Walking speed estimation using shank-mounted accelerometers

We studied the feasibility of estimating walking speed using two shank-mounted accelerometers. Our approach took advantage of the inverted pendulum-like behavior of the stance leg during walking to identify a new method for dividing up walking into individual stride cycles and estimating the initial conditions for the direct integration of the accelerometer signals. To test its accuracy, we compared speed to known values during treadmill walking. The speed estimation method worked well across treadmill speeds yielding a root mean square speed estimation error of only 8%. This accuracy is comparable to that achieved from shank-mounted inertial measurement unit, providing a robust and low-cost alternative in using accelerometer for walking speed estimation. Shank-mounted accelerometer may be of great benefit for estimating speed in walking for the embedded control of knee-mounted devices such as prostheses and energy harvesters.