JPH0795074B2 - Track slip detector for bulldozer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a track slip detection device for a bulldozer, and controls, for example, an engine output and a transmission speed stage based on the output from the device of the present invention. However, the application of the present invention is wide, such as the optimization of the pulling force of the bulldozer can be optimized.

(Prior Art) In a bulldozer, crawler belt slip occurs if the load increases during the earth-filling work by the bulldozer and the ripping work by the ripper device, and the work cannot be performed efficiently.

Therefore, as shown in Japanese Patent Publication No. Sho 58-49661, the vehicle speed is detected by the Doppler speed detecting means, and the track slip is detected based on the vehicle speed detected by the speed detecting means and the rotational speed detected by the wheel drive mechanism. It is known to detect the load and thereby reduce the load on the working machine.

(Problem to be Solved by the Invention) The speed detecting means by the Doppler method detects the absolute speed of the vehicle body with respect to the ground, that is, the vehicle speed by transmitting the microwave toward the ground and receiving the reflected wave. Therefore, the output becomes unstable if it is on the surface of water or on uneven terrain, the response time is slow, and if multiple sensors are nearby, it may malfunction, and expensive equipment such as a laser generator may be used. The cost increases because it is used.

Bulldozers are different from ordinary vehicles that run on paved roads.
I was forced to drive on rough roads, which resulted in severe vehicle body inclination.
Therefore, when the bulldozer detects the acceleration and calculates the slip ratio using the acceleration, the detected acceleration contains noise such as a tilt acceleration component, so that an accurate slip ratio cannot be obtained. Therefore, even if the engine output control and the transmission shift control are performed using such a slip ratio, these controls are unstable.

Therefore, an object of the present invention is to provide a track slip detection device for a bulldozer that can solve the above-mentioned problems.

(Means for Solving the Problem) In order to achieve the above object, a track slip detection device for a bulldozer according to the present invention will be described, for example, with reference to FIG. 1. (a) Means for obtaining a theoretical speed V _{THEO of the} bulldozer 15, 1
6 and 12, (b) means 13 for detecting the bulldozer acceleration α ₀ , (c) means 14 for detecting the bulldozer inclination angle θ, and (d) the detected acceleration α ₀ . Means 11 for calculating the actual speed V _CAL by correcting the inclination angle θ, and (e) the slip ratio (= (V of the bulldozer) based on the calculated theoretical speed V _THEO and the calculated actual speed V _CAL.
THEO −V _CAL ) / V _THEO ).

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 to 4.

(1) Structure of the device As shown in FIG. 1, the power generated by the engine 22 is transmitted to the crawler belt 25 through the torque converter 23, the transmission 24, the traveling clutch, and the final deceleration 26 to move forward and backward. At 20, the vehicle body 21 is provided with an acceleration sensor 13 for detecting an acceleration α ₀ in the vehicle front-rear direction, an inclinometer 14 for detecting an inclination angle θ in the vehicle front-rear direction, and a transmission speed stage m for detecting a track speed. Sensor to detect
15 and a tachometer 16 for detecting the torque converter output shaft speed N, and a controller 10 for inputting and calculating the detection signal and outputting a track slip ratio signal S.
Further supplementing, a device which is an application example of the device of the present invention, that is, a controller 30 which inputs the track slip signal S and outputs the operation signals f ₁ and f ₂ of the actuator 30.
An actuator 31 for inputting the signal f ₁ to control the fuel of the engine injection pump, and an actuator 32 for inputting the signal f ₂ to control the shift of the transmission speed stage.
It is a bulldozer to which the device consisting of and is attached.

(2) Description of Operation of Device The operation of this device will be described with reference to FIGS. 1 to 4. First, an outline of the operation of this device will be described. The actual vehicle speed V _caL calculated while correcting the detected acceleration, the torque converter output rotation speed N, the gear ratio K, and the sprocket circumference l were calculated. With theoretical vehicle speed V _THEO The crawler belt slip ratio S is calculated, compared with a predetermined judgment value, and output as an operation signal to an external actuator. Details will be described in order below. First theoretical vehicle speed
As for V _THEO , the torque converter output speed N is detected by the rotation sensor 16, and the gear ratio K is already stored in the controller from the speed stage m detected by the transmission speed stage sensor 15. This is the speed reduction ratio of the speed stage m, and these data and the sprocket outer circumference execution length 1 are calculated as V _THEO = N × K × l. This calculation is performed by the track speed calculating circuit 12 shown in FIG. Done in.

Next, describing the actual vehicle speed V _CaL , V _CaL is V _CaL = ∫
The result calculated as (α-g · sin θ) dt, and α and g · sin θ in the equation will be described below with reference to FIG.

The acceleration sensor 13 detects a combined acceleration α ₀ that is α ₀ = α ₁ + α ₂ + α _3, but the only acceleration component useful for this device is α ₁ . Α ₁ here is Is the acceleration based on the vehicle speed, α ₂ is the acceleration based on the vehicle body inclination θ where α ₂ = g · sin θ, and α ₃ is the acceleration based on the vehicle body vibration, and the measured value is the acceleration consisting of a high frequency component. Therefore, this synthetic acceleration α ₀ is detected by the characteristics of the acceleration sensor 13 as shown in FIGS. Α ₃ is removed by the filter 17 and α ₀ −α ₃ =
It becomes α ₁ + α ₂ . The α ₁ + α ₂ is α in the above formula. The acceleration α is converted into a digital signal by the A / D converter 18 and input to the controller 10. On the other hand, g · sin θ in the above formula is α (= α ₁ + α ₂ )
Is to remove α ₂ from the vehicle body. Specifically, the inclination angle θ detected separately by the vehicle body inclinometer 14 is converted into a digital signal by the A / D converter 18 and input to the controller 10 in the same manner as the input of α. Then, V _caL = ∫ (α−g · sin θ) dt is calculated. Next, the correction calculation will be described. First, regarding the necessity of correction calculation, the first error is the error of the input data, and the second error is the drift error, which prevents the correct crawler track slip ratio from being output as the cumulative error if it is not always corrected. To do. Next, each error correction will be described. As for the first error, in the present embodiment, the input signals α, θ, m, N are read every 0.001 seconds, and V _THEO , V _caL , S are calculated with 20 readings as one unit. To put it simply, an error occurs due to factors such as integrated cumulative error. Therefore, in the present embodiment, the track slip acceleration is used as the criterion for the correction calculation. This is done separately for the past 5 unit data (0.1 seconds). Note Referring to this error, when reviewing the alpha _S, negligible alpha _S becomes error as shown in Figure 3 is the maximum 0.1G occur in one second in this embodiment. Therefore, this is to be compared with the calculated value α _S with α _Smax = 0.005 G / 0.05 sec as the average value of the fluctuation for 0.1 second. That is, if α _S > 0.005 G, the actual vehicle will generate a slip, and the output S is calculated without considering the error. On the other hand, α _S <0.
If it is 005G, if this error is ignored, the slip output S may be transmitted even if there is no slip, so the track slip ratio V _CAL back in component V _CAL the V _CAL at each unit in the past
₌ V caL -0.02α _S, so that V _CAL = as V _CAL -0.04α _S, also correct output signals by shifting the point O alpha _S input acceleration calculating correction put out.

This calculation correction is shown in the flow chart of FIG.
And and.

Next, regarding the second error, the sensing result of the sensor and the calculation performance of the controller may change due to changes in the outside air temperature and humidity, and the calculation result may change with a tendency. Also, sudden change data α, N, θ, m are detected and only at that time is abnormal data (this is not something that can be called an abnormality,
For example, when a shock during gear shifting is normal, but the sensor detects abnormal data and transmits it to the controller), normal output cannot be output unless this is corrected. Therefore, in this embodiment, the α _S is calculated for the past 5 data to obtain the variance S ^2, and this is compared with 0.003 (km / h) ² . If S ² > 0.003, no correction is necessary, and S ² <0.003
If so, I try to correct the drift. This is shown in the flowchart of FIG.

Regarding the output of the crawler belt slip ratio S calculated in consideration of the above corrections, a supplementary note is added. In the present embodiment, if S> 30%, the controller determines whether to reduce the engine speed or the transmission speed stage. 30 is performed, and as a result, f ₁ and f ₂ are output to the respective actuators 31 and 32. Also, if S <10%, the outputs f ₁ and f ₂ for performing the paired operation are transmitted so that the hysteresis operation can be performed on the actual machine.

(3) Results Since the tilt acceleration α ₂ and the vibration acceleration α ₃ are removed from the detected acceleration α _{0 as} described above, an index called the track slip acceleration α _S is provided and the actual speed V
_{Since the CAL} is corrected, the obtained slip ratio will be accurate.

The above operation is shown in the flow chart of FIG.

(Effects of the Invention) As is apparent from the description of the above embodiments, according to the configurations described in the claims, it is possible to obtain a slip ratio that is not affected by the inclination when traveling on a rough road. Therefore, the engine output and the speed stage of the transmission can be optimally controlled based on this slip ratio. Further, for example, there are many inexpensive and simple means for detecting the inclination angle, and correction or the like may be performed by only partially changing the program of the controller such as the microcomputer permanently installed in the bulldozer. , Economically superior.

Since the crawler belt slip ratio can be detected based on the acceleration of the acceleration sensor 13, it can be detected accurately on the surface of water and on uneven terrain, and it does not malfunction, and the cost can be reduced because it can be configured by the acceleration sensor and the arithmetic circuit.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a general view, FIG. 2 is an explanatory view of acceleration detection, FIGS. 3 (g) to (h) are explanatory views of slip acceleration, and FIG. 4 is a flowchart. is there. 10 …… Controller 11 …… Crawler track slip ratio calculation circuit 12 …… Crawler track speed calculation circuit, 13 …… Accelerometer 14 …… Inclinometer, 15 …… Speed stage sensor 16 …… Rotation sensor

Claims (1)

[Claims] 1. A method for obtaining a theoretical speed of a bulldozer, a method for detecting acceleration of a bulldozer, a method for detecting an inclination angle of a bulldozer, and a method for detecting an acceleration of the bulldozer. And means for calculating an actual speed by correcting the detected inclination angle, and (e) means for calculating a slip ratio of the bulldozer from the calculated theoretical speed and the calculated actual speed. A track slip detection device for bulldozers.