Design and Prototyping of One Degree-of-Freedom Rehabilitation Robotic Arm with Variable Weights

In this paper, a novel concept is proposed to design a robotic arm for rehabilitating individuals with muscle disability. Wearable robots are used for dealing with this challenge. Many of these robots can only reduce certain amounts of hand weight and whatever it grabs, and the system force does not change with the weight of hand. The existing systems are designed for certain weights and with any variation in length, the device should be set to static balance manually; a process which takes time and expertise. The proposed mechanism, when the device is connected to the individual's hand, it synchronizes itself with the weight and torque automatically using a novel force sensor, which is based on a barometer device, and the reaches statistic balance. In addition, if a weight is lifted, the device rebalances with the new weight and reaches statistic balance accordingly. In order to provide statistic balance in this system, counterweight is used which neutralizes 98% of sum of weight of hand and the weight.