NSF National Robotics Initiative Project Funded (High-Power Physically Interactive Human-Robot Collaboration through Balanced Active-Passive Hybrid Actuation)

A new project, entitled “High-Power Physically Interactive Human-Robot Collaboration through Balanced Active-Passive Hybrid Actuation” has been funded through the National Science Foundation’s (NSF) National Robotics Initiative (NRI).  An overview of the project is given below:

  • Prof. Peter Adaczyk
  • Department of Mechanical Engineering
  • University of Wisconsin – Madison
  • Prof. Michael Zinn
  • Department of Mechanical Engineering
  • University of Wisconsin – Madison


The research will investigate techniques for modeling, analysis, design and control of robots intended for high-power, high-bandwidth human interaction. These applications may include robots in collaborative manufacturing, shared or human-directed robotic materials handling, and rehabilitation robotics, among others. The applications are distinct in their demand for physical human interaction (in addition to information transfer), and the need for specific interaction characteristics including the ability to behave as both a low-stiffness and a high-stiffness device in different circumstances, and the ability to control interaction forces precisely and quickly. Existing actuation technologies such as electric motors, pneumatic or hydraulics cannot achieve this combination of features, so a new approach to robotic actuators is required. This approach will enable ubiquitous co-robotics by expanding the useful range of an individual robot to a wider array of human-interaction scenarios.

The research will study modeling, analysis, and control of robots that use a balanced combination of multiple active actuators (motors) and passive actuators (controlled brakes or dampers) in parallel. This approach, termed “balanced active-passive hybrid actuation,” exploits the benefits of both active actuators (high output power and bandwidth, fine control) and passive actuators (high stiffness, high power absorption, inherent safety). The proposed study will develop techniques to characterize, model, design and control a single-degree-of-freedom robot based on these principles, and then deploy a two degree-of-freedom robotic system to examine the complex interactions of multiple actuated joints of this type.

Finally, the research will evaluate and demonstrate the use of this new technology in a prototypical high-power human-robot collaborative application: retraining of human motor control in the leg. The new robotic system will be used to apply novel force fields to perturb a person’s foot during foot-reaching movements, and to track the person’s accuracy and rate of improvement. Success in these initial tests will lead to future studies of robotic lower-limb rehabilitation using a wide range of force or motion disturbances, to promote recovery from impairments due to stroke and other injury.