Ankle-knee prosthesis with active ankle and energy transfer: Development of the CYBERLEGs Alpha-Prosthesis

Louis Flynn, Joost Geeroms, Rene Jimenez-Fabian, Bram Vanderborght, Nicola Vitiello, Dirk Lefeber

Research output: Contribution to journalArticlepeer-review


This paper presents the development of the CYBERLEGs Alpha-Prototype prosthesis, a new transfemoral prosthesis incorporating a new variable stiffness ankle actuator based on the MACCEPA architecture, a passive knee with two locking mechanisms, and an energy transfer mechanism that harvests negative work from the knee and delivers it to the ankle to assist pushoff. The CYBERLEGs Alpha-Prosthesis is part of the CYBERLEGs FP7-ICT project, which combines a prosthesis system to replace a lost limb in parallel with an exoskeleton to assist the sound leg, and sensory array to control both systems. The prosthesis attempts to produce a natural level ground walking gait that approximates the joint torques and kinematics of a non-amputee while maintaining compliant joints, which has the potential to decrease impulsive losses, and ultimately reduce the end user energy consumption. This first prototype consists of a passive knee and an active ankle which are energetically coupled to reduce the total power consumption of the device. Here we present simulations of the actuation system of the ankle and the passive behavior of the knee module with and without the energy transfer effects, the mechanical design of the prosthesis, and empirical results from testing of the physical device with amputee subjects.

Original languageEnglish
Pages (from-to)4-15
Number of pages12
JournalRobotics and Autonomous Systems
Publication statusPublished - Nov 1 2015


  • Active
  • Ankle
  • Energy efficiency
  • Energy transfer
  • Knee
  • Prosthesis
  • Transfemoral

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Software
  • Mathematics(all)


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