JPH01165925A - Method for operating collision experimental apparatus of vehicle - Google Patents

Abstract

PURPOSE:To perform test running at a highly accurate collision speed, by calculating the optimum acceleration curve by estimating the running resistance value of the whole of a system and the damped vibration phenomenon of a traction rope and operating an electromotor according to said curve. CONSTITUTION:The wt. of a vehicle to the tested is performed and acceleration is started on the basis of a preset rising curve and a predetermined current value. At this time, moving body passage detectors are provided at a point (tp1) wherein the sped of the vehicle C to be tested at the starting point and a current value are extremely low and at two points (tp2, tp3) in a relatively low speed region where a rising curve SL is finished and acceleration is performed on the basis of a constant current value and the speeds of a take-up drum at the point of time when the passage at the respective points is detected are set to V1-V3. In the take-up drum, the take-up length of a traction rope is measured. By this method, the take-up length of the traction rope during a period when the vehicle C runs between two points tp1, tp2 is measured. In general, when the running resistance of a car is set F and the speed thereof is set to V, a formula F=A+B.V+CV<2> (A-C are a constant) is formed. Therefore F is a quadratic equation of V and a function can be determined.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention accelerates the vehicle under test by driving the winding drum of the tow rope by a drive motor and pulling the tow rope to reach a predetermined speed. The present invention relates to a method of operating a vehicle collision test apparatus in which the connection between the vehicle under test and a traction rope is cut at a certain point, and the vehicle under test is caused to coast and collide with an object.

``Prior Art'' In general, the traction ropes used in vehicle collision test equipment or methods are used to avoid acceleration and high-speed running of heavy test vehicles, so they naturally have a corresponding strength. Its rigidity is also quite high. However, when considering the length of the towing rope in a high-speed collision test device or method, even if it is an intermediate loop type (only the rope on the towing side), the length of the towing rope must be several hundred, including the length of the test vehicle's running path. In the case of closed-loop type ropes (with a rope also on the rear side of the vehicle being tested), this round trip usually exceeds 1 meter.

Therefore, when the necessary tension is applied to the tow rope to tow and accelerate the vehicle under test, the elongation of the tow rope becomes extremely large, sometimes reaching tens of meters. Therefore, the winding length of the tow rope is not always equal to the distance traveled by the tested vehicle, and the vehicle position can be estimated by the winding length of the tow rope, or the speed of the vehicle can be estimated by the winding speed of the tow rope. It is unreasonable to assume that.

So, should I increase the rigidity of the tow rope?
The higher the rigidity of the towing rope, the thicker the towing rope becomes, the larger the outer diameter of the winding drum and the winding pitch, and the larger the diameter of the sheave, etc. for changing the direction of the towing rope. . Therefore, the size of the machine inevitably increases, which not only impairs the economic efficiency of the machine itself, but also causes a significant increase in motor output due to an increase in the amount of acceleration inertia, resulting in a very redundant and uneconomical device.

On the other hand, since the vehicle under test has a large amount of inertia, the water system can be thought of dynamically as being like a weight attached to the end of a long spring, and the elastic and inertial bodies interact with each other. They influence each other and cause vibration. As a result, when the acceleration changes, the vehicle runs while pulsating at a very low frequency, making it extremely difficult to accurately adjust the speed to a desired value. In order to solve this problem, we have developed a method that changes the tension according to a slope function or transition curve when the acceleration changes (at the start of acceleration and when moving to a constant speed) instead of applying the necessary tension changes all at once. Furthermore, methods have been adopted in which the rope is kept under a certain maximum tension at all times up to the point of separation to prevent it from loosening.

By the way, as a conventional example of this type of driving method,
For example, it is proposed in Japanese Patent Publication No. 55-48252.

This embodiment is described in the scope of claims [(former 1B8)...
..., the speed control system calculates the traveling distance of the test machine by integrating the speed detection amount, ...... (the rest omitted)
"It has said. Here, it seems that the current position of the test vehicle at any given moment is considered and a speed command value is input into the speed control system in accordance with that position, but it takes a lot of time to calculate the basic traveling distance. This is done by integrating the detected amount of rope speed.

However, as mentioned above, the rope stretches when tension is applied, so the amount of rope winding does not match the actual distance traveled by the test vehicle, and it is expected that the integral value of the speed will not match even more. Also, in the latter part of the claims column, the minimum tension amount of the rope is referred to as a tension command function generator that multiplies the characteristics obtained, and ``the minimum tension amount J of the rope means that the rope does not slacken. Although it seems to be the premise,
Considering the elongation of a rope, it is thought that once the maximum tension has been applied to the rope, it is impossible to loosen the tension in order to prevent it from loosening in a strict sense. Mechanically, it would have to be a very difficult method to separate the vehicle under test in this state.

Other embodiments have been proposed in JP-A-57-116237 and JP-A-62-12833; They seem to think that it is equivalent to the mileage of the vehicle under test.
The elongation of the towing rope is not taken into account, and the latter measures the distance as an input variable in the speed pattern calculation device using a winding drum, and the amount of winding of the towing rope on the winding drum and the distance traveled by the test vehicle are calculated. It is not considered that these do not always match.

Furthermore, due to the elasticity of the tow rope, even if the acceleration of the drive motor becomes zero at the breakaway point, the acceleration of the vehicle under test will not become zero. Either a constant-speed running section must be provided, or the dynamic behavior of the rope must be taken into account, and the constant-speed transition curve must be sufficiently gentler than that.

As mentioned above, these methods do not take into account the elongation of the towing rope, so they have the disadvantage that it is extremely difficult to eliminate speed fluctuations due to the dynamic behavior of the rope at the end of acceleration. I'm here.

[Problems to be Solved by the Present Invention] In view of the drawbacks of the conventional methods as described above, the present invention solves the following problems:
First, we focused on the expansion and contraction movement of the towing rope when the acceleration of the vehicle under test changes, or in other words, when the tension of the towing rope changes, which was overlooked in the prior art. In other words, it is assumed that the test vehicle is separated from the tow rope when the test vehicle's acceleration is near zero, which is reasonable for the vehicle and mechanical equipment, and that the elongation of the rope at maximum acceleration is more constant than the acceleration. The problem is that the speed of the winding drum does not match the speed of the vehicle under test, and therefore the speed of the vehicle under test cannot be accurately adjusted to a predetermined target value. In order to find a solution, we are focusing on the expansion and contraction movement of the towing rope.

In other words, considering the tow rope as an elastic body, we set an acceleration decreasing curve that shifts from acceleration to constant speed, taking into account the amount of stretch and response time of the rope, and when a predetermined target speed is reached, the rope contracts at the same time. It is intended to make the movement stable.

Next, after actually starting the experiment, the system has a learning function that calculates the running resistance of the system and corrects the subsequent acceleration curve based on this. With high-speed experimental equipment, the running resistance value of the test vehicle that approaches the target speed becomes quite large, and the value takes various trends depending on the type of test vehicle.On the other hand, The vehicle crash test method is difficult to conduct a test drive in advance, so
It is not possible to accurately set the running resistance value of the vehicle under test before driving. In order to solve this problem, the present invention measures the running resistance of the entire system after the actual experiment has started, estimates the subsequent running resistance value from this, and then measures the running resistance of the test vehicle at a desired speed. The objective is to obtain an ideal acceleration curve to stabilize the speed of the vehicle.

As described above, the present invention provides an operation system for a vehicle collision test that is capable of immediately separating a test vehicle at a predetermined position at a target speed without conducting a test run in advance, and causing the vehicle to collide with an object at a highly accurate collision speed. There's a way to get there.

``Means for Solving the Problems'' In the operating method of the vehicle collision test apparatus of the present invention, the winding drum of the tow rope is driven by a drive motor, and when the vehicle under test reaches a predetermined speed, the tow rope is In a method of operating a vehicle collision test device in which the vehicle under test coasts and collides with an object, the speed of the vehicle under test at least at the starting point of the vehicle under test or near the starting point is extremely low. Acceleration travel path at point tl) 1 and point tp in a relatively low speed range
A moving object passage detector is installed on the acceleration traveling path of No. 2, and the driving force of the drive motor is measured or calculated at these detection points tp1 and tp2, and the winding force between the detection points is determined. Measure the winding length of the towing rope on the drum, estimate the running resistance of the entire system and the damped vibration phenomenon of the towing rope, find the optimal acceleration curve, and then operate the motor according to this curve. It is characterized by

"Embodiment of the Present Invention" Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

First, the present invention drives the winding drum of the traction rope with a drive motor, and when the vehicle under test reaches a predetermined speed, it is disconnected from the traction rope and the vehicle under test is moved. The premise is a method of operating a collision test device in which a vehicle collides with an object by coasting.

Figure 1 shows a method of accelerating the vehicle under test with a constant acceleration by controlling the speed of the drive motor on the winding drum side that winds up the tow rope. Vehicle speed (vertical axis Y)] curve. FIG. 1 shows a conventional example, where the solid line m represents the drive motor and the dotted line VC represents the speed of the vehicle under test C.

Note that tc is the time at which the engagement between the tow rope and the vehicle under test C is severed. In this case, when the drive motor starts accelerating, the rope is stretched by a certain amount, and the speed of the vehicle under test falters and then rises.After that, the rope elongation becomes stable, and the speed of the vehicle under test and the speed of the winding drum are will once have approximately the same value. However, as the speed increases, the running resistance of the entire system increases, and even if the acceleration of the winding drum is kept constant, the elongation of the towing rope increases again and the test vehicle C starts to elongate. The speed gradually decreases compared to the speed of the winding drum.

Therefore, even if the speed of the winding drum approaches the predetermined target separation speed and the speed of the winding drum is adjusted to the predetermined speed according to an acceleration reduction curve based on some calculation, the speed of the vehicle under test at that time The subsequent behavior of the vehicle under test due to the speed and elasticity of the rope is unknown, and the speed of the vehicle under test at the separation point must be accurately adjusted to the target value (in the drawing, the solid line m and dotted line VC are drawn at time tc). ) was difficult.

FIG. 2 shows the same curve in one embodiment of the present invention, in which the solid line Vm represents the drive motor and the dotted line Vc represents the speed of the vehicle under test C. horizontal axis (time) tpl, tp at X
2, tp3 is the time when the test vehicle itself or a moving object such as a towing truck passes the passage detector on the acceleration road. Hereinafter, we will discuss the case where the drive motor is a DC shunt motor, which is common in large-scale crash test equipment, and explain the method in accordance with the order in which the test is actually performed.

First, the weight of the vehicle under test C is set, and acceleration is started using a preset rise curve (current value rise curve) and a predetermined current value. At this time, there is a point at or near the starting point where the speed and current value of the tested vehicle are extremely low (tpl point), and a relatively low speed area where the rising curve S1- ends and acceleration is performed at a constant current value d3. A passing detector for a moving object such as a vehicle or a tow truck (dolly) is installed at the 2-point comb (point 02 and point 3), and winding is performed at the time when the passing of a moving object such as a vehicle or a towing dolly is detected at each of these points. Let the drum speeds be Vl, V2, and V3.

On the other hand, the winding length of the tow rope is measured on the winding drum. For this, it is possible to use the speed detection signal, and if the speed signal is analog, by integrating it, or if the speed detector is a pulse transmitter, by converting the distance pulse, The length of the tow rope can be easily measured. As a result, the winding length of the towing rope while the tested vehicle travels between the points tp1 and tp2 is measured.

In general, if the running resistance of a car is F and the speed is ■, then approximately between F and V, F = A + B −v −+
It is well known that the following formula holds true: -C·V2 (A, B, and C are constants). In addition to the running resistance of the vehicle under test, this system also includes transfer resistance of drums, sheaves, guide rollers, etc., drag resistance of towing ropes, running resistance of dolly, etc. can also be expressed in the form of the sum of the constant, -order function, and quadratic function related to ■ above, so the running resistance of the entire system including these can be rewritten as F=A0B −V0C・■2 I can express myself.

Therefore, since this F is a quadratic expression of ■, it is understood that this function can be determined by obtaining the values of F in three types of ■.

Measurement of the value of F at these three types of V is as follows: tp1,
tl) Measure the torque of the drive motor at that time (dynamometer, torque meter, etc.) at drum speeds V1, ■2, and V3 at the time when the passing of points 2 and tp is detected.
Alternatively, it is naturally possible to measure the tension of the rope (tension roller, etc.) by providing a mechanism, but the driving force can be calculated approximately from the current value of the drive motor, and from this value the inertial body The simplest method is to subtract the driving force for accelerating.

At the tpl point, the speed and driving force are very low, and at the to2 and tp3 points, the current is constant (which can be considered as a constant driving force), and the traction rope changes due to changes in the traction driving force. Since it can be assumed that there is no change in the amount of extension of Even if there is no winding drum, it can be replaced by the speed of the winding drum. Therefore, Vl, V
2. At V3, calculate each F at that time, and from this, the running resistance of the entire system can be calculated. In addition, if it is difficult to secure the time required for calculation, set several types of quadratic curves in advance to shorten the calculation time, and
It is also possible to use a convenient method such as selecting or modifying any one of these depending on the value of F for L, V2, and V3.

In the collision test method, the “time to speed” of the test vehicle
When defining a curve, in the prior art, it is common to set the curve based on acceleration as described above.

However, in the present invention, contrary to conventional wisdom, acceleration is performed so as to keep the torque of the drive motor, that is, the tension of the traction rope constant, without using acceleration as a reference.

This is because the present invention focuses on the expansion and contraction movement of the tow rope, so in order to keep the amount of stretch of the tow rope constant, the method of controlling the acceleration is not intentionally adopted, but the torque of the drive motor is controlled to be constant. method.

By estimating the running resistance curve of the entire system using the above method, on the other hand, by measuring the winding length of the towing rope while the vehicle C runs between the two points tpl and tp, and comparing it with the actual distance during this time. Since it is possible to know the extension of the towing rope until the drive motor produces the specified torque, the spring constant and damping constant of the towing rope (these are known or can be obtained through prior experiments) can be set in advance. By doing so, it becomes possible to determine the critical damping condition for the damped vibration system when transitioning from the acceleration range to the constant speed range, and to set the optimum acceleration reduction curve.

1. Effects of the present invention" In the prior art, as can be seen from the proposals cited in the "Prior Art" section, there are The winding speed of the test vehicle was equated with the running speed of the test vehicle, and the dynamic behavior of the vibration system, which uses an elastic body called a towing rope, was not taken into consideration.

As mentioned above, the present invention considers the towing rope as a spring with a damping effect, takes this characteristic into consideration, and at the same time measures the amount of elongation of the towing rope during towing and the running resistance value of the entire system, and evaluates these results. Since this method uses a method to obtain an acceleration reduction curve using conventional crash test equipment or methods, at the point where the engagement between the test vehicle and the tow rope is severed, the contracting motion of the tow rope causes the test vehicle to This greatly contributes to solving the problem that the speed does not match the speed of the winding drum and the speed of the separated test vehicle does not match a predetermined target speed.

[Brief explanation of the drawing]

Figure 1 shows a conventional example of a vehicle under test.
2 is a curve similar to that in FIG. 1 in an embodiment of the present invention. tpl, tp2, tp3...Time of detection, tc...Time of disconnection between the tow rope and the test vehicle.Patent applicant: Nissan Motor Sales Co., Ltd. Representative: Hikaru Miura, patent attorney
Yasushi @ Figure 2 Wg

Claims (1)

[Claims] 1) Drive the winding drum of the tow rope with a drive motor,
A method of operating a vehicle collision test device in which the test vehicle is disconnected from a tow rope when it reaches a predetermined speed, and the test vehicle coasts to collide with an object, at least at the starting point of the test vehicle. Alternatively, moving object passage detectors are provided on the acceleration travel path at a point tp1 where the speed of the test vehicle near the starting point is extremely low, and on the acceleration travel path at a point tp2 in a relatively low speed range, and these detection points tp1, The driving force of the drive motor at tp2 is determined by measurement or calculation, and the winding length of the traction rope by the winding drum between the detection points is measured, thereby determining the running resistance value of the entire system and the damped vibration of the traction rope. 1. A method of operating a vehicle collision experiment apparatus, characterized in that an optimum acceleration curve is determined by estimating a phenomenon, and thereafter an electric motor is operated according to this curve.