JP3232561U - Automatic grinding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic grinding apparatus capable of grinding an object having a complicated shape, having high safety, and having improved grinding quality. An automatic grinding device is a device that grinds an object using a grinder whose load current increases or decreases according to the amount of grinding per unit time, and includes a current detecting means for detecting the load current of the grinder. Compare the current setting value of the grinder with the load current detection value, and adjust the distance between the grinder and the target surface to be ground so that the load current becomes a constant value to determine the amount of grinding per unit time. It is equipped with a control device that controls the elevating mechanism to adjust the amount, and a head that can be attached to an industrial robot that can move in three dimensions. A predetermined extension time 9 is secured until the above time is reached, and a means for gradually increasing the pressing force on the grinding surface during the predetermined extension time 9 is provided. [Selection diagram] Fig. 2

Description

The present invention relates to an automatic grinding device. More specifically, the present invention relates to an automatic grinding device that controls a grinder to keep the amount of grinding and removal constant.

Grinding work with a grinder covers a wide range of tasks such as removing excess weld beads, deburring cutting members, and finishing the cast surface. Grinding using a grindstone inevitably involves the consumption of the grindstone, and as the grinding efficiency is increased, the grindstone is consumed more, and the work becomes harsh if it is a manual work due to the scattering of chips and the like.

Therefore, an automatic grinding device using a grinder is disclosed (Patent Document 1). This device is a device that grinds and removes the welding surplus using an electronic grinding machine whose load current increases or decreases according to the amount of grinding per unit time, and runs along the welding line at a constant speed. An electronic grinder movably supported three-dimensionally on a trolley via a lateral moving frame and an elevating mechanism, a current detecting means for detecting the load current of the electronic grinding machine, and a current set value and load current detection of the electronic grinding machine. Compare with the value, adjust the distance between the electronic grinding machine and the surface to be ground of the welding surplus so that the load current becomes a constant value, and adjust the grinding amount per unit time by adjusting the elevating mechanism. It is characterized by having a control circuit for controlling and an overload prevention circuit for outputting operation signals of rotation stop, ascending / retracting, and running stop of the electronic grinding machine when the load current of the electronic grinding machine reaches a limit value. It comprises an automatic grinding machine (claim 1) of a welding surplus. According to this device, the load current of the electron grinder is detected, compared with the set current value by a comparator, and when the actual load current is smaller than the set current value, the electron grinder is lowered (pressurized), and vice versa. When the actual load current is larger than the set current value, the elevating mechanism is controlled so as to raise the electron grinder. Since the load current of the electronic grinder is kept constant, it is possible to grind and remove a certain amount of surplus at all times as long as the moving speed of the traveling mechanism (traveling carriage) is constant (“action”).

However, in recent years, the shape of the object to be ground is often complicated, and there are some that cannot be handled by a linear traveling mechanism. However, in order to maintain international competitiveness, it is desirable to enable automatic grinding of these objects as well. At the same time, it is also desired that the grinding quality is further improved.

Jitsukaihei 06-0832 54

Therefore, it is an object of the present invention to provide an automatic grinding apparatus capable of grinding an object having a complicated shape, having high safety, and having improved grinding quality.

In order to solve the above problems, the automatic grinding device of the present invention is a device that grinds objects such as welding surplus, black skin, burrs, etc. using a grinder whose load current increases or decreases according to the magnitude of the grinding amount per unit time. The grinder and the target surface to be ground are compared with the current detecting means for detecting the load current of the grinder and the current set value and the load current detection value of the grinder so that the load current becomes a constant value. A control device that controls the elevating mechanism to adjust the distance between the two and adjust the amount of grinding per unit time, and a head mounted on an industrial robot that can move three-dimensionally, and the control device starts grinding. In operation, a predetermined extension time is secured from the start of pressurization control after the grinder comes into contact with the grinding surface until the load current reaches a constant value, and the pressing force on the grinding surface is gradually applied during the predetermined extension time. It consists of providing a means to raise it.

Further, the automatic grinding device of the present invention is a device that grinds and removes an object using a grinder whose load current increases or decreases according to the magnitude of the grinding amount per unit time, and is a current detecting means for detecting the load current of the grinder. , And the current setting value of the grinder and the load current detection value are compared, and the distance between the grinder and the target surface to be ground is adjusted so that the load current becomes a constant value, and grinding per unit time is performed. A control device that controls the elevating mechanism to adjust the amount and a head attached to an industrial robot that can move three-dimensionally are provided, and the control device starts pressurization control after contact with the grinding surface of the grinder in the grinding start operation. From time to time, a predetermined extension time is secured, and a means for gradually increasing the control load current detection value by a lowering operation during the predetermined extension time is provided.

Further, it is preferable to provide means for setting and controlling the predetermined time to an arbitrary time. Further, in the grinding start operation, it is preferable to provide a means for lowering the pressurization control start pressurization to be lower than the pressurization in which the current set value and the load current detection value match. Further, in the grinding start operation, it is preferable to provide a means for arbitrarily setting and controlling the pressurization control start time after the contact with the grinding surface.

The invention of the present application is to improve the safety and the grinding quality while making it possible to grind an object having a complicated shape. In the technique of Patent Document 1 described above, since the moving means in the horizontal and vertical directions are mainly linear, it is difficult to follow an object having a more complicated shape. However, in the present invention, by mounting the robot on the wrist of an industrial robot via a mounting head, it is possible to grind a complicated shape such as a curved surface or a plurality of points. In addition, by mounting it on an industrial robot, the grinder itself does not require a special sensor or parallel mechanism, and it is not affected by the grinding posture and has excellent follow-up performance.

As described above, the automatic grinding device mounted on the industrial robot has many advantages and improves work efficiency. However, when an actual test was conducted, it was found that a conspicuous step was generated between the non-grinded portion and the ground portion at the grinding start position, and the ground product may be defective. This means that when the grinder is lowered at the start of grinding to grind, the industrial robot can instantly lower the automatic grinding device to the grinding start position and apply the required pressing force at once (contact with the grinding surface). Until then, the grinder "descends", but if it continues to descend even after it comes into contact with the ground surface, it will "pressurize" the ground surface by the grinder.) However, when the amount of grinding is large, a step is inevitably stepped. In addition to the fact that when the descent (pressurization) speed is high, it is considered that the cause is that grinding more than the expected value is likely to occur at the starting position due to a slight difference between the assumed position and the actual position. Therefore, in the present invention, the control device on the grinder side specifically touches the grinder to the grinding surface to start running and pressurizes it "slowly" to a predetermined load current in the grinding start operation. It was made possible. That is, at the grinding start position, it is possible to adjust the descending speed until it comes into contact with the grinding surface, and the pressing force at the start of pressurization control is set to be lower than the pressing force corresponding to the set current value. Further, a predetermined extension time is provided so that the pressing force gradually increases until a desired constant value is reached while traveling. With this configuration, no step is generated between the non-grinding portion and the grinding portion at the grinding start position, smooth grinding quality is obtained, and complicated control settings on the industrial robot side are not required.

In the present application, the term "gradual rise" includes a case where the vehicle rises at a constant rate of descent, a case where the speed gradually increases, and a case where the vehicle rises in several stages. Typically, it is preferable in terms of efficiency and quality to ascend at a constant descending rate.

The "predetermined extension time" is the time between the start of pressurization control and the gradual increase in the pressurization and / or load current detection value, and typically, when the predetermined extension time elapses, a desired pressurization It is controlled to be a pressure (load current detection value, current set value, or pressing force that the load current is assumed to match the current set value). Normally, the operation of an industrial robot is very fast, and the arm can be raised and lowered instantly. Therefore, if it is attempted to set the pressurizing speed slow only at the grinding start position in the industrial robot, it is necessary to specifically teach on the industrial robot side, which is not efficient. Therefore, in the present invention, the control device side of the grinder lowers by controlling the slide mechanism so that the desired pressing force (the pressing force that the load current is assumed to match the current set value) is obtained when a predetermined extension time elapses. Pressurization) The speed is reduced to pressurize "slowly" while driving.

The predetermined extension time can be a fixed value as a set value (for example, 1 second), but the desired extension time may differ depending on the rotation speed, the grindstone material, the grinding object, and the like. Therefore, it is preferable that the user can input an arbitrary time to the control device. Based on this input extension time, grinding is executed by calculating and adjusting the descent speed (pressurization speed) so that the pressing force corresponds to the current set value when the extension time elapses. Here, if the input predetermined extension time is set longer, the pressurization can be performed more slowly, and the ground surface becomes smoother. On the other hand, if it is set short, the pressure can be pressed to a desired value more quickly, and a predetermined grinding amount can be reached faster. It should be noted that the load current does not necessarily have to match the current set value when the extension time elapses, and it is sufficient that the load current is controlled so as not to cause overgrinding at the grinding start position and to ensure smooth grinding quality.

Further, at the grinding start position, the current setting value and the load current detection value match the means for making it possible to adjust the descending speed until the grinding surface comes into contact with the grinding surface and the pressing force at the start of contact with the grinding surface of the grinder. By providing a means for lowering the pressing force, the grinding machine comes into contact with the grinding surface with a lighter pressing force when it first contacts the grinding surface. That is, it allows the grinder to "softly" touch the ground surface. It is preferable that the user can input an arbitrary value to the control device for the pressurization control start pressurization. For example, when the pressing force at which the current set value and the load current detected value match is set to 100, it may be configured so that it can be arbitrarily set within 1 to 100% of the pressing force. If it is about 10%, the pressurization control will be started very softly, and if it is 90%, the pressurization control will be started from a state close to the required pressing force. The descending speed until it comes into contact with the ground surface can also be arbitrarily set within, for example, 1 to 100% of the normal descending speed. In any case, it suffices if the pressurization control start pressurization in the grinding start operation can be brought into contact at a value lower than the pressurization at which the current set value and the load current detection value substantially match.

In the present invention, by combining both gradually increasing the pressing force while traveling with an extension time and decreasing the downward pressing force when the grinding surface comes into contact, it is possible to flexibly deal with any grinding object with a simple operation. It is possible to improve the grinding efficiency and the grinding quality.

Then, after the extension time has elapsed, the current set value of the grinder and the load current detection value are compared, and the distance between the grinder and the target surface to be ground is adjusted so that the load current becomes a constant value. Grinding proceeds while controlling the elevating mechanism in order to adjust the grinding amount per unit time. By outputting the running start signal from the control device on the grinder side to the industrial robot, the setting work on the industrial robot side becomes unnecessary, so that it can be provided as a highly versatile device for selecting the industrial robot. ..

According to the present invention, it is possible to provide an automatic grinding apparatus capable of grinding an object having a complicated shape, having high versatility and safety, and having improved grinding quality.

FIG. 1 is a diagram showing an automatic grinding device of the present invention. FIG. 2 is a time chart diagram showing an example of the control of the present invention.

Hereinafter, an example of implementation of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an automatic grinding device 1 of the present invention. The grinder mechanism 2 is provided on the elevating slider 3, and is connected to the control device 4 and the high-frequency inverter power supply device 5, respectively. The elevating slider 3 is configured to be detachable from the wrist tip of an industrial robot (not shown) via an upper mounting head. The elevating slider 3 controls the distance in the height direction between the grindstone grindstone 6 and the target surface to be ground. The elevating slider 3 is slidable in the vertical direction by the elevating motor, and the grinding grindstone 6 can be raised and lowered by rotating the elevating motor in the forward and reverse directions via the control device 4. The grinder mechanism 2, the elevating slider 3, the control device 4, the high-frequency inverter power supply device 5, and the industrial robot are electrically connected to each other by various cables.

The control device 4 compares the current set value with the load current detection value of the grinder mechanism 2, and adjusts the distance and the pressing force between the grindstone grindstone 6 and the target surface to be ground so that the load current becomes a constant value. To adjust. The control device 4 is for controlling the elevating slider 3 in order to keep the grinding amount of the grinding machine 6 constant per unit time or adjust it, and is a rectifying element for rectifying the load current of the grinding motor and a rectifying element. It is equipped with a sequencer with a built-in smoothing circuit that removes noise from the output and a forward / reverse switch that determines the forward / reverse rotation of the elevating motor by calculating / outputting a comparator that compares the load current with the set value current. .. The comparator compares the current value set in the current value setter in advance with the load current, and when the absolute value of the difference exceeds the value predetermined by the sensitivity adjustment circuit, it rises from the forward / reverse switcher. Or output a descending signal. When the load current of the grinder mechanism 2 is smaller than the set current value, the grinder is lowered, and conversely, when the actual load current is larger than the set current value, the elevating mechanism is driven to raise the grinder to provide a certain amount of surplus. Can be ground and removed. In addition to the set current value, the input items include the descending speed until the contact with the grinding surface, the pressing force at the start of contact, and the predetermined extension time from the contact with the grinding surface until the load current becomes a constant value. When the descent speed until contact with the grinding surface is set, the elevating mechanism is controlled at a speed decelerated from the normal descent speed. When the pressure at the start of contact is set, the set value current and the load current value are controlled to come into contact with the target with the pressure reduced to the same pressure, and a travel signal is sent to the robot to allow the robot to travel. To start. When a predetermined extension time is set, control is performed to gradually increase the pressing force so that the set value current and the load current value match when the extension time elapses. These settings are preferably configured by an input mechanism such as a touch panel of the control device, but are not particularly limited as long as the above means can be realized.

FIG. 2 is a time chart diagram showing an example of the control of the present invention. First, the grinding wheel 6 moves to just above the grinding start position by the operation of the industrial robot. After that, the start signal is received from the industrial robot, and the grinder grindstone 6 starts rotating. Then, after the preliminary time (2 seconds) has elapsed, the elevating slider 3 descends and comes into contact with the ground surface (7 at the time of detecting the contact with the ground surface). The descent speed at this time is a descent speed arbitrarily input to the control device 4, and it is possible to "softly" contact the descent speed. At the same time that the contact is detected by the change in the load current, the control device 4 issues a traveling signal to the industrial robot, and the industrial robot starts traveling. Further, the pressurization control is also started, but the pressurization control start pressurizing force 8 is lower than the pressurizing force corresponding to the current set value. The pressurizing control start pressing force 8 is a value arbitrarily set for the control device 4. For example, if the input value is 50%, the control device 4 sets the set value current at the grinding start position to 50%, so that the grinding start position is a pressing force during traveling by the same method as the above-mentioned elevating control. It will be pressurized with a force of about 50%.

Until the grinder pressurizes the set value current and the load current value to match, the pressurization is not performed at once, but is gradually strengthened for an arbitrarily set extension time 9. The extension time 9 can be input as, for example, 1 second or 3 seconds. By controlling during this extension time, from the grinding start position to the position where the set value current and the load current value match, there is no noticeable step between the non-grinding part and the grinding part, and the grinding is very smooth and high. Quality can be ensured.

If the control device 4 constantly controls the pressurization speed so that the set value current is obtained when the extension time 9 elapses, the pressurization speed can be increased to almost a desired pressurization. However, if the set value current and the load current value match during the extension time, in order to prevent over-grinding, it is desirable that no further pressurization is performed and the elevating slider 3 is not lowered. .. When the set value current and the load current value match, or after the extension time 9 has elapsed, grinding is executed while controlling the set value current and the load current value to match as described above (normal grinding execution time 10). When the grinding is completed (11 at the end of grinding), the rotation of the grindstone grindstone 6 is stopped, the robot running is ended, and the grinding grindstone 6 is raised to end the grinding.

With the above configuration, it is possible to prevent a conspicuous step from occurring at the non-grinding portion and the grinding portion at the grinding start position, and the grinding quality is improved. Further, since it is not necessary to directly instruct the industrial robot to perform the above operation of the grinding start position, it is excellent in versatility. In addition, since automatic grinding is possible even on complicated ground surfaces, manual work is not required and safety is high. Further, since the elevating slider 3 can be operated independently of the industrial robot, inspection and maintenance of the automatic grinding device 1 is easy.

Claims (7)

A device that grinds an object using a grinder whose load current increases or decreases according to the amount of grinding per unit time. A current detecting means for detecting the load current of the grinder, a current set value of the grinder, and a load current. Control that controls the elevating mechanism to adjust the distance between the grinder and the target surface to be ground so that the load current becomes a constant value by comparing with the detected value and adjust the grinding amount per unit time. Equipped with a device and a mounting head for an industrial robot that can move in three dimensions, the control device secures a predetermined extension time from the time of contact with the grinding surface of the grinder to the constant value of the load current in the grinding start operation. However, the automatic grinding apparatus is provided with means for gradually increasing the pressing force on the grinding surface during the predetermined extension time. A device that grinds and removes an object using a grinder whose load current increases or decreases according to the amount of grinding per unit time. A current detecting means for detecting the load current of the grinder, and a current set value and load of the grinder. The elevating mechanism is controlled to adjust the distance between the grinder and the target surface to be ground so that the load current becomes a constant value by comparing with the current detection value and adjust the grinding amount per unit time. It is equipped with a control device that can be mounted on an industrial robot that can move three-dimensionally, and the control device secures a predetermined extension time in the grinding start operation from the start of pressurization control after contact with the grinding surface of the grinder. An automatic grinding device comprising means for gradually increasing the control load current detection value by a descending operation during the predetermined extension time. The automatic grinding apparatus according to claim 1 or 2, further comprising means for setting and controlling the predetermined extension time to an arbitrary time. The automatic grinding apparatus according to any one of claims 1 to 3, further comprising means for arbitrarily setting and controlling the pressurization control start pressurizing force on the grinding surface of the grinder in the grinding start operation. The automatic grinding apparatus according to any one of claims 1 to 4, further comprising means for arbitrarily setting and controlling the descending speed of the grinder until it comes into contact with the grinding surface. The descending speed of the grinder until it comes into contact with the predetermined extension time or the grinding surface, and
The automatic grinding apparatus according to claim 1, further comprising means for arbitrarily setting and controlling the pressurization control start pressurizing force on the grinding surface of the grinder in the grinding start operation. A device that grinds an object using a grinder whose load current increases or decreases according to the amount of grinding per unit time. A current detecting means for detecting the load current of the grinder, a current set value of the grinder, and a load current. The elevating mechanism is controlled to adjust the distance between the grinding machine and the target surface to be ground to adjust the grinding amount per unit time so that the load current becomes a constant value by comparing with the detected value. An automatic grinding machine characterized by having a control device and a mounting head for an industrial robot that can move three-dimensionally.

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