Community Research and Development Information Service - CORDIS

Periodic Report Summary 1 - WANDER (Wander)


Falling is the leading cause of accident-related injury among all age groups, but is particularly threatening among sufferers of conditions that affect motor control or result in sensory or cognitive impairment. Adults over the age of 65 are at great risk of serious injury during falling, and, in the event that the hip is fractured, have a 25% chance of dying from their injuries within 6-12 months of the event.

Falling can also have a profound psychological impact. Even if physical injury has not occurred, loss of confidence can reduce mobility and, as a result, lead to decreased independence in performing normal daily functions and a subsequent withdrawal from social and physical activities.

Main Project Objective

In many cases, the exact circumstances of a fall are difficult to predict and often come as a surprise; hence, to prevent falls, the chosen strategy is to assist balancing in general, regardless of the reason for instability. Conventional means of assisting balance, such as walkers and canes, have the shortcomings that (1) their effectiveness is dependent on the ability of the user to detect when a loss of balance has occurred, which is difficult for people with sensory impairment, and (2) these objects must be held when in use, which means that they prevent the hands from performing other tasks and that constant use may result in developing excessive reliance or maladaptation.

To develop a hands-free balance-assisting device capable of automatic detection and correction of instability, the field of wearable robotics offers great potential. Because many conventional robotic orthoses, such as exoskeletons, are too bulky and cumbersome for convenient daily usage by the elderly, the fellow’s group is currently developing a minimalistic and unobtrusive alternative. This device will take the form of a lightweight backpack-like corset (right) that can be quickly and easily mounted/dismounted and leaves the limbs free and uninhibited to allow comfortable movement in daily life. To promote healthy body dynamics, the device will provide assistance only when it is needed and will otherwise not influence the wearer’s motions.

Contained within the backpack will be two actuators called control moment gyroscopes (CMGs) that, like reaction wheels (e.g. ETH Zurich’s Cubli balancing cube robot), are capable of modifying their angular momentum to impart a moment (torque) on a body. Like reaction wheels, CMGs consist of rotating flywheels, but the mode of operation is fundamentally different: rather than change the spin rate of the flywheel to generate a moment, rotation of an outer gimbalreorients the flywheel and produces a significantly larger gyroscopic moment. Because this moment is orthogonal to the gimbal and flywheel spin axes, it is applied directly to the gimbal bearings, rather than the gimbal or flywheel motor; the implication of this is that, for a relatively small gimbal motor torque and power, a considerably larger output moment is possible, allowing for the construction of a lightweight, yet effective wearable device.

Work performed

Within WANDER, the fellow’s research group has constructed a proof-of-concept testbench [1]. The group managed to accurately reproduce arbitrary moments in the intended range, and have demonstrated the feasibility of using CMGs to stabilize an inverted pendulum in a single axis. In the proof-of-principle, a single CMG is used to generate moments that simulate a virtual spring holding the inverted pendulum upright.

Using other hardware setups, the group has also conducted experiments on how such a balance-assisting device should be controlled, in particular how human balance can be influenced by robotic interventions on the upper body [4].

Expected final results

The group is now beginning construction of a prototype device consisting of 2 CMGs that combines a number of unique features over comparable balancing technology:

- Versatile functionality: balance assistance in any potential fall direction
- Lightweight design: the design target is 3 kg
- High moment output: maximum assistive moment of 100 Nm, applied as a short “nudge” upon loss of balance
- Low power consumption: nominally < 50 W, with enough battery life for over 2 h of continuous balance assistance or considerably longer when assistance is not required.
- Compact and robust design: will fit into a 55 x 33 x 27 cm envelope (approximately a 40 L backpack)


The fellow is pleased to acknowledge technical collaboration with Hyperion Technologies B.V. (Delft, NL) and partnerships with both Leiden University Medical Center (LUMC, Leiden, NL) and VU University Medical Center (VUMC, Amsterdam, NL) for feedback in designing the device and preliminary clinical evaluation. Formal clinical evaluation of the device will be performed in cooperation with the Rehabilitation Institute of Chicago (RIC).


Besides support through the Marie Curie Career Integration Grant “WANDER” (PCIG13-GA-2013-618899), funding for this work has been gratefully received from the US Dept of Education RERC (Rehabilitation Engineering Research Centers) MARS3 initiative under NIDRR grant number H133E120010.

Selected publications

[1] D. Lemus, H. Vallery, Towards Gyroscopic Balance Assistance: Proof of Concept, Proceedings of the 36th International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), August 26-30, 2014, Chicago, USA.

[2] D. Li, H. Vallery, Gyroscopic Assistance for Human Balance, Proceedings of the 12th IEEE International Workshop on Advanced Motion Control (AMC), March 25-27, 2012, Sarajevo, Bosnia and Herzegovina.

[3] H. Vallery, C. O’Brien, A. Bögel, R. Riener, Cooperative Control Design for Robot-Assisted Balance during Gait, at-Automatisierungstechnik, 2012, 60 (11), 715-720.

[4] Fritschi, M.; Jelinek, H.; McGloughlin, T.; Khalaf, K.; Khandoker, A. & Vallery, H. Human balance responses to perturbations in the horizontal plane Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE, 2014, 4058-4061

Patent Applications

H. Vallery and D. Li, Gyroscopic-assisted device to control balance, US patent: US20140260714 A1, Issued Sept. 18, 2014.

Further information, animations, and videos on the working principle:

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Life Sciences
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