Controlling a lamprey-based robot with an electronic nervous system

Abstract

We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a polyurethane strip. The behavior of the robot is controlled by an electronic nervous system (ENS) composed of networks of discrete-time map-based neurons and synapses that execute on a digital signal processing chip. Motor neuron action potentials gate power transistors that apply current to the SMA actuators. The ENS consists of a set of segmental central pattern generators (CPGs), modulated by layered command and coordinating neuron networks, that integrate input from exteroceptive sensors including a compass, accelerometers, inclinometers and a short baseline sonar array (SBA). The CPGs instantiate the 3-element hemi-segmental network model established from physiological studies. Anterior and posterior propagating pathways between CPGs mediate intersegmental coordination to generate flexion waves for forward and backward swimming. The command network mediates layered exteroceptive reflexes for homing, primary orientation, and impediment compensation. The SBA allows homing on a sonar beacon by indicating deviations in azimuth and inclination. Inclinometers actuate a bending segment between the hull and undulator to allow climb and dive. Accelerometers can distinguish collisions from impediment to allow compensatory reflexes. Modulatory commands mediate speed control and turning. A SBA communications interface is being developed to allow supervised reactive autonomy.

Fundamentals of soft robot locomotion

“…Robots with a long streamlined body inspired by eels [100] or lampreys [101,102] can be very useful for exploring narrow environments without the obstacle of limbs. They can swim efficiently thanks to their flexible bodies actuated by SMA wires, which have high power/weight ratios and allow energy storage when negative work is performed during undulation [103].…”

Designing and Implementing Nervous System Simulations on LEGO Robots

“…The LEGO Mindstorms NXT platform can serve as a stepping stone to a more thorough testing of systems level hypotheses as demonstrated by such robots as RoboLamprey 9 and Barbara Webb's robotic cricket 23 . Simple components of extensive biomimetic control architectures can be tested in a rapid and straightforward manner.…”

“…We present a method to execute the biorobotic approach using a commercially available robotics kit (LEGO Mindstorms NXT 2.0). The goal of this method is to provide a rapid and efficient way to test systems level neuroscience hypotheses on robotic 9 or bio-hybrid 10 embodied neural network simulations. Accelerating the process from hypothesis to experiment improves research productivity.…”

SMA-Based Muscle-Like Actuation in Biologically Inspired Robots: A State of the Art Review

“…In [81] a sea Lamprey has been developed. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis.…”