Five Minutes With Professor Mitra Hartmann

The professor of Mechanical Engineering discusses her research and how robotics support her professional interests.

Mitra Hartmann is a professor of Mechanical Engineering and a professor of Biomedical Engineering at Northwestern University.

Mitra HartmannHer research — and her laboratory — revolves around better understanding how movement and touch are combined in the brain to enable perception. The hope is that this research could ultimately help people disabled by either stroke or a brain injury.

Hartmann has been named Teacher of the Year at Northwestern Engineering on three different occasions.

As the latest school year gets underway, she took time to talk about how her work is impacted by robotics and what she would say to a prospective student considering Northwestern Engineering's Master of Science in Robotics (MSR) program.

How do you summarize your research interests to someone with little to no background in engineering?

I'm interested in how animals, including humans, sense and perceive the world around them.  At this point, it's well established that sensing is an active process. For example, the way you move your eyes influences what you see, which in turn influences the way you move your eyes. My lab focuses particularly on the sense of touch because it is so closely intertwined with movement. Touch is a good model for the study of active sensing.   

To study active sensing, my lab uses the rodent (rat and mouse) whisker system. Dozens of neuroscience laboratories study rodent whiskers because the neural pathways that carry information from the human hand through the brain are in many ways analogous to the pathways that carry information from the rodent's whiskers through its brain. As an engineering lab, we study rodent whiskers not only because of this similarity in neural pathways, but also because whiskers are relatively mechanically simple — just like a hair, they have no sensors on their length. This simplicity allows us to quantify all the mechanosensory signals at each whisker base, and to build artificial ("robotic") whiskers that sense in a similar way.

What are some of the most significant ways robots have helped the study of neuroscience?

In general, robots are critical to the study of neuroscience, and particularly to the study of active sensing, because they "close the loop" between sensing and movement in a real environment. Animals close that loop too, but it's impossible to measure the animal's complete sensory input or its complete motor output while recording from neurons in its brain. With a robot, you know the sensory input it receives, you know the computations its software performs, you know its motor command signals, and you can measure how those motor commands influence the robot's interaction with the environment.  

For example, in our lab, we constructed a robotic whisker array to gain a better understanding of the signals at the base of a whisker as it "slips" along different objects. This understanding allows us to make predictions for the kinds of signals that the rat's brain has to process and interpret, and we can then go record from the brain to test these predictions.

How do you think robots could continue to be improved to help further the study of neuroscience?

In general, robot technology could be improved in four ways:

  1. Power — Nervous systems operate at phenomenally low power that artificial systems come nowhere close to matching
  2. Parallelism and wiring — Animals rely on massively parallel computation that's hard to implement, and it's even harder to think about how to fit all those wires on board a mobile robot
  3. Learning — Even our most advanced machine learning algorithms still require considerably more data than required by animals, and often result in "brittle" solutions that fail in response to specific challenges
  4. Materials — The growing field of "soft robotics" aims to use more compliant materials in robots, and these new materials will in turn influence how the robots move and interact with the environment. 

But from the very practical standpoint of how robots might specifically be improved to benefit neuroscience labs, the issue is that robots are hard to build, hard to operate, and generally hard to maintain. They break! Having more plug-and-play, simple, modular robots for neuroscientists might help allow us to better understand animal locomotion and sensing.

What do you think is the biggest misconception about robotics today?

Many people seem to think that working with robotics is fundamentally about working with motors. It's certainly true that motors are an important part of any robot, but fundamental problems lie in sensing, control, and ensuring that the robot can adapt to varying conditions and tasks. I also think that in general, humans underestimate our tendency to anthropomorphize robots, and that this tendency could influence the field of robotics in unforeseen ways.

What do you enjoy most about being involved with the MSR program?

The students in the MSR program are exceptionally creative and willing to think outside the box.  They often come up with fun projects on their own and suggest them as options to our lab, in addition to working on projects that our lab has thought of.

What would you say to a prospective student considering the MSR program?

It's a great way to "test the waters" to see if it's really a field that you're excited about. It gives you a great launching pad if you ultimately decide you're interested in a PhD, and great background for industry. To me, it seems to be a great combination of required classes and more flexible project-based learning.