Full-scene motion capture system and rehabilitation application based on UWB-IMU fusion technology (On-going) Funded by national college student innovation and entrepreneurship project as the project leader. (National level grant 20,000 CNY.)
Research Introduction
In the current field of rehabilitation, the use of digital assessment and training methods has become a trend
Body Sensor Networks (BSNs) can perform continuous physiological and behavioral monitoring of the wearer [1], among which inertial measurement units (IMU) are widely used [2]
The literature review found [3] that IMU-based motion capture systems are most commonly used for assessment applications in rehabilitation applications, such as joint range of motion (ROM) measurement, followed by rehabilitation training.
The reason is that inertial motion capture equipment is difficult to use for long periods of time
Current Difficulities
Wireless inertial system communication methods lack robustness
• Lack of anti-interference capability
• The number of simultaneous links is limited
• Limited communication distance
IMU information is Insufficient Posture drift over time
• Displacement is the quadratic integral of acceleration, and the cumulative position error increases over time
• The heading angle continues to produce heading drift
• Ultimately affecting the accuracy of the inverse kinematics
UWB-IMU Fusion Motion Capture
Ultra Wide Band (UWB)
| Communication method | Wi-Fi | UWB | Bluetooth | Zig Bee | RFID |
| Working frequency | 2.4/5Ghz | 3-10Ghz | 2.4Ghz | 784~915Mh、 2.4Ghz | 860-960Mhz |
| Penetration | Poor | Good | Good | Good | Very poor |
| Anti-interference | Average | Robust | Weak | Robust | Weak |
| Power consumption | High | Low | Low | Low | Very low |
| Transmission rate | <600Mbps | <1Gbps, usually6Mbps | <3Mbps | <0.25Mbps | / |
| Maximum transmission distance | 1000m | 200m | 100m | 100m | 5m |
| Positioning accuracy | 3-10m | <10cm | 1-3m | 3-5m | 3-10m |
Three advantages of UWB:
Strong anti-interference ability
The distance of approximate pulsed light can be calculated.
Larger bandwidth and high transmission rate
By closely integrating UWB and IMU in software and hardware, we develop a body sensor network system based on UWB communication and with accurate pose estimation – the iCapturer system to achieve human body motion capture and positioning and use it for rehabilitation. field to explore its application potential in rehabilitation assessment and training.
The hardware part:
A wearable sensor node
A receiving base station (BS)
The software part:
Embedded system software based on Zephyr Internet of Things operating system
Attitude calculation based on Opensim Docker,
Real-time visualization based on Unity
Demos
Motion Reconstruction from sparse IMU-UWB sensors
Idea inspired by Xinyu Yi Physical Inertial Poser (PIP): Physics-aware Real-time Human Motion Tracking from Sparse Inertial Sensors
(On-going)
