Abstract
Kinetic models of human motion rely on boundary conditions which are defined by the interaction of the body with its environment. In the simplest case, this interaction is limited to the foot contact with the ground and is given by the so called ground reaction force (GRF). A major challenge in the reconstruction of GRF from kinematic data is the double support phase, referring to the state with multiple ground contacts. In this case, the GRF prediction is not well defined. In this work we present an approach to reconstruct and distribute vertical GRF (vGRF) to each foot separately, using only kinematic data. We propose the biomechanically inspired force shadow method (FSM) to obtain a unique solution for any contact phase, including double support, of an arbitrary motion. We create a kinematic based function, model an anatomical foot shape and mimic the effect of hip muscle activations. We compare our estimations with the measurements of a Zebris pressure plate and obtain correlations of for double support motions and for a walking motion. The presented data is based on inertial human motion capture, showing the applicability for scenarios outside the laboratory. The proposed approach has low computational complexity and allows for online vGRF estimation.
Highlights
The analysis of forces driving the human motion and the forces exerted to the surrounding via contacts with the human body are part of kinetic human motion analysis, which is an important tool for instrumented human motion analysis [1,2]
Overall, the results show that the force shadow method (FSM) can approximate measured pressure values and vertical GRF (vGRF) reasonably well, based on the kinematics of the human body, its center of mass (CoM) and the force shadow function
We presented the FSM which is an approach to estimate and distribute vGRF for multiple contact regions, using only kinematic data of a human body, approximate segment weight distributions and the person’s overall weight
Summary
The analysis of forces driving the human motion and the forces exerted to the surrounding via contacts with the human body are part of kinetic human motion analysis, which is an important tool for instrumented human motion analysis [1,2]. According to Newton’s third law, the ground exerts a force on the human body by mirroring the acceleration of the body’s center of mass (CoM). This force is called ground reaction force (GRF) and carries important information to analyze gait parameters, e.g., in rehabilitation, sports, robotics, etc. The peak vertical GRF is a reliable parameter to evaluate lower extremity functional strength during sport-specific movements and can be used, together with the vertical impulse, which is the product of force multiplied by time during the propulsion phase of a vertical jump, for prognoses after sports-related injuries [4]. The landing phase in running sports produce high-frequency peaks in the vertical GRF trajectories and are assumed to play a crucial role in the development of injuries [5]. The vertical GRF can be used for online estimation of (unknown)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
