Robotics Institute | Carnegie Mellon University
Director: Prof. Hartmut Geyer
The Legged Systems Group is engaged in research on dynamics, control and learning of human locomotion and related applications in rehabilitation robotics. Our group combines physics, biomechanics and neuroscience with control theory and machine learning to understand how the human system locomotes and to translate the resulting insights into functional lower-limb assistive robots.
Our research is organized around four interconnected themes:
We create mathematical models that capture essential principles of legged locomotion with a focus on dynamic gait stability, balance recovery, and agility. These simplified models reveal core mechanical principles that enable stable and efficient locomotion in any legged system, whether human or humanoid.
Active spring-mass locomotion: Biomimetic ground reaction forces in multi-terrain environments
Simple models provide clear insight but often lack the complexity needed for real-world control. We establish principled frameworks for systematically decomposing complex control systems. These decomposition frameworks enable automated discovery of hierarchical controllers and offer a physics-informed alternative to pure machine learning approaches. The methodology extends beyond locomotion to other robotics domains including manipulation and flight.
Policy decomposition: Automated discovery of controllers that minimize performance loss compared to intractable optimal solutions
We investigate how the human neuromuscular system controls and learns locomotion. Our work bridges biomechanics and neuroscience. We seek to understand how (bio)mechanical principles of legged locomotion connect to neural control and how this control adapts through learning. Knowledge about these fundamental neural mechanisms can help explain the effects of aging and damage to the motor system on human gait, and inform rehabilitation strategies after spinal cord injury and stroke. This knowledge also produces human-like control strategies for powered leg prostheses, exoskeletons, and legged robots.
Spinal control learning: Transfer of control from brain to spinal cord through hetero-synaptic modulation at spinal interneurons
We explore novel control strategies for powered lower-limb assistive robots that can improve human mobility and quality of life. Our research combines human-like neuromuscular control strategies with machine learning approaches to create artificial lower limbs that continuously reason about and adapt to their human user and the environment, advancing technologies for safer, more agile, and natural locomotion in real-world conditions.
Collaborative prosthesis control: combining human intent prediction and environment perception to step on, over and off any object, near or far