SIGMO
Encyclopedia
SIGMO is a humanoid robot
designed to demonstrate the applications of passive dynamics
technologies.
SIGMO stands for Synthetic, IntelliGent, MObility, and was developed by a team of high school students to demonstrate the capabilities of passive-dynamic actuation techniques.
The technology used to enable SIGMO to walk is being applied to advanced prosthetic devices. Current prosthetic devices are nearing the limitations of the available technologies and require advancements such as customized motion, lower cost, and the development of light-weight materials.
Existing humanoid robot systems such as ASIMO
and QRIO
use many motors to achieve locomotion
. These motors reduce efficiency and add unnecessary weight and cost to the robot. SIGMO attempts to alleviate these symptoms by providing a system which uses no motors for locomotion, instead employing passive-dynamic technology.
Passive-dynamic systems cite low power consumption, high durability, and low cost. The design is based on the skeletal structure of the human body
, consisting of two legs with hip, knee, and ankle joints, each representing 1 degree of freedom
(DOF). Movement is accomplished with the aid of gravity (walking down a slope) or by minimal actuation to enable the machine to walk on level ground. SIGMO was developed using proven methods of gravity-driven passive dynamic bipeds. Small actuators were added to the legs to provide walking capability on level ground.
This method of locomotion is very energy efficient because it uses no motors for walking. The omission of motors also cites a drastic weight reduction, further enhancing the locomotive efficiency. This also frees up room inside the torso for the circuitry that controls SIGMO's movements, unlike other robots that require a "backpack" like attachment.
SIGMO has an upper torso which mimics the movements of actual humans. The arms are motorized with small servo motors which enable SIGMO to manipulate objects within its grasp. The main chassis is fabricated of aluminum sheet metal, which has a high strength and light weight. The knee
sockets are fabricated out of steel and aluminum. While the steel
weighs more than the aluminum, this helps to transfer the weight load from the torso (contains heavy servo
components) to the legs and feet which rest on the ground.
An updated model of SIGMO, currently in the research and development stage, will incorporate more precise control over limb movement and directional stability. To add more functionality SIGMO will have more motors, but use each more efficiently than previous designs. Knowledge of actuation techniques gained from previous experiments will be applied to reduce complexity and maintain an efficient method of locomotion. A framework is in development to allow multiple configurations of the robot to lower production costs over time and increase flexibility of design during testing. The robust internal skeleton
will be modifiable to serve as a platform for future designs. Intelligent maneuvering will also be tested with the new prototype to develop efficient algorithm
s and control models for both simple and complex environments.
Humanoid robot
A humanoid robot or an anthropomorphic robot is a robot with its overall appearance, based on that of the human body, allowing interaction with made-for-human tools or environments. In general humanoid robots have a torso with a head, two arms and two legs, although some forms of humanoid robots...
designed to demonstrate the applications of passive dynamics
Passive dynamics
Passive dynamics is an approach to robotic movement control , based on utilising the momentum of swinging limbs for greater efficiency. This method is based on using the morphology of a mechanical system as a basis for necessary controls...
technologies.
SIGMO stands for Synthetic, IntelliGent, MObility, and was developed by a team of high school students to demonstrate the capabilities of passive-dynamic actuation techniques.
The technology used to enable SIGMO to walk is being applied to advanced prosthetic devices. Current prosthetic devices are nearing the limitations of the available technologies and require advancements such as customized motion, lower cost, and the development of light-weight materials.
Existing humanoid robot systems such as ASIMO
ASIMO
is a humanoid robot created by Honda. Introduced in 2000, ASIMO, which is an acronym for "Advanced Step in Innovative MObility", was created to be a helper to people. With aspirations of helping people who lack full mobility, ASIMO is used to encourage young people to study science and mathematics...
and QRIO
QRIO
QRIO was to be a bipedal humanoid entertainment robot developed and marketed by Sony to follow up on the success of its AIBO toy. QRIO stood approximately 0.6 m tall and weighed 7.3 kg...
use many motors to achieve locomotion
Motion planning
Motion planning is a term used in robotics for the process of detailing a task into discrete motions....
. These motors reduce efficiency and add unnecessary weight and cost to the robot. SIGMO attempts to alleviate these symptoms by providing a system which uses no motors for locomotion, instead employing passive-dynamic technology.
Passive-dynamic systems cite low power consumption, high durability, and low cost. The design is based on the skeletal structure of the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
, consisting of two legs with hip, knee, and ankle joints, each representing 1 degree of freedom
Degrees of freedom (engineering)
In mechanics, degrees of freedom are the set of independent displacements and/or rotations that specify completely the displaced or deformed position and orientation of the body or system...
(DOF). Movement is accomplished with the aid of gravity (walking down a slope) or by minimal actuation to enable the machine to walk on level ground. SIGMO was developed using proven methods of gravity-driven passive dynamic bipeds. Small actuators were added to the legs to provide walking capability on level ground.
This method of locomotion is very energy efficient because it uses no motors for walking. The omission of motors also cites a drastic weight reduction, further enhancing the locomotive efficiency. This also frees up room inside the torso for the circuitry that controls SIGMO's movements, unlike other robots that require a "backpack" like attachment.
SIGMO has an upper torso which mimics the movements of actual humans. The arms are motorized with small servo motors which enable SIGMO to manipulate objects within its grasp. The main chassis is fabricated of aluminum sheet metal, which has a high strength and light weight. The knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
sockets are fabricated out of steel and aluminum. While the steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
weighs more than the aluminum, this helps to transfer the weight load from the torso (contains heavy servo
Servomechanism
thumb|right|200px|Industrial servomotorThe grey/green cylinder is the [[Brush |brush-type]] [[DC motor]]. The black section at the bottom contains the [[Epicyclic gearing|planetary]] [[Reduction drive|reduction gear]], and the black object on top of the motor is the optical [[rotary encoder]] for...
components) to the legs and feet which rest on the ground.
An updated model of SIGMO, currently in the research and development stage, will incorporate more precise control over limb movement and directional stability. To add more functionality SIGMO will have more motors, but use each more efficiently than previous designs. Knowledge of actuation techniques gained from previous experiments will be applied to reduce complexity and maintain an efficient method of locomotion. A framework is in development to allow multiple configurations of the robot to lower production costs over time and increase flexibility of design during testing. The robust internal skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
will be modifiable to serve as a platform for future designs. Intelligent maneuvering will also be tested with the new prototype to develop efficient algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
s and control models for both simple and complex environments.