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Castable Bulk Metallic Glass Strain Wave Gears: Towards Decreasing the Cost of High-Performance Robotics

View Article: PubMed Central - PubMed

ABSTRACT

The use of bulk metallic glasses (BMGs) as the flexspline in strain wave gears (SWGs), also known as harmonic drives, is presented. SWGs are unique, ultra-precision gearboxes that function through the elastic flexing of a thin-walled cup, called a flexspline. The current research demonstrates that BMGs can be cast at extremely low cost relative to machining and can be implemented into SWGs as an alternative to steel. This approach may significantly reduce the cost of SWGs, enabling lower-cost robotics. The attractive properties of BMGs, such as hardness, elastic limit and yield strength, may also be suitable for extreme environment applications in spacecraft.

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Related in: MedlinePlus

Testing the BMG flexspline in a robotics application.(a–c) Assembling the BMG flexspline into a SWG used for the joint of the robot. (d,e) JPL’s wall gripping robot moving to engage a wall using the BMG-containing SWG. (f) A side-by-side setup to fatigue flexsplines while measuring the input current. (g) Enlargement of the setup showing a BMG flexspline being fatigued. (h) A plot of current versus number of rotations of the wave generator for a steel flexspline, a BMG LM1b that was commercially cast, a BMG GHDT that was machined and one that was commercially cast. The red lines indicate locations where cracks were observed.
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f3: Testing the BMG flexspline in a robotics application.(a–c) Assembling the BMG flexspline into a SWG used for the joint of the robot. (d,e) JPL’s wall gripping robot moving to engage a wall using the BMG-containing SWG. (f) A side-by-side setup to fatigue flexsplines while measuring the input current. (g) Enlargement of the setup showing a BMG flexspline being fatigued. (h) A plot of current versus number of rotations of the wave generator for a steel flexspline, a BMG LM1b that was commercially cast, a BMG GHDT that was machined and one that was commercially cast. The red lines indicate locations where cracks were observed.

Mentions: To demonstrate the load-bearing operation of the BMG flexspline, the part shown in Fig. 2 was installed in NASA JPL’s microspine, wall-gripping robot, shown in Fig. 322. The robot grips by engaging hundreds of sharp metal microspines with imperfections in rough terrain. The 5 kg arm of the robot is positioned by one CSF-8 SWG, shown in Fig. 3. The hybrid steel/BMG SWG was loaded into the robot arm and then used to lift the arm approximately ten times. Figure 3(d,e) shows the BMG SWG rotating the robot arm to engage the rock wall. Video of the SWG operating the robot arm is shown in the Supplementary Material.


Castable Bulk Metallic Glass Strain Wave Gears: Towards Decreasing the Cost of High-Performance Robotics
Testing the BMG flexspline in a robotics application.(a–c) Assembling the BMG flexspline into a SWG used for the joint of the robot. (d,e) JPL’s wall gripping robot moving to engage a wall using the BMG-containing SWG. (f) A side-by-side setup to fatigue flexsplines while measuring the input current. (g) Enlargement of the setup showing a BMG flexspline being fatigued. (h) A plot of current versus number of rotations of the wave generator for a steel flexspline, a BMG LM1b that was commercially cast, a BMG GHDT that was machined and one that was commercially cast. The red lines indicate locations where cracks were observed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121900&req=5

f3: Testing the BMG flexspline in a robotics application.(a–c) Assembling the BMG flexspline into a SWG used for the joint of the robot. (d,e) JPL’s wall gripping robot moving to engage a wall using the BMG-containing SWG. (f) A side-by-side setup to fatigue flexsplines while measuring the input current. (g) Enlargement of the setup showing a BMG flexspline being fatigued. (h) A plot of current versus number of rotations of the wave generator for a steel flexspline, a BMG LM1b that was commercially cast, a BMG GHDT that was machined and one that was commercially cast. The red lines indicate locations where cracks were observed.
Mentions: To demonstrate the load-bearing operation of the BMG flexspline, the part shown in Fig. 2 was installed in NASA JPL’s microspine, wall-gripping robot, shown in Fig. 322. The robot grips by engaging hundreds of sharp metal microspines with imperfections in rough terrain. The 5 kg arm of the robot is positioned by one CSF-8 SWG, shown in Fig. 3. The hybrid steel/BMG SWG was loaded into the robot arm and then used to lift the arm approximately ten times. Figure 3(d,e) shows the BMG SWG rotating the robot arm to engage the rock wall. Video of the SWG operating the robot arm is shown in the Supplementary Material.

View Article: PubMed Central - PubMed

ABSTRACT

The use of bulk metallic glasses (BMGs) as the flexspline in strain wave gears (SWGs), also known as harmonic drives, is presented. SWGs are unique, ultra-precision gearboxes that function through the elastic flexing of a thin-walled cup, called a flexspline. The current research demonstrates that BMGs can be cast at extremely low cost relative to machining and can be implemented into SWGs as an alternative to steel. This approach may significantly reduce the cost of SWGs, enabling lower-cost robotics. The attractive properties of BMGs, such as hardness, elastic limit and yield strength, may also be suitable for extreme environment applications in spacecraft.

No MeSH data available.


Related in: MedlinePlus