ELECTRIC POWER STEERING APPARATUS
First Claim
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1. An electric power steering apparatus comprising:
- an electric motor for applying an assistive steering force to a steering system;
a steering torque sensor for detecting a steering torque of the steering system;
a torque sensor circuit for generating a steering torque signal based on the torque detected by the steering torque sensor;
a first electric motor drive signal generator for generating a first electric motor drive signal based on the steering torque signal;
an electric motor driver for driving the electric motor based on the first electric motor drive signal; and
a second electric motor drive signal generator for directly converting the steering torque signal generated by the torque sensor circuit into a second electric motor drive signal, which changes depending on the magnitude of the steering torque signal,wherein, in the event of a failure of the first electric motor drive signal generator, the electric motor driver drives the electric motor based on the second electric motor drive signal, which is generated by the second electric motor drive signal generator.
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Abstract
In the event of a failure of a first electric motor drive signal generator, e.g., the microcomputer, which generates a first electric motor drive signal for performing a feedback control, a second electric motor drive signal generator, e.g., a PWM signal generator, which is made up of discrete circuit components, directly converts a steering torque signal into a second electric motor drive signal. An electric motor, which generates the assistive steering force, is driven by the second electric motor drive signal.
56 Citations
10 Claims
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1. An electric power steering apparatus comprising:
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an electric motor for applying an assistive steering force to a steering system; a steering torque sensor for detecting a steering torque of the steering system; a torque sensor circuit for generating a steering torque signal based on the torque detected by the steering torque sensor; a first electric motor drive signal generator for generating a first electric motor drive signal based on the steering torque signal; an electric motor driver for driving the electric motor based on the first electric motor drive signal; and a second electric motor drive signal generator for directly converting the steering torque signal generated by the torque sensor circuit into a second electric motor drive signal, which changes depending on the magnitude of the steering torque signal, wherein, in the event of a failure of the first electric motor drive signal generator, the electric motor driver drives the electric motor based on the second electric motor drive signal, which is generated by the second electric motor drive signal generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification