Robohands from the TIME’s Cover. Bionic prostheses production by Esper Bionics — how it looks in photos
Esper Bionics is a company founded by Ukrainians. It has been developing advanced bionic prostheses. Last year, its robohand appeared on a TIME magazine cover. The editors recognized it as one of the 2022 TOP 200 Best Products. Now, the company continues to develop robotic hand functions and plans to manufacture bionic legs. AIN.Capital visited its production facility in Kyiv.
Esper Bionics is located in a 3-floor building in an industrial area of Kyiv. It moved here in August 2023 from a facility that was too small for mass production. We are welcomed by the Esper Bionics’ Chief of Strategy, Bohdan Diorditsa, and Chief of Marketing, Dmytro Hanush, who lead us to the ground floor. Here we see the prostheses shop. We are wondering where to begin our tour. The production is not linear.
OK, let’s start with the definition. What is a robotic hand? It consists of a stump socket and a prosthesis. The stump socket is fixed at a stump, the remaining part of a mangled arm. The myosensors within help get signals from the brain and transfer them to the prosthesis so that a person can move the hand. In other words, the socket serves as an intermediary between the artificial and the biological part of the arm. It is developed individually for each customer and installed in specialized clinics. According to Bohdan, even the most up-to-date 3D scanners and expensive 3D printers can’t create better sockets than prosthetists. So, Esper Bionics manufactures only robotic hands.
We decided to start our tour on the ground floor with a CNC 3-axis milling machine. Using it, Serhii crafts metal parts for the future robohand, for example, for a palm. Most parts are made from aircraft aluminum, bronze, and stainless steel.
We may watch the production through the glass. Serhii leads the mechanism with software written and installed here at Esper Bionics. The machine is pretty large. The facility owner let the workers disassemble a wall and some windows to bring the machine inside.
Next to it is a universal lathe. There are some plans above it. Serhii follows them during the production. There are also essential tools needed for the production. For instance, here you see the finger assembly platform. The operator shows us its model on the screen a few seconds after the mill cut a detail from an aluminum bar. Doing so creates a lead nut bracket for a future platform.
“These assemblies are unique for our product. We cannot order them in some online shop, e.g. Rozetka,” Serhii explained.
Then, we move to a place Bohdan called “a warehouse of a healthy man.” He meant the shelves with boxes full of prosthesis parts. Each box is numbered and signed, so the workers save time searching for required components.
“You can find anything here—from separate arm parts to some stump socket components,” Bohdan said.
Andrii, a senior assembly specialist, shows us boxes located closer. They have codes with letters and digits. The letters explain to which prosthesis parts in the box belong. For example, LL means Large Left, the large prosthesis of the left arm.
Maksym fills the boxes. He works in the Esper Bionics warehouse. Not all pieces in the boxes are manufactured by Serhii with his machine. Some are imported. For example, prosthesis engines come from Sweden.
Andrii tells Maksym a box number, gets the right box, and the prosthesis assembly begins. For this, the mechanic takes a frame that looks like an artificial palm.
He puts it and the cables inside the hub. Then, he attaches the cables to the commutation board and motherboard that will receive signals. Andrii prepares the first module to be attached to the next one.
The modules are separate arm knots, for example, fingers. An engine, a lead screw, a spring, and a plate bow them.
So, when the motherboard transfers a signal via the commutation board to the cables, it arrives at the engine and produces a new signal. The engine starts, so the user can bend and straighten fingers.
Andrii works only on the first floor. However, the operators Vitalii and Pavlo are active on the first and the third floors, where the R&D department is located. New models are developed there. Then, they order the components from Serhii and assemble prototypes in the shop.
Later, the products are tested on special tables. And only after all tests are done, mass production may start.
In total, four assemblers work in the shop. There is also one assembly specialist who is involved in R&D. The orders come in batches. One batch takes six weeks on average for production. The number of prostheses in a batch can differ. Up to 15 Esper hands are manufactured per month. However, due to high demand, the production is going to be expanded. The team also plans to increase the number of its members to 16. New engineers work their first month under the supervision of the senior assembler, Andrii, no matter how experienced they are. This affects productivity and requires a lot of time.
“They are real engineers. They know how to code, print, cast, and braze some details,” Bohdan described Esper Bionics workers.
Esper Bionics R&D
We skip the second floor (it doesn’t belong to the production) and go to the third floor. It is the R&D department. Here, we meet the firmware team. Their job is to develop software for finger action algorithms. Next to them are specialists who deal with the electronics — cables and boards.
“Usually, they first create a large board and test it completely to ensure everything works fine. And then, they make the board smaller according to the arm size,” Bohdan explained.
The R&D specialists work on the correct functioning and signal transferring of robohands to provide the user with the same functions as a natural arm. It can be set up via smartphone.
A smart hand
Bohdan holds a robohand and his smartphone. He opens the Esper Bionics app and shows how to change the control scheme or set up the myosensor sensibility. For example, if a person’s stump enlarges in the morning, they can lower the sensibility. And the opposite—when the stump shrinks in the evening, and the skin does not perfectly match the myosensor, it is recommended to increase the sensibility for better signal transfer.
The myosensors are sensors that read the tension in the body, create the so-called biopotential, and transfer the signal to the control unit. They are part of the stump socket. The myosensors are installed in a place with the highest detected muscle activity at the remaining arm. However, the signal of the muscle contraction is very low. So, the myosensors and software in the hand apply special filters to increase the signal and disperse “noises” generated by other electronic devices.
Bohdan assures two myosensors are enough to control an arm. You can put much more, but remember that each cost about $1,000.
In the smartphone, you can also set up grab gestures the user can create with fingers. For instance, a sign of the horns during a rock concert. Or straighten the index finger to scroll a newsfeed in your smartphone (tap grab). Or form the hand comfortably to pick up a pen (pen grab). The fingers go into the position of the bottle grab if you need to take some round items.
“Speaking of a traumatic amputation, not a planned one, muscles are often damaged and the stump, with a non-perfect form. Accordingly, the users must learn how to strain different muscles again. That’s why people who begin to master the robotic arm are recommended to start with the simplest control scheme that they learn to strain two groups of muscles,” said Bohdan.
Suppose a person doesn’t plan to use some gestures for some time. In that case, grabs can be temporarily deactivated via the smartphone, so the fingers will not be able to form a deactivated combination. If needed, the grabs can be enabled anytime. At the moment, there are 18 combinations available in the app.
Parameters of robotic arms and how to improve them
The prosthesis phalanges can carry up to 12 kg. The arm can handle up to 30 kg—for example, it is enough to make push-ups. Bohdan says there are no problems with a prosthesis during push-ups, but one can feel pain in the stump because it is a living tissue stuck in the socket. There is also no problem in the case of pull-ups. However, some users fear the stump can slip out of the socket.
The prosthesis has a 2-year guarantee. Currently, Esper Bionics calculates the production costs for the prosthesis with a 5-year warranty.
However, the team works on how to prolong the life of the prosthesis and how to make it energy-efficient. The most active users charge the robohand every two to three days.
“Made, tested, broken, made different. Tested, broken again. Made again, not broken. It’s cool. Tested 100 times, not broken. That’s it—the thing is ready for mass production,” Bohdan described the development of new products.
The arm sizes are more or less universal. There are large and small sizes. The latter is suitable for women, not tall men, and teenagers. For kids, it is not recommended to use prostheses with myosensors since they grow fast, and their stumps grow as well. Then, the stump socket must be updated, and it costs time and money.
The Chief of Strategy of Esper Bionics said that a state program in Ukraine provides people with prostheses of different functionality. This program, however, doesn’t include functional prostheses with external power sources for children or adults. The only exception is the military, which can apply for robotic extremities with advanced functions or sports prostheses after a year of wearing a simple (mechanic or cosmetic) prosthesis.
The manufacturer is flexible in direct communication with donors and users. A person who needs a prosthesis should apply on the Esper Bionics website. The person will be contacted then by the physician, Lidiia, who will learn about the circumstances and parameters of the trauma, post-surgery complications, etc. She will tell the client more about the prostheses, and if the client agrees, look for a sponsor for this patient. It can be the opposite: First, a sponsor is ready to pay for several prosthesis installations, and the company looks then for people who need prostheses. After the installation, the company can organize a private meeting for the sponsor and the patient. Of course, if they want to.
Localization of production
“It must be great when the prosthesis service is located where a user is,” Bohdan says, speaking about the repair of the bionic robotic arm.
According to him, those who have received an Esper Bionics prosthesis can simply send it to the production facility to repair or improve the model in case of damage. The situation is different with bionic arms from foreign manufacturers: users must wait a month for the prosthesis to reach the service center and then wait for it to be repaired and returned to the owners. That’s why Bohdan emphasizes that Ukraine should have its solutions for prosthesis manufacturing.
“First of all, it is difficult for people who need prosthetics to have their prostheses serviced abroad. Secondly, in a year or two, humanitarian aid in the form of prostheses from other countries will end. And the guys will ask: What have you been doing since 2022? Where are our prostheses?” he explains.
According to Bohdan, only a few prosthetists in Ukraine can make robotic arms controlled by myosensors. Esper Bionics works with only six or seven prosthetists in the whole country.
While we chatted about postal delivery, Bohdan showed us the box where customers receive their prosthetics. It can be opened with a single movement—by tilting the lid. This is just one example of Esper Bionics’ attention to detail when it comes to people who are missing one limb or even both.
Plans for 2024
The company intends to significantly expand bionic hand production and develop its prosthetic leg this year. But Bohdan says that a prosthetic leg is much harder to bring to life than an arm, as more research is needed and certification of such a product is more complicated. In addition, the liability of an artificial leg manufacturer is higher than that of an artificial arm manufacturer: “If the leg doesn’t work, you’re likely to fall. Accordingly, a malfunction of a lower limb prosthesis can do much more harm than a malfunction of an upper limb prosthesis.”
The company is also planning to work on an alternative control system that will allow signals to be transmitted faster and without unnecessary effort. Dmytro has already designed such a control system, which will consist of an array of sensors.
“A person transmits a signal to the arm through sensors. The prosthesis has to ‘understand’ them and take a particular position. Then, the artificial limb presses the interface designed for the arm. This algorithm has many steps, but this is how the prosthesis works. We plan to develop an alternative control system with a conditional keyboard made of myosensors and designed for an amputee,“ says Dmytro.
There are already technologies in the world that are used in multi-sensor prosthesis control systems. One of them is Pattern Recognition, which recognizes specific patterns of muscle contraction. But this is not the same as myosensor interfaces.
“It would be good for us to create our own sensor system next year, which would also allow us to use algorithms for recognizing muscle contraction patterns and add a wider range of hand control. But that’s a story that will take time,“ Dmytro says.