Electric power steering apparatus

• US 20050231145A1
• Filed: 02/16/2005
• Published: 10/20/2005
• Est. Priority Date: 04/20/2004
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Nakano, Yasuhiro, Mukai, Yoshinobu, Horii, Hiroaki, Morishita, Fumihiro, Tsurumiya, Osamu, Kuribayashi, Takashi, Takagi, Masanori
• Granted Patent: US 7,042,179 B2
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 5/0487 detecting motor faults B62D5/0496 takes precedence
• CPC Class Codes: B62D 5/0493 detecting processor errors, e.g. plausibility of steering direction

Abstract

An electric power steering apparatus using a brushless motor is disclosed. The electric power steering apparatus has a microcomputer for calculating a target current to the brushless motor on the basis of a torque signal outputted from a steering torque detecting part. The microcomputer has a table stored in ROM. The microcomputer calculates the angular position of the brushless motor by referring to the table on the basis of a signal outputted by a resolver.

Claims

1. An electric power steering apparatus comprising:

a brushless motor for applying a torque to a steering mechanism;

angular position detecting means for detecting an angular position of the brushless motor;

steering input detecting means for detecting a steering input;

control means for calculating a target current on the basis of at least a signal from the steering input detecting means; and

motor driving means for supplying current to the brushless motor,

wherein the calculation of the angular position is carried out with reference to a predetermined table provided in the control means.

2. An electric power steering apparatus according to claim 1, further comprising second control means additional to the first control means, wherein the second control means performs the same angular position calculation as the first control means and an abnormality is detected by a value calculated by the first control means and a value calculated by the second control means being compared.

3. An electric power steering apparatus according to claim 1, further comprising second control means additional to the first control means, wherein the second control means performs the same angular position calculation as the first control means and the first control means and the second control means have direction prohibiting means for restricting rotation of the brushless motor on the basis of a steering input of a driver.

4. An electric power steering apparatus according to claim 1, wherein the angular position detecting means is a resolver and there are further provided sample-hold circuits for sample-holding outputs from the resolver and the first control means outputs a reference clock pulse to the resolver and a sample-hold timing pulse to the sample-hold circuits.

5. An electric power steering apparatus according to claim 2, wherein the angular position detecting means is a resolver and there are further provided sample-hold circuits for sample-holding outputs from the resolver and the first control means or the second control means outputs a reference clock pulse to the resolver and a sample-hold timing pulse to the sample-hold circuits.