JPH0564746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a device for measuring a fall impact occurring on cargo during transportation, and particularly to an impact recording device suitable for determining the falling height of cargo.

[Background of the invention]

Many of the causes of cargo damage during transportation are due to drop impacts, and in order to provide appropriate packaging to prevent damage, it is necessary to know the exact drop height. Conventionally, it was necessary to measure the impact acceleration generated on the cargo, compare it with a number of pre-measured drop height-generated acceleration characteristics depending on the falling posture of the cargo, and convert it into a fall height. It was hot. In addition, there was a problem in that it was difficult to distinguish between impacts that were not caused by a fall, and the height of the fall was converted into the height of the fall.

The invention of this type of device is described in Japanese Patent Application Laid-open No. 50-84279, and the conventional method for determining the height of fall during transportation is described in "Sharp Technical Report" published by Sharp Co., Ltd.
This is discussed in a paper titled ``Analysis of drop impact data generated during logistics processes and its discussion'' by Nishioka et al. in September 1956, No. 21.

[Purpose of the invention]

An object of the present invention is to provide an impact recording device that can directly measure the falling height of cargo during transportation.

[Summary of the invention]

When an object begins to fall freely due to gravitational acceleration,
The gravitational acceleration on the article will be zero. next,
When an article collides with the floor, an acceleration several tens of times the acceleration of gravity is applied. The impact recorder has a function to detect this change in acceleration, measure the falling time, and calculate the falling distance (falling height) from the falling time.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of an impact recording device according to the present invention.

The acceleration detection unit 1 includes an acceleration sensor 1a that converts the acceleration generated in the cargo of the object to be measured into a voltage signal;
The acceleration sensor 1a consists of an amplifier 1b, and the acceleration sensor 1a uses three strain gauge type acceleration converters fixed in three axes directions orthogonal to each other. The voltage signal of the acceleration detected here is passed through the A-D converter 2 and μ-
The data is sent to the arithmetic processing unit 3 using the CPU. Also,
A calendar unit 5 that sends out a time signal and a measurement timing pulse generator 6 are connected to the arithmetic processing unit 3. The memory section 4 consists of a ROM 4a that stores a program for controlling this device and a RAM 4b that stores measurement data.The RAM 4b has a memory function maintained by a dedicated backup battery 8b. The stored measurement data is outputted via the RS-232C interface unit 7 to an external personal computer 9 using an output command. The power used in the entire apparatus is supplied from the measurement battery 8a of the power supply section 8.

FIG. 2 is a timing chart showing the data processing procedure of the embodiment shown in FIG. When a cargo equipped with this device falls from a stationary state and collides with the floor, the acceleration detection section 1 obtains an analog acceleration waveform shown at 1 in the figure. A case will be explained in which a fall occurs in the axial direction of one of the acceleration sensors 1a attached in three directions.

t ₁ is at rest when gravitational acceleration of 1G is detected, t ₂
is the time when the fall started, and _t3 is the time when the cargo collided with the floor. This analog acceleration waveform is sampled in the A/D converter 2 by the timing pulse 2 given from the measurement timing pulse generator 6, converted into a digital signal 3, and sent to the arithmetic processing section 3.

The interval between the measurement timing pulses 2 varies depending on the required accuracy, but is approximately 200 microseconds.

In the arithmetic processing unit 3, a preset reference value is
Compare G _O (for example 0.1G) and digital signal 3,
Time t ₂ when digital signal 3 becomes less than reference value G _O
is stored as the falling start time.

Next, when the cargo collides with the floor, an acceleration of several tens of G is generated, so first, the start-up time _t3 of the acceleration is determined using the falling start determination criterion G _O. After confirming that the next acceleration data exceeds the fall confirmation reference value G _I (for example, 5G), the fall time T is determined as t ₃ −t ₂ and the fall distance (height) due to gravitational acceleration is calculated.

In order to eliminate the effects of vibration, etc., the falling start time
After memorizing t _2, the falling time that cannot occur during normal transportation or cargo handling, for example, 0.6 seconds (fall height approximately 2 m).
If the acceleration signal does not exceed the fall confirmation reference value _GI even after the time period (equivalent to 100%) has passed, it is determined that no fall has occurred, and the setting returns to the initial state. Furthermore, the falling time T is the vibration discrimination time T _O (for example, 0.1 seconds = approximately 5 cm
The device is returned to its initial state even when it is smaller than the drop (equivalent to a fall), so that phenomena caused by collisions with other objects or vibrations are not measured as falls.

The above arithmetic processing is performed in the arithmetic processing section 3, which is composed of a microprocessor or the like.

The processed data is stored in the data recording RAM 4b of the memory section 4.

FIG. 3 shows the above data processing procedure as a flowchart. An example of the data storage contents and format is shown in FIG.

The measurement is terminated in the arithmetic processing unit 3 by detecting the storage capacity of the data recording RAM 4b, but the configuration is such that it can be terminated at any necessary interruption by an external signal.

In the explanation of the above embodiment, the falling start time
Although we used the same acceleration sensor to detect t ₂ and the acceleration sensor to measure the impact caused by a fall, it is also possible to improve measurement accuracy and reduce the cost of the device by using sensors with different measurement sensitivities.

According to this embodiment, the fall height can be directly measured for falls that occur on cargo during transportation, which eliminates the drawbacks of conventional methods in which impact acceleration that is not caused by a fall is mistakenly converted into fall height as being caused by a fall. It can be improved.

〔Effect of the invention〕

According to the present invention, since the falling height of cargo during transportation can be directly measured, there are the following advantages over the conventional method of recording the impact acceleration due to the fall and estimating the falling height from the acceleration.

(1) There is no need to measure the falling height-acceleration characteristic of cargo in order to convert acceleration to falling height.
Data analysis time can be reduced to about 1/10.

(2) Since shocks caused by collisions with other objects can be distinguished from those caused by falls, the number of falls can be accurately determined, making it easier to analyze the conditions of falls during transportation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figures are a data processing timing chart in the embodiment shown in FIG. 1, FIG. 3 is a flowchart in the arithmetic processing section, and FIG. 4 is a format showing an example of recording fall data. 1... Acceleration detection section, 1a... Acceleration sensor,
2... A-D converter, 3... Arithmetic processing unit, 4...
Memory section, 5...Calendar section, 6...Measurement timing pulse generation section, 7...RS-232C interface section, 8...Power supply section, 8a...Measurement battery,
8b...Backup battery, 9...Personal computer, _t2 ...Fall start time, _t3 ...Collision time, T...Fall time, 41...Data No., 43...
...fall height.

Claims (1)

[Claims] 1 An acceleration detector that measures the acceleration generated in the cargo being transported and the output signal of the acceleration detector are input, and the time when gravitational acceleration is no longer detected by the acceleration detector is determined as the time when the object to be measured starts falling. , a calculation processing unit that calculates the fall height due to gravitational acceleration from the fall time, which is the difference between the time when the impact acceleration at the time of fall collision with the floor is detected, and a calculation processing unit that calculates the fall height due to gravitational acceleration. An impact recording device characterized by being equipped with a storage device that records fall height along with acceleration.