Humans know intuitively or from experience that if we put weights on our wrists or elbows, it becomes more difficult to move our arms. If we apply the same force we used without any weights, our arm will move more slowly.
It’s no surprise, then, that we see the same result in robots: as joints get heavier, the arm moves more slowly when the same force (or torque) is applied. Conversely, removing weight from the wrist or elbow actuator using a lighter weight transmission/gear drive results in higher speeds for the same applied torque.
What does a 10-15% increase in robot speed imply for robot owners?
The U.S. Robotics Industries Association (RIA) has made available to the public a robot ROI calculator that might give some insights. One of the default assumptions made by the calculator for a dual-robot system are:
- $250,000 total system cost
- Robots used 2 shifts/day, 5 days/week, 50 weeks/year
- $45,000 labor costs per operator
- 2 operators per shift removed
- 10% labor retained to operate system
- 27% expected productivity gain
Based on these assumptions, the RIA calculator estimates that for the reference system the owner will see productivity savings of $760 thousand. Accounting for an increase in productivity proportional to our speed increase (1.15 x 27%) boosts the expected productivity savings to around $870 thousand – an amount covering over 40% of the expected system cost!
Torque Density Impacts Robot Speed
We have considered how torque density – through its effect of decreasing or increasing actuator weight – can have a dramatic effect on the speed of a robot arm. Increased robot speed translates directly into significant productivity gains for robot end users.
Motus Labs M-DRIVE transmissions are a critical component for robot actuators. The M-DRIVE unique cam-follower design greatly increases contact between output and input surfaces, thus increasing by two-fold or more the amount of torque that can be delivered per unit weight.
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If you would like to see this kind of analysis done for your application, please contact us at firstname.lastname@example.org.