ULTRA-EFFICIENT WIRELESS POWERED MICRO-ROBOTIC JOINT FOR HEALTH APPLICATIONS

Project Information

UWIPOM2

Grant agreement ID: 857654

DOI

10.3030/857654

Project closed

EC signature date 30 August 2019

Start date 1 October 2019

End date 30 June 2023

Funded under

• EXCELLENT SCIENCE - Future and Emerging Technologies (FET)

Total cost

€ 2 987 118,75

EU contribution

€ 2 987 118,75

Coordinated by

UNIVERSIDAD DE ALCALA
Spain

Periodic Reporting for period 2 - UWIPOM2 (ULTRA-EFFICIENT WIRELESS POWERED MICRO-ROBOTIC JOINT FOR HEALTH APPLICATIONS)

Reporting period: 2020-10-01 to 2023-06-30

Summary of the context and overall objectives of the project

During surgery interventions, the smaller is the access to patients´ body, the faster is the recovery time and the fewer are the complications that appear. Although, minimally invasive techniques are well far developed, there is still a large number of medical interventions that can not be done without damage and risks. For example, mitral regurgitation, rotational atherectomies, arrhythmia ablations, brain tumors resections or intracranial angioplasties constitute risky interventions that produce large collateral damages due to the use of too large and rigid tools. Robotic arms and automatic mechanisms tools could be a solution for those risky interventions, but they can not be constructed in the microscale because simply there are no rotational actuators / robotic joints strong that are small enough.
Our project seeks to develop the first micrometric-size Ultra-Efficient Wireless Powered Micro-robotic joint (UWIPOM2), enabling the creation of micro-robotic complex mechanisms for minimally invasive micro-surgery techniques and in-vivo health treatments. Moreover, the robotic joint will be wireless powered through gigahertz electromagnetic waves, thus avoiding any access to control the tool and providing infinite autonomy to any micro-robot activated by UWIPOM2.
The technical target of UWIPOM2 project is to reach orders of magnitude higher torque-to-weight and power-to-weight ratio than any previous system in the microscale, enabling the creation of micro-robots with complex mechanical and control capacities. Future robotics developers will have powering building blocks to create micro-robotic arms or other type of mechanical systems in the microscale. These tools will provide unprecedented capacities for doctors worldwide.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The main objective of the H2020 UWIPOM2 project is to develop a ultra-efficient wireless micrometer-sized microrobotic joint (UWIPOM2). The envisioned robotic joint contains a micromotor and in addition, it should be able to be powered wirelessly.
In the project, we have demonstrated that this micrometer-sized, micromotor has been designed, fabricated and tested with the capability to operate in fluid environments inside the body and whose power consumption is compatible with the wireless energy harvesting system also developed within the framework of the H2020 UWIPOM2 project.
The 1 Fr micromotor offers torque density similar to macroscopic motors. It is the thinnest motor in history, as far as we are concerned, with 0.4 mm of outer diameter. Being this size it can be integrated into ultra-thin catheters for use in minimally invasive surgical interventions and provide additional degrees of mobility to these tools.
The motor has proven to be durable over time demonstrating a life of more than 70 hours of operation at low speed, to be able to move masses even greater than its own weight, to be able to rotate at very fast speeds of 27000 revolutions per minute and to withstand and dissipate in an efficient way the overall internal heat.
It has also been demonstrated that the energy consumption of the motor is compatible with the power delivered by the wireless energy harvesting system also developed in the project. This wireless power transfer rectenna system is also an innovation and an advance with respect to the state of the art. It is a rectenna system with very small dimensions,1 x 0.6 x 5 mm, that has a good efficiency.
As an additional contribution and after discussing with cardiologists and neurosurgeons possible applications, it was suggested to develop in addition an actuator of much higher torque and controllability.
In addition, and very notably, the smallest ball bearing in history of less than 800 μm diameter has been developed with balls of 100 μm diameter. This micro-bearing have a rolling resistance coefficient significantly smaller than sliding bearings used currently in micro-scale while operating under relatively high loads.
With thiss motors, it will be possible to create steerable catheters, ultra-precious laser ablation systems, IVUS systems, abrasion systems, valve positioning systems in catheters with one degree of freedom and high precision, among other possible medical applications. Rectenna will be also compatible with medical applications like cardiac pacemakers or pulmonary artery pressure monitors. Finally, these results are also expected to have application in other industrial fields like space or microelectronics where miniaturization of actuators, motors and electromagnetic components is always a requirement.
The complete list of activities and publication can be found at www.uwipom2.eu and at UWIPOM2 community at zenodo.org .

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The list of results beyond the state of the art is given next:
- 1Fr motor: thinnest electric motor, Outer Diameter < 400 μm, Length < 800 μm, Speed > 27 krpm, Torque density > 298 Nm/m3, Power consumption < 4.8 mW, compatible with wireless powering.
- Wireless Power Transfer ASPAT-based rectenna, 1 x 0.6 x 5 mm, 1.175 GHz, Unique Gain/Size ratio, Output Power > 4 mW under 550 V/m of incident electric field. In-body tested. ICNIRP compliant.
- 3Fr motor: high torque stepper micromotor, Outer Diameter < 1000 μm, Length < 800 μm, Minimum step angle < 1.8 °, Torque density > 1050 Nm/m3, tethering powering.
- Double Thrust Ball Microbearing, Smallest Ball Bearing, Diameter < 800 μm, Thickness < 400 μm, Rolling Resistant Coefficient < 0.008 for loads 150 – 1500 mN.
- SmCo thick micromagnet manufacturing process, smallest SmCo micromagnet, Size and Thickness < 100 μm, Br > 1.1 T, Hcb > 850 kA/m, Magnetic Product > N30.
- LIGA microfabrication process to develop complex ferromagnetic mesoscopic-sized components with high aspect ratios and micrometric accuracy.
- Ferromagnetic yoke made in FeCo + copper wire windings, 4 layers, > 16 turns, low resistance, low impedance.
- Multilayered microcoils windings up to 5 layers, > 25 turns, Outer Diameter < 150 μm, Current Density > 600 A/mm2 in room temperature and ambient pressure.
- NdFeB micro-sized bonded permanent magnets for integration in microdevices, Br > 0.4 T, Hc > 956 kA/m, Size = 100-1000 μm.
- NdFeB N30 hollowed micromagnets, Outer Diameter < 220 μm, Inner Diameter >100 μm, Height < 400 μm.
- Pr-Fe-B Thin films prepared by sputtering.
- Multipolar micrometric magnetic rotors, Nº of Dipoles > 11, Diameter < 800 μm, Quality > N30.
- Microassembly and bonding process for micromotors, Diameter < 900 μm, Size of parts < 300 μm.
- Ultrathin Flexible High Gain Helical Antenna for In-Body Medical Applications, Outer Diameter < 400 μm, Resonance 4.7 GHz, S11 = -25.1 dB, Gain = -4.7 dBi.
- Miniaturized Archimedean antennas for WPT, Outer Diameter < 1.1 mm, Thickness < 0.52 mm, Resonance 4.9 GHz.
UWIPOM2 will constitute the key element for the foundation of micro-robotics technology for health applications but also for other fields like nano-satellites, security, mechatronics or micro-electronics. Not only high power-density allows opening this new road-map, but also, as UWIPOM2 based micro-robots will follow similar macroscopic design, similar strategies of control and automation can be directly applicable. Mechatronics engineers will be able to design any type of micro-machines operating inside the body with minimally invasive accesses and wireless powered.

Miniaturized Flexible High-Gain Microantennas

1Fr Micromotor, Thinnest motor 0.4 mm outer diameter

LIGA and Laser-Based Microfabrication of Ferromagnetic Components

Ferromagnetic Core Multilayered Microcoils

Wireless Power Transfer ASPAT-based Rectenna

3Fr High Torque Stepper Microactuator

Double Thrust Ball Microbearing