''A six-legged walking robot should not be confused with a

Stewart platform A Stewart platform is a type of parallel manipulator that has six prismatic joint, prismatic actuators, commonly hydraulic jacks or electric linear actuators, attached in pairs to three positions on the platform's baseplate, crossing over to thr ...

, a kind of

parallel manipulator A parallel manipulator is a mechanical system that uses several computer-controlled serial chains to support a single platform, or end-effector. Perhaps, the best known parallel manipulator is formed from six linear actuators that support a mo ...

used in robotics applications''. Beetle robot

A hexapod robot is a mechanical vehicle that walks on six legs. Since a robot can be statically stable on three or more legs, a hexapod robot has a great deal of flexibility in how it can move. If legs become disabled, the robot may still be able to walk. Furthermore, not all of the robot's legs are needed for stability; other legs are free to reach new foot placements or manipulate a payload. Many hexapod

robots" \n\n\n\n\n\n\nrobots.txt is the filename used for implementing the Robots Exclusion Protocol, a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the website they are allowed to visit.\n\nThe sta ...

are biologically inspired by

Hexapoda The subphylum Hexapoda (from Greek for 'six legs') or hexapods comprises the largest clade of arthropods and includes most of the extant arthropod species. It includes the crown group class Insecta (true insects), as well as the much smaller c ...

locomotion – the insectoid robots. Hexapods may be used to test biological theories about insect locomotion, motor control, and neurobiology.

Designs

Hexapod designs vary in leg arrangement. Insect-inspired robots are typically laterally symmetric, such as the RiSE robot at Carnegie Mellon. A radially symmetric hexapod is ATHLETE (All-Terrain Hex-Legged Extra-Terrestrial Explorer) robot at JPL. Typically, individual legs range from two to six

degrees of freedom In many scientific fields, the degrees of freedom of a system is the number of parameters of the system that may vary independently. For example, a point in the plane has two degrees of freedom for translation: its two coordinates; a non-infinite ...

. Hexapod feet are typically pointed, but can also be tipped with adhesive material to help climb walls or wheels so the robot can drive quickly when the ground is flat.

Locomotion

Most often, hexapods are controlled by gaits, which allow the robot to move forward, turn, and perhaps side-step. Some of the most common gaits are as follows: * Alternating tripod: 3 legs on the ground at a time. * Quadruped. * Crawl: move just one leg at a time. Gaits for hexapods are often stable, even in slightly rocky and uneven terrain. Motion may also be nongaited, which means the sequence of leg motions is not fixed, but rather chosen by the computer in response to the sensed environment. This may be most helpful in very rocky terrain, but existing techniques for

motion planning Motion planning, also path planning (also known as the navigation problem or the piano mover's problem) is a computational problem to find a sequence of valid configurations that moves the object from the source to destination. The term is used ...

are computationally expensive.

Biologically inspired

Insects are chosen as models because their

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

are simpler than other animal species. Also, complex behaviours can be attributed to just a few

neurons A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

and the pathway between sensory input and motor output is relatively shorter. Insects' walking behaviour and neural architecture are used to improve robot locomotion. Conversely,

biologists A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in ...

can use hexapod robots for testing different hypotheses. Biologically inspired hexapod robots largely depend on the

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

species used as a model. 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 ...

and the

stick insect The Phasmatodea (also known as Phasmida or Phasmatoptera) are an order of insects whose members are variously known as stick insects, stick bugs, walkingsticks, stick animals, or bug sticks. They are also occasionally referred to as Devil's da ...

are the two most commonly used insect species; both have been ethologically and neurophysiologically extensively studied. At present no complete

is known, therefore, models usually combine different insect models, including those of other insects. Insect gaits are usually obtained by two approaches: the centralized and the decentralized control architectures. Centralized controllers directly specify transitions of all legs, whereas in decentralized architectures, six nodes (legs) are connected in a parallel network; gaits arise by the interaction between neighbouring legs.

List of robots

* Hexbug (insectoid toy robot) *

Stiquito Stiquito (pronounced sti ke to) is a small, inexpensive hexapod (i.e., six-legged) robot commonly used by universities, high schools, and hobbyists, since 1992. Stiquito's "muscles" are made of nitinol, a shape memory alloy that expands and c ...

(inexpensive insectoid robot) * Rhex * Whegs * LAURON

References

External links