Robot Mechanisms
Photos of various robots removed for copyright reasons.Sony Aibo™, Honda ASIMO, robotic hands, industrial manipulator arm.
Courtesy of JPL.
Sample Return Rovers with articulated suspension mechanisms
Images courtesy of JPL.
3/16 Axle Shaft
3/16 Axle Shaft
5/32 Axle Shaft
5/32 Axle Shaft
5/32 EZ Adjustabl
eAxle
Open-Loop Kinematic Chains
Serial Linkage
Photos of various robots removed for copyright reasons.Sony Aibo™, Honda ASIMO, robotic hands, industrial manipulator arm.
Two-Branches of Open-Kinematic Chains
Photo removed for copyright reasons: ASIMO robot descending stairs.
See http://world.honda.com/ASIMO/.
Figure by MIT OCW.
(a) Prismatic joint (b) Revolute joint
Primitives of Robot MechanismsTwo Types of Single-Axis Joints
Three Prismatic Joints
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
y
x
z2
z1
z0
z
3
21
ι
Figures by MIT OCW.
Photo removed for copyright reasons.GMF Robotics M-100 arm.
Figures by MIT OCW.
Photo removed for copyright reasons.
Figures by MIT OCW.
Photo removed for copyright reasons.
z0z1
d3
z2
1
2
1
12
3
0
12
3
0
12
3
0
12
3
0
θ
Figure by MIT OCW.
Photo removed for copyright reasons.
Figure by MIT OCW.
Pros and Cons of Open-Loop Kinematic Chains
Serial Linkage
Pros• Large work space• Dexterity• (Lower inertia)• (Lower cost)
Cons• Low stiffness• Low accuracy• Rapid increase of inertial
load along the linkage• Small load bearing capacity
End Effecter
Joint 1
Link 4
Passive joints
Link 3
Point AJoint 5
Link 2
Joint 4Link 1
Joint 3 Link 0
Joint 2
Closed Loop
Active Joints
Schematic removed for copyright reasons.
Parallel LinkagePosition and Orientation
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Figure by MIT OCW.
Passive
Active
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
P
S
S
S
S
SS
S
S
P
S
S
S(Spherical Joint)
(Spherical Joint)
S
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Moving Platform
Fixed Base
(Prismatic Joint)
Figure by MIT OCW.
Photo removed for copyright reasons.
Open-LoopClosed-Loop
Figure by MIT OCW.