Apparatus and method for detecting acceleration of motor vehicle with high accuracy and anti-skid control apparatus using the same

Claim 3

An acceleration determining apparatus for a motor vehicle according to claim 1, wherein said mean value of the output of said acceleration sensor is determined in the state where at least undermentioned conditions (a) to (c) are continuously satisfied during said period: (a) accelerations of said wheels determined on the basis of said wheel speeds are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value.

Claim 4

An acceleration determining apparatus for a motor vehicle according to claim 2, wherein said predetermined values used in said conditions (a) and (b) are so selected as to correspond to approximately zero output of said acceleration sensor.

Claim 5

An acceleration determining apparatus for a motor vehicle according to claim 2, wherein said predetermined values used in said condition (c) is so selected as to substantially correspond to a cruising speed of said motor vehicle.

Claim 8

An acceleration determining apparatus for a motor vehicle according to claim 5, wherein said offset quantity value of the output of said acceleration sensor is determined cyclically when said conditions (a) to (c) are satisfied, and further comprising: storage means for storing said offset value and updating said offset value whenever said mean value is newly determined.

Claim 11

An acceleration determining apparatus for a motor vehicle according to claim 7, wherein said mean value of the output of said acceleration sensor is determined in the state where at least undermentioned conditions (a) to (c) are continuously satisfied during said period: (a) accelerations of said wheels are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value.

Claim 16

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: an acceleration sensor for detecting acceleration of said motor vehicle; wheel speed sensors for detecting wheel speeds of individual wheels of said motor vehicle; and a controller for controlling braking forces to be applied to said wheels, respectively, on the basis of differences between a vehicle speed of said motor vehicle and said wheel speeds; wherein said controller includes: means for determining a mean value of the output of said acceleration sensor over a predetermined period when the condition that said motor vehicle is making a substantially straight drive at a substantially constant speed on a substantially level ground surface during said predetermined period is continuously satisfied during said predetermined period; and means for determining said vehicle speed of said motor vehicle during periods subsequent to said predetermined period on the basis of a value obtained by subtracting said mean value from the output of said acceleration sensor.

Claim 17

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: an acceleration sensor for detecting acceleration of said motor vehicle; wheel speed sensors for detecting wheel speeds of individual wheels of said motor vehicle; and a controller for controlling braking forces to be applied to said wheels, respectively, on the basis of differences between a vehicle speed of said motor vehicle and said wheel speeds; wherein said controller includes: means for determining a mean value of the output of said acceleration sensor over a predetermined period when the condition that said motor vehicle is making a substantially straight drive at a substantially constant speed on a substantially level ground surface during said predetermined period is continuously satisfied during said predetermined period; and means for determining said vehicle speed of said motor vehicle during periods subsequent to said predetermined period on the basis of a value obtained by subtracting said mean value from the output of said acceleration sensor.

Claim 18

An anti-skid control apparatus for a motor vehicle according to claim 11, wherein said mean value of the output of said acceleration sensor is determined in the state where at least undermentioned conditions (a) to (c) are continuously satisfied during said period: (a) accelerations of said wheels are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value.

Claim 19

An anti-skid control apparatus for a motor vehicle according to claim 12, wherein said predetermined values employed in said conditions (a) and (b) are so selected as to correspond to approximately zero output of said acceleration sensor.

Claim 20

An anti-skid control apparatus for a motor vehicle according to claim 12, wherein said predetermined values employed in said conditions (c) is so selected as to correspond to substantially a cruising speed of said motor vehicle.

Claim 21

An anti-skid control apparatus for a motor vehicle according to claim 12, wherein said mean value of the output of said acceleration sensor is determined cyclically when said conditions (a) to (c) are satisfied, further comprising: storage means for storing said mean value and updating said mean value whenever said mean value is newly determined.

Claim 22

An anti-skid control apparatus for a motor vehicle according to claim 12, wherein said condition (b) is invalidated when said motor vehicle is driven with four driving wheels.

Claim 23

An anti-skid control apparatus for a motor vehicle according to claim 11, wherein said vehicle speed is determined by integrating a signal derived by subtracting said mean value from the output of said acceleration sensor means.

Claim 24

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: means for determining as an offset quantity a mean value of the output of said acceleration sensor over a predetermined period on the condition that (a) accelerations or decelerations of said wheels, (b) differences in the wheel speed among different wheels, (c) change in the wheel speed of each of said wheels and (d) change in the output of said acceleration sensor means are continuously maintained smaller than respective predetermined values during said period and that the (e) wheel speed of each of said wheels is continuously greater than a predetermined value during said predetermined period; and means for determining said vehicle speed of said motor vehicle during periods subsequent to said predetermined period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 25

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: means for determining as an offset quantity a mean value of the output of said acceleration sensor over a predetermined period on the condition that (a) accelerations or decelerations of said wheels, (b) differences in the wheel speed among different wheels, (c) change in the wheel speed of each of said wheels and (d) change in the output of said acceleration sensor means are continuously maintained smaller than respective predetermined values during said period and that the (e) wheel speed of each of said wheels is continuously greater than a predetermined value during said predetermined period; and means for determining said vehicle speed of said motor vehicle during periods subsequent to said predetermined period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 26

An anti-skid control apparatus for a motor vehicle according to claim 18, wherein said vehicle speed is determined by integrating a signal derived by subtracting said offset quantity from the output of said acceleration sensor.

Claim 27

An anti-skid control apparatus for a motor vehicle according to claim 19, wherein said offset quantity value of the output of said acceleration sensor is determined cyclically when said conditions (a) to (e) are satisfied, further comprising: storage means for storing said mean value and updating said mean value whenever said mean value is newly determined.

Claim 28

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: averaging means for determining a mean value of the output of said acceleration sensor over a defined period during which the condition that said motor vehicle is making a substantially straight drive at a substantially constant speed on a substantially level ground surface during said predetermined period is continuously satisfied during said predetermined period; vehicle acceleration determining means for determining a vehicle acceleration on the basis of changes in the wheel speeds during said predetermined period; subtraction means for subtracting said vehicle acceleration outputted from said vehicle acceleration determining means from said mean value outputted from said averaging means; store means for storing a value obtained from said subtraction as an offset quantity; and means for determining a vehicle speed of said motor vehicle during a period subsequent to said defined period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 29

An anti-skid control apparatus for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: averaging means for determining a mean value of the output of said acceleration sensor over a defined period during which the condition that said motor vehicle is making a substantially straight drive at a substantially constant speed on a substantially level ground surface during said predetermined period is continuously satisfied during said predetermined period; vehicle acceleration determining means for determining a vehicle acceleration on the basis of changes in the wheel speeds during said predetermined period; subtraction means for subtracting said vehicle acceleration outputted from said vehicle acceleration determining means from said mean value outputted from said averaging means; store means for storing a value obtained from said subtraction as an offset quantity; and means for determining a vehicle speed of said motor vehicle during a period subsequent to said defined period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 30

An anti-skid control apparatus for a motor vehicle according to claim 21, wherein said vehicle speed is determined by integrating a signal derived by subtracting said offset quantity from the output signal of said acceleration sensor.

Claim 31

An anti-skid control apparatus for a motor vehicle according to claim 22, wherein said mean value of the output of said acceleration sensor is determined in the state where at least undermentioned conditions (a) to (c) are continuously satisfied during said defined period: (a) accelerations of said wheels are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value.

Claim 32

An anti-skid control apparatus for a motor vehicle according to claim 23, wherein said predetermined values employed in said conditions (a) and (b) are so selected as to correspond to approximately zero output of said acceleration sensor.

Claim 33

An anti-skid control apparatus for a motor vehicle according to claim 23, wherein said predetermined values employed in said conditions (c) is so selected as to correspond to substantially a cruising speed of said motor vehicle.

Claim 34

An anti-skid control apparatus for a motor vehicle according to claim 23, wherein said mean value of the output of said acceleration sensor is determined cyclically when said conditions (a) to (c) are satisfied, and said store means stores said mean value and updating said mean value whenever said mean value is newly determined.

Claim 35

An anti-skid control apparatus for a motor vehicle according to claim 22, wherein said condition (b) is invalidated when said motor vehicle is driven with four driving wheels.

Claim 36

An anti-skid control apparatus for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: averaging means for determining a mean value of the output of said acceleration sensor over a time period on the conditions that accelerations or decelerations of the wheels and differences in the wheel speed among different wheels are both smaller than respective predetermined values and that said motor vehicle is driven with two driving wheels; subtraction means for subtracting said vehicle acceleration determined on the basis of changes in the wheel speeds during said time period from the aforementioned mean value; store means for storing a value obtained from said subtraction as an offset quantity for said acceleration sensor; and means for determining a vehicle speed of said motor vehicle during a period subsequent to said time period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 37

An anti-skid control apparatus for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising: acceleration sensor for detecting vehicle acceleration of said motor vehicle; wheel speed sensors for detecting speeds of individual wheels of said motor vehicle; and control means for controlling braking forces to be applied to said wheels, respectively, on the basis of the outputs of said acceleration sensor and said wheel speed sensors; wherein said control means includes: averaging means for determining a mean value of the output of said acceleration sensor over a time period on the conditions that accelerations or decelerations of the wheels and differences in the wheel speed among different wheels are both smaller than respective predetermined values and that said motor vehicle is driven with two driving wheels; subtraction means for subtracting said vehicle acceleration determined on the basis of changes in the wheel speeds during said time period from the aforementioned mean value; store means for storing a value obtained from said subtraction as an offset quantity for said acceleration sensor; and means for determining a vehicle speed of said motor vehicle during a period subsequent to said time period on the basis of a value obtained by subtracting said offset quantity from the output of said acceleration sensor.

Claim 38

An anti-skid control apparatus for a motor vehicle according to claim 28, wherein said vehicle speed is determined by integrating a signal derived by subtracting said offset quantity from the output of said acceleration sensor.

Claim 39

An anti-skid control apparatus for a motor vehicle according to claim 28, wherein said offset quantity value of the output of said acceleration sensor is determined cyclically when said conditions are satisfied, further comprising: storage means for storing said mean value and updating said mean value whenever said mean value is newly determined.

Claim 40

An anti-skid control method for a motor vehicle for controlling breaking forces applied to individual wheels of the motor vehicle on the basis of difference between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising the steps of: (I) detecting acceleration of said motor vehicle; (II) detecting wheels speed of individual wheels of said motor vehicle; and (III) controlling braking forces to be applied to said wheels, respectively, on the basis of differences between a vehicle speed of said motor vehicle and said wheels speeds; said control step (III) including the steps of: (i) determining a mean value of said detected acceleration over a time period in the state where undermentioned conditions (a) to (c) are continuously satisfied during said time period: (a) acceleration of said wheels are not greater than a predetermined value; (b) differences in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value, and (ii) determining said vehicle speed by integrating a signal derived by subtracting an offset quantity from the acceleration actually detected, said offset quantity being a measured acceleration of said motor vehicle detected during a time when the actual acceleration of said motor vehicle is zero.

Claim 41

An anti-skid control method for a motor vehicle for controlling breaking forces applied to individual wheels of the motor vehicle on the basis of difference between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising the steps of: (I) detecting acceleration of said motor vehicle; (II) detecting wheels speed of individual wheels of said motor vehicle; and (III) controlling braking forces to be applied to said wheels, respectively, on the basis of differences between a vehicle speed of said motor vehicle and said wheels speeds; said control step (III) including the steps of: (i) determining a mean value of said detected acceleration over a time period in the state where undermentioned conditions (a) to (c) are continuously satisfied during said time period: (a) acceleration of said wheels are not greater than a predetermined value; (b) differences in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value, and (ii) determining said vehicle speed by integrating a signal derived by subtracting an offset quantity from the acceleration actually detected, said offset quantity being a measured acceleration of said motor vehicle detected during a time when the actual acceleration of said motor vehicle is zero.

Claim 42

An anti-skid control method for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising the steps of: (I) detecting vehicle acceleration of said motor vehicle; (II) detecting speeds of individual wheels of said motor vehicle; and (III) controlling braking forces to be applied to said wheels, respectively, on the basis of said acceleration and said wheel speeds; said control step (III) including the steps of: (i) determining a mean value of the output of said detected acceleration over a predetermined period in the state where undermentioned conditions (a) to (c) are continuously satisfied during said period; (a) accelerations of said wheels are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value; (ii) determining a vehicle acceleration on the basis of changes in the wheel speeds during said predetermined period; (iii) subtracting said vehicle acceleration outputted from said step (ii) from said mean value outputted from said step (i); and (iv) storing a value obtained from said subtraction as an offset quantity; and (v) determining said vehicle speed by integrating a signal derived by subtracting said offset quantity from the acceleration actually detected.

Claim 43

An anti-skid control method for a motor vehicle for controlling braking forces applied to individual wheels of the motor vehicle on the basis of differences between a vehicle speed and wheel speeds in order to prevent skid of the wheels relative to the ground surface, comprising the steps of: (I) detecting vehicle acceleration of said motor vehicle; (II) detecting speeds of individual wheels of said motor vehicle; and (III) controlling braking forces to be applied to said wheels, respectively, on the basis of said acceleration and said wheel speeds; said control step (III) including the steps of: (i) determining a mean value of the output of said detected acceleration over a predetermined period in the state where undermentioned conditions (a) to (c) are continuously satisfied during said period; (a) accelerations of said wheels are not greater than a predetermined value; (b) difference in the wheel speed among said individual wheels is not greater than a predetermined value; and (c) said wheel speed is continuously higher than a predetermined value; (ii) determining a vehicle acceleration on the basis of changes in the wheel speeds during said predetermined period; (iii) subtracting said vehicle acceleration outputted from said step (ii) from said mean value outputted from said step (i); and (iv) storing a value obtained from said subtraction as an offset quantity; and (v) determining said vehicle speed by integrating a signal derived by subtracting said offset quantity from the acceleration actually detected.