The LUKE Arm is one of two bionic arms to come out of DARPA’s Revolutionizing Prosthetics program, and the only commercial arm to offer a powered shoulder option.
What’s On This Page?
- A Quick Look at the LUKE Arm
- Possible Configurations
- Grip Patterns & Control System
- Thumb Rotation
- Proportional Speed Control
- Auto Grip
- Sensory Feedback
- Shoulder Design
- Humeral Rotation
- Elbow Design
- Wrist Design
- Lift Capacity & Grip Strength
- Water and Dust Resistance
- Glove Options
- User Software
- Suitability for Below-the-Elbow Solutions
- Clinical Insights
- User Feedback Survey & Results
- Considerations Before Buying a LUKE Arm
- Related Information
A Quick Look at the LUKE Arm
The LUKE Arm was originally developed for DARPA by DEKA Research and Development Corporation and approved for commercial use by the FDA in 2014. Mobius Bionics then took over the commercialization of the arm in late 2016.
Here is a look at the LUKE Arm’s first two recipients around the time of the hand-off to Mobius:
The LUKE Arm is available in three different configurations reflecting the various levels of upper-limb amputation:
Both the price and the control system options may vary depending on the selected configuration.
Grip Patterns & Control System
The hand component of the LUKE Arm is capable of performing at least six pre-programmed grip patterns. We say “at least” because we have been unable to verify whether it is possible to add additional grip patterns.
When talking about control systems with the LUKE Arm, it is important to remember that the arm can have up to ten powered joints. This allows the arm to mimic all the main movements of a natural arm plus one (a rotating wrist) that exceeds natural capabilities.
To accommodate the physical circumstances of almost any user, a range of control systems are provided for the arm. These include myoelectric control and various types of transducers and switches.
Inertial Measurement Units (IMUs) are a popular choice for Humeral and Shoulder configurations. These are typically worn on the user’s shoes and read the tilt of the user’s foot to control the arm like a joystick. A good demonstration of this is provided in split-screen format beginning at 1:06 of this video:
The LUKE Arm will automatically rotate the thumb into its proper position (either opposing fingers or lying parallel to them) as required by the selected grip.
Proportional Speed Control
Proportional speed control is included with the LUKE Arm for all the powered joints and is controlled by how gently or aggressively the user triggers the input signal.
There is no auto grip feature with the LUKE Arm (where the hand can sense if an object is slipping and automatically compensate by increasing the grip force). However, the combination of proportional speed control and sensory feedback (below) helps address this issue.
Mobius provides a simple pressure sensor in the thumb combined with a small vibratory motor mounted on the user’s socket to provide grip-force feedback.
Other efforts are underway to provide more sophisticated feedback such as this project at the University of Utah:
The LUKE Arm’s powered shoulder can move both forward and back (flexion and extension) and out to the side (abduction and adduction).
If you attempt to arm wrestle with a natural arm, it can move across your body (victory) and away from it (defeat). So can the LUKE Arm.
The LUKE Arm’s elbow can both flex (scratch your nose) and extend (reach out to shake someone’s hand).
The LUKE Arm’s wrist can flex (knuckles pointed toward the ground), extend (knuckles pointed toward the sky), and rotate 360 degrees (try doing that with your natural wrist!).
Lift Capacity & Grip Strength
We do not yet have any data on the LUKE Arm’s lift capacity or grip strength other than a statement from Mobius that the arm has been designed for daily activities such as lifting a bag of groceries or moving a gallon of milk. If you know more, please tell us through our contact form.
We do not yet have any information on the LUKE Arm’s durability. Again, if you have more information, please submit it through our contact form.
Water and Dust Resistance
When installed and its covers are in place, the LUKE Arm has an IP rating of 52, meaning it is resistant to light rain and limited dust. It should not be submerged in water or used in dirty environments.
The LUKE Arm comes with a Mobius Bionics glove, which improves grip, allows for the proper use of the functional fingernails, does not impede motion, and provides protection from water and dust.
You can use alternative gloves but these may restrict the hand’s speed, grip force, load capacity, and range of motion.
The LUKE Arm provides a standard external battery. It also provides an optional internal battery for the Humeral and Shoulder configurations, which can be used to extend the overall battery capacity for the arm.
We do not have any performance data on these batteries in terms of how long they last (too many variables) or how long it takes to recharge them. If you know, please share your knowledge through our contact form.
As far as we can tell, the LUKE Arm does not provide software for the end-user. It does provide software for the clinician to set up and configure the arm. This same software also allows the user to test and practice the controls of a virtual arm before using the real thing.
Suitability for Below-the-Elbow Solutions
Because of its modular design, the LUKE Arm’s Radial configuration is perfectly suitable for below-the-elbow solutions.
However, before choosing the LUKE Arm for this purpose, be sure to check out our article on Current Options for Bionic Hands.
We do not have an official price for the LUKE Arm. We know that a complete arm solution (all components) is at least $100,000 US. But we don’t have an official price for the Humeral or Radial configurations. If you know, please share this information with us through our contact form.
According to our information, the LUKE Arm comes with a standard two-year manufacturing warranty. We do not have any indication that the user can purchase an extension to this warranty. If you know, please let us know through our contact form.
The following comments are from clinicians with extensive experience with the LUKE Arm:
I am one of the few prosthetists who has been able to see this arm in action in my practice as there are only 23 Luke arm prostheses in patient action today and they can only be provided in the US. The functionality of this arm is amazing but it can come at a cost. The arm is quite heavy and requires a very well fit socket and harness design to properly support the prosthesis during wear. The arm can use all typical myoelectric control options ( electrode, pattern recognition) or Mobius Bionics’ proprietary option for the Luke arm, which uses accelerometer sensors on the user’s feet to control the arm with foot motions. Control can be switched from the elbow to the wrist or the hand as needed. If anyone is interested in the details of how this control system works, just contact me and I’ll be happy to explain it.
Overall, this technology is fascinating and provide an awesome innovation in prosthesis control. But key to this and all advanced upper limb prosthetic technology is a well-designed, good-fitting socket coupled with knowledge of the arm’s functions and limitations.
Tony Gutierrez, Bionic Prosthetics and Orthotics Group
Munster & Lafayette, Indiana
User Feedback Survey & Results
Are you or have you previously been a LUKE Arm user? If so, please share your insights with others looking at the LUKE Arm as a possible prosthesis.
We do not yet have a sufficient number of survey participants to publish fair and accurate results for the LUKE Arm.
As soon as we do, we’ll update this section.
Considerations Before Buying the LUKE Arm
Aside from suggesting that you take a close look at all possible competitors before making a decision, we don’t yet have anything to add to this section.
Before we can do so, we need to find actual LUKE Arm users. If you are one of those and have some valuable insights to share, please consider filling out our User Satisfaction Survey (above) or sending us your input via our contact form.
For a list of competitive devices, see Current Options for Above-the-Elbow Bionic Arms.
For a comprehensive description of all current upper-limb technologies, devices, and research, see our complete guide.
Click here for more information on Mobius Bionics.