Exploring Human Performance: The Importance of Studying our Limitations

A research talk to given to the Neuromuscular Biomechanics Lab led by Professor Scott Delp at Stanford University on May 10th, 2023.

Abstract: An understanding of the underlying control strategies employed by humans is required to develop technology that interacts with humans (e.g. prosthetics, exoskeletons, human-robot collaboration, and robotic rehabilitation). However, at present, both the robotics and motor control communities are far from complete comprehension. To close this knowledge gap, the motor control community has extensively studied human performance. This presentation takes that research a step further by exploring the limitations of current simple models that describe human motor control. Namely, three studies are presented. In the first, we falsify the assumption that humans can directly control force during upper-limb physical interaction by showing that subjects cannot regulate force independent of motion due to mechanical impedance. In the second, we show that an aspect of mechanical impedance is encoded in human motor perception; furthermore, this observation is robust to limitations previously found in motor action. Finally, we probe and expand on a common simplification of human hand manipulation – the presence of kinematic hand synergies. The knowledge gleaned from these studies have implications that can improve existing rehabilitation technologies as well as help develop new ones.

Mechanical Impedance: A Necessity in Both Human Motor Action and Human Motor Perception

A research talk given to the Control Conclave at IIT Delhi on January 6th, 2023

Abstract: An understanding of the underlying control strategy employed by humans is required to develop technology that interacts with humans (e.g. prosthetics, exoskeletons, human-robot collaboration, and robotic rehabilitation). However, at the present time, both the robotics and motor control communities are far from complete comprehension. Understanding the coupled relation between human motor action and motor perception, we conducted a separate experiment in each domain to enhance our understanding of the latent human neuromotor controller. In the first, we falsified the assumption that humans can directly control force by showing that subjects could not regulate force independent of motion due to mechanical impedance. In the second, we showed that an aspect of mechanical impedance is encoded in human motor perception; furthermore, this observation was robust. Thus, we conclude that when modeling a system that incorporates human interaction, one should take special consideration of the human’s mechanical impedance.

Mechanical Impedance: A Key Component in Both Human Motor Action and Human Motor Perception

A research talk given to the Future Leaders in Mechanical and Aerospace Engineering: Celebrating Diversity and Innovation Seminar on March 10, 2021