Apparatus and method for weight measurement during motion using force waveforms

A method for estimating a weight of a subject while moving, the method comprising:

• attaching one or more force sensors to the subject such that the force sensors measure a force exerted between each foot of the subject and a surface on which the subject is positioned;
• monitoring the one or more force sensors while the subject is stationary to obtain a stationary force measurement;
• estimating the weight of the subject based on the stationary force measurement to obtain a stationary weight;
• monitoring the one or more force sensors while the subject is moving to obtain a moving force measurement;
• during a first walk cycle of the subject:
• processing the moving force measurement to determine a reference peak level of the moving force measurement, which is a maximum value of the moving force measurement during a given period, a reference valley level of the moving force measurement, which is a minimum value of the moving force measurement within a given period, and a reference force range of the moving force measurement, which is a difference between the reference peak level and the reference valley level;
• and
• determining a reference acceleration of center of mass of the subject from the stationary weight;
• during a subsequent walk cycle of the subject:
• processing the moving force measurement to determine a peak level of the moving force measurement, which is a maximum value of the moving force measurement during a given period, a valley level of the moving force measurement, which is a minimum value of the moving force measurement within a given period, and a force range of the moving force measurement, which is a difference between the peak level and the valley level;
• determining a force range ratio between the force range and the reference force range;
• and
• determining an acceleration of center of mass of the subject from the force range ratio;
• and
• estimating the weight of the subject while moving from the peak level and the acceleration of center of mass.

A method for estimating a weight of a subject while moving, the method comprising:

• attaching one or more force sensors to the subject such that the force sensors measure a force exerted between each foot of the subject and a surface on which the subject is positioned;
• monitoring the one or more force sensors while the subject is stationary to obtain a stationary force measurement;
• estimating the weight of the subject based on the stationary force measurement to obtain a stationary weight;
• monitoring the one or more force sensors while the subject is moving to obtain a moving force measurement;
• during a first walk cycle of the subject:
• processing the moving force measurement to determine a reference peak level of the moving force measurement;
• and
• determining a reference acceleration of center of mass of the subject from the stationary weight;
• during a subsequent walk cycle of the subject:
• processing the moving force measurement to determine a peak level of the moving force measurement;
• determining a force peak ratio between the peak level of the moving force measurement and the reference peak level;
• and
• determining an acceleration of center of mass of the subject from the force peak ratio;
• and
• estimating the weight of the subject while moving from the peak level and the acceleration of center of mass.

An apparatus for estimating a weight of a subject while moving, the apparatus comprising:

• one or more force measurement sensors configured to be attached to the subject such that the force sensors measure the force exerted between each foot of the subject and a surface on which the subject is positioned;
• processing circuitry;
• and
• a memory storing instructions, which, when executed by the processing circuitry cause the apparatus to:
• monitor the one or more force sensors while the subject is moving to obtain a moving force measurement;
• process the moving force measurement to determine a peak level of the moving force measurement, which is a maximum value of the moving force measurement during a given period, a valley level of the moving force measurement, which is a minimum value of the moving force measurement within a given period, and a force range of the moving force measurement, which is a difference between the peak level and the valley level;
• determine an acceleration of center of mass of the subject from the force range;
• and
• estimate the weight of the subject while moving from the valley level and the acceleration of center of mass.