US 12,752,750 B2 · Method for determining a tractor longitudinal force threshold value

Abstract

A method for determining a tractor longitudinal force threshold value for a tractor longitudinal retardation force that can be imparted on a tractor of a vehicle combination including the tractor and a trailer for retarding the vehicle combination, the tractor including a set of tractor wheels adapted to engage the ground supporting the tractor, each wheel of the set of set of tractor wheels including a tire, the method including: determining a tractor lateral force value, determining a tractor tire lateral force limit value using a tire model for determining a tire lateral force limit; determining a reference lateral force value using said tractor lateral force value and the tractor tire lateral force limit value; determining a horizontal friction force value, and determining the tractor longitudinal force threshold value.

A method for braking a vehicle combination comprising a tractor and a trailer, said tractor comprises a tractor brake assembly for regenerative braking of said tractor and said trailer comprising a trailer brake assembly for braking said trailer, said method comprising:

determining a tractor longitudinal force threshold value
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for a tractor longitudinal retardation force
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that can be imparted on the tractor of the vehicle combination,
said trailer having a trailer longitudinal extension in a trailer longitudinal direction (LTL), a trailer lateral extension in a trailer lateral direction (TTL) and a trailer vertical extension in a trailer vertical direction (VTL), wherein said trailer longitudinal direction (LTL) corresponds to an intended direction of travel of said trailer when said vehicle combination is travelling straight ahead, said trailer vertical direction (VTL) corresponds to a direction of a normal to a planar surface supporting the trailer and said trailer lateral direction (TTL) being perpendicular to each one of said trailer longitudinal direction (LTL) and said trailer vertical direction (VTL),
said tractor having a tractor longitudinal extension in a tractor longitudinal direction (LTR), a tractor lateral extension in a tractor lateral direction (TTR) and a tractor vertical extension in a tractor vertical direction (VTR), wherein said tractor longitudinal direction (LTR) corresponds to an intended direction of travel of said tractor when said vehicle combination is travelling straight ahead, said tractor vertical direction (VTR) corresponds to a direction of a normal to a planar surface supporting the tractor and said tractor lateral direction (TTR) being perpendicular to each one of said tractor longitudinal direction (LTR) and said tractor vertical direction (VTR), wherein said tractor longitudinal retardation force
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parallel to said tractor longitudinal direction (LTR), said tractor comprising a set of tractor wheels adapted to engage the ground supporting said tractor, each wheel of said set of tractor wheels comprising a tire,
wherein determining the tractor longitudinal force threshold value comprises:
determining a tractor lateral force value
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,
indicative of a tractor lateral force being or predicted to be imparted on said tractor, using a tractor lateral force value determination procedure comprising:
obtaining a trailer mass value (mtrailer) indicative of a current mass of said trailer;
obtaining a trailer operating value indicative of a current operating condition or a predicted operating condition of said trailer;
determining an articulation angle value (Ψ) indicative of a current articulation angle between said tractor longitudinal direction (LTR) and said trailer longitudinal direction (LTL), and determining said tractor lateral force value
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using said trailer mass value (mtrailer), said trailer operating value and said articulation angle value (Ψ);
determining a tractor tire lateral force limit value (FTTRtire) using a tire model for determining a tire lateral force limit, taking at least one characteristic of the tire into account, for each wheel of at least a subset of said set of tractor wheels;
determining a reference lateral force value
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using said tractor lateral force value
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and said tractor tire lateral force limit value (FTTRtire);
determining a horizontal friction force value
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indicative of a possible total horizontal frictional force obtainable between said ground supporting said tractor and said set of tractor wheels, and
determining said tractor longitudinal force threshold value
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using said reference lateral force value
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and said horizontal friction force value
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wherein said method for braking said vehicle combination comprises operating said tractor brake assembly so as to provide a braking force being smaller than or equal to said tractor longitudinal force threshold value
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.

257 more elements

Method for determining a tractor longitudinal force threshold value

Life of this patent

Method for determining a tractor longitudinal force threshold value

Life of this patent

Abstract

Claims17