Vehicle steering control system and control method therefor
First Claim
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1. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
- a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism; and
a correcting section for correcting the steering assist force according to the estimated gear temperature,wherein the temperature estimating section estimates the gear temperature based on convective heat from a radiator or based on self-heating of an electric motor that applies the steering assist force or based on radiant heat from the internal combustion engine or based on ambient temperature,wherein the correcting section corrects the steering assist force by adding a low-temperature correcting assist force determined according to the gear temperature to a normal assist force, which is applied when the gear temperature is above a prescribed temperature, andwherein the prescribed value of the gear temperature is a temperature at which the preload of the gear mechanism begins to increase.
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Abstract
A vehicle steering control system that controls the operation of an electric vehicle steering device, which applies a steering assist force to a steering mechanism via a gear mechanism and includes: a temperature estimating section for estimating the temperature of or around the gear mechanism; and a correcting section for correcting the steering assist force according to the estimated gear temperature.
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Citations
16 Claims
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1. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
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a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates the gear temperature based on convective heat from a radiator or based on self-heating of an electric motor that applies the steering assist force or based on radiant heat from the internal combustion engine or based on ambient temperature, wherein the correcting section corrects the steering assist force by adding a low-temperature correcting assist force determined according to the gear temperature to a normal assist force, which is applied when the gear temperature is above a prescribed temperature, and wherein the prescribed value of the gear temperature is a temperature at which the preload of the gear mechanism begins to increase.
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2. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
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a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism based on a difference between a temperature of a control unit that controls the operation of the vehicle steering device and an ambient temperature; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates that the gear temperature is equal to the gear temperature that is last estimated while an internal combustion engine is previously being driven, in a case where the ambient temperature at a time when the internal combustion engine is started is equal to the ambient temperature that is last detected while the internal combustion engine is previously being driven, and the temperature of the control unit at the time when the internal combustion engine is started is higher than the temperature of the control unit that is last detected while the internal combustion engine is previously being driven. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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3. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
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a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism based on a difference between a temperature of a control unit that controls the operation of the vehicle steering device and an ambient temperature; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates that the gear temperature is equal to the ambient temperature at a time when the internal combustion engine is started, or the temperature of the control unit at the time when the internal combustion engine is started, in a case where an absolute value of a difference between the ambient temperature at the time when the internal combustion engine is started and the temperature of the control unit at the time when the internal combustion engine is started is smaller than a prescribed threshold.
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4. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
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a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism based on a difference between a temperature of a control unit that controls the operation of the vehicle steering device and an ambient temperature; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates that the gear temperature is equal to a value obtained by an equation, the ambient temperature at a time when the internal combustion engine is started+{(the temperature of the control unit at the time when the internal combustion engine is started−
the ambient temperature at the time when the internal combustion engine is started)/(the temperature of the control unit that is last detected while the internal combustion engine is previously being driven−
the ambient temperature that is last detected while the internal combustion engine is previously being driven)×
(the gear temperature that is last estimated while the internal combustion engine is previously being driven−
the ambient temperature that is last detected while the internal combustion engine is previously being driven)}, in a case where an absolute value of a difference between the ambient temperature at the time when the internal combustion engine is started and the temperature of the control unit at the time when the internal combustion engine is started is equal to or larger than a prescribed threshold.
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11. A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising:
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a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates the gear temperature based on convective heat from a radiator or based on self-heating of an electric motor that applies the steering assist force or based on radiant heat from the internal combustion engine or based on ambient temperature wherein the correcting section corrects the steering assist force when the gear temperature is less than a predetermined temperature, wherein the correcting section corrects the steering assist force by adding a low-temperature assist force to a normal assist force, the low-temperature assist force is determined according to the gear temperature and the normal assist force is applied when the gear temperature is above the predetermined temperature, and wherein the low-temperature assist force is calculated by multiplying a base low-temperature assist torque by a correcting gain, the correcting gain is based on the gear temperature and the correcting gain equals zero if the gear temperature equals the predetermined temperature. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification