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  Vehicle motion control systemUSPTO Application #: 20070219690Title: Vehicle motion control system Abstract: A vehicle motion control system is provided. In a first state requiring understeer suppressing control, a controller determines, based on a yaw rate deviation, a first control amount of an actuator selected so as to generate an inward turning moment a vehicle. In a second state requiring spin suppressing control, the controller determines, based on the sideways slip angular velocity, a second control amount of an actuator selected so as to generate an outward turning moment in the vehicle. When the first and second states are concurrent, the controller selects an actuator to be controlled by the larger of the absolute values of first and second cooperative control amounts, and determines a control amount of the selected actuator as the sum of the first and second cooperative control amounts. Accordingly, the understeer suppressing control and the spin suppressing control can be performed in parallel, improving control performance. (end of abstract) Agent: Carrier Blackman And Associates - Novi, MI, US Inventors: Naoto Ohkubo, Osamu Yamamoto, Yuki Ito, Hiromi Inagaki USPTO Applicaton #: 20070219690 - Class: 701 41 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070219690. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001]The present invention claims priority under 35 USC 119 based on Japanese patent application No. 2006-74602, filed on Mar. 17, 2006. The subject matter of this priority document is incorporated by reference herein. BACKGROUND OF THE INVENTION [0002]1. Field of the Invention [0003]The present invention relates to a vehicle motion control system, and particularly to a vehicle motion control system capable of performing, in parallel, motion control based on yaw rate and motion control based on sideways slip angular velocity. [0004]2. Description of the Related Art [0005]Japanese Patent No. 3324965 discloses a vehicle motion control system which performs motion control based on a yaw rate deviation between a reference yaw rate determined based on a steering angle and a vehicle speed, and a detected yaw rate, when the vehicle turns in an understeer state. In addition, the vehicle motion control system performs motion control based on a sideways slip angular velocity when the vehicle turns in an oversteer state. [0006]The oversteer suppressing control, the understeer suppressing control and the spin suppressing control of a vehicle are performed according to yaw rate deviation and sideways slip angular velocity in respective regions illustrated in FIG. 4. In the figure, there is a region where motion control based on yaw rate deviation and motion control based on sideways slip angular velocity overlap each other. Particularly, in a region where understeer suppressing control for suppressing understeer based on yaw rate deviation and spin suppressing control based on sideways slip angular velocity overlap each other, the directions of turning moment required in these controls are opposite to each other. Accordingly, when the understeer suppressing control for suppressing understeer based on yaw rate deviation and the spin suppressing control based on sideways slip angular velocity are performed in parallel to generate a turning moment, either an inward turning moment or an outward turning moment is generated depending on the situation. Thus, the driver of the vehicle has difficulty in predicting whether the motion controls will proceed in a turn accelerating direction or a turn suppressing direction, resulting in a deterioration in vehicle control performance. SUMMARY OF THE INVENTION [0007]The present invention has been achieved in view of the above circumstances, and has as an object to provide a vehicle motion control system which can perform, in parallel, understeer suppressing control based on yaw rate deviation and spin suppressing control based on sideways slip angular velocity, and which can improve control performance. [0008]In order to achieve the above object, according to a first feature of the present invention, there is provided a vehicle motion control system comprising: a steering angle detecting device for detecting a steering angle input by a driver; a vehicle speed detecting device for detecting a vehicle speed; a yaw rate detecting device for detecting a yaw rate of a vehicle; a sideways slip angular velocity detecting device for detecting a sideways slip angular velocity of the vehicle; a reference yaw rate calculating device for calculating a reference yaw rate intended by the driver based on the steering angle detected by the steering angle detecting device and the vehicle speed detected by the vehicle speed detecting device; a yaw rate deviation calculating device for calculating a yaw rate deviation being a deviation between the reference yaw rate calculated by the reference yaw rate calculating device and the yaw rate detected by the yaw rate detecting device; and a control amount determining device which, based on the value detected by the sideways slip angular velocity detecting device and the value calculated by the yaw rate deviation calculating device, selects an appropriate actuator from plural actuators each generating a turning moment in the vehicle, and which determines a control amount of the selected actuator. In a first state where the absolute value of the reference yaw rate is larger by a predetermined value or more than the absolute value of the detected yaw rate, the control amount determining device selects, based on the yaw rate deviation calculated by the yaw rate deviation calculating device, one of the actuators which generates an inward turning moment in the vehicle, and determines a first control amount of the selected actuator. In addition, in a second state where the absolute value of the sideways slip angular velocity detected by the sideways slip angular velocity detecting device exceeds a predetermined value, the control amount determining device selects, based on the sideways slip angular velocity, one of the actuators which generates an outward turning moment in the vehicle, and determines a second control amount of the selected actuator. When the first and second states occur at the same time, the control amount determining device separately determines a first cooperative control amount and a second cooperative control amount based on the first control amount and second control amount having increase/decrease directions opposite to each other. In addition, the control amount determining device selects an actuator to be controlled by the larger of the first cooperative control amount and the second cooperative control amount, and determines a control amount of the selected actuator as the sum of the first cooperative control amount and the second cooperative control amount. [0009]With the first feature, when the first state, in which the absolute value of the reference yaw rate is larger by a predetermined value or more than the absolute value of the yaw rate detected by the yaw rate detecting device, i.e., the state where the understeer suppressing control is required, occurs concurrently with the second state, in which the absolute value of the sideways slip angular velocity exceeds a predetermined value, i.e., the state where the spin suppressing control is required, then the absolute value of the first cooperative control amount dependent on the first control amount for generating an inward turning moment based on the yaw rate deviation is compared with the absolute value of the second cooperative control amount dependent on the second control amount for generating an outward turning moment based on the sideways slip angular velocity. Based on the comparison, the actuator to be controlled by the larger of the first cooperative control amount and the second cooperative control amount is selected, and the control amount of the selected actuator is determined as the sum of the first and second cooperative control amounts. Accordingly, in a state where both the understeer suppressing control and the spin suppressing control are required, the inward turning moment control and the outward turning moment control are prevented from interfering with each other, and thus the understeer suppressing control based on the driver's will is effected even during spin suppressing control, thereby improving control performance. [0010]According to a second feature of the present invention, in addition to the first feature, the device further comprises a lateral acceleration detecting device for detecting a lateral acceleration of the vehicle. The predetermined value is set so as to vary in accordance with the lateral acceleration detected by the lateral acceleration detecting device. [0011]The above-mentioned object, other objects, characteristics, and advantages of the present invention will become apparent from a preferred embodiment, which will be described in detail below by reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0012]FIG. 1 is a block diagram illustrating a configuration of a motion control system according to an embodiment of the present invention. [0013]FIG. 2 is a flowchart illustrating a control amount determination procedure used by the control amount determining device. [0014]FIG. 3 is a graph of lateral acceleration versus side slip angular velocity, illustrating a predetermined value of sideways slip angular velocity for determining whether to perform control of generating an outward turning moment. [0015]FIG. 4 is a graph of yaw rate deviation versus side slip angular velocity illustrating regions where oversteer suppressing control, understeer suppressing control and spin suppressing control are to be performed, respectively. DETAILED DESCRIPTION [0016]First, referring to FIG. 1, a four-wheeled vehicle includes wheel brakes as actuators in the front/rear/left/right sides as follows: a front left wheel brake 5FL; a front right wheel brake 5FR; a rear left wheel brake 5RL and a rear right wheel brake 5RR. When motion control is performed during turning of a vehicle, the one of the wheel brakes 5FL to 5RR which is required for the motion control is selected, and the selected wheel brake performs a braking operation, thereby performing the motion control of the vehicle during turning. [0017]When motion control of the vehicle is performed during turning, a steering angle input by the driver is detected by steering angle detecting device 6, a yaw rate of the vehicle is detected by a yaw rate detecting device 7, a lateral acceleration of the vehicle is detected by a lateral acceleration detecting device 8, and a vehicle speed is detected by a vehicle speed detecting device 9, for example, based on a speed of follower wheels. [0018]The steering angle detected by the steering angle detecting device 6 and the vehicle speed detected by the vehicle speed detecting device 9 are input to a reference yaw rate calculating device 10. The reference yaw rate calculating device 10 calculates, based on the steering angle and the vehicle speed, a reference yaw rate intended by the driver. Further, the reference yaw rate calculated by the reference yaw rate calculating device 10 and the yaw rate detected by the yaw rate detecting device 7 are input to a yaw rate deviation calculating device 11. The yaw rate deviation calculating device 11 calculates a yaw rate deviation that is a deviation between the reference yaw rate and the detected yaw rate. [0019]The yaw rate deviation calculating device 11 performs a procedure of assigning a positive sign to the reference yaw rate and detected yaw rate on a right turn side, and assigning a negative sign to the reference yaw rate and detected yaw rate on a left turn side, for example; and then subtracting the detected yaw rate from the reference yaw rate. Continue reading... Full patent description for Vehicle motion control system Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Vehicle motion control system patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Vehicle motion control system or other areas of interest. ### Previous Patent Application: Method of checking the operating characteristics of an electronic unit designed for a wheel of a vehicle Next Patent Application: Work vehicle steering system with flow-metering curve selection and associated method Industry Class: Data processing: vehicles, navigation, and relative location ### FreshPatents.com Support Thank you for viewing the Vehicle motion control system patent info. 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