Walking One Leg Flexion
Measure and train left or right hip, knee, and ankle flexion angles during walking.
Nodes Required: 6
Sensing (4):
foot (top, switch pointing forward),
shank (lateral, switch pointing up),
thigh (lateral, switch pointing up),
pelvis (back center, switch pointing up)
Feedback (2): feedback_min, feedback_max
Algorithm & Calibration
Algorithm Information
The raw quaternions from the IMU are converted to Euler angles, and the roll angle is extracted using well established mathematical principles. If you'd like to learn more about quaternion to Euler angles calculations, we suggest starting with this Wikipedia page: Conversion between quaternions and Euler angles
Calibration Process:
The angle calculated is the global roll angle for the IMU. This must be aligned with the segment. The app will take the starting position to determine yaw offset.
Description of Data in Downloaded File
Calculated Fields
time (sec): time since trial start
step_count: steps of walking
Gait_Phase: gait phase of either left foot or the right foot as selected in the app configuration.
0 is “Early stance”;
1 is “Middle stance” ;
2 is “Late stance”;
3 is “Swing”
feedback_max: feedback status for feedback_max node.
0 is “feedback off”
1 is - “feedback on”
feedback_min: feedback status for feedback_min node.
0 is “feedback off”
1 is “feedback on”
Sensor Raw Data Values
Please Note: Each of the columns listed below will be repeated for each sensor
SensorIndex: index of raw sensor data
AccelX/Y/Z (m/s^2): raw acceleration data
GyroX/Y/Z (deg/s): raw gyroscope data
MagX/Y/Z (μT): raw magnetometer data
Quat1/2/3/4: quaternion data (Scaler first order)
Sampletime: timestamp of the sensor value
Package: package number of the sensor value