In a recent interview, Lisa Eitel of The Robot Report chatted with Mike Hilton, CEO of startup Genesis Robotics. This spinoff of Genesis Advanced Technology focuses on R&D in robotics, oil and gas, medical, human performance, and clean-energy industries. The company recently announced an actuator that’s particularly suitable for powering the joints in SCARA robot arms and other kinematic setups.
Called the LiveDrive, the actuator delivers three times more torque than conventional direct-drive motors. Innovations include amplified magnetics (with a design that doubles the effective force of already-strong neodymium permanent magnets), a structure to resist internal collapse from the tremendous magnetic forces, and good thermodynamic design for heat dissipation.
Eitel • Robot Report: Genesis Robotics has a direct-drive offering called LiveDrive, and we’d like to know more about whether this constitutes a torque motor.
Hilton • Genesis Robotics: Genesis Robotics is a R&D company, so we don’t actually commercialize components. Instead we do contract R&D and assume R&D projects and then move developments off to commercialization. We began our R&D on the LiveDrive with the intent of building a better actuator, as we saw tremendous inefficiencies in robotics and industrial automation. So we worked through gear designs for it, but realized the real limiting factor was motors: Engineers often can’t get enough torque out of motors, so must add complex gear systems to their assemblies. That led us to investigate ways to build better motors.
After making some discoveries on this front, we came to build a specialized brushless dc motor — but with our IP to impart very high torque. We realized our motor could (for some applications) actually eliminate the gearbox altogether. So that became our primary focus — to eliminate the gearbox. After all, in most industrial-automation scenarios, engineers would prefer to use direct-drive motors — as such drives avoid the issues of backlash, boost output-motion precision, and allow for backdriving.
For applications where even the LiveDrive can’t produce sufficient torque, we wanted to allow for use of the lowest-ratio gearboxes possible — to get the benefits of low or no backlash and full backdrivability.
Eitel • Robot Report: Tell us more about your motor’s high pole count and the patents you hold on variations that take the form of radial-flux and linear-motor arrangements as well as axial-flux (pancake or Lorenz-force) motors.
Hilton • Genesis Robotics: Well, we amplify the available magnetic force with magnet geometry and orientation to nearly double the flux that’s available out of the magnets. Consider our reference design — a 25-cm axial-flux motor we’ve built for demonstrating to the industry what’s possible with our technology. The 25-cm design delivers nearly 2,000 lb or 1,000 kg of force between the rotor and the stator — quite powerful. It has a structure that includes a solid stator and a solid rotor. That’s in contrast with motors that use laminates to manage eddy currents in the stator.
More specifically, the LiveDrive stator structure uses a solid piece of material (of high-carbon steel or cast iron) with numerous poles that are very short — so these stator poles can actually behave as laminates (to minimize eddy currents). But the solid material sustains the magnets’ effective force. Actually, their shortness also allows for less distance between the copper and the back iron for more efficient heat extraction — so the motor can also be run more aggressively.
Eitel • Robot Report: Getting back to robotics applications: You made the actuators to be low cost and gracefully fit into existing robotic and industrial automation designs.
Hilton • Genesis Robotics: That’s why we made the motor as simple as possible — and avoided exotic controls. For our own testing and prototype builds we use drives and controllers from Elmo Motion Control, though one can use any number of motion controllers and drivers with the LiveDrive. Our motor presents to motion controls as a brushless dc motor, but one can also run it as a stepper motor.
To promote commercialization of our design, we’ve built reference designs and SCARA demonstration robots. For the latter, we’ve simulated 300 picks per minute and shown how our actuator’s high toque-to-inertia ratio allows for quick acceleration that’s typical of SCARA applications. We’ve also just completed a delta (spider) robot reference design incorporating LiveDrive — also a gearless setup. This is all part of an outreach effort to find a large global partner to help commercialize the LiveDrive — whether in the form of an acquisition, investment, licensing arrangement, or joint venture.
Eitel • Robot Report: Some literature compares the LiveDrive to setups incorporating strain-wave gearing. Why is that? Also tell me about the gears one might pair with a LiveDrive if more torque were needed.
Hilton • Genesis Robotics: That’s been a hurdle for us, as comparing our gearless LiveDrive setups to designs with gearboxes and strain-wave or cycloidal actuators are apples-to-oranges comparisons. So we underscore torque density and torque-to-weight values — and our motors have torque-to-weight ratios that are similar to those of today’s geared systems.
But for circumstances where the torque requirement is huge, the LiveDrive pairs nicely with gearing. In fact, our team has a background in gear systems, and we’re currently building our own low-ratio backdrivable gearboxes with zero backlash for pairing with the LiveDrive.
In this conversation, we’re focusing on robotics and industrial automation. But just consider automated valve systems in undersea oil and gas installations, or oil refineries and water-treatment plants. These valve systems require very high-torque actuators for closing, as they must cut through high-pressure screens — even to 20,000 Nm. Even here our high-torque motors can dramatically reduce the gearbox ratios needed.
Another potential application is in the automotive industry as cars go to semi-autonomous and autonomous control. Such designs need actuators in the steering column. Today, most actuators in steering columns are really just designed for power assist — not control. LiveDrive can operate here and in setups for drive by wire … or setups needing a tunable driving experience for haptic feedback [where one gets a realtime feel for the road or terrain] changeable on the fly. In fact, LiveDrive excels here because it delivers the high torque needed for the actual steering control plus works as a mirrored actuator to provide haptic feedback.
Eitel • Robot Report: You use common “off the shelf” neodymium permanent magnets in your motor. How do you get more force out of them?
Hilton • Genesis Robotics: We give the magnets special geometry and orient them in a special way in the rotor; the rotor mechanism I described earlier also helps amplify those magnetic forces. Reconsider the thinness of the LiveDrive — especially for axial-flux designs having 2-cm thickness. Such compactness is useful in exoskeletons and walking robots.
The gearless nature of the LiveDrive also helps address the impact forces of walking. Consider how when a foot or a leg makes contact with the ground, there’s a jarring force that travels up the leg. Many walking robots use pneumatic or hydraulic actuators because gearboxes of traditional motor-driven systems can’t sustain such impact. In contrast, direct-drive motors easily withstand these forces.
Eitel • Robot Report: How does the form factor affect the morphology of robots?
Hilton • Genesis Robotics: Most multi-axis robots today have 90° joints — so a collaborative robot is usually just a series of 90° linkages. The challenges here are how torque must be on the rotary axis at that 90° point — and (from a safety perspective) how these joints act as a bunch of pinch points as linkages cross over each other. The latter means arms and hands can get trapped when the robot moves.
In contrast, our actuator has a thin form factor to actually rotate the axis in the joint to vertical. Then wedges between each actuator can effectively create a series of rotating inclined planes to do two things. First, they change the arm movement while eliminating pinch points. Second, they impart mechanical advantage. To illustrate, if one rotates two ramps against each other, not only does that change the ramp angle, but using two ramps creates a mechanical advantage that almost functions as an external gearbox. Again, only very thin actuators such as LiveDrive allow this.
Eitel • Robot Report: One of the main design objectives with collaborative robots is safety, so this mode of actuation is helpful.
Hilton • Genesis Robotics: Yes, that’s why we get so excited about this application. We’ve solved a fundamental safety problem in cobot design — and plants can let cobots that are inherently safer run faster for higher throughput. In fact, this relates to another design — what we call assist robotics. Here, the robot doesn’t follow preprogrammed motion paths, but rather follows the commands of a human on the fly. Because LiveDrive is so responsive (thanks to the low inertia of the gearless setup) it excels here.
Eitel • Robot Report: Think of the fictional exoskeleton Power Loader that Ellen Ripley wears in the movie Alien.
Hilton • Genesis Robotics: It’s the same basic concept. Instead of a having preprogrammed motion points, handheld controls at the end of the robot arm let the operator take full control of the arm and use it as an augmented-strength device. So now in a highly customized manufacturing environments instead of worrying about slow preprogrammed collaborative motion paths, an operator I can simply grab the robot arm ends and use the robot to lift heavy items — for a zero-gravity and zero-inertia floor mounted exoskeleton arm to do heavy lifting. Then they can release the arm and go do something else — getting the assistive-robot benefit without the complexity of motion-control programming.
Eitel • Robot Report: What are some robotic applications outside the factory?
Hilton • Genesis Robotics: This is where we get most excited. Think of healthcare workers injured every year from lifting patients out of beds or tubs. Here, temporary help from assistive robot arms could boost worker and patient safety. Add compactness and zero-pinch-point design, and now we have suitable assistive robots to help elderly people live independently in their homes for longer. My own mother is independent but struggles to lift heavy pots off the stove. If she had an assistant robot in her kitchen that could lift heavy pots or put bags of flour back into the cupboard, and things of that nature — well, that doesn’t have to be a preprogrammed robot. It could almost work like slipping on a pair of oven mitts; she could lift and move things and then get on with her regular tasks. That would have a huge impact on both quality of life and independent living for our growing elderly population.
Eitel • Robot Report: We’ve covered the designs of patient-lift systems in Design World magazine, and they seem very helpful but are bulky.
Hilton • Genesis Robotics: Yes, and these gantry systems are inefficient, costly, and not always productive. To be honest, they also make patients feel less human. If one needs a big gantry that to get hoisted out of bed to get to the bathroom, that degrades patient experience. So here, less intrusive lifts that just provide augmented strength are better.
Eitel • Robot Report: We see a lot of innovation, and it’s always gratifying when design improvements are of a mechanical nature.
Hilton • Genesis Robotics: Yes. I actually have a software background, and a lot of students go into software these days … and in fact, software along with electronics has advanced tremendously over the past several years. There’s been less innovation in mechanical systems, and we don’t emphasize the mechanical innovation as much as need. Our aim for the robotics industry and other industries was to deliver a true piece of mechanical or electromechanical innovation.
Eitel • Robot Report: Just out of curiosity, is there a reason you’re using Elmo Motion Control products for your reference designs?
Hilton • Genesis Robotics: We looked for a versatile motion controller, and not one with limited peak current or limited peak voltage. There are a lot of motion controllers designed for sub-70-V operation, for example — and they work extremely well for set designs. But because we aren’t building specific products — we’re really building a portfolio of reference designs — we wanted a motion controller and driver technology that would let us try high-voltage versions with low current as well as low-voltage versions with high current — even while staying with the exact same motion controller for all the designs.
Eitel • Robot Report: We see increasing demand for this kind of component flexibility, especially for configurable sensors and encoders that allow for programming to an array of designs and even mounting customization — even with one given piece of actual hardware.
Hilton • Genesis Robotics: These offerings certainly let engineers initialize designs without having to become experts or build their own motion controls. It was critical to us that our controls have plug-and-play functionality, because that in turn lets designers put our LiveDrive into existing robot joints having controls already. Now, it’s unlikely someone would do that, because once they get a LiveDrive they’ll likely see its unique characteristics and say, “Why would I limit this by simply putting it into a normal 90° angle robotic joint or Cartesian robot? I should leverage its other capabilities.” So the Elmo controls let us do (for example) 12-turn versions using lower voltage and 24-turn versions that use higher voltage — to manipulate the IP to meet the needs of specific industries.
Filed Under: The Robot Report, Motors (direct-drive) + frameless motors, Motors • stepper