Active Foot Pressure Control for Diabetic Patients

Foot Ulcer in diabetic patients is a serious medical problem. A major contributor for the development of diabetic foot ulcers is a high, localized plantar foot pressure. It is believed that in diabetes the nerves in the extreme parts of the human body are damaged and cause deregulated blood flow, which may cause an insufficient blood supply. This can lead to a loss of feeling, change in shape of the feet, necrosis and ulcerations, and ultimately to partial or total amputation of the body part. The loss of feeling in the feet results in a loss of feedback to control the foot pressure distribution. It is proposed that high foot pressure concentration can be avoided by using an active, intelligent shoe insert, which is based on the mechanics of smart materials. This paper investigates the controls schemes necessary to accomplish an external foot pressure distribution scheme for preventing ulcerations or the progression of existing ulcers. A simple mathematical model of the shoe insert is developed. Foot pressure distributions for healthy subjects are used as a basis to control elevated foot pressures by changing the shape of the shoe insert. The optimal shape of the shoe insert with regard to the existing pressure distribution is computed. The optimal shape is implemented using different control schemes. The performance and the efficiency of the proposed control schemes are compared and analyzed. The main advantage of the proposed active shoe insert is its capability to sense the pressure peaks, change the pressure distribution, and provide stimuli for increased blood flow in the diabetic feet. [1,2,3]