Matt Carlson is the Vice President of Business Development at WiBotic Inc, a company that provides reliable wireless power solutions to charge aerial, mobile and aquatic robot systems.
Why are wireless charging solutions so important to the future of robotics?
Robots need the ability to autonomously charge for most applications. It simply isn’t cost effective to hire a staff of workers to manage battery charging or battery swapping. However, most autonomous charging today is done using docking stations that require physical mating of electrical contacts.
This requires very precise navigation into the charging dock which is difficult to program and is not always reliable. Failing to properly align the contacts can mean a missed charging cycle and robot downtime. Contact based stations will also wear out over time, or the contacts may become dirty or corroded – again resulting in inconsistent charging. Finally, robot OEMs use a wide range of electrical contact types, making it nearly impossible to have a single charging station that can charge any robot.
Wireless systems have none of these issues. WiBotic systems offer several centimeters of alignment tolerance, so it’s not necessary to have an extremely precise navigation stack. Because the antennas can be fully sealed to the elements and don’t make physical contact with one another, wireless systems are also highly reliable and can handle an unlimited number of charge cycles. Finally, as robot use grows, most companies will employ more than one type of robot. Rather than having a wall or room dedicated to many different charging docks, a single wireless charging station can recharge any robot that is retrofitted with a simple receiver antenna, saving money and space.
Wibotic’s initial focus was on powering medical devices, what was the reason to pivot towards robots, drones, and Autonomous Underwater Vehicles (AUVs)?
WiBotic’s two founders, Ben Waters and Josh Smith, did indeed focus on wireless power for medical devices during much of their research at the University of Washington. Their technology increased the range and reliability of wireless power, which were both critical for the medical market. However, when Ben received his PhD and founded WiBotic, the company immediately focused on robotics as its primary market. This was based on demand from the robotics industry.
Robot and drone OEMs and end-users recognized the benefits of WiBotic technology in terms of power level and range when compared with other wireless systems. They were also beginning to struggle with the deployment of contact-based chargers for large fleets of robots and were looking for more reliable solutions.
For the drone market, contact based charging is a non-starter in most cases since drones operate outdoors (mostly) where water becomes an issue with any physical electrical contacts. And, of course, underwater applications also benefit from the fully sealed nature of wireless power.
What are the power transfer technologies being used?
WiBotic uses elements of both electrical induction and magnetic resonance for power transfer. These two methods are relatively well proven at a wide range of power levels. What sets WiBotic apart is our ability to manage the connection (technically the impedance) between antennas in real time. We call this Adaptive Impedance Matching.
One of the biggest challenges with wireless power, especially for robotics, is that the electrical environment is constantly changing. If the robot docks in a slightly different position, if it’s internal electronics turn on and off during charging, and as the battery itself charges up, the impedance between the transmit and receive sides of the system changes. This can dramatically affect efficiency and range. Our AIM technology constantly monitors changes in impedance so we can maintain efficiency and power levels, even as all of those other elements in the system are changing.
Could you discuss the efficiency of the units, such as how much power is lost during power transmission?
For WiBotic’s 250-300 Watt systems we have an end-to-end efficiency level of between 70% and 80%. This represents the full system efficiency from the input to our transmitter all the way to the output to the battery. The actual antenna-to-antenna portion of that equation is about 95% efficient, but there are losses in the transmitter circuitry and also in the battery charging circuitry. That last part is important to note since even a very well designed “plug in” battery charger is typically only around 90-95% efficient.
Using a wireless system like ours therefore results in about 10% less efficiency than the status quo of contact based charging.
What are the distance constraints with how close the robotic unit needs to be near the power source?
This depends on the size of the antennas used. Our standard transmitter antenna is 20cm in diameter and the receiver antenna is 10cm in diameter. With those antenna sizes, we allow for 5cm of face-to-face air gap between antennas and up to 5cm of side-to-side offset from a concentric position (so 10 total cm of side to side range).
Unlike other wireless power systems, and due to our AIM technology, we deliver full power to the battery at any point within that range. Ranges can be increased by increasing the diameter of the antennas. Because our antennas are relatively simple PCBAs (which are also very thin and lightweight) we’re able to modify and produce custom versions of them relatively inexpensively for customers who prefer a different size.
Are multiple robots able to use the same charging station?
Absolutely! Only one robot can charge at a wireless charging station at a time, but entire fleets of diverse robots can all share the same charging station (or set of charging stations). This is possible because, unlike most contact based chargers, the transmitter station is not sending out a specific voltage and current level. Instead it is sending wireless power at a designated frequency. Our Onboard Charger, installed on the robot, then converts that wireless energy into the specific voltage and current needed by that vehicle.
We support batteries from 0-60V and current levels from 0-30A with our current product line.
Could you discuss some of the power optimization software that is currently offered?
Our wireless power hardware ships with a web-based GUI that allows customers to configure the system for a wide range of parameters. For instance, users can choose to charge to the typical “100% charge” level for a particular battery. But if they do this every time, they may not get as many charge cycles out of the battery. So if 100% charge isn’t needed, the maximum voltage level can be adjusted downward to extend battery lifespan.
Similarly, if the battery is always charged with the maximum current (amps) it’s lifespan will be reduced. Using our GUI and APIs, users can actually proactively schedule charging so they charge as fast as possible when the robot needs to get back into service, or more slowly when they know they have more time (overnight for example). These configurability and battery optimization features are available with our standard GUI and by using our APIs.
We also offer a new software product that allows users to map and then aggregate charging information from across and entire fleet of WiBotic transmitters and receivers. This allows robots to know when and where charging stations are available to help them maximize uptime. It also allows detailed reporting on the charging performance of batteries over time, helping identify battery issues and optimizing power delivery across the entire fleet. These features become particularly useful if the end-user is able to implement opportunity charging schemes, where robots are charging many times per day for shorter periods of time, rather than leaving service for several hours at a time for charging.
Offering wireless power to Autonomous Underwater Vehicles (AUVs) seems like it would be extremely challenging, could you discuss this?
Yes, there are definitely many challenges with underwater applications. From a power transfer perspective a couple centimeters of saltwater will attenuate power transfer by about 50%, so it will take longer to charge the same sized batteries underwater than it would in air.
The antenna range is also more restricted for that same reason, which means the UAV must have very good navigation to successfully find and dock at the charging station. This is usually aided by some sort of physical alignment device that directs the UAV into the charging station and helps to align the antennas.
The benefit of wireless power underwater however, is that the antennas can be fully potted or sealed. WiBotic systems are currently operating at the MBARI MARS research station off the coast of Monterey, CA at a depth of nearly 3000ft. In that case, the transmitter and receiver electronics are housed in 1atm pressure bottles, but electronics can also be designed for oil filled enclosures to withstand even greater depth.
WiBotic continues to work with the DoD, various universities, non-profits and commercial partners to expand the use of our systems underwater, but it is definitely a challenging environment!
WiBotic has recently announced equipment authorization from the Federal Communications Commission (FCC) for its high power transmitters and receivers. These products are the first systems – operating at up to 300 Watts – to receive FCC approval for use in mobile robots, drones, and other industrial devices. Why is this important and what does this mean for the future of robotics and drones?
As the robotics industry continues to grow, OEMs and robot end-users are facing an increasing level of regulation and stricter safety requirements. It’s important for our customers to know that WiBotic products, as a component within their larger robotic solutions, will meet those regulatory requirements. In short, it allows robot and drone manufacturers to focus on additional features and functionality for end-users rather that dealing with certification questions. This will let them deploy larger fleets faster than would otherwise be possible.
Is there anything else that you would like to share about Wibotic?
Because most people think of the physical antennas and circuit boards when they think of wireless power, the immense amount of work we have put into our software and firmware is often overlooked. In many ways, it is the advanced firmware we’ve developed that allows our hardware to perform at such useful ranges and power levels.
We’re also continuing to add to our fleet power optimization software capabilities to allow for even greater analysis and benchmarking of the use of power and durability of batteries across a wide range of robotic applications.
Thank you for the great interview, readers who wish to learn more should visit at WiBotic Inc, or read about how WiBotic Received an Industry-First FCC Approval for High Power Wireless Charging of Robots & drones.