JPH076810U - Joystick malfunction prevention device - Google Patents

Abstract

(57) [Summary] [Structure] In a joystick that outputs a control signal using potentiometers 3 and 5 that operate according to the amount of operation of the operating lever 1, a neutral sensor 6 is arranged at an appropriate portion of the operating lever to operate. It detects the departure from the neutral state of the lever, and determines the operating direction of the operating lever based on the increase or decrease in the detection voltage of the potentiometer before and after the release, and excludes the detection voltage from the potentiometer that violates this determination result. It is characterized by performing processing. [Effect] The operation direction is determined based on the fluctuations in the detected voltage from each potentiometer, before and after the operation lever is separated from the neutral state, and an erroneous signal contrary to the operation direction is eliminated, so that a malfunction can be prevented with a simple configuration.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for preventing malfunction of a joystick, which is a lever-type input means used for position and direction control by an actuator incorporated in a crane or the like.

[0002]

[Prior art]

 Conventionally, this kind of joystick is configured to output a control signal in accordance with an operation amount of an operation lever using a potentiometer. In this case, there was a problem of malfunction that the control signal in the opposite direction to the operation direction was output due to the abnormality of the potentiometer, causing the boom of the crane, which is the control target, to operate in the opposite direction, leading to danger. . That is, for example, foreign matter such as abrasion powder or dust is caught between the resistor and the contact brush that constitute the potentiometer, and the resistance value changes, which causes a detection voltage opposite to the neutral voltage and causes a malfunction. There was a problem of making. FIG. 5 shows an example of a conventional structure taken to solve such a problem. In the figure, 101 is an operating lever, 102 is a first detection shaft, 103 is a potentiometer attached to the first detection shaft 102, 104 is a second detection shaft, and 105 is a potentiometer attached to the second detection shaft 104. It is shown. Then, when the operation lever 101 is rotated back and forth and left and right, a detection voltage corresponding to the operation amount is output via the potentiometers 103 and 105. In this case, in order to solve the above-mentioned problem, a pair of cam plates 106 and 107 are attached to the first detection shaft 102, and detection switches 108 and 109 are arranged corresponding to the cam plates 106 and 107, respectively. The mechanism is configured. As a result, the operating direction of the operating lever 101 is detected, and the control signal in the opposite direction contrary to this is determined to be an output due to a malfunction. On the other hand, a similar operation direction detection mechanism (not shown) is attached to the second detection shaft 104, and the same determination is made.

[0003]

As described above, although the malfunction prevention means is adopted in the prior art as well, it is necessary to attach the operation direction detection mechanism for preventing malfunction to each detection shaft. The mechanism was complicated, the number of parts was large, and the cost was high. The present invention has been made in view of such circumstances of the prior art, and it is an object of the present invention to simplify and compact the structure of the joystick malfunction preventing mechanism.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a neutral sensor at an appropriate portion of the operating lever to detect the detachment of the operating lever from the neutral state, and detects the detachment of the operating lever from the neutral state. The operation direction of the operation lever is determined based on the increase / decrease of the detection voltage of the potentiometer before and after, and the detection voltage in the opposite direction contrary to the determination result is eliminated to perform the signal processing.

[0005]

[Action]

 The neutral sensor provided at an appropriate portion of the operating lever detects the departure of the operating lever from the neutral state. Based on the detection of the detachment, the operating direction of the operating lever is determined by increasing / decreasing the detection voltage from the potentiometer before and after the detachment. The control signal is output by excluding the detection voltage from the potentiometer that is contrary to this determination result.

[0006]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a main part of an embodiment of the present invention. In the figure, 1 is an operating lever, 2 is a first detection axis, 3 is a potentiometer attached to the first detection axis 2, 4 is a second detection axis, and 5 is a potentiometer attached to the second detection axis 4. Since it is shown, it has the same function as the above-mentioned conventional technique. In the figure, 6 is a neutral sensor composed of a limit switch and the like, which is disposed at the lower end of the operating lever 1 and determines whether the operating lever 1 is in the neutral state or has left the neutral state.

FIG. 2 is a circuit configuration diagram of the present embodiment, FIG. 3 is an operation explanatory diagram thereof, and FIG. 4 is an operation flow chart of the microcomputer. The detected voltages from the potentiometers 3 and 5 are input to the microcomputer 8 via the A / D conversion circuit 7, respectively. At the same time, the neutral data from the neutral sensor 6 is input to the microcomputer 8. As shown in FIG. 3, the potentiometers 3, 5 output a proportional detection voltage Vp corresponding to the operation state of the joystick 1, that is, the operation amount Jd such as the operation angle or the operation position. A certain neutral range Jn is set in the neutral part of the joystick 1, and if it is within this range, it is determined that it is in the neutral state, and if it is outside this range, it is determined that the neutral state has left. The neutral sensor 6 is a means for making this determination, and is configured to output an on / off neutral determination signal Sn corresponding to the inside and outside of the neutral range Jn. In FIG. 2, reference numeral 9 indicates a pull-down resistor for detecting disconnection.

Therefore, the microcomputer 8 operates as follows based on the detected voltage Vp from the potentiometers 3 and 5 and the neutral determination signal Sn from the neutral sensor 6. That is, in step S101 of FIG. 4, the neutral condition is set, the neutral flag is set, and the preset neutral voltage Vn is set. In step S102, it is determined whether there is a change in the signal voltage Vs, that is, the voltage obtained by subtracting the neutral voltage Vn from the detection voltage Vp from the potentiometers 3, 5. In this case, since the detection voltage Vp does not change within the play range in the neutral state of the operation lever 1, the signal voltage Vs does not change. That is, when the operating lever 1 is operated in a certain direction beyond the range of play, the signal voltage Vs fluctuates. If the signal voltage Vs has changed, the process proceeds to step S103, and the signal voltage Vs is integrated to obtain ΣVs / N (N is the number of samplings). As a result, fluctuations in the signal voltage Vs during the process of operating the operating lever 1 in a certain direction beyond the play range are averaged. Therefore, even if some erroneous signal is included in the process of this operation, it is absorbed in the ΣVs / N, and the result is not affected. A similar result can be obtained by using the integrated value ΣVs itself instead of this averaging.

In step S 104, it is determined based on the neutral determination signal Sn from the neutral sensor 6 whether or not the vehicle is out of the neutral state. If it is determined that the vehicle is out, it proceeds to step S105, and it is determined whether ΣVs / N accumulated in step S103 is positive or negative. As a result, the operating direction of the operating lever 1 is determined. Then, in the case of plus, the Pramai flag is set to plus in step S106, and in the case of minus, the Pramai flag is set to minus in step S107.

In step S108, the detected voltage Vp is read and the neutral voltage Vn is subtracted to obtain the signal voltage Vs at that time. Further, in step S109, it is determined whether the state is neutral, and if the state is returned to the neutral state, the neutral process is performed in step S110 and the process returns to step S101. If the state of leaving the neutral state continues, the process proceeds to step S111, where the sign of the signal voltage Vs and the sign of the Pramai flag are compared, and if they match, the process proceeds to step S113. Then, the output process is performed to output the signal voltage Vs as a control signal, and the process returns to step S108 to wait for the next signal voltage Vs to be input. On the other hand, if the signs do not match, the signal voltage Vs is canceled in step S112, the process returns to step S108, the next signal voltage Vs is waited for, and the above operations are repeated until the neutral state is restored. become. In the application of the present invention, the point is that the neutral sensor detects the detachment of the operating lever from the neutral state, and the operating direction of the operating lever is determined based on the increase / decrease in the detection voltage of the potentiometer before and after the detachment. However, the detection voltage from the potentiometer that is contrary to the determination result may be excluded as long as signal processing is performed, and the operation flow is not limited to the above.

[0011]

[Effect of device]

 The present invention can obtain the following effects based on the above configuration. (1) The mechanical part that is added as a malfunction prevention means is only the neutral sensor, and it is not necessary to attach a complicated operation direction detection mechanism to each detection axis as in the past, so the configuration is simple and compact. It is effective for (2) The operation direction is determined by the fluctuations in the detected voltage from each potentiometer, before and after the operation lever is released from the neutral state, so stable operation can be obtained with a simple configuration. (3) Since the determination regarding the operation direction is performed by a simple electrical configuration, a joystick with high responsiveness, less trouble, and higher safety can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main part of an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation.

FIG. 4 is an operation flow chart of the microcomputer.

FIG. 5 is a schematic perspective view showing a main part of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Operation lever, 2 ... 1st detection axis, 3 ... Potentiometer, 4 ... 2nd detection axis, 5 ... Potentiometer, 6 ... Neutral sensor, 7 ... A / D conversion circuit, 8 ... Microcomputer, 9 ... For disconnection detection Pull-down resistor

Claims (1)

[Scope of utility model registration request] 1. A joystick that outputs a control signal using a potentiometer that operates according to the amount of operation of an operating lever, and a neutral sensor is provided at an appropriate portion of the operating lever to separate the operating lever from the neutral state. The operation direction of the operation lever is determined based on the increase / decrease of the detection voltage of the potentiometer before and after the operation lever is separated from the neutral state, and the detection voltage from the potentiometer that is contrary to the determination result is excluded. A device for preventing malfunction of a joystick, characterized in that it performs signal processing.