A novel robotic negative pressure therapy method for lymphedema treatment on unstructured surfaces

Negative pressure(NP) therapy with bandage compression is the primary conservative treatment for upper and lower limb lymphedema with great efficacy. With the growing number of lymphedema patients and a shortage of qualified therapists, not all patients can benefit from manual lymphedema management. One possible solution could be used for robotic devices to perform NP therapy. However, the unstructured skin surface can make seal formation difficult for the robot. Therefore, a novel robotic NP therapy is designed to complete suction on complex skin surfaces with pneumatic control and self-tuning Cartesian impedance control. The pneumatic control could track the target pressure command stably and quickly, while the self-tuning Cartesian impedance control could regulate the normal force during the NP physiotherapy. Then, based on these two control strategies, robotic NP therapy that converts normal force into position error is introduced for seal formation before suction. Besides, four experiments were carried out to demonstrate this robotic therapy. The results showed that robotic NP treatment can complete suction on unstructured skin surfaces with a high success rate and normal force regulation, making the treatment highly efficient and allowing patients to change the normal force to vary the degree of comfort according to their tolerance during treatment.