JPH0255246B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a platform vehicle speed control device.

In order to test the durability of a vehicle, the vehicle is driven on a platform equipped with rotating rollers.

When driving a vehicle on a bench, this invention controls the throttle opening in response to large fluctuations in the load torque, which is typically caused by vehicle running resistance, so that the vehicle speed faithfully returns to the target speed. The purpose is to control it so that it follows.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a command generator, which issues command vehicle speed V(t) and command load torque R(t) according to a predetermined vehicle speed pattern and torque pattern. Each command is expressed as a function of time.

2 is the commanded vehicle speed V(t) given as the target value
This is a deviation device that detects the deviation between the vehicle speed when the test target vehicle (hereinafter referred to as the target vehicle) is being driven on the bench, and the deviation value from this is detected by the control amplifier 3.
It is increased in width. 4 is an adder, and 5 is a deviation device, which detects the deviation between the output of the adder 4 and a signal corresponding to the throttle opening of the target vehicle. This deviation value is amplified by a control amplifier 6 and given by an operating device 7 that operates the throttle opening of the target vehicle. This causes the target vehicle's accelerator pedal to be operated. Further, the amount of operation by the operating device is detected as a throttle opening position by a position detector 8, and is provided to a deviation device 5 as a signal corresponding to the throttle opening position. The deviation device 5, control amplifier 6, operating device 7, and position detector 8 are a minor loop of the vehicle speed control system. The vehicle speed of the target vehicle is detected by a vehicle speed detector 9 and provided to a deviation device 2.

The command load torque R(t) is given as a target value to the deviation device 10, and the deviation from the load torque of the target vehicle is calculated. This deviation value is amplified by a control amplifier 11 and then by a current amplifier 12. As will be described later, this amplified output applies a load torque to the target vehicle running on the platform, and is specifically used to cause current to flow through the dynamometer. The load torque applied to the target vehicle is detected by detector 1.
3 and provided to the deviation device 10.

The target vehicle 14 is placed on rollers 15 that are rotatably supported. A flywheel 17 having an inertia equivalent to that of the target vehicle 14 and a dynamometer 18 acting as a load on the roller 15 are attached to the rotating shaft 16 of the roller 15. The operating device 7 is installed to operate the accelerator pedal of the target vehicle 14, and the operating device 7 is installed to operate the accelerator pedal of the target vehicle 14.
The rotational speed is detected by the vehicle speed detector 9 as the vehicle speed of the target vehicle 14. Current from current amplifier 12 is supplied to the coil of dynamometer 18 .
As this supplied current increases, the rotational load on the roller 15 increases. The torque of the dynamometer 18 is detected by the torque detector 13 as the load torque of the target vehicle. When the engine of the target vehicle is accelerated, that is, when the roller 15 acts as a load from the viewpoint of the target vehicle 14, a positive torque is output from the detector 13, and conversely, when engine braking is applied, That is, roller 1
5, when the target vehicle 14 acts as a load, negative torque is generated. 20 is an arithmetic unit that converts the load torque into engine output torque, and 22 is a second
This is a storage device that stores an engine output torque curve as shown in the figure. Reference numeral 23 denotes an arithmetic unit for interpolating the throttle opening value.

In the above configuration, each command is issued from the command generator 1 while the engine of the target vehicle is driven. If there is a difference between the vehicle speed of the target vehicle 14 detected by the vehicle speed detector 9 and the commanded vehicle speed V(t), a deviation value is output from the control amplifier 3. Here, assuming that there is no adder 4, the deviation value is calculated by the deviation device 5 from the signal from the position detector corresponding to the throttle opening of the target vehicle at that time, and the throttle opening is determined. The signal is applied to the control amplifier 6 as a signal. As a result, the amount of operation by the operating device 7 is increased or decreased so that the vehicle speed of the target vehicle 14 always matches the commanded vehicle speed. Also, in this driving process, the dynamometer 18 is controlled according to the commanded load torque R(t) and acts as a load on the roller 15, so the target vehicle 14 is operated in a state where it receives a load torque according to the commanded load torque. That will happen.

By the way, in the above configuration, it is assumed that the command load torque R(t) fluctuates greatly at a certain point in time, and as a result, the deviation value from the deviation device 2 becomes large. Originally, the above-mentioned correction operation is performed using the gain of the control amplifier 3 based on this deviation value, but if the load torque fluctuates greatly, this gain is not infinite, so the correction operation is performed. becomes insufficient, and the deviation value increases. This makes it impossible to control the vehicle speed faithfully as instructed. Even if it is possible to avoid this by increasing the gain, hunting is likely to occur in that case, which is inconvenient.

In this case, by adding an integral element, even if the gain is small, when the command load torque fluctuates greatly, it becomes possible to control the vehicle speed faithfully according to the command as described above. However, it takes a long time to reach the target value (command vehicle speed).

In this invention, even when the load torque fluctuates greatly, the deviation value is attempted to be reduced as much as possible in a short time, and for this purpose, the adder 4
was set up.

FIG. 2 is an example of a characteristic curve of output torque versus engine speed, plotted in 10% increments using throttle opening as a parameter. θ _p is 0
%, when fully closed, θ ₁ is 10%, θ ₂ is 20%...
θ ₁₀ indicates 100%, ie, fully open. These curves are stored in the storage device in advance.

Measure the engine rotation speed and applied load torque of a vehicle running on a bench,
Convert load torque to engine output torque. The necessary throttle opening degree is determined from the engine rotational speed and engine output torque by referring to the stored engine output torque curve.

When the engine rotation speed E and the engine output torque T have values as shown in FIG. 2, the throttle opening degree is determined by interpolating between θ ₂ and θ ₃ . An example of an interpolation formula is shown below.

θ=θ ₂ +T-TB/TA-TB (θ ₃ -θ ₂ )...(1) In the above equation, TA is the engine output torque when the throttle opening is θ ₃ and the engine rotation speed is E.
TB is the engine output torque when the throttle opening is θ ₂ and the engine rotation speed is E.

The throttle opening obtained in this way becomes the output of the calculator 23 in Fig. 1, and by adding it to the adder 4, the throttle opening can be changed immediately even if the load torque fluctuates greatly. , Therefore, the vehicle speed deviation, which is the output of the deviation device 2, does not change significantly. Note that θ ₁ , θ ₂ . . . do not necessarily need to be stored in 10% increments, and even if they are stored roughly, the effect is sufficient. On the other hand, the more detailed the information is stored, the more accurate the correction becomes possible.

The calculation unit 20 that converts the load torque into engine output torque performs the following calculation. The gear ratio of the vehicle is KT, the reduction ratio is KD, the efficiency from engine rotation to tire rotation is η, and load torque detector 13
If the detected value of is TD, then the engine output torque TE
can be written as follows.

TE=TD/η×KT×KD (2) If the measurement delay of the torque detector 13 is large, the command torque may be used instead. If command torque is used, on the other hand, the correction will be made earlier than the torque is actually applied, so it may be necessary to take measures to delay the correction a little.

As described in detail above, according to the present invention, even if the load torque command fluctuates greatly when driving the vehicle on the bench according to the command, the vehicle speed can be controlled faithfully and in a short time according to the command. Achieve the desired effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the invention, and FIG. 2 is a characteristic curve diagram for explaining the operation. 1... Command generator, 2... Deviation device, 3... Control amplifier, 4... Adder, 5... Deviation device, 7... Operating device, 8... Position detector, 9... Vehicle speed Detector,
10...deviator, 13...torque detector, 14...
...Target vehicle, 20...Arithmetic unit, 22...Storage device, 23...Arithmetic unit.

Claims (1)

[Claims] 1. A command generator that generates a commanded vehicle speed and a commanded load torque to be given to a vehicle, and a control amplifier that amplifies the deviation between the commanded vehicle speed and the vehicle speed of the target vehicle on the platform;
a device that applies a load torque to the target vehicle according to the command load torque; a storage device that stores engine output torque for each throttle opening for each engine rotational speed of the target vehicle; and a target that is being driven on the platform. an adder for adding the output of the control amplifier to a throttle opening signal based on a stored value read from the storage device based on the engine rotational speed obtained from the vehicle and the engine output torque converted from the load torque; and a device for determining the throttle opening of the target vehicle based on the output of the device.