Method of estimating vehicle speed
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorTetsuji Muto
Life of this patent
Estimating the term…
Abstract
In estimating a vehicle speed from a wheel speed and comparing the wheel speed with a reference threshold provided on the basis of that vehicle speed to control the supplying of a hydraulic braking pressure to wheel brakes, when the wheel speed is larger than the estimated vehicle speed, a predetermined value is added to that estimated vehicle speed to amend the latter, and conversely, when the wheel speed is smaller than the estimated vehicle speed, a predetermined value is subtracted from that estimated vehicle speed to amend the latter. Thus, the amended values are used as an estimated vehicle speed for controlling the hydraulic braking pressure.
Claims12
A method of estimating a vehicle speed of a vehicle, comprising estimating a vehicle speed on the basis of a wheel speed and comparing a reference threshold derived from said estimated vehicle speed with said wheel speed to control the supplying of a hydraulic braking pressure to a wheel brake, wherein when the wheel speed is larger than the estimated vehicle speed, a first predetermined value is added to that estimated vehicle speed to give a new estimated vehicle speed, and when the wheel speed is smaller than the estimated vehicle speed, a second predetermined value is subtracted from that estimated vehicle speed to give a new estimated vehicle speed, and wherein said first and second predetermined values are independent of the wheel speed.
A method of estimating a vehicle speed of a vehicle, comprising estimating a vehicle speed on the basis of a wheel speed and comparing a reference threshold devised from said estimated vehicle speed with said wheel speed to control the supplying of a hydraulic braking pressure to a wheel brake, wherein when the wheel speed is larger than the estimated vehicle speed, a first predetermined value is added to that estimated vehicle speed to give a new estimated vehicle speed, and when the wheel speed is smaller than the estimated vehicle speed, a second predetermined value is subtracted from that estimated vehicle speed to give a new estimated vehicle speed, and whenever said wheel speed is greater than said estimated vehicle speed for a time period longer than a predetermined period of time, said wheel is judged to be in a raced condition, and wherein said first and second predetermined values are independent of the wheel speed.
A method of estimating a vehicle speed of a vehicle, comprising estimating a vehicle speed on the basis of a wheel speed and comparing a reference threshold derived from said estimated vehicle speed with said wheel speed to control the supplying of a hydraulic braking pressure to a wheel brake, wherein when the wheel speed is larger than the estimated vehicle speed, a first predetermined value is added to that estimated vehicle speed to give a new estimated vehicle speed, and when the wheel speed is smaller than the estimated vehicle speed, a second predetermined value is subtracted from that estimated vehicle speed to give a new estimated vehicle speed, wherein said first and second predetermined values are independent of the wheel speed;
- and wherein a wheel speed of said driving wheel is normally used as said wheel speed, and when said driving wheel is detected to be in a raced condition, a wheel speed of said driven wheel of the vehicle is substituted for said wheel speed of said driving wheel.
A method of estimating a vehicle speed of a vehicle, comprising estimating a vehicle speed on the basis of a wheel speed and comparing a reference threshold derived from said estimated vehicle speed with said wheel speed to control the supplying of hydraulic braking pressure to a wheel brake;
- wherein, when the wheel speed is larger than the estimated vehicle speed, a first predetermined value is added to that estimated vehicle speed to give a new estimated vehicle speed, and when the wheel speed is smaller than the estimated vehicle speed, a second predetermined value is subtracted from that estimated vehicle speed to give a new estimated vehicle speed;
- wherein, said vehicle speed is independently estimated from speeds of driving and driven wheels of said vehicle, and one of thus estimated vehicle speeds is selectively used, depending upon rotational conditions of said driving and driven wheels, to control the supplying of the hydraulic braking pressure to the wheel brakes for said driving and driven wheels;
- wherein said first and second predetermined values are independent of the wheel speed and wherein, one of said driving and driven wheels is not in a raced condition, and estimated vehicle speed given from said one wheel is used, and when said one wheel is in a raced condition, an estimated vehicle speed given from the other wheel is used.
An apparatus of estimating vehicle speed, comprising an arithmetic circuit including a wheel speed input terminal to which is inputted a wheel speed of a wheel of a vehicle, the arithmetic circuit further including a comparator circuit having input terminals and an output terminal, first and second transistors connected in series with each other and having bases connected to the output terminal of said comparator circuit, a buffer circuit having input terminals and an output terminal, and a capacitor which is grounded, a junction between said first and second transistors being connected to one of the input terminals of said buffer circuit, said capacitor being connected to a point between said junction and said buffer circuit, wherein said wheel speed input terminal is connected to one of the input terminals of the comparator circuit and said output terminal of the buffer circuit outputs an estimated vehicle speed and is connected to another of the input terminals of the comparator circuit, and wherein said first transistor and said second transistor are associated with respective constant-current circuits in such a manner that when the output terminal of said comparator circuit generates an output of a low level due to the estimated vehicle speed being smaller than the wheel speed, a constant current is charged into said capacitor from one of the constant-current circuits connected to a power source via its associated transistor whereas when the output terminal of said comparator circuit generates an output of a high level due to the estimated vehicle speed being larger than the wheel speed, a constant current is discharged from said capacitor by means of the other of the constant-current circuits and its associated transistor.
Dependencies are inferred from the claim text.