Xsens ForceShoe

The Xsens ForceShoe is a unique, fully ambulatory system for 3D measurement of forces and torques under the foot, as well as 3D kinematics of the foot.

In effect, it is an ambulatory gait lab.

Xsens ForceShoe (Research Use Only)

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The Xsens ForceShoe™ enables full kinematic and kinetic measurements in ambulatory settings, making it possible to analyze joint forces and torques even outside laboratory settings, for example in a factory or on the sports field. The Xsens ForceShoe is a unique, fully ambulatory system for 3D measurement of forces and torques under the foot, as well as 3D kinematics of the foot.

The complete measurement system includes Xsens motion trackers (MTx) and 6DOF force sensors built into an advanced lightweight carbon fiber shoe sole allowing complete freedom of movement, in and outside of the lab. Data from the ForceShoe is collected, time synchronized and wirelessly transmitted to the PC using the Xsens Xbus Master. All measurement data is available in real-time in the easy to use MT SDK, which includes MT Manager.

The ForceShoe is independent of external devices; making it ideal for research and clinical studies incorporating many successive strides, difficult to re-create in a lab environment.

Xsens has licensed the technology behind the ForceShoe from Prof. P.H. Veltink of the University of Twente, a leading group in advanced 3D ambulatory measurement techniques, and are now making this technology more widely available for further research in clinical, ergonomics and sports applications.

The current version of the ForceShoe has a prototype status and is not offered for sale as a standard item product from Xsens. However, Xsens is making prototypes commercially available for research use only, to enable further adoption and research into use and applications of this technology.

Product Overview

The ForceShoe Development Kit is delivered in a compact carrying case, including:

Hardware

1 x Pair ForceShoes
2 x MTx per Shoe
2 x Force Load Cells per Shoe
1 x Xbus Master
1 x Bluetooth Transceiver USB

Software

MT Manager
MT Software Development Kit

3D Force [N] and 3D Torque [Nm] real-time in MT Manager
(click image for enlarged version)

Fully ambulatory, the Xsens ForceShoe can be worn anywhere. Biomechanists can appreciate how this revolutionizes biomechanics research. Never before was it possible to create a statistical average of 10 strides made by actually walking only these 10 strides consecutively¹.

Using the ForceShoe, 3D measurement of forces and torques under the foot, as well as 3D kinematics of the foot is possible.

Force and kinematic hardware are built into the outer sole of a shoe. Data is time-synchronized and transmitted wirelessly to the PC via the Xsens Xbus Master (XM). Using dedicated Xsens software, all collected data can be visualized in real-time and recorded / saved for further processing.

Applications

Biomechanics
Rehabilitation
Sports
Ergonomics
Gait analysis

Features

Freedom of movement
- Use anywhere, outside, in the office, no lab required
- Portable case for easy transportation
Wireless data transmission
No data loss
- No occlusion or line-of-sight restrictions
- No special needs regarding foot placement
- No need to aim for a full foot strike on a built-in force plate
Force and inertial sensors completely integrated
Complete and correct 3D force, torque, acceleration and rate of turn for every step taken
- Combine with additional MTx for kinematics of additional segments
Easy “roll-off” during walking due to a special mechanical construction
Ease of use
- Intuitive Windows software for real-time view, easy logging and export
- SDK with example code facilitating real-time access to all levels of component data
Sensor fusion algorithms ensures highly accurate, drift-free output

¹ Excluding of course the gait inititiation and termination steps

Leaflet

Download the ForceShoe leaflet

Features

Ambulatory measurement of 3D: force, torque, acceleration, angular velocity and magnetic field
Wireless data transmission via an on-body hub (Xbus Master)
Combine with additional MTx for kinematics of other segments
Use anywhere, outside, in your office, no lab required
Force and inertial sensors completely integrated
Highly accurate MEMS inertial sensors
No need to aim for a full foot strike on the built-in force plate
No data loss due to incomplete foot placement
Complete and correct 3D force and torque for every step taken
Investigate stride assymetry of every step
Easy “roll-off” during walking due to a special mechanical construction
Modular design
Weight comparable to mountain hiking shoes

Output

3D Orientation
- (Quaternions/Matrix/Euler angles)
3D Acceleration (m/s2)
3D Angular Velocity (deg/s)
3D Earth Magnetic Field (normalized) (mGauss)
3D Force (N)
3D Torque (Nm)

Orientation Performance

Dynamic Range
Angular Resolution¹
Static Accuracy (Roll/Pitch)
Static Accuracy²(Heading)
Dynamic Accuracy³

all angles in 3D
0.05 deg
<0.5 deg
<1 deg
2 deg RMS

Shoe specifications

Shoe Type: Open Sandal
Sole height: ~32 mm (sensors module height)
Weight: ~1100 gr per shoe

Construction

Forefoot: Easy roll-off
Heel: Rigid construction with damping
Mounting sole-shoe: M5 bolts (accessible from inside under insole)

¹ 1σ standard deviation of zero-mean angular random walk
² In homogenous magnetic environment³ May depend on type of motion

Sensor Component Performance: MTx


Sensor Performance	Rate of Turn	Acceleration	Magnetic Field
Dimensions	3 axes	3 axes	3 axes
Full Scale (standard)	± 1200 deg/s	± 180 m/s²	± 750 mGauss
Linearity	0.1 % of FS	0.2 % of FS	0.2 % of FS
Bias Stability⁴	1 deg/s	0.02 m/s²	0.1 mGauss
Scale Factor stability⁴	-	0.03%	0.5%
Noise	0.05 deg/s/√Hz	0.002 m/s²/√Hz	0.5 mGauss
Alignment error	0.1 deg	0.1 deg	0.1 deg
Bandwidth	40 Hz	30 Hz	10 Hz
Max update rate	512 Hz	512 Hz	512 Hz

Sensor Component Performance: Force Cells


	Force		Torque
	Fx, Fy	Fz	Tx, Ty	Tz
Sensing range	±580 N⁵	±1160 N⁶	±20 Nm⁷	±20 Nm⁷
Resolution	~1/2 N⁸	~1/2 N⁸	~1/94 Nm⁸	~1/188 Nm⁸
Single-Axis Overload	5100 N	10000 N	110 Nm	140 Nm
Stiffness (calculated)	7.4x10⁷ N/m	9.8x10⁷ N/m	1.7x10⁴ Nm/rad	3.x10⁴ Nm/rad

⁴ deviations over operating temperature range (1σ) specifications subject to change without notice
⁵ extended to non-calibrated approximately ±1100 N
⁶ extended to non-calibrated approximately ±2200 N
⁷ extended to non-calibrated approximately ±38 Nm
⁸ increased due to ext. range

The ForceShoe uses Xsens MT Manager to collect and display real-time 3D orientation, 3D inertial and 6DOF force sensor component data. It is possible to replay logged data in graphical format and to export ASCII files for further analysis.

MT Manager has the following features

Intuitive user interface
Real-time graphical data visualization and export of:
- 3D Angular Velocity (deg/s)
- 3D Acceleration (m/s2)
- 3D Earth Magnetic Field (a.u.)
- 3D Orientation
- (Quat or deg in Euler Angles)
3D Force (N)
3D Torque (Nm)
Record and save data with ease
Export data as ASCII text for further processing

MT Software Development Kit (MT SDK)

MT SDK is a software package made available for users to gain real-time access to ForceShoe data. The SDK provides access to all levels of data (3D orientation, 3D calibrated inertial, force and torque sensor data) and enables application developers to create their own specialized environments for visualizing, recording and processing. To facilitate this process, example code is provided for:

Matlab
Excel
C/C++

The MT SDK is Windows 7 compatible and partially supported under Linux.

Click image for lager view

Click image for lager view

Gait analysis in the natural environment	Gait analysis of stair climbing


No need for full foot force plate strike

Published Peer Reviewed Research Articles

Schepers, H. M., van Asseldonk, E. H. F., Baten, C. T. M., Veltink, P. H. “Ambulatory estimation of foot placement during walking using inertial sensors” Journal of Biomechanics (2010), doi:10.1016/j.jbiomech.2010.07.039

Faber, G. S., Kingma, I., van Diëen, J. H. “Bottom-up estimation of joint moments during manual lifting using orientation sensors instead of position sensors” Journal of Biomechanics 43 (2010) 1432–1436

Faber, G. S., Kingma, I., Schepers M. H., Veltink, P. H., van Diëen, J. H. “Determination of joint moments with instrumented force shoes in a variety of tasks” Journal of Biomechanics 43 (2010) 2848–2854

Schepers, M. H., van Asseldonk, E. H. F, Buurke, J. H., Veltink, P. H. “Ambulatory Estimation of Center of Mass Displacement During Walking” IEEE Transactions on Biomedical Engineering 56 (2009) 1189-1195

Liedtke, C., Fokkenrood, S. A. W., Menger J. T., van der Kooij, H., Veltink, P. H. “Evaluation of instrumented shoes for ambulatory assessment of ground reaction forces” Gait & Posture 26 (2007) 39–47

Schepers, H. M., Koopman, H. F. J. M., Veltink, P.H., “Ambulatory Assessment of Ankle and Foot Dynamics” IEEE Transactions on Biomedical Engineering, 54 (2007) 895-902

Veltink, P.H., Liedtke, C., Droog, A., van der Kooij, H. “Ambulatory Measurement of Ground Reaction Forces” IEEE Transactions on Neural Systems And Rehabilitation Engineering, 13 (2005) 423-427

Xsens ForceShoe

Xsens ForceShoe (Research Use Only)

Product Overview

Applications

Features

Technical Specifications

Features

Output

Orientation Performance

Shoe specifications

Construction

Individual Sensor Specification

Sensor Component Performance: MTx

Sensor Component Performance: Force Cells

MT Software Development Kit (MT SDK)

Gait analysis in the natural environment

Gait analysis of stair climbing

No need for full foot force plate strike

Published Peer Reviewed Research Articles

News

New paper: Motion analysis assessment of alterations in the scapulo-humeral rhythm after throwing in baseball pitchers

Xsens UK User Meeting at the University of Central Lancashire

Events

Tech Cloud

Xsens ForceShoe

Xsens ForceShoe (Research Use Only)

Product Overview

Applications

Features

Technical Specifications

Features

Output

Orientation Performance

Shoe specifications

Construction

Individual Sensor Specification

Sensor Component Performance: MTx

Sensor Component Performance: Force Cells

MT Software Development Kit (MT SDK)

Gait analysis in the natural environment

Gait analysis of stair climbing

No need for full foot force plate strike

Published Peer Reviewed Research Articles

News

New paper: Motion analysis assessment of alterations in the scapulo-humeral rhythm after throwing in baseball pitchers

Xsens UK User Meeting at the University of Central Lancashire

Events

Newsletter

Tech Cloud