Walking Distance Measurement Systems
POSIFA Microsystems developed walking distance measurement
systems as shown above. These systems can measure the distance for many walking
ways to take including:
- Walk with your spouse, child, or friend
- Walk the dog
- Use the stairs instead of the elevator
- Park farther from the store
- Better yet, walk to the store
- Get up to change the channel
- Window shop
- Plan a walking meeting
- Walk over to visit a neighbor
- Walk around the garden or do a little weeding
There are countless physical activities out there, but
walking is a good form of exercise for many people. Knowing walking distance
will help people develop an exercise program that's effective for losing weight,
increasing aerobic fitness, and improving heart health.
Many efforts have been made to measure the distance traveled
by humans for a long time. There are several ways to measure the distance moved
by walking or running in daily life, some of which already use commercial
products, but none of them is ideal and perfect.
As well know, one way is based on radio frequency, such as
GPS, or may use optical-based systems, such as video tracking. Such systems are
not available indoors and degrade significantly in deep city canyons.
As an alternative, the measurement can be made by
self-contained tracking systems. Such systems use commercially available MEMS
inertial sensors and magnetic sensors. However, the performance of MEMS
accelerometers and angular rate sensors is limited by random noise and
calibration error. When they are used in a position tracking systems, it
becomes the source of unbounded growth in position error.
A new walking distance measurement system is developed by
POSUFA Microsystems, which is based on their MEMS thermal flow sensors. Human
walking exhibits variability from step to step. As above listed walking ways, all
most each step may be different in walking direction or in step length. It is
impossible to do correct and precise measurement using available distance
measurement systems. Only the POSIFA systems can do that because it measures
the distance simply by adding all step length together.
Each human walking step consists of stance phase, swing
phase, and stance phase again. In any stance phases the foot traveling velocity
is zero. In the swing phase the foot traveling velocity increases from zero to
maximum and then decreases from maximum to zero like a pendulum curve. The
thermal flow sensor can be managed to measure any instantaneous velocity of a particular
foot traveling step. Then the instantaneous velocity is integrated over the traveling
time of the particular step to produce the length of the particular step. All
the lengths of each traveling steps can be accumulated to provide the distance
of this human walking event.
In such systems, the thermal flow sensor only measures the instantaneous
velocity. The measurement signals are
sent to a smart phone using Wi-Fi communication. The Smart phones are useful in
this application because they are portable and have sufficient computational
power to compute and analyze the measurement signals to provide the walking
distance and other information people are interested.
