3D model of byu_cmr
The models were repaired and checked for printability.
The following three designs are compliant linear-motion large-displacement mechanisms.
...Show more Linear-motion mechanisms are usually constructed using a support structure that guides a shuttle in linear movement. This movement is wanted, and needed in many mechanisms and is generally created using prismatic joints. Prismatic joints are sliding joints that can restrict linear-motion devices to one degree of freedom; but these joints also present challenges including friction, wear, and difficulty in lubrication. Because of these inherent issues, engineers have developed alternatives to prismatic joints in some linear-motion large-displacement mechanisms.
Printer brand:
Prusa
Printer:
i3 MK3
Rafts:
No
Supports:
No
Resolution:
0.2
Infill:
20%
Filament brand:
Prusa
Filament color:
Black
Filament material:
PLA
Notes:
N/A
The three devices published here have been developed to create linear-motion in a generally large-displacement comparative to their footprint. Compliant mechanisms improve traditional linear-motion mechanisms by offering improved functionality, and decreased wear, friction, and cost of production.
The folded beam suspension is a popular design because of its simplicity and predictability. The basis of the device is a parallel-guiding mechanism, a linkage where the legs opposite each other are the same length. To form a folded-beam suspension, a number of parallel-guiding mechanisms are combined in series and parallels as shown in the image below. The Folded beam suspension shows high torsional off-axis stiffness but low transverse stiffness.
This combination of parallel-guiding devices constrains the shuttle to approximate straight-line motion.
The X-Bob, as illustrated below, is another example of a planar, large-displacement device consisting of a center shuttle on a compliant suspension. An X-Bob is created by combining four Robert’s mechanisms in a reflective way so as to restrain the shuttle’s movement to one-degree-of-freedom. The X-Bob configuration has proven to be effective for micro-systems; a micro machined version is also shown below. The X-Bob shows low torsional off-axis stiffness but high transverse stiffness.
The CT joint was proposed colleagues at the University of Michigan as an improvement of a leaf spring joint, increasing the range of motion and improving the transverse stiffness. The mechanism is composed of compliant members constrained by the parallel arrangement of two identical plates. The joint can be modeled as a parallel four-bar mechanism and allows only pure translational motion. The CT joint is illustrated in the figure below; the dashed lines show the deflected state of the mechanism with the left plate being considered ground. Of these designs, the CT joint with thin flexures is the one with the longest travel but also has low off-axis stiffness in both transitional and torsional cases.
https://www.instagram.com/byucmr/
