JPH10185938A - Method for detecting vehicle speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch speed detectors provided for left and right wheels without causing any abrupt variation in the speed detection values. SOLUTION: A speed detection value Ndet for vehicle control is obtained by switching detection values NL' and NR from speed detectors 5, 6 and a cushion circuit 11 for speed detection selection produces weight functions KL, KR (KL+KR=1.0). The circuit is arranged such that the KL decreases gradually from 1.0 to 0 whereas the KR increases gradually from 0 to 1.0 when a speed detection selection signal PPSEL selects a speed detector 5(L). Detection values NL, NR from the detectors 5, 6 are multiplied by KL, KR by multipliers 13, 14 and added by an adder 15 before being switched by the weight function values KL, KR. Since the detection value Ndet is not varied abruptly by switching, comfortability of a vehicle 1 being controlled through a speed control system 8 is not damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the speed of a vehicle for smoothly controlling the speed and the advance of a moving body such as an automobile having a speed detector mounted on a plurality of wheels.

[0002]

2. Description of the Related Art Generally, many moving objects such as automobiles and trains measure the rotational speed of wheels to measure the speed of the moving object. However, speed detectors may be installed on a plurality of wheels in order to prevent speed detection from being disabled due to abnormal wheel contact or the like.

[0003] However, when traveling on a curve, there is a difference in peripheral speed between the inner and outer wheels. Therefore, when the speed detectors are provided on the left and right wheels of the vehicle, the detected value is higher on the outer peripheral side and lower on the inner peripheral side than the average speed.

FIGS. 9 and 11 show the configuration of a vehicle speed control system having two speed detectors on the left and right sides of the vehicle. In FIG. 1, reference numeral 1 denotes a vehicle, and reference numerals 3 and 4 denote left and right speed detection encoders (P) installed on left and right wheels of the vehicle 1, respectively.
_{P L), (PP R)} , 5,6 is PP _L 3, PP left signal from _R 4 each, right speed detection value N _L, the speed detector changing the N _R, 7 is the speed command value N * And a speed detector 8 for detecting the difference between the speed detection value N _det and the speed detection value N _det .

[0005] The system shown in FIG.
P selection signals (speed detection switching signal) PP left by switch S1 switched by _SEL, right speed detection value N _L,
N and _R are switched are outputted to the deviation detector 7 as a speed detection value N _det.

The system shown in FIG. 11 is provided with an averaging circuit 21 for obtaining an average value of the left and right speed detection values, and the speed detection value _NL or the speed detection value is provided by a switch S2 switched by a PP selection signal PP _SEL from the controller. N _R is configured once to output a speed detection value N _det to the deviation detector 7 switches the speed detection value N _R or N _L after being switched to an average speed detection value from.

[0007]

In the speed control system of FIG. 9 [0005], left by the switch S1 is running at speed setting value N * in the curve, right speed detection value N _L, switching the N _R, FIG. As shown in FIG. 10, the speed control system 8 considers a rapid change in the speed detection value N _det due to the switching of the speed detection value as a change in the actual vehicle speed, and the torque command suddenly changes to control the motor speed of the vehicle 1. Would. As a result, rapid acceleration / deceleration occurs.

In the speed control system shown in FIG. 11, since the average speed detection value is temporarily changed from one speed detection value to the other speed detection value by the switch S2, the speed detection value N _det is changed. Although becomes smaller but changes suddenly, sudden acceleration / deceleration still occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and has as its object to detect the speed of a vehicle in which sudden acceleration / deceleration does not occur when the speed detector is switched. It is to provide a method.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a method for detecting a speed of a vehicle which selects individual speed detection values from a plurality of speed detectors installed in the vehicle to obtain a speed detection value for vehicle speed control. The weight function value for applying a weight function for speed detection switching to each speed detection value from each speed detector by a cushion circuit or a function device, and the weight function value for the detection value of the selected detector gradually increases. , The weight function values for the detection values of the other detectors are generated so as to gradually decrease.

Each of the weight function values is multiplied by a corresponding speed detection value to obtain a speed detection value with a weight function, and the detected speed values are added to obtain a speed detection value for control. When the speed detection value is switched, the ratio of the previously selected detection value gradually decreases when the detection value is switched, and the ratio of the newly selected detection value gradually increases and switches, so that the detection value switches smoothly.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment FIG. 1 shows a configuration of a vehicle speed control system according to a first embodiment. In FIG. 1, reference numeral 1 denotes a vehicle, reference numerals 3 and 4 denote speed detection encoders (PP _L ) and (PP _R ) installed on left and right wheels of the vehicle 1, respectively, and reference numerals 5 and 6 denote _PPL 3, PP _R 4. speed detection signal from the value N _L, the speed detector changing the N _R, 7
Is the speed deviation △ N between the speed command value N * and the detected speed value N _det
A speed control system 8 controls the vehicle by PI-calculating the speed deviation ΔN and outputting a current to the vehicle 1.

[0013] 11 is a cushion circuit speed detection switching, PP selection signal from the controller (speed detection switching signal) PP _SEL is the case of a signal for selecting the PP _L, cushioning signal (weights gradually increasing from 0 to 1.0 outputs a cushion signal K _R which gradually decreases from the function value) K _L and 1.0 to 0, P
When signal P selection signals for selecting the PP _R, 0 to 1.0
In order to gradually increase the cushion signal K _L and K _R from 1.0 to 1.0, two weighting function units are used to maintain the sum of the signals K _L and K _R so as to be 1 and change the signal into an S shape. It is configured.

Reference numeral 13 denotes a speed detection value N _L from the speed detector 5.
A multiplier multiplying a cushion signal K _L from the cushion circuit 11, 14 is a multiplier multiplying the cushioning signal K _R from the speed detection value N _R and the cushion circuit 11 from the speed detector 6, 15 a multiplier 13, 14 And outputs the speed detection value N _det to the speed deviation detector 7.

The operation of this system will be described with reference to FIG. When PP _L is selected by the PP selection signal PP _SEL from the controller as in (a) Figure, gradually increases the cushioning signal K _L from 0 to 1.0 from the cushion circuit 11 as (d) diagrams, The cushion signal K _R gradually decreases from 1.0 to 0. Thus, the speed detection signals output from the multipliers 13 and 14 correspond to changes in the cushion signals K _L and K _R , and the speed detection value N output from the adder 15
_det is switched on gradually N _R from N _L. Further, when the PP _R is selected by the PP selection signal PP _SEL, similarly the speed detection value N _det is switched gradually N _L from N _R.

The speed control system 8 outputs a current output I so that the speed detection value N _det matches the speed command value N *, and the vehicle 1
(B), the speed command value N _det changes smoothly as shown in FIG. 3 (b), and the current output I, that is, the torque, also changes smoothly as shown in FIG.

Therefore, rapid acceleration / deceleration due to switching of the speed detector does not occur.

Second Embodiment FIG. 3 shows the configuration of a vehicle speed control system according to a second embodiment. The same components as those shown in FIG.
The same reference numerals are given and the duplicate description will be omitted.

In FIG. 3, reference numerals 17 and 18 denote switching function units (1) and (2) for switching the speed detection signals N _L and N _R , and their weight function values K _L and K _R are used for PP selection of the PP selection signal. The speed detection values N _L and N _R from the speed detectors 5 and 6 which gradually change in accordance with the mode are input to the weight function values K _L and K _R , respectively.
Is output as the product of An adder 19 adds signals from the function units 17 and 18 and outputs a speed detection value N _det to the speed deviation unit 7. Other configurations are the same as those in FIG.

The operation of this system will be described with reference to FIG. Function unit (1), (2) if the PP selection signal is in a PP average selection mode, each of the weighting function value K _L, K _R is selected together 0.5, the speed detection value N _L, the N _R Each is output at 0.5 times. Turning now to PP _R selection mode, the weighting function value K _L is gradually reduced to 0 from the 0.5, function unit (1) outputs reduces gradually 0 times 0.5 times the N _L . At the same time, the weighting function value K _R is 0.5 to 1.0.
And the function unit (2) gradually increases _NR from 0.5 times to 1.
The output is increased by 0 times.

When the mode shifts from this mode to the PP average selection mode, the weight function value K _L gradually increases from 0 to 0.5, and the function unit (1) gradually increases N _L from 0 to 0.5. And output. At the same time, the function value K _R gradually decreases to 0.5 from the 1.0, function unit (2) outputs gradually reducing the N _R to 0.5 times 1.0 times. Turning this mode to PP _L selection mode, the function value K _L is gradually reduced to 1.0 from the 0.5, function unit (1) is gradually N _L to 1.0 times 0.5 times increase And output. At the same time, the function value K _R gradually decreases to zero from the 0.5, function unit (2) outputs gradually reducing the N _R to 0 times 0.5 times.

As described above, since the function units (1) and (2) are configured, when the PP selection mode changes, that is, when the speed detection values N _L and N _R are switched, the adder 15 outputs. The speed detection value N _det gradually switches from _NL , and the speed detection value N _det does not change suddenly. Therefore, as in the first embodiment, it is possible to perform control without occurrence of sudden acceleration / deceleration due to switching of the speed detector.

Third Embodiment FIG. 5 shows a configuration of a vehicle speed control system according to a third embodiment. This system is provided with a speed detection abnormality judging unit 12 between the speed detectors 5 and 6 and the multipliers 13 and 14 in the system of FIG. In addition to outputting PP _SEL , a normal speed detection value N _L (or N _R ) is output to the multiplier 13 (or 14), and the speed detection value N _R (or N _L ) immediately before the speed detection value becomes abnormal. Is stored and output to the multiplier 14 (or 13).

If one of the wheels of the vehicle 1, for example, the wheel on the side of the PP _R4, has a poor contact with the ground, the speed detection by the PP _R 4 becomes impossible, and the speed detection value N _R from the speed detector 6 becomes negative. An abnormal value N _R 'is obtained as shown in FIG.

The speed detection abnormality determining unit 12 performs determination of the velocity detection error by comparing a speed detection value N _L and N _R from the speed detector 5 and 6, normally as shown in FIG. 6 (a) PP selection signal PP _SEL for selecting the appropriate speed detection value N _L (or N _R )
Is output to the cushion circuit 11 and the normal speed detection value N _L (or N _R ) is output to the multiplier 13 (or 14) to hold the speed detection value N _R (or N _L ) immediately before the abnormality. And outputs the result to the multiplier 14 (or 13).

In the case of a signal which the PP selection signal PP _SEL selects PP _L, as shown in FIG. 6 (d), the cushion circuit 1
The cushion signal (weight function) K _R from 1 is 1.0 to 0
, And at the same time, K _L gradually increases from 0 to 1.0. Therefore, the detected speed value output from multiplier 13 gradually increases like K _L, and the detected speed value output from multiplier 14 is K _L
Increases like _R. If PP selection signal PP _SEL is a signal for selecting the PP _R, cushioning signal K _L, K _R increases and decreases in the opposite as above.

Therefore, as in the case of FIG. 1, control can be performed without causing rapid acceleration / deceleration due to switching of the speed detector, without outputting the PP selection signal from the controller as shown in FIG.

Fourth Embodiment FIG. 7 shows a configuration of a vehicle speed control system according to a fourth embodiment. In this system, a speed detection abnormality determination unit 16 is provided between the function detectors (1) and (2) of the speed detectors 5, 6 and 17, 18 in the system of FIG. A PP selection signal is output to (1) and (2).

The speed detection abnormality determining unit 16 performs the determination of the velocity detection error by comparing a speed detection value N _L and N _R from the speed detector 5 and 6, the function unit (1), (2) the PP selection signal as shown in FIG. 8, (when the PP _L abnormality) speed detection value N _L abnormality and PP selection signal and PP _R selection mode, also,
(When the PP _R abnormality) speed detection value N _R abnormality of PP selection signal and PP _L selection mode. PP _R or PP _L selection mode from PP average mode during normal or PP _R or the function unit when the from PP _L selection mode to PP average mode, (1), the function value K _L of (2), K _R Figure 8, changes as in FIG.

Therefore, as in the case of FIG. 3, control can be performed without causing sudden acceleration / deceleration by switching the speed detectors, without outputting the PP selection signal from the controller as shown in FIG.

Although each of the above embodiments has two speed detectors, it goes without saying that the same can be applied to the case of three or more speed detectors.

[0032]

Since the present invention is configured as described above, the following effects can be obtained.

(1) When a plurality of speed detectors are switched, the speed detection values are switched smoothly, so that the control characteristics shift smoothly.

(2) As a result, a smooth ride without acceleration on transient ripples can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle speed control system according to a first embodiment.

FIG. 2 is a graph showing changes in signals of various parts when the speed detector is switched.

FIG. 3 is a block diagram showing a configuration of a vehicle speed control system according to a second embodiment;

FIG. 4 is a graph showing a change in a function from a function unit when the speed detector is switched.

FIG. 5 is a block diagram showing a configuration of a vehicle speed control system according to a third embodiment.

FIG. 6 is a graph showing changes in signals of various parts when the speed detector is switched.

FIG. 7 is a block diagram showing a configuration of a vehicle speed control system according to a fourth embodiment.

FIG. 8 is a graph showing a change in a function from a function unit when the speed detector is switched.

FIG. 9 is a block diagram showing a configuration of a vehicle speed control system according to a conventional example.

FIG. 10 is a graph showing changes in signals of various parts when the speed detector is switched.

FIG. 11 is a block diagram showing a configuration of a vehicle speed control system according to another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vehicle (motor) 3, 4 ... Speed detection encoder (pulse pickup) 5, 6 ... Speed detector 7 ... Speed deviation detector 8 ... Speed control system 11 ... PP switching cushion circuit (speed switching cushion circuit) 12, 16 ... speed detection abnormality determining unit 13, 14 ... multipliers 15, 19 ... adder 17 ... function 21 ... averaging circuit S1, S2 ... changeover switch PP, PP _L, PP _R ... speed detecting encoder (Pulse pickup) PP _SEL ... PP selection signal (speed detection switching signal) N _L , N _R , N _det ... speed detection value N * ... speed command K _L , K _R ... cushion signal, weight function value I ... current output

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ryuko Matsumoto 2-1-1, Osaki, Shinagawa-ku, Tokyo Inside the Meidensha Corporation (72) Inventor Yasuhiro Yamamoto 2-1-1, Osaki 2-chome, Shinagawa-ku, Tokyo Inside the company Meidensha

Claims (4)

[Claims] 1. A speed detecting method for a vehicle, which obtains a speed detection value for controlling a vehicle speed by selecting individual speed detection values from a plurality of speed detectors installed in a vehicle, when a speed detection selection mode is switched. The sum of the weight function values is 1
A cushion circuit that outputs a weight function value corresponding to each speed detector that gradually changes so that a weight function value corresponding to the newly selected speed detector becomes 1 while maintaining the speed function; A vehicle wherein the detected values are multiplied by the respective weight signals, and the signals are added to obtain a speed detection value for the control, and the speed detection value is switched smoothly when the speed detector is switched. Speed detection method. 2. The speed detection selection mode switching signal according to claim 1, wherein a speed detection abnormality is determined by comparing speed detection values from the speed detectors, and a speed detection selection mode switching signal is output to the cushion circuit. Vehicle speed detection method. 3. A speed detection value for vehicle speed control is selected by selecting individual speed detection values from a plurality of speed detectors installed in the vehicle or a speed detection value obtained by averaging the individual speed detection values. In the obtained vehicle speed detection method, when the speed detection selection mode is switched, the sum of the weight function values is set to 1
A plurality of functions that gradually change so that each weight function value becomes a value corresponding to the selection mode while maintaining the speed, and output the speed detection value from the corresponding speed detector according to each weight function value And a speed detection value for the control by adding the respective speed detection signals whose weight function values have been changed, so that the speed detection value switches smoothly when the speed detector is switched. Vehicle speed detection method. 4. The apparatus according to claim 3, wherein a speed detection abnormality is determined by comparing each speed detection value from each speed detector, and a speed detection selection mode switching signal is output to each function unit. Vehicle speed detection method.