An insectoid robot is a, usually small, robot featuring some insect-like features. These can include the methods of locomotion (including

flying Flying may refer to: * Flight, the process of flying * Aviation, the creation and operation of aircraft Music Albums * '' Flying (Cody Fry album)'', 2017 * ''Flying'' (Grammatrain album), 1997 * ''Flying'' (Jonathan Fagerlund album), 2008 * ...

), methods of

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...

, and

artificial intelligence Artificial intelligence (AI) is the capability of computer, computational systems to perform tasks typically associated with human intelligence, such as learning, reasoning, problem-solving, perception, and decision-making. It is a field of re ...

based on insect models. Many of the problems faced by miniature robot designers have been solved by insect evolution. Researchers naturally look to insects for inspiration and solutions.

Locomotion

Walking

Robot locomotion has frequently been inspired by insect physiology. These robots typically take the form of a hexapod. Research has become multidisciplinary, involving not only robotics engineers, but also biologists, especially

neurobiologist A neuroscientist (or neurobiologist) is a scientist specializing in neuroscience that deals with the anatomy and function of neurons, neural circuits, and glia, and their behavioral, biological, and psychological roles in health and disease. ...

s. Engineers gain from thisrelationship by acquiring a better understanding of the functioning of the insects they have used to model their robots. Biologists in turn, gain a platform on which they can test their theories of insect motor control. Building a robot that can walk on a flat surface in the laboratory is a fairly straightforward task. A hexapod robot with mechanically linked simple pegs for legs will achieve this task. Then again, a wheeled robot might be even simpler, but may be entirely unable to solve the much more difficult problem of crossing rough terrain with unpredictable obstacles. For this, articulated joints in legs like a real insect, with sensor-motor control like the neurology of a real insect are needed. A simple rhythmic cycle of the legs will not do. The legs and joints must be controlled individually and in combination according to information received from limb position and load sensors. The

gait Gait is the pattern of Motion (physics), movement of the limb (anatomy), limbs of animals, including Gait (human), humans, during Animal locomotion, locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on s ...

of insects changes with desired speed. Research has shown that these gait patterns can still be generated locally in many insects even when completely disconnected from the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

. In some insects, for instance the

cockroach Cockroaches (or roaches) are insects belonging to the Order (biology), order Blattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known Pest (organism), pests. Modern cockro ...

, the gait changes in a running insect partly because the nervous system of the insect cannot respond rapidly enough. A running cockcroach changes its gait to pushing with all three legs on one side together. The characteristic side-to-side motion of the animal is at the biomechanical

resonant frequency Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

set by the insect's weight and

spring stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a ...

of the combined legs. This mode needs no input from an external controller and it is both efficient and stable. Researchers recognise the advantages of features of real insects, but as of 2004, "they have only rarely come together in a robot..."

Flying

For a very small aircraft, fixed-wing flight becomes impractical due to rapidly decreasing

lift-to-drag ratio In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the Lift (force), lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficie ...

with size. Insect flight, on the other hand, is always

ornithopter An ornithopter (from Greek language, Greek ''ornis, ornith-'' 'bird' and ''pteron'' 'wing') is an aircraft that flies by flapping its wings. Designers sought to imitate the flapping-wing flight of birds, bats, and insects. Though machines may dif ...

ic which suggests an approach for insectoid robots. Ma ''et al.'' for instance, developed a tethered robot fly with flapping wings constructed of piezoelectric material. Ma chose to model the robot on the fly because, according to their paper, it is the most agile creature alive, and therefore the most difficult to emulate as a robot.

Artificial intelligence

Insects have very little resource to devote to intelligence in the human sense of brain

processing power In computing, computer performance is the amount of useful work accomplished by a computer system. Outside of specific contexts, computer performance is estimated in terms of accuracy, efficiency and speed of executing computer program instruction ...

. The number of neurons in an insect varies by species from one million to as few as ten thousand. By comparison, humans have 86 billion neurons. Further, large brains are extremely energy hungry. Insects must therefore find other methods of developing intelligence such as embodying intelligence in hardware, local sensor-motor connections, and swarm intelligence. At one time it was hoped that robots would avoid the need for such solutions because of the rapidly increasing processing power and decreasing size of computers according to

Moore's law Moore's law is the observation that the Transistor count, number of transistors in an integrated circuit (IC) doubles about every two years. Moore's law is an observation and Forecasting, projection of a historical trend. Rather than a law of ...

. However, this process seems to be reaching its limit and insect solutions look increasingly attractive. Walking rhythms independent of the central nervous system in cockroaches have already been mentioned. A major breakthrough in flying insectoid robots came by applying the same principles to the wings. Attempts to control the angle of attack of the wings with a central processor were not successful because a lift to weight ratio greater than unity could not be achieved. Removing the processor and allowing the wings to rotate passively at the

natural frequency Natural frequency, measured in terms of '' eigenfrequency'', is the rate at which an oscillatory system tends to oscillate in the absence of disturbance. A foundational example pertains to simple harmonic oscillators, such as an idealized spring ...

of the mechanical system reduced the weight sufficiently to allow controlled insectoid flight for the first time in 2008 with a fly-like robot. However, the robot was externally powered through an umbilical rather than completely free flight. Swarms of robots can solve problems that are not possible to solve with the limited processing resource of a single robot. They are particular useful in exploration tasks. They can be used to find the shortest route to a destination, and have been proposed to search for gas sources in dangerous environments. Another proposal is robots that self-assemble into a structure to allow the swarm to cross a gap in the manner of ants.

Navigation

Flying insects have poor visual spatial resolution, must respond rapidly, and have little to no advanced neural processing power. Due to limitations of space and weight, flying insectoid robots have a very similar set of problems. In 2003, Franceschini ''et al.'' investigated the possibility of using insect solutions to solve robot navigation problems. Franceschini built a research robot based on the neural physiology of a fly. The robot was not actually a flying robot, rather, it was a wheeled vehicle. The aim of the research was to show that simple sensor-motor control using only visual motion detection could navigate a course. Using insect intelligence in robot navigation has been going on since 1986, but initially was not taken up by engineers building robots. It was felt that because insects lack a

visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalam ...

, and hence cannot perform advanced visual processing and image formation, a robot based on such technology would not be very successful. Franceschini argues that it is not necessary to possess a visual cortex for the navigation task, and it would in fact be an unnecessary burden on an insect robot (both weight and processing time would be issues). Franceschini points out that many of the visual systems in humans do not pass through the visual cortex either. It is not always necessary to form images and identify objects.Franceschini ''et al.'', pp. 31–32.

References

Bibliography

* G.C.H.E. de Croon, J.J.G. Dupeyroux, S.B. Fuller, J. A. R. Marshall
"Insect-inspired AI for autonomous robots"
''Science Robotics'', vol. 7, no. 67, 2022 . * Fred Delcomyn
"Insect walking and robotics"
''Annual Review of Entomology'', vo. 49, pp. 51–70, 2004. * N. Franceschini, J. M. Pichon, C. Blanes
"From insect vision to robot vision"
''Philosophical Transactions of the Royal Society B'', vol. 337, iss. 1281, 29 September 1992 . * Kevin Y. Ma, Pakpong Chirarattananon, Sawyer B. Fuller, and Robert J. Wood
"Controlled flight of a biologically inspired, insect-scale robot"
''Science'', vol. 340, iss. 6132, pp. 603–607, 3 May 2013 . * Bradley Voytek
"Are there really as many neurons in the human brain as stars in the Milky Way?"
''Scitable'', 20 May 2013. * Robert J. Wood
"The first takeoff of a biologically inspired at-scale robotic insect"
''IEEE Transactions on Robotics'', vol. 24, iss. 2, pp. 341–347, April 2008 {{doi:10.1109/TRO.2008.916997. Robots Insects and humans