Necessity of Gyroscopes and Accelerometers in Angle Estimation for Quantitative Physiotherapy Evaluation of Lower Limb Kinematics During Walking

Abstract

This article evaluates the need to utilize an accelerometer to correct the vertical offset of the gyroscope angle when calculating certain gait parameters for quantitative evaluation of gait during walking. The finding shows that various quantitative evaluations such as waveform pattern comparison, range of motion, and walking speed do not require any vertical offset (also known as bias) correction, hence simplifying the computational process with just the need for a gyroscope for angle estimation. However, to compare the angles among normal reference values at specific gait phases, the accelerometer is still required to provide the vertical offset reference. This article also proposes an improved method for getting the vertical offset reference by utilizing the accelerometer only during the stance phase when the lower limb has minimal movement. Additional findings reported in this article include recommending utilizing the shank angles to calculate the walking speed as it has the largest movement range compared to the thigh and knee, and recommending utilizing the knee gait parameters rather than that of the thigh and shank for quantitative evaluation of lower limb kinematics as the knee gait parameters have more distinctive differences when comparing against the normal references.