Some unilateral lower-limb amputees, have through continued exertion, increase the foot reaction force of the sound leg. The asymmetric gait with a prosthetic leg may thus negatively affect the musculoskeletal health of the leg on the healthy side. Therefore, it is important for these amputees to learn how to adjust the balance of each foot load in training. The aim of this study is to develop a training support system visualizing floor-reaction forces using a color-depth sensor. The pose of the entire body of the amputee is measured by the depth sensor, and the floor reaction force is estimated based on Zero Moment Point (ZMP), which is calculated using the center of mass of the amputee. Evaluation experiments of the proposed method were performed and they confirmed the effectiveness of the estimation method and the training with the visualization of reaction force.

We introduced a new electret condenser Microphone (ECM) water repellent coating structure for protection against common hazards, such as water or alcohol. This protection structure is composed of small acoustical holes with a water-repellent coating. The water-repellent coating has a contact angle of more than 150 degrees for water on a small acoustical hole having less than 0.2 mm aperture, which blocks water invasion but allows acoustical transmission. The reliability of the coating was confirmed by several tests, such as long-term immersion in water and alcohol, re-flow soldering test and surface scratching. These tests produced no damage to the coating. The fabricated ECM meets the requirements for the IEC 60526 class 7, which is 30 minutes under water at a depth of 1 meter. The diameter and number of holes is determined both by acoustic characteristics and water resistance.