- Analyzing data received from pressure sensors w.r.t gait
- Analyzing data received from gyro sensors w.r.t gait
- Merging both the data (gait assessment)
- User gets information/alert/feedback via application (Product)
- Segregating the data received from each pressure sensor
- Attaching the sensors in the shoe
- Testing the sensors with a subject (person)
- Understanding the data received
- Data Analysis
- Observations
- Gyro part continues…
- Arduino UNO
- Piezoelectric pressure sensors
- Connecting wires
- Gyro sensors
A normal walking gait cycle is divided into eight different gait phases, that is, initial contact, loading response, midstance, terminal stance, pre-swing, initial swing, mid-swing, and terminal swing. Each gait phase has a functional objective and a critical pattern of selective synergistic motion to accomplish its goal. Based on the basic tasks of limb movement, the gait phases may be detected effectively after orientations of the leg segments are accurately obtained.
- Gait Speed
- Stride length
- Cadence or Cycle time
- Foot angles
- Image processing
- Floor sensors
- Sensors located on the body, carried by the users (wearable sensors)
A gyroscope is an angular velocity sensor. Gyroscopes could be mounted on the foot, shank, or thigh to measure the angular rate and obtain angular information on various joints during the gait to realize the reorganization of the various gait phases. In the gait analysis, a gyroscope is usually combined with an accelerometer to construct a complete initial sensing system.
An accelerometer is a type of inertial sensor that can measure acceleration along its sensitive axis. Three common types of accelerometers are available, namely, piezoelectric, piezoresistive, and capacitive accelerometers. Piezoresistive and capacitive accelerometers can provide dual acceleration components and have higher stability. Thus, these types of accelerometers are suitable for measuring the motion status in the human gait.
Pressure sensors can be embedded into footwear to realize ambulatory measurements of Ground Reaction Force(GRF) during the gait. This GRF is a 3D vector, with the actual direction depending on the nature of the interface between the foot and the ground.
If a magnetic flux is applied, a Lorentz force proportional to the magnetic flux density will deflect the current path. As the current path is deflected, the current flows through the plate for a longer distance, causing the resistance to be increased. That is, the magnetoresistive effect refers to the change in the resistivity of a current carrying ferromagnetic material resulting from a magnetic field, with the resistance change proportional to the tilt angle in relation to the magnetic field direction. Based on this magnetoresistive effect, magnetoresistive sensors can estimate changes in the orientation of a body segment in relation to the magnetic North or the vertical axis in the gait analysis. Such sensors can provide information that cannot be determined by accelerometers or the integration of gyroscope signals.
The electromagnetic tracking system is a kind of 3D measurement device based on Faraday’s law of magnetic induction. When an object carrying sensor coils performs a motion inside controlled magnetic fields, the induced voltages in the sensor coils will change, with respect to the change of the object’s position and orientation, relative to the source of controlled magnetic fields. In the ETS, the controlled magnetic fields are generated by a fixed transmitter and detected by the receivers fixed on the object in motion. Therefore, the positions and orientations of the object in relation to the transmitter can be calculated.
The sensing fabric is a combination of sensing technology and fabric, which ranges from very superficially attached electronic components to a substitution of fibers and yarns with sensing properties inserted in normal fabrics, to electronic components made of fabric materials. They can be used to record the movement of body segments in gait kinematics.
A flexible goniometer can be used to measure the relative rotation between two human body segments. The flexible goniometers used in gait analysis can be divided into strain gauges, mechanical flexible, inductive, and optical fiber goniometers. A mechanical flexible goniometer is designed to obtain angular change by measuring the longitudinal displacement of two parallel wires bent in the plane of rotation, which is demonstrated by measuring the knee joint during human walking.
Electromyography (EMG) was developed to perform an indirect measurement of muscle activity using surface or wire electrodes. These electrodes are a kind of sensor for EMG and can detect voltage potentials to provide information on the timing and intensity of muscle contraction. EMG sensors can be used to realize the assessment of muscle activity in human gait and play an important role in evaluating the walking performance of individuals with problems in their lower extremities.
- Inertial sensors (gyro+acc) - Segment position, Step Detection, Stride length
- Pressure sensors - Foot Plantar, Pressure Distribution, Gait Phase Detection, Step Detection
- Ultrasound - Step length, Gait Phase Detection
- Goniometer - Joint angles, Step Detection