JPH01219331A - Engine controller - Google Patents

Abstract

PURPOSE:To prevent resonance and unstable actuation in a servo system from occurring by determining a final feedback controlled variable on the basis of output from two decision means to determine the feedback controlled variable by both proportional and integral items. CONSTITUTION:A target opening signal of a throttle valve 1 out of a throttle controller 4, an actuator position signal out of a first position sensor 17 and a throttle valve opening signal out of a second position sensor 18 are all inputted into a central processing unit 9 which compares each output value of these position sensors 17, 18 with the target opening, and determines a feedback controlled variable by proportional control, derivative control and integral control on the basis of the deviation. Then, a final feedback controlled variable is determined in the shape of totaling these controlled variables, whereby a current value to be made flowing in a motor 3 and the current direction are calculated. With this constitution, resonance and unstable actuation in a servo system is prevented from occurring, and that accuracy and responsiveness in feedback can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine throttle control device that controls the drive of output adjusting means such as a throttle valve through an electric actuator.

(Prior Art) In the engine of a vehicle, output adjustment means such as a throttle valve are generally mechanically connected to the accelerator pedal via a wire. It is uniquely determined by the amount of depression of the accelerator pedal, that is, the amount of accelerator operation.However, in a control where the amount of accelerator operation and the throttle position are in a unique relationship, that is, a one-to-l correspondence, for example, Even when a particularly high output is required, such as during acceleration, the output simply corresponds to the amount of depression of the accelerator, making it difficult to accurately respond to various required driving conditions.

Therefore, by connecting the accelerator pedal, throttle valve, etc. via an electric actuator, and operating the actuator with characteristics according to each required driving condition, we can realize engine control that always meets the driver's will. Various things have been proposed in the past.

For example, in the vehicle accelerator control device described in Japanese Patent Application Laid-Open No. 60-198343, a plurality of functional characteristics between the accelerator operation amount and the throttle valve opening are set, and one of them is set based on the accelerator operation speed. The target throttle valve opening degree is determined in accordance with the selected function characteristics.

Incidentally, in engine control devices that perform feedback control of a throttle valve using an electric actuator motor, a direct drive type in which a motor is directly attached to the throttle valve has conventionally been common. However, due to the nature of the installation around the throttle valve and the durability of the intake manifold, there is a desire to avoid making the intake system around the throttle valve too large or heavy. can be,
Therefore, it has been proposed to attach the motor to the vehicle body and link the motor and throttle valve with a wire to make the intake system around the throttle valve more compact.

However, when trying to feedback-control the throttle valve opening to a target value using a control device that links the motor (throttle actuator) and throttle valve with a wire as described above, the feedback signal is originally the throttle valve opening. It would be best to directly detect the actual position (opening), but in reality, if you use a servo loop that directly detects the throttle valve opening, there will be a lot of disturbance caused by the wire. often enters the servo loop, causing resonance or hunting in the servo system, making it unstable. This tendency becomes more pronounced as the servo gain is set larger to improve positioning accuracy. However, if the gain is lowered to prevent resonance, positioning accuracy cannot be maintained.

Another possibility is to configure a servo loop that prevents disturbances by applying feedback at the motor drive position, but this does not mean that you are looking at the actual throttle valve opening. However, since wire errors inevitably come into play, control accuracy cannot be sufficiently improved.

(Object of the Invention) The present invention has been made in view of the above problems, and is intended to prevent resonance and unstable operation of the servo system in an engine control device equipped with an actuator that drives an output adjustment means via a wire. The purpose is to prevent this and ensure control accuracy and responsiveness.

(Structure of the Invention) The present invention divides a servo loop for engine output control into a loop that includes a disturbance and a loop that does not include a disturbance.The loop that includes a disturbance is a loop with an integral term that is less likely to cause resonance. This is based on the discovery that control accuracy and responsiveness can be ensured while suppressing resonance and unstable operation of the servo system by making the non-containing loop a highly responsive loop that has at least a proportional term. The overall configuration is as shown in FIG. That is, the engine control device according to the present invention includes an actuator that drives the output adjustment means via a wire, a first position sensor that detects the operating position of the actuator, that is, the actuator position, and a first position sensor that detects the drive position of the output adjustment means. a second position sensor that directly detects the target position, a target position setting means that sets the target position of the output adjustment means, and a comparison result of comparing the output of the first position sensor with the output of the target position setting means. a first feedback control amount determining means that determines a feedback control amount using at least a proportional term based on the above, and a first feedback control amount determining means that compares the output of the second position sensor with the target position, and determines a feedback control amount using an integral term based on the comparison result. A final feedback control amount is determined based on the outputs of the second feedback control amount determination means and the first and second feedback control amount determination means, and the control signal corresponding to the final feedback control amount is The present invention is characterized by comprising final feedback control amount determining means for outputting to the actuator.

(Operation) The first feedback control amount determining means compares the actuator position detected by the first position sensor with the target throttle position set by the target throttle position setting means, and based on the deviation, at least a proportional value is determined. Determine the first feedback control amount by. Further, the second feedback control amount determining means compares the actual throttle position detected by the second position sensor with the target throttle position, and determines the feedback control amount based on the integral term based on the deviation. The final feedback control amount is determined by at least the feedback control amount based on the proportional term and the feedback control amount using the integral term.

Then, the actuator is controlled by a control signal corresponding to this final control amount, thereby driving the output adjustment means via the wire. In this way, the throttle position is feedback-controlled to the target throttle position.

Although disturbances caused by the wire enter the output of the second position sensor, feedback control using an integral term causes relatively gradual changes in the control amount, so resonance and hunting are unlikely to occur. Furthermore, since the actual throttle position is directly detected, the accuracy of the feedback control using the integral term is high.

Furthermore, responsiveness to changes in the target throttle position is ensured by at least feedback control using a differential term. Since the differential term uses the detected value of the first position sensor, which is free from disturbance, as a feedback signal, this does not cause resonance or hunting.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is an overall diagram of a servo system according to an embodiment of the present invention applied to control of a throttle valve.

In this embodiment, the throttle valve l is connected to a motor 3 (throttle actuator) via a wire 2 (throttle cable), and is driven to open and close by rotating the motor 3 in forward and reverse directions.

The control system for the motor 3 includes a throttle controller 4, a servo controller 5, and a drive circuit 6.

The throttle controller 4 calculates a target value for the throttle opening based on signals such as the output signal of the accelerator sensor 8 that detects the amount of depression of the accelerator pedal 7, the engine speed, the vehicle speed, the slope, the steering angle, and the water temperature. An abnormal signal is determined and two signals, a throttle valve target opening signal and a motor cut signal, are output to the servo controller 5.

The servo controller 5 is a microprocessor (CPU).
) 9, and an AD converter 10 is installed around the CPU 9.
．． ROMI 1 and RAM 12 are attached. C
The PU 9 is also provided with a counter 13 for performing pulse conversion (PWM) on the CPU internal value (duty). The reference clock of the counter 13 is a signal from an external crystal oscillator 14 divided by a flip-flop 15, and has a frequency of about 4 MHz. counter 13
The frequency is approximately 15 KHz, which is 1/256 of the 4 MHz clock (duty is 8 bits). The servo controller 5 also includes a logic circuit 16 that receives three signals (to be described later) as input, and is configured to control the drive circuit 6 using four outputs of the logic circuit 16.

The drive circuit 6 includes four transistors T, l, T, 2 . Tr3. T1
．． It is composed of 4. The motor 3 includes a first transistor T,1 (PNP) and a fourth transistor T,
4 (NPN) are both conductive, they rotate in the positive direction, that is, in the throttle valve opening direction, and the second transistors T, 2 (
NPN) and the third transistor T,3 (PNP) both turn on, the throttle valve rotates in the opposite direction, that is, in the throttle valve closing direction.

A first position sensor 17 is attached to the motor 3 to detect the actuator position.

Further, the throttle valve 1 is attached with a second position sensor 18 that directly detects the opening degree of the throttle valve.

The target opening signal of the throttle valve 1 outputted by the throttle controller 4 is analog, and is converted into a digital signal by the AD converter 10 and sent to the CPU 9.

In the same way, the actuator position signal (first feedback signal) from the first position sensor 17 and the throttle valve opening signal (second feedback signal) from the second position sensor 18 are also AD converted and input by the CPU 9 manually. be done.

The CPU 9 first compares the output value (actuator position) of the first position sensor 17 with the target opening degree, and determines the feedback control amount by proportional control/differential control based on the deviation. The output value of the sensor 18 (throttle valve opening) is compared with the target opening, and the feedback control amount is determined by integral control based on the deviation, and the final feedback control amount is determined by summing these control amounts. , thereby calculating the current value and current direction to be passed through the motor 3. The calculated current value is then converted into an 8-bit duty value, converted into a pulse by the counter 13, and output. The logic circuit 16 contains this pulse-converted duty signal, a current direction signal corresponding to the calculated current direction, and a current cut signal output from the CPU in response to the motor cut signal from the throttle controller 4. Three signals are input.

The logic circuit 16 is composed of seven logic elements, and its four output terminals are connected to four transistors T, 1 . T,,2. The bases of TP3, T, and TP4 are connected to each other.

The first transistor T,1 is controlled by a logic circuit in which an exclusive OR circuit inverts the output of an AND circuit which receives two inputs, a duty signal and a current direction signal. That is, when both the duty signal and the current direction signal are at high level (1), the base of this transistor NIO1 becomes low level and conducts. Also, the fourth
The transistor T4 is controlled by the output of an AND circuit that receives two inputs, a current direction signal and a current cut signal, and when both of these signals are at high level (1), the base becomes high level and conducts. do. Therefore, as long as the current cut signal is high (1) and the current direction signal is high (1), the fourth transistor T, 4 remains on, and the duty signal exclusively controls the motor 3 in the opening direction. The rotation will be controlled.

On the other hand, the third transistor T,3 receives the output of an AND circuit which has one input as the duty signal and the other input as a signal obtained by inverting the current direction signal in the exclusive OR circuit. It is controlled by a logic circuit that inverts the signal at . That is, when the duty signal is at a high level (1) and the current direction signal is at a low level (0), the bases of the transistors T and 3 are at a low level and conductive. In addition, the second transistor Tt
2 uses the inverted signal of the current direction signal as one input,
It is controlled by the output of an AND circuit whose other input is the current cut signal. That is, when the current direction signal is at a low level (0) and the current cut signal is at a high level (1), the base of the transistor T,2 becomes conductive.

Therefore, as long as the current cut signal is high (1) and the current direction signal is low (0), the second transistor Tr2
remains conductive, and the rotation of the motor in the closing direction is controlled exclusively by the duty signal. Further, when the current cut signal is at a low level (0), the fourth and second transistors Tt4, T, and 2 are non-conductive, and the motor 3
No current flows through.

Table 1 shows three signals (DUTY: duty signal, D
IR: current direction signal, MCUT: current cut signal) and each transistor (Ttl, T, 2.T.

3, Tr4) logic is shown.

Table 1 In this way, for the rotation of the motor in the opening direction, the first
and a fourth two transistors T, 1. T.

4, only the first transistor Ttl, and for the rotation of the motor in the closing direction, the third and second two transistors T, 3. T, the third transistor T of 2,
Since only one transistor is controlled in each case, there is no problem of asynchronization between the two transistors, and reliable duty control is performed. The first and fourth transistors T, 1. Tr4 and third and second transistors T, 3. Since T and 2 do not conduct at the same time, CP
Even if U goes out of control and the logic of the output port is not compensated for, the drive circuit 6 and motor 3 will not be burnt out due to short circuit. Furthermore, since the drive control of the motor 3 is performed via such a logic circuit 16, the CP
U's software burden will be reduced.

FIGS. 3 to 9 show flowcharts for executing control in this embodiment.

First, FIG. 3 shows the main routine. The main routine consists of five subroutines S.t.S.5.

Start and initialize first (S.1). Then, input signals from the first position sensor 17 and the second position sensor 18 are sampled (S.2). Next, first, based on the input signal from the first position sensor 17,
Feedback calculation (S.3) of the current value is performed by control consisting of two differential terms (P, D control), and then,
Integral control (
(2) Perform feedback calculation (S.4) using control).

Finally, the motor cut signal is checked to control whether or not to cut the motor current (S.5).

The first subroutine S.1 (FIG. 4) starts and first sets each port as input or output. Next, the timer and PWM for interrupt processing
Initialize the counter.

Next, various registers used in calculations are initialized, and the process returns.

Next, in the third input signal sampling subroutine S.2 shown in FIG. Store in. Also, the first
The actuator position signal from the position sensor 17 of
D conversion and store the data in the value TVOR. Next, the throttle valve target opening signal is A/D converted and the data is stored in a value called TVOT. This converts all three analog signals.

Next, the third subroutine S.3 (Fig. 6) of feedback calculation (P, D control) starts and first reads the output value TVOA of the first position sensor 17, and then the target opening. Read the TVOT value.

Then, the deviation ΔT between the sensor output value T VOA and TVOT
Calculate VO. In addition, the current sensor output value TVOA of the first position sensor 17 and the previous sensor output value TVOAL
The moving speed of the actuator position ΔSPD is obtained by subtracting
Calculate.

Next, from the value obtained by multiplying the calculated deviation ΔTVO by the feedback constant KP of the proportional term, the speed ΔSPD calculated earlier is calculated.
By multiplying by the feedback constant KD of the differential term, the motor current value FB is obtained. Finally, the previous value TV'O of the sensor output value used for calculating the differential term.
Update AL to this TVOA.

Next, in the fourth subroutine S.4 (Fig. 7) of feedback calculation (I control), after starting,
The output value (TVOR) of the second position sensor 18 is read, and then the target opening degree TVOT is read.

Next, the deviation ΔTVO2 between TVOR and TVOT(7) is determined. Then, the previously calculated deviation ΔTVO is added to the previous I-value integrated value TΔTVO to obtain the I-value integrated value TΔTVO.

Next, add the I value integrated value TΔTV to the current value obtained in S.3.
The final motor current FBF is obtained by adding O multiplied by the feedback constant Kl of the integral term.

Next, the current direction is determined depending on whether the current value FBF is positive. Then, to set the flag for interrupt processing, first, if FBF is positive,
The current direction flag PDIR, that is, the boat output level flag FD (R) that sets the direction of the motor current is set to 0 (opening direction).Also, if FBF is not positive, FDIR is set to 1 (closing direction). do.

Next, for duty conversion, the absolute value of the current value FBF is determined, and the current-duty conversion coefficient Ka
Let the value multiplied by uty be the duty value.

FIG. 8 shows the fifth current cut subroutine S.5.
It shows. This routine starts and first reads the current cut input from the throttle controller 4. Then, it is determined whether or not the current is cut, and if it is determined that the current is cut, the current cut port (M
CUT) to low (current cut) to ensure that the transistor does not conduct, and when the current is not cut, set the current cut port to high (current conduction).

This completes the main routine of this embodiment, but apart from this there is a timer interrupt processing routine shown in FIG. This interrupt processing is started at regular intervals (1 to 2 m5), and when started, it first reads the interrupt processing cycle (T I NT) and then sets the next interrupt time. Therefore, the cycle TINT is added to the current time and stored in the interrupt register.

Next, to read the PWM duty (DUTY), read the value DUTY obtained in S.4 of the main routine, and to set the PWM timer, store the value DtJTY in the PWM timer register. . In other words, write to the counter. S.
Since the counter has been initialized with 1, the counter outputs a pulse according to the value of DUTY from the time of writing.

Next, the current direction is determined by looking at the current direction flag FDIR set in S4 of the main routine. And F
If DIR is O, the DIR boat is set to a high level (open direction), and if F'DIR is not 0 (1), the DIR boat is set to a low level (closed direction).

Although the above embodiments relate to throttle valve control of an engine, the present invention is not limited to throttle valve control, but also applies to other output adjustment means of an engine (effects of the invention). Therefore, it is possible to prevent resonance and unstable operation of the servo system in an engine control device equipped with an actuator that drives the output adjustment means via a wire, and to ensure accuracy and responsiveness of feedback control. can.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is an overall diagram of an embodiment of the invention, and FIGS. 3 to 9 are flowcharts for executing control of the embodiment. 1: Throttle valve, 2: Wire, 3: Motor (actuator), 4: Throttle controller, 5: Servo controller, 6: Drive circuit, 9: Microprocessor (CPU), 17, 18: Position sensor. Agent Patent Attorney Jun Shinfuji - Figure 8 S.5 Figure 9

Claims (1)

[Claims] (1) An actuator that drives the output adjustment means via a wire, a first position sensor that detects the operating position of the actuator, that is, the actuator position, and a second position sensor that directly detects the drive position of the output adjustment means. and target position setting means for setting a target position of the output adjustment means; and comparing the output of the first position sensor with the output of the target position setting means, and based on the comparison result, a feedback control amount using at least a proportional term. a first feedback control amount determining means for determining a feedback control amount by an integral term, and a second feedback control amount determining means for comparing an output of the second position sensor with the target position and determining a feedback control amount by an integral term based on the comparison result.
and a final feedback control amount determining means for determining a final feedback control amount based on the outputs of the first and second feedback control amount determining means, and outputting a control signal corresponding to the final feedback control amount to the actuator. 1. A control device for an engine, comprising: feedback control amount determining means.