Monitoring aggressive driving operation of a mobile asset
First Claim
Patent Images
1. A method of monitoring operation of a mobile asset installed with a monitoring device comprising:
- installing in the mobile asset an accelerometer device for providing outputs representing accelerations along three orthogonal axes;
low-pass filtering the outputs with one or more filters;
transforming, by said monitoring device, the low-pass filtered outputs to represent acceleration along orthogonal forward, sideways and vertical axes of the mobile asset;
configuring, in said monitoring device, one or more acceleration envelopes to correspond to one or more events, each acceleration envelope defined by a duration of time and an amplitude;
determining, by said monitoring device. a speed of the mobile asset;
comparing, by said monitoring device, the determined speed of the mobile asset to a threshold speed;
determining, by said monitoring device, that the determined speed is above the threshold speed;
determining, by said monitoring device, an acceleration profile of the mobile asset by;
recording over a duration of time a plurality of values of acceleration of the mobile asset, wherein the transformed, low-pass filtered outputs are used to determine the values of acceleration of the mobile asset;
compensating said values of acceleration for gravity (G);
low pass filtering the acceleration along the vertical axis to obtain â
z;
calculating a pitch of a slope upon which the mobile asset is moving;
ρ
=cos−
1(â
z/G);
determining a sign of the slope; and
correcting the acceleration along the forward axis by subtracting therefrom G·
sin ρ
;
comparing, by said monitoring device, the determined acceleration profile of the mobile asset to said acceleration envelopes;
determining, by said monitoring device, that the determined acceleration profile of the mobile asset lies entirely outside at least one of said acceleration envelopes; and
reporting the event that corresponds to said one of said acceleration envelopes.
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Abstract
The acceleration of a mobile asset is sensed and compared to threshold acceleration levels when the speed of the mobile asset is above a threshold speed. When the acceleration exceeds a threshold a report is created allowing aggressive driving behavior to be logged.
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Citations
11 Claims
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1. A method of monitoring operation of a mobile asset installed with a monitoring device comprising:
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installing in the mobile asset an accelerometer device for providing outputs representing accelerations along three orthogonal axes; low-pass filtering the outputs with one or more filters; transforming, by said monitoring device, the low-pass filtered outputs to represent acceleration along orthogonal forward, sideways and vertical axes of the mobile asset; configuring, in said monitoring device, one or more acceleration envelopes to correspond to one or more events, each acceleration envelope defined by a duration of time and an amplitude; determining, by said monitoring device. a speed of the mobile asset; comparing, by said monitoring device, the determined speed of the mobile asset to a threshold speed; determining, by said monitoring device, that the determined speed is above the threshold speed; determining, by said monitoring device, an acceleration profile of the mobile asset by; recording over a duration of time a plurality of values of acceleration of the mobile asset, wherein the transformed, low-pass filtered outputs are used to determine the values of acceleration of the mobile asset; compensating said values of acceleration for gravity (G); low pass filtering the acceleration along the vertical axis to obtain â
z;calculating a pitch of a slope upon which the mobile asset is moving;
ρ
=cos−
1(â
z/G);determining a sign of the slope; and correcting the acceleration along the forward axis by subtracting therefrom G·
sin ρ
;comparing, by said monitoring device, the determined acceleration profile of the mobile asset to said acceleration envelopes; determining, by said monitoring device, that the determined acceleration profile of the mobile asset lies entirely outside at least one of said acceleration envelopes; and reporting the event that corresponds to said one of said acceleration envelopes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for monitoring operation of a mobile asset comprising:
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three orthogonal accelerometers for providing outputs representing accelerations along three orthogonal axes, said accelerometers installed in the mobile asset; a low-pass filter connected to each accelerometer output for providing filtered outputs; a device for transforming the filtered outputs into accelerations along orthogonal forward, sideways and vertical axes of the mobile asset; a further low-pass filter for further filtering the acceleration along the vertical axis of the mobile asset; and a device into which is input the further filtered acceleration along the vertical axis and the filtered accelerations along the forwards and sideways axes and which outputs compensated accelerations along orthogonal forward, sideways and vertical axes of the mobile asset; wherein said device compensates said filtered and further filtered accelerations for gravity (G) and slope on which the mobile asset is moving by; low pass filtering the acceleration along the vertical axis to obtain â
z;calculating a pitch of a slope;
ρ
=cos−
1(â
z/G);determining a sign of the slope; and correcting the acceleration along the forward axis by subtracting therefrom G·
sin ρ
;a monitoring device, operative when the mobile asset is moving and the speed of the mobile asset is above a threshold speed, wherein said monitoring device; records over a duration of time a plurality of values of compensated acceleration of the mobile asset to form an acceleration profile; compares the acceleration profile to a predetermined accelerating envelope that is defined by the duration of time and an amplitude; determines that the profile of compensated acceleration lies entirely outside the acceleration envelope; and reports an event that corresponds to said acceleration envelope.
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Specification