JPS62241736A - Timing advance control system for constant speed driving unit - Google Patents

Abstract

PURPOSE:To prevent control at a high speed range from going to instability, by restraining speed hunting from occurring by what a higher order differential term is contained in a timing advance vehicular speed, while making a coefficient of this higher order differential term have speed dependency. CONSTITUTION:The vehicular speed signal inputted is processed for its timing advance by way of a vehicular speed signal processing part 1 or the like, and such a timing advance speed that is more advanced in phase than the inputted vehicular speed is found. In this case, a lower order differential term [for example, a primary differential term f' (t)] and a higher order differential term [for example, a secondary differential term f'' (t)] are added to the input vehicular speed f (t), setting it down to a timing advance vehicular speed g (t). At this time, the input vehicular speed f (t) is differentiated by differentiator, doubling a coefficient K1, and furthermore differentiated by a differentiator 7, doubling a coefficient K2, finding the timing advance vehicular speed g (t). In addition,this coefficient K2 is varied according to the setting vehicular speed. With this constitution, an overcompensation part by the lower order differential term f' (t) is offset by the higher order differential term f'' (t), while when the stored vehicular speed is higher, the coefficient K2 is made smaller than a low speed range.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention compensates for control delays in a constant speed traveling device, and
This invention relates to an advance angle control method that does not impair stability at high speeds.

[Conventional technology]

The vehicle speed signal obtained from the vehicle speed sensor is input into the control microcomputer, the vehicle speed at that point in time is stored, and the throttle opening is automatically controlled so that the subsequent traveling vehicle speed matches the stored vehicle speed (set vehicle speed). Since the high-speed traveling device has a mechanical response delay of the actuator that controls the throttle opening and other delay elements, it is difficult to obtain a highly accurate control system due to the control delay.

For this reason, conventionally, advance angle control is sometimes performed to compensate for the control delay, as shown in FIG. 5, for example. Figure <a) shows an outline of the control system of the constant speed traveling device, and by reflecting the vehicle speed on the vehicle speed signal, the entire system becomes a closed loop. Processing from vehicle speed signal processing to output processing is performed by a control microcomputer, and an actuator (not shown) automatically controls throttle opening.

The vehicle speed signal processing includes filtering the input vehicle speed signal to remove noise, and finally outputs the traveling vehicle speed f (t). This traveling vehicle speed is stored as the subsequent target vehicle speed vM when the center switch is turned on, and becomes the basis for detecting the difference from the stored vehicle speed vM while the vehicle is traveling at a constant speed.

The actuator is then driven based on this speed difference.

This output processing includes, for example, a duty control method in which the stored vehicle speed is set as a duty, and the actuator is driven by a pulse train with a duty adjusted or subtracted based on the speed difference.

However, if the actuator is controlled based on the difference between the vehicle speed f (tl) and the stored vehicle speed vM, a control delay will occur, so in the method shown in FIG.
Advance angle vehicle speed g (t) g(
Advance angle control is performed using f(tl+K + ·f'(t)).

Since this advanced vehicle speed g (tl has a phase advance with respect to the input vehicle speed r (t) as shown in FIG. 5(b), the control delay can be compensated for by that amount. This is the case for input.

[Problem to be solved by the invention] By the way, since the advance angle vehicle speed g (t) in FIG.
The maximum value of is 90° as shown in FIG. 6, and the higher the frequency, the shorter the advance time. For this reason, for example, when the vehicle gain is high, sufficient compensation for the delay element cannot be obtained, and vehicle speed hunting is likely to occur. FIG. 7 is an example of this operation, and shows how hunting continues for a long time when the setting is in the 40 Kml h range under a high gain.

The present invention suppresses the above-mentioned vehicle speed hunting by including a high-order differential term in the advance angle vehicle speed g (t), and also makes the coefficient of the differential term dependent on the vehicle speed in a high-speed range. This is intended to prevent control from becoming unstable.

[Means for solving problems]

The present invention provides an advance angle control method for a constant speed traveling device that advances an input vehicle speed to obtain an advanced vehicle speed that is ahead in phase than the input vehicle speed. and calculate the advance vehicle speed by multiplying each differential term by the respective coefficient and adding it to the input vehicle speed, and also make the coefficient of the higher-order differential term smaller in the high-speed range of the set vehicle speed than in the low-speed range. This is a characteristic feature.

[Effect]

Input vehicle speed f (tl has its low-order differential term (for example, first-order differential term f'(t)) and high-order differential term (for example, second-order differential term r/F)
(t)) to obtain the advanced vehicle speed g (t), the overcompensation part due to the low-order differential term can be canceled out by the high-order differential term, so even if the vehicle gain is high, vehicle speed hunting can be suppressed in a short time. It can be converged. Therefore, the same type of controller can be mass-produced and used in a wide range of vehicles with different gains.

However, in this case, if there is any disturbance in the vehicle speed signal such as high frequency modulation due to gear play or cable twist,
On the contrary, control at high speeds becomes unstable. Therefore, in the present invention, when the set vehicle speed (memorized vehicle speed) is high, the coefficient of the higher-order differential term is made smaller than in the low speed range, thereby avoiding unstable control.

Even if this is done, the advance angle compensation effect in the high speed range will not be significantly reduced. This is because control delays are generally more likely to occur in low speed ranges, and delays in high speed ranges can be sufficiently compensated for by the first-order differential term.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, where ■ is a vehicle speed signal processing section, 2 is a set switch, 3 is a set vehicle speed storage section, 4 is an output processing section, 5 is an actuator, and 6 is a first-order differential 7 is a second-order differentiator.

In this example, the input vehicle speed f (t) is differentiated by the differentiator 6 and multiplied by 1 into a coefficient, while it is further differentiated by the differentiator 7 and multiplied by 2 into a coefficient, so the advance angle obtained by adding these Vehicle speed g
(t) is g(tl-f(t)+K + ・f' (t)+K 2
・f(t)・・・(11)

The third term on the right side of the above equation is a part that is not present in the method shown in FIG. 5, and this is part B shown in FIG. 2 (ta). This portion B has the effect of canceling out the overcompensation portion A caused by the second term on the right side of the above equation.

Figure 3 shows KI=1.8. This is an advance angle characteristic diagram of the present invention in which 2=1.8×0.6, and the advance angle phase is expanded to 180°. Therefore, a sufficient phase lead time can be maintained up to a high frequency range.

FIG. 4(A) is an operational waveform diagram in this case, where the vehicle speed is increased from 40 Km/h to 5 Km/h under high gain. As is clear from a comparison with FIG. 7, the absolute amount of hunting is small and converges in a short time.

Note that a moving average of higher-order differential terms may be taken in order to alleviate duty fluctuations. In other words, the advance angle vehicle speed calculation in the microcomputer is VSn = VRn +K + ・(VRn −vl?n
-1)+K 2 ((VRn-VRn-+) (V
Rn-I VRn-2)) However, VSn: Advance angle vehicle speed VRn: Traveling vehicle speed at the measurement point 1: Coefficient of first-order differential term 2: Coefficient of second-order differential term, for example, two-time moving average By adopting the method, the third term on the right side of the above equation is expressed as K 2 ・((VRn-VRn-1) (VRn-
1-VRn-2)+(VRn-+ VRn-2)
(VRn-2VRn-3))/2, duty fluctuation can be alleviated. In this case, the calculation cycle is 50m
If s is +=36°K2=216 or so.

The above explanation relates to the basic operation in which the coefficient of the second-order differential term is kept constant at 2, but in the present invention, the coefficient is further changed to 2 in accordance with the set vehicle speed. An example of this is shown in Figure 2 (bl). In the figure, when the set vehicle speed (VM) exceeds a certain value (40 km/h in this example), the initial value TK2 is set to 2 as a coefficient.
It shows characteristics that gradually decrease from . In this case, 2 is TK2 = 1, 08 s, and K 2 = TK2 - 0.015S/K11l/ h x
(VM-40Km/h), VM=12
At 4 Km/h, 2=0.

In addition, there are methods to lower K2 in stages, for example, V
A two-stage switching method may be adopted in which 2=TK2 is used in the low speed range and 2″=0 in the high speed range, with M=80 Km/h as the boundary.

FIG. 4(B) shows the case where the vehicle is traveling at a constant speed in a high speed range with (2) fixed in equation (1). If there is a disturbance in the vehicle speed signal at such times, the duty will change significantly. This change in duty is larger than in the conventional method shown in FIG. 4(C), indicating the disadvantage of adding a second-order differential term. However, if K2 is made small in the high speed range, the effectiveness of the second-order differential term decreases, so as shown in FIG. 4 (DJ), the range of change in duty becomes narrower and stability of control is maintained.

〔Effect of the invention〕

As described above, according to the present invention, vehicle speed hunting is unlikely to occur even when the vehicle gain is high, so that sufficient phase is maintained even in low vehicle speed ranges with large control delays or in control systems where the vehicle speed signal processing section has a large time constant. Compensation can be provided. Also,
This has the advantage of preventing unstable control at high speeds even if there is a disturbance in the vehicle speed signal.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram of its operation, Fig. 3 is a lead angle characteristic diagram of the present invention, Fig. 4 is an operation waveform diagram of the present invention, and Fig. 5 6 is an explanatory diagram of a conventional advance angle control method, FIG. 6 is a diagram of its advance angle characteristics, and FIG. 7 is a diagram of conventional operation waveforms. In the figure, l is a vehicle speed signal processing section, 2 is a set switch, 3 is a storage section, °4 is an output processing section, 5 is an actuator, 6 is a first-order differentiator, 7 is a second-order differentiator, and K2 is a second-order differentiator. is the coefficient of the term. Applicant Fujitsu Ten Ltd. Representative Patent Attorney Minoru Aoyagi Invention/1? Fig. 4 (A) 2nd floor A Kubu method % type % () 1 pυ @ Min method Fig. 4 (C) Conventional hidden corner installation p method

Claims (1)

[Claims] In an advance angle control method for a constant speed traveling device that advances an input vehicle speed to obtain an advanced vehicle speed whose phase is more advanced than the input vehicle speed, a low-order differential term and a high-order differential term of the input vehicle speed are determined, and each The advance angle vehicle speed is calculated by multiplying the differential terms by respective coefficients and adding them to the input vehicle speed, and the coefficient of the higher order differential term is made smaller in a high speed range of a set vehicle speed than in a low speed range. Advance angle control method for speed running equipment.