Optimum design of a knee orthosis powered by series elastic actuators

The statistical studies indicate that diseases, accidents and wares are the principal causes to increase the number of amputees in the world. These studies also show that the most of mutilation disabilities are related to musculoskeletal. Obesity, sedentary, lack of proper exercise as well as the risk of some diseases, cause weaken in knee muscles and other difficulties of this hand. As a consequence, the knee muscles can`t apply a mighty torque to accomplish knee motion. The objective of this study is to propose a proper solution to improve the life quality of those who suffer from weak knees.in this study, by investigating the biomechanical behavior of a healthy foot in a normal gait, the indispensable power which can enforce a 50% weak Knee to achieve the same gait can be calculated. To naturalize the mentioned knee, a new control-active orthosis is designed. The proposed design is specified by an electromechanical actuator and an elastic component articulated in a light weight four-bar mechanism. Its mechanical behavior is tested in a simulated walking gait and the optimum value of elastic coefficient is estimated as 7KN/m. In this case, the maximum torque applicable to knee joint has increased by 34 per cent.