Dynamic Scaling and Synthetic Nervous Systems: Two Frameworks for Building Robots that Model Animals

Robots are useful tools for studying the nervous system and its control of body mechanics because they can be used to perform experiments that would be difficult to perform with an animal. For example, in a robot, data can be recorded from every sensor on the body simultaneously as the robot performs a task. Such data may approximate what sensory feedback the animal would experience while performing the same task. Unanticipated results may inspire future experiments to describe the function of the animal’s nervous system in greater detail, and the robot can be used to generate concrete hypotheses for such experiments. The utility of a robotic model is greatest when it mimics key characteristics of the model organism, e.g., its kinematics, dynamic scale, sensing modalities, and computation and control.

To study the sensorimotor control of legged locomotion, my group constructs robots modeled after walking insects. When modeling a particular species, the kinematics of the robot are designed to mimic those of the animal. To ensure that the same forces (e.g., gravity, inertia, elastic) dominate the motion of the robot and the animal, the speed of the robot’s motion is dynamically scaled to that of the animal. To provide the control system with sensory feedback similar to that which the animal experiences, the robot has special sensors whose signals are processed through biomimetic filters. These filters can provide necessary adjustments for inherent differences in the mass, material, and other properties between the robot and the animal. To create control systems that are constrained to the types of computations the nervous system performs, the robot’s control system is a real-time simulation of neural dynamics. The resulting robot is a substrate onto which to accumulate experimental discoveries and test that particular mechanisms function as understood in vivo.

Learning Objectives: 

1. Describe some ways in which body mechanics affect the neural control of movement.

2. Explain some interdisciplinary methods for investigating nervous system function using biomimetic robots.

3. Evaluate the applicability of a biomimetic robot to the organism it is modeling.