Control apparatus for motor-driven power steering system in which power suppy to an electric clutch is reduced upon detection of a malfunction
First Claim
1. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a vehicle speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor in dependence on said vehicle speed,an apparatus for controlling said motor-driven power steering system, comprising:
- abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value which corresponds to the vehicle speed detected by said vehicle speed detecting means;
load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means;
torque comparison means for comparing said load torque with said abnormal torque decision reference value; and
motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value while decreasing the coupling effort of said coupling effort control means wherein said coupling effort control means comprises an electric clutch and wherein when the coupling effort of said coupling effort control means is decreased, said electric clutch assumes a semi-coupling state.
1 Assignment
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Accused Products
Abstract
A control apparatus for a motor-driven power steering system of a motor vehicle for preventing generation of actuation noise of a clutch without sacrificing reliability of the steering system. A current calculating/driving means 91 calculates a motor current command value I0 on the basis of a vehicle speed V and a steering torque T for driving a motor 13. An abnormal torque decision reference value arithmetic means 901 calculates an abnormal torque decision reference value T0 and a reference time t0 in dependence on the vehicle speed V, while a load torque calculating means 902 calculates a load torque TL on the basis of the steering torque T and the motor current command value I0. A motor rotation decision means 907 estimates a rotation number NM of the motor 13 from a motor regeneration voltage. When the load torque TL is greater than the abnormal torque decision reference value T0 and when a duration tL thereof is greater than the reference time t0, power supply to the motor 13 is interrupted under the control of a motor fault monitor/control means 904, provided that the rotation number NM is not greater than a motor stop decision reference rotation number N0. A clutch control means 92B is also so controlled that the steering torque T becomes equal to a preset torque limitation triggering value T1 so that the steering can be performed without encountering any appreciable obstacle.
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Citations
48 Claims
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1. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a vehicle speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor in dependence on said vehicle speed,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value which corresponds to the vehicle speed detected by said vehicle speed detecting means; load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value while decreasing the coupling effort of said coupling effort control means wherein said coupling effort control means comprises an electric clutch and wherein when the coupling effort of said coupling effort control means is decreased, said electric clutch assumes a semi-coupling state. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value in dependence on the vehicle speed detected by said vehicle speed detecting means; assist torque determining means for determining assist torque applied by said electric motor; load torque arithmetic means for arithmetically determining a load torque on the basis of a steering torque detected by said steering torque detecting means and on the determined assist torque; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value while decreasing the coupling effort of said coupling effort control means. - View Dependent Claims (8, 9, 10, 11, 12)
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13. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value and a reference time in dependence on the vehicle speed detected by said vehicle speed detecting means; load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operating of said electric motor when said load torque exceeds said abnormal torque decision reference value and when in duration in which said load torque exceeds said abnormal torque decision reference value is longer than said reference time, while decreasing the coupling effort of said coupling effort control means. - View Dependent Claims (14, 15, 16, 17, 18)
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19. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value and a reference time in dependence on the vehicle speed detected by said vehicle speed detecting means; assist torque determining means for determining assist torque applied by said electric motor; load torque arithmetic means for arithmetically determining a load torque on the basis of a steering torque detected by said steering torque detecting means and on the determined assist torque; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value and when duration in which said load torque exceeds said abnormal torque decision reference value is longer than said reference time while decreasing the coupling effort of said coupling effort control means. - View Dependent Claims (20, 21, 22, 23, 24)
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25. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value in dependence on the vehicle speed detected by said vehicle speed detecting means; load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value while controlling the coupling effort of said coupling effort control means so that the steering torque value detected by said steering torque detecting means does not exceed a predetermined value at which a steering wheel of said motor vehicle can be manipulated by a driver wherein said coupling effort control means comprises an electric clutch and wherein when the coupling effort of said coupling effort control means is decreased, said electric clutch assumes a semi-coupling state. - View Dependent Claims (26, 27, 28, 29, 30)
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31. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value in dependence on the vehicle speed detected by said vehicle speed detecting means; assist torque determining means for determining assist torque applied by said electric motor; load torque arithmetic means for arithmetically determining a load torque on the basis of a steering torque detected by said steering torque detecting means and on the determined assist torque; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value while controlling the coupling effort of said coupling effort control means so that the steering torque value detected by said steering torque detecting means does not exceed a predetermined value at which a steering wheel of said motor vehicle can be manipulated by a driver. - View Dependent Claims (32, 33, 34, 35, 36)
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37. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value and a reference time in dependence on the vehicle speed detected by said vehicle speed detecting means; load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value and when duration in which said load torque exceeds said abnormal torque decision reference value is longer than said reference time while controlling the coupling effort of said coupling effort control means so that the steering torque value detected by said steering torque detecting means does not exceed a predetermined value at which a steering wheel of said motor vehicle can be manipulated by a driver. - View Dependent Claims (38, 39, 40, 41, 42)
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43. In a motor-driven power steering system for a motor vehicle which includes vehicle speed detecting means for detecting a speed of said motor vehicle, steering torque detecting means for detecting a steering torque applied to a steering mechanism of said motor vehicle, and an electric motor operatively coupled to said steering mechanism through the medium of coupling effort control means, wherein an assist torque is applied to said steering mechanism by driving said electric motor,
an apparatus for controlling said motor-driven power steering system, comprising: -
abnormal torque decision reference value arithmetic means for determining an abnormal torque decision reference value in dependence on the vehicle speed detected by said vehicle speed detecting means; assist torque determining means for determining assist torque applied by said electric motor; load torque arithmetic means for arithmetically determining a load torque on the basis of at least a steering torque detected by said steering torque detecting means and on the determined assist torque; torque comparison means for comparing said load torque with said abnormal torque decision reference value; and motor fault monitor/control means for stopping operation of said electric motor when said load torque exceeds said abnormal torque decision reference value and when duration in which said load torque exceeds said abnormal torque decision reference value is longer than said decision reference time while controlling the coupling effort of said coupling effort control means so that the steering torque value detected by said steering torque detecting means does not exceed a predetermined value at which a steering wheel of said motor vehicle can be manipulated by a driver. - View Dependent Claims (44, 45, 46, 47, 48)
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Specification