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Deformed forms of elementary joint |
Rigidity
For elementary beam there are two groups of DOF with different rigidities:
'rigid' (DOF:1,2,3,4) and 'compliant'(DOF:5,6).
Deformability
Maximal deformation (rotation angle) =
function1(properties of the material)
function2(geomentry of the joint)
function3(loading scheme)
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Substitution of elastic joint by an elementary beam |
The width of equivalent beam is: a*/a=function(a/R)>0
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3-beam revolute joint with stable center |
3-beams revolute structure is one detail made by electro-erroision.
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Radial-beam revolute joint |
'Elastic bearing' has maximal rotation angle 10 degrees.
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Cardan revolute joint (2DOF) |
Cardan joint included thin-walled beams is made from one detail.
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Cardan revolute joint (2DOF) |
Cardan joint included 2 'elastic bearing' is made from one detail.
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Revolute joint with compensation of parazit movement |
To compensate parasit transmision of the center of rotation 3-beam structure
with coincided axis is used as revolute joint.
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Actuator for linear translation with 3 piezos |
The inch-worm (diameter 22 mm, length 100 mm) gives maximal force 25
kg and resolusion defined by amplifier.
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3DOF moving table and 3DOF revolving ball |
Examples of wave piezo-movers (piezo-propulseurs)
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3DOF moving table (actuator) with 5 piezos |
Parameters of microrobot with elastic frame.
Structure 3DOF
Material steel
Sizes 66*66*26 mm
Weight 240 g
Maximal displasement 0.9 mm 0.9 mm 1.5degree
Deformability index 0.027
Relative stiffness : 1 - 4354 - 2960
Displacement : 0.9 mm 1.05 mm 1.54 mm
Corresponding force : 14N 10N 10N
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6DOF microrobot |
Assembling of three inch-worms with 3 DOF gives the parrallel structure with 6DOF.
Parameters of microrobot with 6 DOF .
Structure 6DOF (3 inch-worms+3 flexible joints)
Material steel
Sizes 120*66*46 mm
Weight 800 g
Maximal displasement 15 mm 15 mm 8 mm 15degrees 3degrees 15degrees
Deformability index 0.12
Limit force 500 N
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Piezomotor with 1 piezo (2 details) |