Design of hybrid variable stiffness human–computer interaction contact unit module based on granular jamming

Existing rehabilitation exoskeleton robots suffer from poor compatibility with the human limb coupling method, large internal power loss, and poor wearable performance, which seriously affect the rehabilitation ability of these robots. Therefore, this study proposes a variable stiffness human–computer interaction contact unit module (VSHCUM) based on the granular jamming mechanism. It is characterized by a double-layer chamber structure: the inner layer is a granular chamber, and the outer layer is an air chamber. The interaction force is transmitted by embedding a rigid support in the inner layer. Unlike the common flexible-belt interactive contact unit, when the exoskeleton is bound to the patient's limb, VSHCUM can realize adaptive fitting of the patient's limb shape using the pressure change in the double-chamber structure. Simultaneously, by adjusting the vacuum level of the granular chamber, the stiffness of the interactive contact unit can be adjusted by a factor of more than five, and the internal work loss caused by self-pulling deformation during the auxiliary force transfer process can be reduced.