US0082390.97B2 (12) United States Patent (10) Patent No.: US 8,239,097 B2 Yasui et al. (45) Date of Patent: Aug. 7, 2012 (54) STEERING CONTROL APPARATUS FORA 6,349,789 B1* 2/2002 Nakano et al. ................ 180,446 VEHICLE 6,360,153 B1* 3/2002 Shinmura et al. ............... TO1/48 6,597,975 B1* 7/2003 Shinmura et al. ............... TO1/48 (75) Inventors: Yoshiyuki Yasui, Nagoya (JP); Hiroyuki 6,856,871 B2 * 2/2005 Mould et al. .................... TO1/41 Kodama, Kariya (JP); Kenji Asano, (Continued) Toyota (JP); Toshihisa Kato, Handa (JP) FOREIGN PATENT DOCUMENTS (73) Assignee: Advics Co., Ltd., Kariya, Aichi Pref. DE 10235039 A1 2, 2004 (JP) (Continued) (*) Notice: Subject to any disclaimer, the term of this OTHER PUBLICATIONS patent is extended or adjusted under 35 German Office Action dated Apr. 15, 2010 issued in the correspond U.S.C. 154(b) by 170 days. ing German Patent Application No. 10 2007 000 319.8-21 and (21) Appl. No.: 12/174,281 English-language translation. (Continued) (22) Filed: Jul. 16, 2008 Primary Examiner — John Nguyen (65) Prior Publication Data Assistant Examiner — Brian J Broadhead US 2008/O281.491 A1 Nov. 13, 2008 (74) Attorney, Agent, or Firm — Buchanan Ingersoll & Rooney PC Related U.S. Application Data (62) Division of application No. 1 1/760,106, filed on Jun. 8, (57) ABSTRACT 2007, now Pat. No. 7,970,513. A steering control apparatus for a vehicle having a power Source for generating power, and drive shafts for transferring (30) Foreign Application Priority Data the power to driving wheels of the vehicle, and a traction control device for controlling braking torque applied to the Jun. 15, 2006 (JP) ................................. 2006-1656.65 wheels. The apparatus comprises a detection device for Jun. 15, 2006 (JP) ................................. 2006-165666 detecting the braking torque applied to the wheels, a calcula tion device for calculating a driving force difference between (51) Int. Cl. the wheels, on the basis of the detected braking torque, a B62D 6/00 (2006.01) power source state detection device for detecting an actuating (52) U.S. Cl. .......................................... 701/41; 180/443 state of the power Source, and a control device for controlling (58) Field of Classification Search .............. 701/41–44, steering torque created by the steering wheel, and applying 701/69; 180/443,446 torque steer reducing torque to the steering wheel. A desired See application file for complete search history. value of the torque steer reducing torque is determined, based on the driving force difference and the actuating state of the (56) References Cited power source. And, the torque steer reducing torque is applied to the steering wheel, according to the desired value of the U.S. PATENT DOCUMENTS torque steer reducing torque, to reduce the torque steer. 6,032,755 A * 3/2000 Blandino et al. .............. 180,446 6,154,696 A 11/2000 Nishi et al. 4 Claims, 17 Drawing Sheets M1 M2 DESIRED VALUE OF Tes POWER STEERING ASSIST TORQUE DRIVING DESRED WALUE OF FORCE TORQUE STEER REDUCING TORQUE MOTOR CONTROL DIFFERENCE FIRST CHARACTERSTC SECOND CHARACTERISTC STATEPOWER SOURCE T FORCEDRIVING - Fd IRANSMISSION Rt. STATE US 8,239,097 B2 Page 2 U.S. PATENT DOCUMENTS JP 2005-67455 A 3, 2005 2003. O158642 A1 8, 2003 Mould et al. wo WO SS A. $39. 2003/022 1898 A1* 12/2003 Yasui et al. ................... 180,446 2004/0167694 A1* 8, 2004 Tamai ............................. TO1/41 OTHER PUBLICATIONS 2006, OO15226 A1 1/2006 Bernzen et al. English-language translation of Chinese Office Action dated Sep. 18, FOREIGN PATENT DOCUMENTS 2009 issued in the corresponding Chinese Patent Application No. EP 1331, 158 A1 T 2003 2007101107699. JP 5-77653 A 3, 1993 JP 11-129927. A 5, 1999 * cited by examiner U.S. Patent Aug. 7, 2012 Sheet 2 of 17 US 8,239,097 B2 U.S. Patent Aug. 7, 2012 Sheet 3 of 17 US 8,239,097 B2 FG. 3 START 1 O1 INTIALIZATIONS O2 NPUT: SENSOR COMMUNICATION SIGNALS O3 PROCESS: SIGNALS CALCULATE: DESIRED WALUE (Tps) 1 O4 OF POWER STEERING ASSIST TORQUE CALCULATE: DESIRED WALUE (Tts) 1 O 5 OF TORQUE STEER REDUCING TORQUE 1 O6 CALCULATE MOTOR CURRENT O7 MOTOR CONTROL RETURN U.S. Patent Aug. 7, 2012 Sheet 4 of 17 US 8,239,097 B2 FG. 4 TORQUE STEER REDUCING TORQUE 2O2 2O3 2O4 205 CALCULATE: DRIVING FORCE DIFFERENCE (AFd) 2O6 TORQUE STEER REDUCING CONTRO CONTROL: TERMINATED 21 O DESIRED WALUE (Tts) OF TORQUE STEER CALUCULATE: DESIRED WALUE (Tts) REDUCING TORQUE - O OF TORQUE STEER REDUCING TORQUE numeroom RETURN U.S. Patent Aug. 7, 2012 Sheet 5 of 17 US 8,239,097 B2 F.G. 5 THROTTLE OPENING: LARGE ENGINE OUTPUT TORQUE (Te) THROTTLE OPENING: SMALL ENGINE SPEED (Ne) F.G. 6 FIRST CHARACTERSTC DES RED WALUE OF TORQUE STEER REDUCING TORQUE (Tts) NEGATIVE POSITIVE SIGN(-) SGN (+) 1. DRWING FORCE < DIFFERENCE (AFd) SECOND CHARACTERISTIC U.S. Patent Aug. 7, 2012 Sheet 6 of 17 US 8,239,097 B2 FG. 7 DRIVING FORCE (Fd): LARGE DESRED WALUE OF TORQUE STEER REDUCING TORQUE (Tts) NEGATIVE SIGN(-) POSITIVE DRIVING FORCE (Fd): LARGE- DRIVING FORCE SGN (+) N-2 DFFERENCE (AFd) 1. M N DRIVING FORCE (Fd): SMALL FIRST CHARACTERISTIC Ttsm ------------------------- DES RED WALUE OF TORQUE STEER REDUCING TORQUE (Tts) NEGATIVE POSITIVE SGN (-) SIGN (+) DRWING FORCE DIFFERENCE (AFd) - - - - - - - - - Y - - a -a - - - - - - - - - - Ttsm2 SECOND CHARACTERISTIC U.S. Patent Aug. 7, 2012 Sheet 7 of 17 US 8,239,097 B2 FG. 9 GRADENT CONSTANT Kits 1 KtS2 DRIVING FORCE (Fd) U.S. Patent Aug. 7, 2012 Sheet 9 of 17 US 8,239,097 B2 F.G. 11 11 O NITALIZATIONS 1 1 O2 INPUT: SENSOR COMMUNICATION SIGNALS 1 1 O3 PROCESS: SGNALS CALCULATE: DES RED WALUE (Tps) 1 1 O4 OF POWER STEERING ASSIST TORQUE CALCULATE: FIRST DES RED WALUE (Tts) 11 O5 OF TORQUE STEER REDUCING TORQUE CALCULATE: SECOND DESIRED WALUE (Tts2) 1 1 O6 OF TORQUE STEER REDUCING TORQUE CALCULATE: DESIRED WALUE (Tts) 1 O7 OF TORQUE STEER REDUCING TORQUE 11 O8 CALCULATE: MOTOR CURRENT 1 1 O9 MOTOR CONTROL RETURN U.S. Patent Aug. 7, 2012 Sheet 10 of 17 US 8,239,097 B2 F.G. 12 CALUCULATE FIRST DESRED WALUE OF TORQUE STEER REDUCING TORQUE 12O1 READ: DRWING FORCE DISTRIBUTION STATE 12O2 CALCULATE: DRIVING FORCE DIFFERENCE (AFd) 12O3 FIRST TORQUE STEER NO REDUCING CONTROL CONTROL: TERMINATED YES 12O6 - 1207 FIRST DESIRED WALUE (Tts 1) OF CALUCULATE: FIRST DESIRED WALUE (Tts 1) TORQUE STEER REDUCING TORQUE - O OF TORQUE STEER REDUCING TORQUE RETURN U.S. Patent Aug. 7, 2012 Sheet 11 of 17 US 8,239,097 B2 F.G. 13 FIRST DES RED WALUE (Tts 1) OF TORQUE STEER REDUCING TORQUE wom-m-ambor DRIVING FORCE DIFFERENCE(AFd) U.S. Patent Aug. 7, 2012 Sheet 12 of 17 US 8,239,097 B2 F.G. 14 CALUCULATE: SECOND DESRED WALUE OF TORQUE STEER REDUCING TORQUE 3O 1 CALCULATE: POWER SOURCE OUTPUT (Te) 13 O2 CALCULATE: GEAR RATIO (Rt) 13O3 CALCULATE: DRIVING FORCE (Fd) 13O4 CALCULATE: DRIVING FORCE WARIATION (dFol) 1305 SECOND TORQUE STEER NO REDUCING CONTROL CONTROL: TERMINATED / 13O8 13 O9 SECOND DES RED WALUE (Tts2) OF CALUCULATE: SECOND DESIRED WALUE (Tts2) TORQUE STEER REDUCING TORQUE - O OF TORQUE STEER REDUCING TORQUE RETURN U.S. Patent Aug. 7, 2012 Sheet 13 of 17 US 8,239,097 B2 F.G. 15 SECOND DES RED WALUE (Tts2) OF TORQUE STEER REDUCING TORQE DRIVING FORCE (Fd) F.G. 16 MODIFIED WALUE (Ttsh) OF TORQUE STEER REDUCING TORQUE DRIVING FORCE WARIATION (dFd) U.S. Patent Aug. 7, 2012 Sheet 14 of 17 US 8,239,097 B2 F.G. 17 In MODIFIED WALUE (Ttsh) OF TORQUE STEER REDUCING TORQUE O TIME F.G. 18 MODIFIED WALUE (Ttsh) OF TORQUE STEER REDUCING TORQUE Ttsm -- Thld TIME U.S. Patent Aug. 7, 2012 Sheet 15 of 17 US 8,239,097 B2 Torv U.S. Patent Aug. 7, 2012 Sheet 16 of 17 US 8,239,097 B2 F. G. 20 WH2 KP2 U.S. Patent Aug. 7, 2012 Sheet 17 Of 17 US 8,239,097 B2 was or im pow we 1-HWHSBAIH0QN00BS||4__ + US 8,239,097 B2 1. 2 STEERING CONTROL APPARATUS FOR A On the other hand, in Japanese Patent Laid-open Publica VEHICLE tion No. 2005-067455, there is disclosed a method for reduc ing the torque steer when a traction control is being per This application is a divisional of application Ser. No. formed. Especially, referring to FIG. 3, it is described that if 11/760,106 filed on Jun. 8, 2007, the entire content of which it is determined that the traction control is being performed, a is incorporated herein by reference. This application claims driving force difference (AFdr) between right and left rear priority under 35 U.S.C. S 119 to Application No. 2006 wheels served as driving wheels is estimated according to a 165665 filed in Japan on Jun. 15, 2006 and Application No. known manner in a technical field in issue, and it is deter 2006-165666 filed in Japan on Jun. 15, 2006, the entire con mined whether the absolute value of the driving force differ 10 ence (AFdr) is larger than a reference value (AEFdr0 of posi tent of both of which is herein incorporated by reference. tive constant), i.e., it is determined whether the torque steer at the time of driving mode will be excessive, or not. If the result BACKGROUND OF THE INVENTION is negative, the torque steer reducing torque (Tdts) at the time The present invention relates to a steering control appara of driving mode is set to be zero.