Transfemoral amputations lead to many difficulties in carrying out daily life activities. This is due to the lack of two joints, knee and ankle, and the associated musculature. Passive prostheses are not able to compensate the lack of energy caused by the missing limb. For this reason, to fulfill actions like Sit-to-Stand, people must employ movement strategies which however result in high asymmetry and therefore in possible complications in the remaining musculature and structure of the healthy limb. To counteract the performance deficiency of traditional passive prostheses, active prostheses have been designed to provide the patient a modulated external torque. They require an effective and reliable controller to regulate the joint power delivery in motion.