Vehicle digital movement data recording apparatus

The main purpose of a vehicle digital movement data recording apparatus according to the present invention is to cope with a shortage of the memory space in the digital movement data recording area of an external record medium. For completing this objective, the recording apparatus, includes a digital movement data generating device for supervising the moving state of the vehicle and producing the digital movement data thereof. A storage device records the digital movement data produced by the digital movement data generating device onto a digital movement data recording area of an external record medium which can be loaded into and unloaded from the recording apparatus. A detecting device detects the situation that there is no more available space for recording the digital movement data the data recording area of the external record medium. When the detecting device detects that there is no available space for recording the movement data in the digital movement data recording area of the external record medium, the storage device records such data as travel starting time, terminating time and a travel distance of the vehicle of each vehicle movement in a memory shortage compensation area provide in an optional recording area of the external record medium.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a digital movement data recording apparatus for 
recording vehicle movement data indicating moving conditions of a vehicle 
such as speed and travel distance onto an external record medium. 
2. Description of the Prior Art 
Vehicle movement data recording apparatuses of the type mentioned above are 
carried on a vehicle for first monitoring the moving state of the vehicle 
to produce digital movement data indicating moving conditions of the 
vehicle, and then compressing the above digital movement data in 
accordance with a predetermined set value so as to finally record the thus 
compressed digital movement data onto an external record medium. The 
external record medium is made of an IC (Integrated Circuit) memory card 
and so forth which can be loaded into and unloaded from the recording 
apparatus, and the data recorded on the external record medium is read out 
by an analyzing apparatus installed at an office for the supervision of 
movements of vehicles from such record medium and expanding and analyzing 
the thus read digital movement data. 
More specifically, the digital movement data recording apparatus comprises 
a CPU (micro-computer) for sampling and receiving electric signals from a 
rotation sensor which is connected to a transmission mechanism of the 
vehicle, by way of a suitable connecting means, and determining an 
instantaneous speed and a travel distance of the vehicle by calculation in 
accordance with the thus received electric signals and executing various 
jobs including compression of data in preparation for recording of the 
speed data and travel distance obtained by the calculation as digital data 
onto an external record medium. 
The above described vehicle movement data digitally recorded in an external 
record medium is excellently effective for supervision of the moving state 
of the vehicle. 
However, with the conventional recording apparatus described above, since 
recording capacity of the external record medium is limited, the recording 
capacity runs short in accordance with the normal recording operation of 
the digital movement data, and as a matter of fact there will be an 
occasion that there is no recording space left in the record medium for 
recording the movement data and that no further data can be recorded after 
the point where the recording capacity has run out, with the result that 
one can not attain the complete recorded data. The same thing can happen 
when an external record medium with no recording space is loaded into the 
recording apparatus, in which case there will be absolutely no recorded 
data left. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a digital movement data 
recording apparatus which can avoid the situation that no digital movement 
data is recorded onto the external medium due to a shortage of the 
recording capacity of the external record medium. 
In order to attain the objectives, there is provided a digital movement 
data recording apparatus, as shown in FIG. 1, which comprises a vehicle 
movement data generating means 11a for supervising the moving state of the 
vehicle and producing the digital movement data thereof, a storage means 
11b for recording the digital movement data produced by the digital 
movement data generating means 11a onto a digital movement data recording 
area 15a2 of an external record medium 15 which can be loaded into and 
unloaded from the recording apparatus and a detecting means 11c for 
detecting the situation that there is no more available space for 
recording the digital movement data in the data recording area 15a2 of the 
external record medium, wherein when the detecting means detects that 
there is no vacancy for recording the movement data in the digital 
movement data recording area of the external record medium, the storage 
means 11b records such data as travel starting time, terminating time and 
a travel distance of the vehicle of each movement in the optional 
recording area 15a3 of the external record medium. 
As shown, in FIG. 1, the external record medium 15 includes an optional 
recording area 15a3, wherein when there is no recordable space left in the 
digital movement data recording area 15a2, the data such as travel 
starting time, terminating time and a travel distance of each one movement 
of the vehicle are recorded in the optional recording area, and 
subsequently, even when there is no available space left for recording 
digital movement data in the external record medium 15, a minimum 
necessary data can still be obtained, avoiding the occurrence of the state 
that there is no digital data recorded in the external record medium 15 
due to a shortage of the recording capacity thereof. 
The above and other objects, features and advantages of the present 
invention will become apparent from the following description and the 
appended claims, taken in conjunction with the accompanying drawings in 
which like parts or elements are denoted by like reference characters.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 2, there is shown one preferred embodiment of a vehicle 
movement data recording apparatus according to the present invention. The 
digital movement data recording apparatus includes a CPU (micro-computer) 
11 which operates in accordance with a preset program. The CPU 11 
comprises a ROM 11a (read-only memory) having a control program for 
regulating the operation thereof, and a RAM 11b (random access memory) for 
recording various data formed during the data processing operation of the 
CPU 11. The CPU 11 is connected to a rotation sensor 12, a connector 13 
and a clock 14 to measure real time, and the connector 13 is removably 
connected to an IC memory card 15 used as an external record medium which 
can be loaded into or unloaded from the connector. 
The rotation sensor 12 is connected to a transmission mechanism of the 
vehicle by a suitable connecting means (no shown), and generates electric 
pulse signals in accordance with the speed of the vehicle, which signals 
are further supplied to the CPU 11. 
The CPU 11 samples and receives the electric signals generated from a 
rotation of the sensor 12 to thereby produce digital movement data 
comprising an instantaneous speed and a travel distance of the vehicle by 
calculation in accordance with the thus received electric signals, and 
record the thus produced data into an IC memory card 15 used as an 
external record medium through data compressing processing. In the above 
occasion, when the IC memory card 15 is loaded into the recording 
apparatus and connected to the connector 13, the various data recorded in 
the IC memory card 15 are read out, and/or the compressed digital movement 
data and so on are written into the IC memory card 15. 
The clock 14 connected to the CPU 11 forms and outputs time information 
including data of a year, a month, a day, an hour and a minute, which are 
incremented at predetermined time intervals. 
The IC memory card 15 includes a memory 15a in which one word is structured 
of eight bits (one byte) as shown in FIG. 3. In the memory 15a, there are 
formed an ID data recording area 15a1 for recording ID data, a digital 
movement data recording area 15a2 for recording such data as speed and 
travel distance and an optional recording area 15a3. 
In the ID data recording area 15a1, the data such as speed sampling time, 
speed allowance, movement starting time, movement terminating time, speed 
record terminating address and travel distance record terminating address 
and so on are recorded. 
On the other hand, the digital movement data recording area 15a2 is 
partitioned into a speed data recording area 15a21 and a travel distance 
recording area 15a22 respectively for recording speed and travel distance 
of each movement. In the optional recording are 15a3, there is provided a 
memory shortage compensation area 15a31 to cope with a shortage of the 
available recording space in the digital movement data recording area 
15a2, which compensation area 15a31 is further partitioned into such areas 
as 15a311 for recording the number incremented in accordance with the 
compensatory recording operation of each movement of the vehicle after 
recording capacity of the digital movement data recording area 15a2 is 
reduced to a stage less than a predetermined value, and other areas 15a312 
to 15a314 respectively recording a starting time, travel distance and 
terminating time of each movement. 
The allowance for the speed data recorded in the above ID data recording 
area 15a represents the error range allowed at the time of recording, 
which allowance is related to precision of the speed data simultaneously 
collected with the sampling time, so that the precision of the data 
obtained by the compression processing depends on the allowance and 
sampling time, and these data are absolutely essential for data expansion 
and analysis on the analyzing side. Further, time data comprising the 
starting time and terminating time respectively recorded at the start and 
the end of each movement are important when analysis is made with the 
digital movement data distributed over the period between the starting 
time and the terminating time thereby to find out the state of speed at 
each point of time in-between. 
One movement is defined, for example, as the time interval between the 
loading of the IC memory card into the digital movement data recording 
apparatus and the removing of the same from the recording apparatus. 
The CPU 11 inputs electric pulse signals generated from the rotation sensor 
12 in accordance with the movement of the vehicle and calculates the 
number of pulse signals, and then determine the speed of the vehicle from 
a difference of the number of pulse signals between predetermined sampling 
times stored in the RAM 11 so as to produce digital speed data based on 
the thus calculated speed. Where after, the CPU 11 determines whether or 
not there is enough recording capacity in the digital movement data 
recording area 15a2 of the Ic memory card, and when there is still more 
capacity than that of a predetermined level, the CPU 11 compresses the 
thus produced digital speed data in accordance with the speed allowance 
which is stored in a predetermined area of the RAM 11 and then records it 
in the speed data recording area 15a21 of the IC memory card. Further, the 
CPU determines a digital travel distance data by supervising whether a 
predetermined distance has been traveled at each predetermined interval, 
and then compresses the thus determined data and records it in the travel 
distance recording area 15a22 of the IC memory card 15. Still further, in 
the recording operation of the digital movement data, if the above data 
are the first data of the starting time and the last data of the 
terminating time of each movement, the CPU 11 records respective time data 
issued by a clock 14 into the ID data recording area 15a1. Then, when the 
CPU determines that the capacity of the digital movement data recording 
area 15a2 of the IC memory card 15 is running short, and finally has come 
to the stage less than a predetermined value, then it starts recording a 
starting time, travel distance and a terminating time, and also the number 
of recording operations incremented by each movement in the memory 
shortage compensation area 15a31 in the optional recording area 15a3. 
Compression processing of an instantaneous speed in the vehicle digital 
data recording apparatus is executed based on the following idea. In 
particular, if a tolerance or allowance to be allowed for each sampled 
speed value is set in advance and a straight line intersecting the 
allowance is considered, then the straight line represents vehicle speed 
information within the allowance. Then, if the length of the straight line 
is represented by and recorded in a sampling number or number of samples 
and a value of a last end of the straight line is also recorded, then the 
vehicle speed for a period of time covered by the straight line can be 
supervised periodically. If the vehicle speed is stored only in length of 
the straight line and last point data in this manner, then much 
information can be stored in a small amount of data, and accordingly, 
compression of data is realized. 
FIG. 4 illustrates a relationship among vehicle speeds V0 to V11 at 
sampling points of time t0 to t11, and each of broken lines in FIG. 4 
represents an allowance of a vehicle speed. 
It is examined whether or not there exists, at each sampling point of time, 
a straight line which intersects the allowance of data at any preceding 
sampling point of time. While such straight line exists at the sampling 
points of time t0 to t9, no such straight line exists at the sampling 
point of time t10. In this instance, among various straight lines which 
include the starting point V0 and intersect an allowance, a straight line 
L2 passing an upper limit and another straight line L1 passing a lower 
limit are drawn, and a middle point V of that range of the allowance for 
the last sampling data V9 which is defined by the straight lines L1 and L2 
is determined as data of the last point and the length is determined to be 
"9". The last point is determined as a starting point of a next straight 
line, and similar operation is performed successively after then. By such 
compression processing as described above, compressed speed data are 
recorded in a sampling number and a speed into the IC memory card 15. 
The IC memory card 15 into which digital vehicle movement data have been 
recorded by the recording apparatus is unloaded from the recording 
apparatus, and then loaded into the analyzing apparatus not shown in order 
to make an analysis of the digital movement data stored in the IC memory 
card 15. 
Referring now to FIG. 5, there is shown a flow chart illustrating operation 
of the digital movement data recording apparatus to be executed in 
accordance with a control program. 
The CPU 11 of the digital movement data recording apparatus starts its 
operation when power is made available and first at step S1, the CPU 11 
executes its initialization to clear the initial flag, that is, to set the 
flag to "0", which flag is assigned to a predetermined area in the RAM 11b 
of the CPU 11. Subsequently, the control sequence advances to step S2 at 
which the CPU 11 determines in accordance with a signal from an ignition 
detecting circuit (no shown) of the vehicle whether or not an ignition 
switch (not shown) of the vehicle is switched on. If the ignition switch 
is off, then the CPU 11 puts itself into a sleeping condition at step S3, 
and then the control sequence returns to step S2 so as to determine 
whether or not the ignition switch is switched on. Then after the 
determination of YES is obtained at step S2, the control sequence advances 
from step S2 to step S4. At step S4, it is to be determined whether or not 
an IC memory card 15 is loaded in a state that the recording is possible 
and that it is ready to record. Then, if the determination at step S4 is 
YES, the control sequence advances to step S5 at which it is determined 
whether or not the initial flag is equal to "1". In case the determination 
at step S5 is NO, the control sequence advances to step S6 at which the 
time data received from a clock 14 is recorded into the ID data recording 
area 15a1 as a vehicle movement starting time, and then to step S7 at 
which the initial flag is set to "1". 
After then, the control sequence advances to step S8 at which data are 
collected, and then further advances to step S9. At step S9, it is 
determined whether or not there is still recording capacity in the digital 
movement data recording area 15a2 of the IC memory card 15, and if there 
is still recording capacity of more than a predetermined level, then the 
control sequence advances to step S10 at which a speed data is determined 
by calculation and the thus determined speed data is recorded in the speed 
data recording area 15a21. Then the control sequence advances to step S11, 
at which it is determined whether or not the vehicle has traveled a 
predetermined distance, and if the determination here is YES, then the 
control sequence advances to step S12 at which the detected travel 
distance data is recorded in the travel distance data recording area 15a22 
of the IC memory card 15, the recording of this travel distance data is 
executed by incrementing each byte of the IC memory card 15, and then the 
control sequence returns to step S2. If the determination at step S11 is 
NO, then the control sequence directly returns to step S2 without 
executing the processing operation of step S12. 
In the above case, when the initial flag is set to "1" in step S7, the 
determination at step S5 thereafter becomes YES, so that after execution 
of step S5 the control sequence advances directly to step S8 without 
executing operations at step S6 and step S7. 
If, as a result of the determination at step S9, it is determined that 
there is not enough recording capacity in the digital movement data 
recording area 15a2 of the IC memory card 15, the control sequence 
advances to step S13 at which it is determined whether or not a starting 
time of the present movement is recorded in the memory shortage 
compensation area 15a31 of the optional recording area 15a3. Then if the 
result of the determination at step S13 is NO, the control sequence 
advances to step S14 at which the time data of the clock 14 is recorded in 
the memory shortage compensation area 15a31 of the optional recording area 
15a3 as a starting time, and simultaneously the number of recording 
operation in the memory shortage compensation area 15a31 is incremented, 
and then the control sequence advances to step S15 at which it is 
determined whether or not the vehicle has traveled a predetermined 
distance, and if the determination here is YES, then it returns to step S2 
after recording travel distance data at step S16. If the determination is 
NO, then the control sequence returns to step S2 jumping off step S16. 
If the determination at step S4 is NO, in other words, in case the IC 
memory card 15 is not ready to record, the control sequence advances to 
step S17 at which it is determined whether or not the initial flag is 
equal to "1", and if the determination here is NO, the control sequence 
returns to step S2. On the contrary, if the determination at step S17 is 
YES, then the control sequence advances to step S18 at which the time data 
from the clock 14 is recorded in the ID data recording area 15a1 or in the 
optional recording area 15a3, and then advances to step S19 at which the 
initial flag is set to "0" to finally return to step S2. 
As described above, in accordance with the flow chart in FIG. 5, even when 
there is no recording capacity left in the digital movement data recording 
area in which speed data and travel distance data are to be recorded, a 
travel distance, a starting time and terminating time of each movement are 
recorded in the optional recording area 15a3, it is much more convenient 
from the vehicle movement managing point of view than prior recording 
apparatuses in which there will be no data recorded if there is no 
recording capacity left in the data recording area. 
As all described above, since the recording apparatus according to the 
present invention comprises an optional recording area in an external 
record medium, and record a travel distance, a starting time and 
terminating time of each movement in case there is no recording capacity 
in the digital movement data recording area thereof, a driver can always 
obtain minimum information even when there is no recording capacity in the 
digital movement data recording area of the external record medium, 
hampering the occurrence of the situation that there is no digital data 
recorded due to a shortage of the recording capacity of the external 
record medium. 
Having now fully described the invention, it will be apparent to one of 
ordinary skill in the art that many changes and modifications can be made 
thereto without departing from the spirit and scope of the invention as 
set forth herein.