Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
1999-10-08
2001-04-03
Chin, Gary (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S071000, C303S176000, C303S191000
Reexamination Certificate
active
06212463
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antiskid control apparatus for controlling the brake force of a vehicle, based on wheel speeds of the respective wheels.
2. Related Background Art
There are a variety of suggestions about vehicle control apparatus for controlling the vehicle, based on rotational speed signals of the wheels outputted from speed sensors set at the respective wheels, and there exists the antiskid control apparatus as a typical example. Electromagnetic induction type speed sensors are used commonly for detecting the rotational speeds of the wheels in this antiskid control apparatus. The electromagnetic induction type speed sensors are sensors making use of the phenomenon in which rotation of a gearlike sensor rotor causes magnetic flux passing in a coil provided in the sensor to vary with time and generate ac voltage of a frequency proportional to the rotational speed of the sensor rotor.
Incidentally, in cold districts road heaters for snow melting are buried in road surfaces of hills or the like in order to prevent a skid of wheels. Specifically, as illustrated in
FIG. 4
, road heaters
64
for snow melting are buried under the surface of uphill road
60
and under the surface of downhill road
62
, for the purpose of melting snow on the road surfaces and preventing freezing of the road surfaces by heat from the road heaters
64
, thereby preventing a skid of wheels.
SUMMARY OF THE INVENTION
However, since heater current (alternating current of 60 Hz or 50 Hz) flows in the road heaters
64
, the heater current induces an alternating magnetic field where the vehicle is located above the road heaters
64
. This alternating magnetic field varies the magnetic flux passing the electromagnetic induction type speed sensors. There are some cases wherein this variation in the magnetic flux is detected and judged as a certain vehicle speed though the vehicle is at a standstill. When the vehicle goes into the road surface under road heating during execution of antiskid control, the antiskid control is kept on to continue generation of actuator sound and transmission of vibration to the brake pedal.
A challenge of the present invention is to provide an antiskid control apparatus free of the influence of the heater noise from the road heaters.
This antiskid control apparatus is an antiskid control apparatus having magnetic rotational speed sensors provided for respective wheels and adapted to control brake force, based on a speed of a first wheel and a speed of a second wheel during braking of a vehicle, the antiskid control apparatus comprising road surface detecting means for detecting a road surface under road heating, and assuming means for assuming that the vehicle is in a state of a predetermined speed, wherein when the road surface detecting means detects the road surface under road heating during execution of the brake force control of the vehicle and when the assuming means assumes that the vehicle is in the state of the predetermined speed, the brake force control of the vehicle is terminated.
Since this antiskid control apparatus is adapted to terminate the brake force control of the vehicle when the road surface detecting means detects the road surface under road heating and when the assuming means assumes that the vehicle is in the state of the predetermined speed, for example, in the state of the speed for terminating the antiskid control, the antiskid control can be terminated at appropriate timing without degradation of stability of the vehicle even if the vehicle is on the road surface under road heating.
The antiskid control apparatus is characterized in that the road surface detecting means detects the road surface under road heating when the vehicle speed computed from the speeds of the wheels is within a predetermined range throughout a predetermined time. This antiskid control apparatus can detect the road surface under road heating properly, because the road surface under road heating is detected, based on the condition that the vehicle speed is within the predetermined range throughout the predetermined time.
The antiskid control apparatus is characterized in that when the vehicle speed is a reference speed greater than the predetermined speed, the assuming means computes a time necessary for the vehicle to reach the predetermined speed, based on a deceleration computed, and the assuming means assumes after a lapse of the time thus computed that the vehicle is in the state of the predetermined speed. This antiskid control apparatus can terminate the antiskid control at appropriate timing even if the vehicle is on the road surface under road heating.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4984163 (1991-01-01), Kuwana et al.
patent: 5852243 (1998-12-01), Chang et al.
patent: 6089682 (2000-07-01), Ishikawa et al.
patent: 9-226548 (1997-09-01), None
Chin Gary
Oliff & Berridg,e PLC
Toyota Jidosha & Kabushiki Kaisha
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