JPH0381161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a detector drift correction device in a control system in which a control lever is operated to select a control signal to operate an actuator to be operated.

[Prior art]

Forces applied to operating levers such as levers and pedals,
In the circuit that amplifies and adjusts the output of the detector that detects the amount of operation, the characteristics of the detector and amplifier change due to environmental changes and aging, and the output of the detector that passes through the amplifier at the neutral point of the lever, pedal, etc. change,
There were cases where a signal was sent and the machine started operating even though the levers, pedals, etc. were in neutral position.

[Problems to be solved by this invention]

Therefore, there is a method of detecting the neutral point using a limit switch or the like and breaking the circuit from the detector to the actuator to prevent the machine to be operated at the neutral point. When the deviation becomes large, the signal enters in a step-like manner during the conduction that follows the interruption at the neutral position, causing the machine to be operated to suddenly operate, which is dangerous.

Therefore, the present invention improves the above-mentioned disadvantages when the neutral point of the conventional control system is deviated, so that even though the control lever is at the neutral point, a signal is output and the machine does not operate. It is an object of the present invention to provide a detector drift correction device that can prevent the detector from being put away and safely control a controlled object.

[Means for Solving the Problems] According to the detector drift correction device according to the present invention, the first detector detects the amount of operation of the operating lever, the second detector detects the neutral point of the operating lever. , a calculation section and a data storage section for storing the reference value and the amount of drift of the detector when the operation lever is in the neutral position are provided, and the calculation section adds the output of the first detector and the amount of drift when the operation lever is not at the neutral point. As a control signal, when the operating lever is at the neutral point, the reference value is output to the controlled object to keep the controlled object at the reference position (stop position), and the difference between the reference value and the first detector output is used as the drift amount. The feature is that the data is updated within the data holding unit.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to illustrated embodiments. FIG. 1 shows a block diagram of an embodiment of the present invention. In this block diagram, an operating lever 1 is provided with a first detector 2 for detecting the amount of lever operation. The first detector 2 is, for example, a potentiometer whose sliding part is mechanically connected, and outputs an operation signal Vi corresponding to the operation position of the operation lever 1. An amplifier 3 is provided at the next stage of the first detector 2, which amplifies the input signal Vi and outputs it to the A/D converter 4 as _VI . The A/D converter 4 A/D converts the signal _VI and outputs a digital signal to the arithmetic unit 7.

Further, the operating lever 1 is provided with a second detector 5 that detects the neutral state of the lever, and when the operating lever 1 reaches the neutral position, the a contact 6 is closed and the arithmetic unit 7
Outputs a neutral point signal to.

The calculation unit 7 also includes a storage unit 9 that holds data.
is provided, and the drift amount △V of the first detector 2
and the reference value Vφ when the operating lever is in the neutral position are stored. Here, as shown in FIG. 2a, the relationship between the operating amount of the operating lever 1 and the output signal Vl of the amplifier 3 will be explained so that Vl=0 when the operating lever 1 is in the neutral state. FIG. 2b shows an example of an output including a drift ΔV due to environmental changes such as temperature and aging.

The relationship between the drift amount ΔV and the reference value Vφ when the operating lever is in the neutral state, which is similarly stored in the storage unit 9, is defined by ΔV=Vφ−V.

A D/A converter 8, an amplifier 10, and an actuator 11 to be operated are connected to the output side of the calculation section 7, and the D/A converter 8 converts the digital signal from the calculation section 7 into an analog signal. The signal is output to the amplifier 10 and actuates the actuator 11.

Next, the operation of the blocks shown in FIG. 1 will be explained according to the flowchart shown in FIG. First, the calculation unit 7 reads the A/D converted value V of Vi from the A/D converter 4. Therefore, if the signal from the second detector 5 that detects the neutral state of the operating lever is not output, the drift amount △V is read from the storage unit 9, and V+△
It calculates V and outputs it to the D/A converter 8. Therefore, the actuator 11 has a D/A of V+△V.
Controlled by the conversion value V _O.

Further, the output signal from the second detector 5 is transmitted to the calculation unit 7.
When it is detected that the control lever 1 is located at the neutral point, the calculation unit 7 reads the reference value Vφ when the control lever is in the neutral position from the storage unit 9 and outputs it to the D/A converter 8 . For this reason, the actuator 11
is held at a position corresponding to the neutral reference value Vφ.

Further, the calculation unit 7 performs the calculation ΔV=Vφ−V to update the drift amount ΔV in the storage unit 9.
Here, instead of storing △V in the storage unit 9, V at the neutral point is stored, and instead of V+△V, V+
It is also possible to adopt a configuration in which Vφ− (V at the neutral point) is output to the D/A converter 8.

In addition, a third
It is also possible to use the bridge shown in the figure.

FIG. 5 shows an embodiment in which the present invention is implemented using hardware. In this embodiment, the amplifier 3 in FIG. 1 is replaced with a differential amplifier, and the arithmetic unit 7 is composed of a relay, a comparator, an AND, a NOR gate, an UP/DOWN counter, and a D/A converter.

The output Vi of the first detector 2 is input to a differential amplifier 17, and after the difference with a reference value, which will be described later, is amplified and adjusted, it is further amplified by the amplifier 10 to operate the actuator 11.

A second detector 5 detects the neutral point of the operating lever 1
A relay 12 operated by the a contact 6 is provided. Further, the b contact 12b of the relay 12 is interposed in the line between the differential amplifier 17 and the amplifier 10, and when the second detector 5 detects the neutral point and the relay 12 is activated, the b contact 12b is connected. The operation of the opening actuator 11 is stopped.

Although the amplifier 10 is used in this embodiment, a configuration may also be adopted in which the actuator 11 is directly actuated by the output of the differential amplifier 17.

Further, the output of the differential amplifier 17 is connected to a set of comparators 1
3, 13', and each comparator 13,
Comparison calculations are made with reference voltages V _H and V _L applied to terminals 13' and 13'. The outputs of the comparators 13 and 13' are input in parallel to an AND gate 15 and a NOR gate 14 to perform logical operations, and the calculated values of each gate 14 and 15 are input to AND gates 16 and 16', respectively. There is. The AND gates 16 and 16' are connected to the relay 12 in parallel with the operation values of the gates 14 and 15, respectively.
The a contact 12a of is connected. Therefore, only when the second detector 5 detects the neutral point of the operating lever 1, the a contact 12a closes and the AND, NOR gates 14, 15 calculate the UP/
It is output to the DOWN counter 18.

The output signal from the UP/DOWN counter 18 is converted by the D/A converter 8 into an analog signal _VN representing the detector output when the operating lever is in the neutral position, and is output to the differential amplifier 17.

In addition, a clock signal is supplied to the UP/DOWN counter 18 and the D/A converter 8,
When the (DOWN) signal is H, the count is increased (DOWN) by one for each clock signal, and when both UP and DOWN are L level signals, the count value is held, and the latest count value is sent to the D/A converter 8. Output.

Here, the differential amplifier 17 outputs the output of the first detector 2.
Vi, the detector output V _N when the operating lever is in the neutral position, the actuator operating signal V _O , and _the constant _K. Shown in the figure.

Moreover, FIG. 8 shows the input/output relationship of comparators 13 and 13', and comparator 13 has input V _O
When V _H or lower, H is output, and when V _H or higher, L is output.
Similarly, the comparator 13' outputs H when the input V _O is below V _L , and outputs L when the input V O is above V _L. Also, V _L <0<
V _H , comparator 13, 13' output and UP/
The input/output relationship of the DOWN counter 18 is shown.

This UP/DOWN counter 18 is UP
While the (DOWN) signal is high, the count increases by one for each pulse of the clock signal (DOWN)
However, while both the UP and DOWN signals are L, the count number is held in the previous state, and the count number at that point is always sent to the D/A converter 8. The A converter 8 sends an analog value V _N corresponding to the count number at that time to the differential amplifier.

In addition, Fig. 9 shows the time axis from when the neutral signal is input from the second detector 5 until V _O is corrected and enters the allowable range, and in this figure, time 0 is when the neutral signal is input. be. Here, the input V _i from the first detector 17 is constant, but each time the clock signal is input, the reference value V _N when the lever is neutral increases, and the output V _O is V _O =K( V _i −V _N ), it decreases to within the allowable range and becomes stable.

In the above configuration, when the second detector 5 does not detect neutrality, the relay 12 does not operate, and the first detector 2 output V _i and the reference output from the D/A converter 8
V _N outputs V _O =K (V _i −V _N ) as an output.

At this time, the input of the UP/DOWN counter 18 is a
Since contact 12a is open, it is configured to be kept at L level, and in this state, UP/
The DOWN counter 18 holds a count value, and the reference value V _N adjusted when the control lever 1 was in the neutral position last time is always outputted from the D/A converter 8 to the differential amplifier 17.

Here, when the second detector 5 detects the neutral state of the operating lever 1, the relay 12 is activated, the b contact 12b is opened, and the output to the actuator 11 is cut off.

If the input Vi and the reference value V _N differ at this time, V _O = K (V _i - V _N ) will be generated as the output of the differential amplifier ₁₇ , but if it is within the allowable range, that is, V _L < V _O < V _H , as shown in FIG. 7, the output of comparator 13 is H, and the output of comparator 1 is H.
3' output becomes L, AND gate 15, NOR
Both outputs of the gate 14 become L, resulting in the state in the upper right corner of FIG.

Also, when neutral, the output of NOR gate 14 counts up, and the output of AND gate 15 counts up.
is configured to be connected to DOWN, but
Since both are L, the UP/DOWN counter 18 does not operate and _VN is not changed.

Also, in the case of V _O ≧ V _H , both the outputs of comparators 13 and 13' become L from FIG. 7, and at this time, NOR
Since the output of the gate 14 becomes H, a count UP signal is input as shown in the upper left state of FIG.

Therefore, as shown in FIG. 9, the count is increased by one every clock, and the reference value V _N is increased step by step.

This operation is repeated until V _N becomes almost equal to V _i , and from the relationship V _O = K (V _i - V _N ), V _O also decreases step by step until V _L < V _O < V _H. Stabilize.

When V _O ≦V _L , the drift is corrected in the opposite way, and the output for the next operation will be the output with the drift corrected.

In this embodiment, the relay 12 and the a contact 12a and the b contact 12b are used, but it is also possible to use a semiconductor switch instead.

〔Effect of the invention〕

According to the detector drift correction device according to the present invention, in a control system that operates an operating lever to select a control signal and operate an actuator to be operated,
This prevents a signal from being output and the machine to operate even though the operating lever is at the neutral point, and enables safe control of the controlled object.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 a and b are graphs showing examples of drift output and correction output, and FIG. 3 is a block diagram showing another example of the configuration of the first detector. Figure 4 is a flowchart showing the operation of the block diagram in Figure 1, Figure 5 is a circuit diagram showing another embodiment, Figure 6 is a graph of output voltage and manipulated variable, and Figure 7 is a set of comparators. Figure 8 is the state diagram of the counter based on the comparator output, Figure 9 is the output waveform diagram of
FIG. 3 is a characteristic diagram showing a state in which V _O is corrected. 1... Operation lever, 2... First detector, 3...
Amplifier, 4... A/D converter, 5... Second detector, 6... A contact, 7... Arithmetic unit, 8... D/A
Converter, 9...Storage unit, 10...Amplifier, 11...
...actuator, 12...relay, 12a...
A contact, 12b...B contact, 13, 13'...Comparator, 14...NOR gate, 15, 16, 16'...
...AND gate, 17...Differential amplifier, 18...
UP/DOWN counter.

Claims (1)

[Scope of Claims] 1. In a control system that operates an operating lever to select a control signal and operate an actuator to be operated, the first detector detects the operating amount of the operating lever and outputs an operating signal; a second detector that outputs a neutral point signal when the neutral point of the operating lever is detected; and a data holding unit that stores and holds an operating signal reference value of the first detector when the operating lever is neutral and a drift amount. , inputting the outputs of the first detector and the second detector,
When there is no output from the second detector, the amount of drift is read from the data holding section and added to the operation signal from the first detector, and this added value is output as a control signal to the actuator, and When the neutral point signal from the second detector is input, the reference value of the data holding section is read and output to the actuator, and the difference between the output from the first detector and the reference value at that time is and an arithmetic unit configured to update the amount of drift in the data holding unit.