plate and the outer side plate, the shank rod is connected with the outer side plate and the inner side plate through the upper connecting rod and the lower connecting rod, the shank rod rotates to drive the upper connecting rod and the lower connecting rod to rotate, and the shank rod can only rotate along a specific track due to limitation of limiting grooves in the inner side plate and the outer side plate. Keeping the instantaneous rotation center track of the exoskeleton knee joint consistent with the instantaneous rotation center track of the human knee joint; in the later swing phase period of the gait cycle, when the heel of the human body touches the ground, under the action of the forwar