New Zealand
January 1, 2023
Article of the Month – January 2023
January 1, 2023

Xsens MTw Awinda

While research on human movement has been going on for millennia, it has recently attracted more attention because of significant technological and computer developments that have made it possible to analyze human kinematics in a quantitative, unbiased, and repeatable way.

Marker-based optical tracking systems have historically been the industry standard for motion capture. However, optical tracking systems have some significant system-immanent drawbacks for motion capture applications. For instance, when moving, marks are readily obscured. The space available for the activities is further constrained by the area that the cameras can capture, the cameras must be mounted in the environment, and the cameras are sensitive to changes in lighting. Because of this requirement for lab-like settings, optical tracking devices are inappropriate for a variety of applications. (2)

About the MTw Awinda

Wearable movement sensors have the potential to revolutionize clinical status and wellness assessments in routine healthcare. Monitoring a patient’s movements can be used to identify, measure, and keep track of their physical handicap, as well as to identify any deterioration and signal a therapeutic response in situations when direct contact is banned, such as those connected with Covid-19-related seclusion. Remote patient assessment may also enable more cost-effective monitoring and offer advantages. In 2011, Xsens announced the first generation MTw, a small wireless inertial-magnetic motion tracker built specifically for extremely precise ambulatory 3D kinematic applications in response to this industry’s demands. The second generation MTw Awinda was released in 2016. Since there is no longer a requirement for tracker-host and inter-tracker cabling, these wireless motion trackers only require the motion trackers themselves to be worn on the body. All motion trackers use the Awinda Master (station or USB dongle) attached to a recording PC to transfer their data to the PC wirelessly. (2)

Xsens created and patented an entirely new signal-processing pipeline, which was then incorporated into their wireless motion-tracking product, the MTw Awinda. In contrast to conventional signal processing pipelines, which suffer from performance degradation when the output rate is reduced, Xsens created the Strap-Down Integration (SDI) method, which ensures excellent accuracy in dynamic settings regardless of output data rate.

The MTw Awinda sensor (henceforth referred to as “MTw”) offered by XSENS is an inertial-magnetic measurement unit (IMMU) comprised of five devices(4): a normal accelerometer, a gyroscope, and a magnetometer, in addition to a barometer and a thermometer, to provide an autonomous self-calibration procedure every 60 seconds of use. In contrast to conventional inertial sensing systems, in which a reduced output rate leads to a loss of accuracy, XSENS created a so-called strap-down integration (SDI) algorithm that assures, in dynamic settings, a high level of accuracy regardless of the output data rate.(4)

The MTw Awinda comes with the MT Software Suite which includes the MT Manager Program and Kit for Software Development. The MT Manager Program is an intuitive graphical user interface that enables real-time viewing of 3D orientation and sensor data as well as recording and exporting of data to ASCII files (American Standard Code for Information Interchange) for additional analysis. (4)

The SDK enables customers to configure and quickly incorporate the MTw motion trackers in their applications by providing direct and real-time access to the output of the MTw motion trackers. It includes documentation, drivers for several operating systems, and numerous other helpful tools. With the help of the Xsens Device API (XDA), which is written entirely in C-code, communication is made simple. The following development tools are part of the MT SDK: 

  • C++ wrapper
  • Examples for C++, C# and Matlab.
  • Supported operating systems: Windows and Linux.
  • DLL for both 32-bit and 64-bit systems.
  • Extensive documentation on the MTw, the XBus protocol, and the SDK (PDF and HTML)

Advantages and disadvantages

The MTw Awinda’s salient characteristics include: 

  • Using an expanded API, integration is simple. 
  • Supplying exact drift-free 3D orientation data 
  • Using the unique Awinda protocol, data across several MTw’s is time-synchronized to within 10μs. 
  • 24/7 technical assistance and worldwide network integration 

The Xsens MT Software Suite makes it very simple to integrate with the MTw. The MT Software Suite is a user-friendly API that supports Windows and Linux and may be accessed via COM, C, and C++ interfaces.(1)

The MTw Awinda can be applied in a variety of circumstances and for a variety of goals; these include:(1)

  • Ergonomics 
  • Ergonomics in the workplace and virtual verification 
  • Healthy and Safe Navigation for pedestrians, therapy, and recovery 
  • Sports performance science and injury prevention 
  • Research 
  • Gait analysis and biomedical analysis 
  • Online Reality 
  • Head tracking, training and simulation, and gaming 
  • Robotics for Human-Machine Interaction. (1)
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