PURPOSE To observe various modes of lower limb locomotion, an inertial measurement unit (IMU) was used. Digital signals were used to identify signal characteristics that help to distinguish among locomotion modes and intensity levels. METHODS A wireless IMU was installed on the outside of shoes and three forms of locomotion (walking, running, and jumping) were assessed at two intensity levels...

This paper proposes a technique to estimate the angular velocity of a rigid body from vector measurements. Compared to the approaches presented in the literature, it does not use attitude information nor rate gyros as inputs. Instead, vector measurements are directly filtered through a nonlinear observer estimating the angular velocity. Convergence is established using a detailed analysis of th...

Cviklovič V., Hrubý D., Olejár M., Lukáč O., 2011. Comparison of numerical integration methods in strapdown inertial navigation algorithm. Res. Agr. Eng., 57 (Special Issue): S30–S34. The numerical mathematical theory provides a few ways of numerical integration with different errors. It is necessary to make use of the most exact method with respect to the computing power for a majority of micr...

2.1 Principles of Inertial Sensors A coordinate system must be defined prior to deployment of an inertial sensor for body motion measurement. If the origin of a moving coordinate system has acceleration (A0) and rotates with a gyroscopic angular velocity (ω), and if a mass (m) has the position vector (r0) and the velocity (u0) with respect to the moving coordinate system, then the inertial forc...

Baseball and softball pitch types are distinguished by the path and speed of the ball which, in turn, are determined by the angular velocity of the ball and the velocity of the ball center at the instant of release from the pitcher’s hand. While radar guns and video-based motion capture (mocap) resolve ball speed, they provide little information about how the angular velocity of the ball and th...

This paper investigates the velocity-free feedback control problem associated with finite time attitude stabilization of a rigid spacecraft subject to external disturbance and input saturation. First of all, to address the lack of angular velocity measurement, a novel, fast, finite time convergent observer is proposed to recover the unknown angular velocity information in a finite time under ex...