| Traditional human-powered augmentation lower exoskeletons have poor ability to follow the movement of human body due to lack of compliance.This dissertation has reviewed the methods of human-powered augmentation lower exoskeleton compliance control,then built a model of the exoskeleton.Based on this model,a compliance control method for the exoskeleton's full-stage movement is proposed,and this algorithm is applied to the control of exoskeletons' weighted walking.The main innovations are as follows:A lower-limb exoskeleton model was constructed,and a dynamic equation that combines the exoskeleton itself and the contact force between the exoskeleton and the human body was deduced.The structure of the traditional exoskeleton model is very complex,and the impact of human force on the exoskeleton movement is underconsidered.Therefore,this dissertation analyzed the process of body posture changes in four situations: normal walking,up and down stairs,and up and down slopes,and establishes a same model of each situation,and established a multi-point human-machine spring damping model.On the basis of the above-mentioned lower extremity assisted exoskeleton model,this paper proposed an assisted exoskeleton full-stage compliance control algorithm.The core idea of this control method is to only actively drive the knee joint.The driving torque consists of the gravity compensation torque estimated by the model plus the inertia compensation torque estimated by the exoskeleton's foot pressure.The progressiveness of this algorithm is that it does not need to control each phase separately from the traditional assisting exoskeleton.At the same time,it solves the problem that the current human-powered augmentation lower exoskeleton is generally based on the dynamic model and depends heavily on the accuracy of the model.The exoskeleton full-stage compliance control algorithm designed in this paper can be applied to the exoskeleton to improve the user's ability to carry the load. |
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