Lesson 8 : WHY THE ARCHIMEDES DRIVE IS SO UNIQUE (part 1)
Summary of the lesson:
How Traction Changes the Game for Precision, Noise, and Speed
In the previous session, we introduced the groundbreaking Archimedes Drive—a hybrid mechanism that combines the compact power of compound drives with the smooth performance of traction rollers. Now, in this eighth class of the Archimedes Academy by IMSystems, we start comparing its unique properties to traditional gear systems.
This isn’t just a numbers game. With traction-based drives, performance isn’t always measured on the same scale as traditional gears. Some traits—like noise, backlash, and thermal limits—require a broader perspective. Let’s explore what makes the Archimedes Drive so special in three areas: precision, noise, and speed.
> Part 1: Precision: Why the Archimedes Drive Is Exceptionally Accurat
When we talk about precision in drive systems, lost motion is the key metric—how much movement is “wasted” between input and output. Most of this is caused by backlash, especially in gear-based systems.
The Archimedes Drive eliminates this entirely:
No gear teeth = no backlash
Uses smooth rolling traction elements, ensuring immediate and accurate response
Higher stiffness than typical solutions, maintaining stable motion even under load
The result? Unmatched precision in any comparable class of drives. This isn’t just theoretical—visual comparisons show that gear drives produce wobble and audible clinks during movement. The Archimedes Drive, on the other hand, rolls quietly and smoothly.
> Part 2: Noise: A Key Factor in Emerging Applications
Noise might not be the first spec you look at in a drive system—but it matters. In sectors like prosthetics, wearable robotics, and collaborative robots (cobots), quiet operation is essential for user comfort and safety.
Understanding Decibels:
Decibel (dB) is a logarithmic scale
Every +3 dB = double the loudness
A +15 dB difference? That’s 32 times louder
Real-World Test:
In a prosthetics application, IMSystems compared two drives:
| Drive Type | Max Noise Level | Equivalent Sound |
|---|---|---|
| Archimedes Drive | 50 dB | Moderate rainfall |
| Strain Wave Gear | 65 dB | Loud conversation / vacuum cleaner |
On top of that, strain wave gears generate higher-pitched tones, which are more irritating. The Archimedes Drive emits a low, consistent hum—calm and unobtrusive.
This quiet profile makes the drive ideal for human-centric robotics and machines operating in shared spaces.
> Part 3: Speed: Lubrication, Temperature, and Untapped Potential
One often-overlooked aspect of drive design is maximum speed, which is heavily influenced by:
Heat generation
Lubricant performance
Material fatigue
Why Temperature Matters:
Lubricants start breaking down around 70°C (160°F)
Above this, even advanced traction fluids can burn, leading to failure
In real-world testing, IMSystems ran their Delta 15 Archimedes Drive up to the limits of their available test motors. At full RPM, the drive only reached 40°C, well below the danger zone. This means there’s still headroom—a faster version is entirely possible.
Competitive Insight:
Strain wave gears may reach 75,000 RPM (as seen in NASA’s rocket program)
However, they suffered metal fatigue—not lubricant failure
Archimedes Drives could likely exceed standard planetary drives in speed without overheating
It’s a promising sign for future high-speed applications, where reliability and temperature control are critical.
> Part 4: What’s Next?
Let’s walk through how this drive architecture improves upon both traction and compound drives:
In the next class, we’ll explore how the Archimedes Drive performs in terms of:
Torque vs. lifespan
Weight trade-offs
Overall drive system efficiency in real-world loads
We’ll also begin constructing a comparative framework to evaluate the Archimedes Drive against all major alternatives, both numerically and contextually.
