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In kinematics
Kinematics is a subfield of physics, developed in classical mechanics, that describes the Motion (physics), motion of points, Physical object, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause ...
, an Assur group is a kinematic chain
In mechanical engineering, a kinematic chain is an assembly of rigid bodies connected by joints to provide constrained (or desired) motion that is the mathematical model for a mechanical system. Reuleaux, F., 187''The Kinematics of Machinery, ...
with zero degree of mobility, which added or subtracted from a mechanism
Mechanism may refer to:
*Mechanism (engineering), rigid bodies connected by joints in order to accomplish a desired force and/or motion transmission
*Mechanism (biology), explaining how a feature is created
*Mechanism (philosophy), a theory that a ...
do not alter its original number of degrees of freedom
Degrees of freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a thermodynamic system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or ...
. They have been first described by the Russian engineer (1878–1920) in 1914.,
The simplest of all Assur groups (also known as dyads) have two links and three joints
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...
, of which two are potential joints. Using an underscore "_" to indicate a guide following or preceding a slider in a translating (prismatic) joint, all possible dyadic isomers will be: RRR, RR_T, RRT_, RT_R, T_R_T, T_RT_, _TRT_, R_T_T, R_T_T, RT_T_, R_TT_ and RT__T.
Higher order Assur groups are known such as simple and multiple triads, simple and multiple thertad, pentad hexad etc.
When an Assur group is connected to the same link, zero degree-of-freedom entities known as Baranov truss
Baranov (masculine) or Baranova (feminine) (russian: Баранов, Баранова) is a common Russian surname. It is derived from the sobriquet ''"баран"'' (argali, lamb). Notable people with the surname include:
*Alexander Andreyevich B ...
es are obtained.
MechDesigner from PSMotion, OSMEC from ESDU
ESDU (originally an acronym of "Engineering Sciences Data Unit" but now used on its own account) is an engineering advisory organisation based in the United Kingdom.
Profile
ESDU provides validated engineering analysis tools to engineers and te ...
and MeKin2D are software programs known to use Assur group/modular approach for the motion analysis of planar linkage mechanisms.
See also
*Kinematics
Kinematics is a subfield of physics, developed in classical mechanics, that describes the Motion (physics), motion of points, Physical object, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause ...
* Kinematic chain
In mechanical engineering, a kinematic chain is an assembly of rigid bodies connected by joints to provide constrained (or desired) motion that is the mathematical model for a mechanical system. Reuleaux, F., 187''The Kinematics of Machinery, ...
* Kinematic pair
In classical mechanics, a kinematic pair is a connection between two physical objects that imposes constraints on their relative movement (kinematics). German engineer Franz Reuleaux introduced the kinematic pair as a new approach to the study o ...
s
* Four-bar linkage
In the study of mechanisms, a four-bar linkage, also called a four-bar, is the simplest closed- chain movable linkage. It consists of four bodies, called ''bars'' or ''links'', connected in a loop by four joints. Generally, the joints are configu ...
References
{{reflist Linkages (mechanical)