How a Toothless Gearbox May be a Breakthrough for Robot Accuracy

The Archimedes drive uses frictional rollers instead of toothed gears for zero backlash power transmission.

Typical industrial robots have accuracies of ±0.1 mm, with some models capable of even higher accuracy. Gear backlash can reduce this accuracy in robots and other precision servomotors, such as in CNC machinery. However, machining gears with minimal backlash is costly. A new drive, developed by Dutch startup IMSystems, could provide a more cost-effective option for these applications. The new drive essentially replaces the gears in an epicyclic or planetary gear train with smooth frictional rollers.

IMSystems and its Archimedes Drive recently won first place in the Automate 2019 Launch Pad Pitch Competition, winning $10,000 in prize money. IMSystems was one of seven startups selected to pitch their product to a judging capital made up of executives from the robotics industry and the world of venture capital.

Thibaud Verschoor, co-founder of IMSystems, reflects: “Competition was hot. A lot of great inventions were presented during the competition.” Thibaud presented IMSystems’s Archimedes Drive. The innovative toothless gearbox may offer advantages when it comes to precision, maintenance and cost – key improvements targeted by the robotics industry. To come to their decision, the Automate judges used criteria which included the “disruptiveness” of the innovation, market fit, business model and the professionalism of the team.

The $10,000 prize money will be invested in further optimizing life cycle testing of the Archimedes Drive and promoting the Archimedes Drive Development Kit.

Last week, IMSystems revealed its plans to start manufacturing development kits to be delivered in Q4 2019. This announcement came in response to pent-up demand for the innovative new gear.

How the Archimedes Drive Works

Image courtesy of IMSystems

Image courtesy of IMSystems

Unlike conventional gears, the Archimedes Drive does not rely on cogs with teeth. Instead frictional contact transforms speed into torque. Flexrollers – made from smooth, hollow steel cylinders – compress and transmit rotational power in the centre to a rotating annulus – the output.

When two wheels are in contact, power will be transmitted between them as long as the tangential force exerted by the driving wheel does not exceed the maximum frictional resistance between them. If it does, the wheels will slip. The Archimedes drive prevents slippage by compressing the system of rollers in a cylinder. The company release did not mention whether wear on the mating surfaces will be a significant factor reducing this force over the life of the drive.

The company claims that the inventive design offers unparalleled accuracy due to the zero backlash operation, made possible by the use of rolling contact. When combined with the Archimedes Drive’s ability to reach single stage ratios of up to 10,000:1, it allows for very high levels of accuracy and control.

The device is also backdrivable and easier to stop, which could contribute to safety-related objectives in robot designs.

Based in the Netherland’s RoboValley, IMSystems is eager to work with companies in a range of industries to test out their innovative new gear. Collaborative robot and exoskeleton developers, as well as e-bike designers and car makers are just some of those interested to test out the Archimedes Drive in their machines. David Faconti, founder of PAL Robotics, comments: “I hope this will new design will be available to small projects too, instead of being licensed only to few big players.” Two of the world’s biggest industrial robotics manufacturers are currently working to incorporate the Archimedes Drive into their next generation robots. The initial production run of the Archimedes Drive will take place in parallel to these pilots, enabling IMSystems to accelerate the gear’s incorporation into a wide range of applications.

Archimedes Drive First Batch Now Shipping Drives in Pre-Order Stage

IMSystems is now accepting advance orders for a first batch of Archimedes Drives. Companies and research institutes interested to try the drive in their own product development can pre-order drives up until May 20th for delivery by Q4 2019. IMSystems engineers will seek feedback from these early adopters and decision makers. That data will be used to tune the Archimedes Drive’s design as production volumes increase. IMSystems founder and CEO, Jack Schorsch comments: “We want to help new product designers develop the next generation of products they dream of. Products that are smaller, lighter, quieter, safer and more precise. Archimedes Drive can help them do just that. Which is why we are really excited to be putting our gear into production now and demonstrate its benefit in a diverse range of applications.”

Manufacturability a Key Benefit of Design

In contrast to existing precision drives, which are complicated to make and suffer from long lead times, the Archimedes Drive is highly manufacturable. Its design employs ordinary bearing-like components, which enable a relatively simple manufacturing process. This may make the Archimedes Drive attractive for a wide-range of applications, especially advanced robots which require multiple actuators – typically six per industrial robotic arm or 32 per surgical robot, adding up to one third of hardware costs. The initial batch of Archimedes Drive will be manufactured by precision manufacturer Hankamp Gears, in Enschede, Netherlands.

The startup challenge victory comes as the engineering firm enters advanced discussions with venture capitalists from Europe and the United States who are drawn to the Archimedes Drive’s market potential. The startup has already raised over €1.6 million in seed funding which has allowed IMSystems to further develop the Archimedes Drive, complete a number of pilot installations and grow the team. With investment capital, the startup is preparing to expand its engineering team, accelerate the validation of its technology and manufacture the Archimedes Drive at scale.

More information can be found at the company website.