JP4427752B2 - Robot system - Google Patents

Description

  The present invention relates to a robot system including a battery for supplying a power supply voltage to store and hold sensor position information, and the battery is periodically refreshed, and the manipulator and the control device are connected by relocation or replacement. It is related with the robot system which can memorize | store and hold the positional information on a sensor, even if is removed.

A general robot system includes a control device and a robot (hereinafter referred to as a manipulator), and a motor and a sensor are installed on a drive shaft of each joint of the manipulator. As a first prior art, a general robot system will be described.
FIG. 3 is a schematic diagram showing the configuration of a conventional robot system. In the figure, 1 is a control device, 2 is a control power supply, 3 is a manipulator, 4-1 to 4-6 are sensors, 5-1 to 5-6 are motors, 6 is a main battery circuit, and 7 and 8 are power supply preventions. Means. Note that only the components related to the present invention are described, and the motor driving device and the like in the control device 1 are omitted. Moreover, although the manipulator 3 shows an example of 6 axes, the number of axes is not limited thereto. The control device 1 and the manipulator 3 are connected by wiring cables such as power supply and drive commands from the control device 1 and joint information signals from the manipulator 3 so that signals can be exchanged with each other.

In the case of normal operation, the sensors 4-1 to 4-6 operate while being supplied with power from the control power supply 2 in the control device 1, and store and hold position information of the sensors 4-1 to 4-6. On the other hand, when the control device 1 is not operating, such as relocation of the robot system and maintenance of the control device 1 and the manipulator 3, that is, power is not supplied from the control power source 2 in the control device 1 to the sensors 4-1 to 4-6. In this case, power is supplied from a battery (not shown) in the main battery circuit 6 to the sensors 4-1 to 4-6, and the position information is stored and held. In general, a battery (not shown) in the main battery circuit 6 is a lithium battery that allows the manipulator 3 to be small in size, has high voltage, high energy density, and long-term stability in consideration of mounting on the manipulator 3. It is done.
The power supply line of the control power supply 2 and the power supply line of the battery are provided with voltage sneaking prevention means 7 and 8 in order to prevent each voltage from sneaking around. As the voltage sneaking prevention means 7 and 8, a reverse current prevention element such as a diode, transistor, FET or the like having a one-way voltage transmission property is generally used.

Next, a backup power supply apparatus having a backup power supply for an absolute encoder will be described as a second conventional technique.
A backup power supply device as a second prior art comprises a battery connection portion for connecting a backup battery and another battery connection portion in parallel, and shuts off the voltage of the main power supply portion while the backup battery is connected to the battery connection portion. Then, a new backup battery is connected to another battery connection part, and then the backup battery is removed from the backup battery connection part (see, for example, Patent Document 1). In this way, the backup power supply device according to the second prior art can replace the backup battery even when the main power is turned off, so there is no possibility of a circuit short-circuit and the like, and the loss of backup data of the absolute encoder is prevented. It can be done.

Next, a backup power supply apparatus different from the second conventional technique having a backup power supply for an absolute encoder will be described as a third conventional technique.
A backup power supply device, which is a third conventional technology, connects a primary battery in parallel to a backup capacitor, and connects a backup power supply device having a detachable connection terminal in parallel to the main power supply unit of the motor control device. One of the second connection terminals is connected, the other second connection terminal is not connected, and the second connection terminal is used when a new backup power supply device is replaced (for example, see Patent Document 2). . As described above, the backup power supply device according to the third prior art makes it easy to replace the backup capacitor, and since two or more second connection terminals are provided, the backup data of the absolute encoder is lost. Thus, the backup power supply device can be replaced.

Next, as a fourth prior art, an encoder apparatus having a backup power source for an absolute encoder will be described.
The encoder device which is the fourth prior art has an encoder body that measures the amount of displacement of the object to be measured, and a backup power source that supplies a backup power source when the main power source that supplies power to the encoder body is shut off. An encoder device that has an auxiliary power supply outside the encoder main body to supply backup power instead of the main battery when the main battery of the backup power supply is replaced. The backup power supply supplies the backup power supply only to the circuits that require backup of the encoder main body. It is set as a structure (for example, refer patent document 3). As described above, the encoder device according to the fourth prior art can realize downsizing of the encoder without mounting a large-capacitance capacitor inside the encoder, and reduces the backup time due to the aging deterioration of the capacitor capacity in a high temperature environment. Since the problem can be solved, the encoder can be used at high temperatures, the current consumption during backup is reduced, backup can be performed for a longer time, and the life of power supply elements such as batteries and capacitors can be extended. It is.
JP 2001-309577 A (page 2-4, FIG. 1) JP 2002-213994 A (page 3, FIG. 1) Japanese Patent Laying-Open No. 2005-221476 (page 4-6, FIG. 1)

The general robot system as the first prior art uses a lithium battery as a battery in the battery circuit. Therefore, when the battery is used again from an unused state, an oxide film is formed in the battery. A phenomenon called a temporary voltage drop occurs.
Here, the closed-circuit voltage characteristics of the lithium battery will be described. FIG. 5 is a schematic diagram showing a closed circuit voltage characteristic of a lithium battery. In the figure, the discharge characteristics of the lithium battery are dominated by the lithium chloride film formed on the negative electrode lithium metal surface. Therefore, when the battery is discharged in a state where the film has grown due to long-term storage or the like, Changes rapidly and exhibits a transient phenomenon (transient minimum voltage). In addition, after a transient phenomenon, the battery exhibits a relatively stable discharge potential (operating voltage). The transient minimum voltage is affected by the state of the lithium chloride film on the lithium surface. If the film state is the same, it is affected by the load size and the ambient temperature. The larger the load and the lower the ambient temperature, the transient minimum voltage. The voltage is lowered. Also, the longer the storage period, the lower the transient minimum voltage. The operating voltage is higher than the transient minimum voltage, but the load voltage and the environmental temperature are almost the same, and the operating voltage decreases as the load increases and the environmental temperature decreases. Become.

  When this transient occurs, the voltage drop is not a big problem when the unused period is short, but when the unused period is long, the voltage drop is large and is necessary for storing and holding sensor information. There is a problem that the position information of the sensor is lost because the voltage drops below the voltage. Further, if the position information of the sensor is lost, there is a problem that when the normal operation is resumed, an alarm is generated in the control device and the work process is stopped. In addition, the lithium battery has a sharp voltage end characteristic, so that there is a problem that the remaining battery life cannot be accurately grasped at the end of the battery life. In addition, since the voltage characteristics of the lithium battery are affected by the magnitude of the load and the environmental temperature, there is a problem in that it must be used in consideration of the installation environment of the manipulator and the number of axes.

The backup power supply apparatus according to the second prior art or the third prior art is similar to the general robot system as the first prior art when the lithium battery is used as the battery, and the above-mentioned voltage drop. The problem that depends on the battery and the problem that the remaining battery life cannot be accurately grasped cannot be solved. The use of a lithium battery as a battery is common in a robot system in that it is small in size, high in voltage, high in energy density, and long-term stable.

As in the case of the general robot system as the first prior art, the encoder device according to the fourth prior art, when using a lithium battery as the battery, accurately corrects the problems caused by the aforementioned voltage drop and the remaining battery life. The problem of not being able to grasp is not solved. The use of a lithium battery as a battery is common in a robot system in that it is small in size, high in voltage, high in energy density, and long-term stable.
The present invention has been made in view of such problems, and includes an auxiliary battery circuit that supplies power to the sensor and a refresh circuit having a load in the control device, and the sensor is based on a plurality of power supply sources. During normal operation when power is supplied and the controller is energized, the main battery circuit and the refresh circuit are connected to reduce the voltage drop when the main battery circuit is reused even when the main battery circuit is not used for a long time. It is an object of the present invention to provide a robot system that can prevent the disappearance of sensor position information, and can extend the sensor position information storage period and accurately grasp the battery remaining period.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a robot system comprising: a manipulator having a main battery circuit that supplies power to the sensor; and a control device that drives the manipulator having a main power source that supplies power to the sensor. An auxiliary battery circuit for supplying power to the main battery circuit, and a simulated load for the main battery circuit. The control device supplies power to the sensor based on a plurality of power supplies, and connects the main battery circuit and the simulated load. The main battery circuit is refreshed.
According to a second aspect of the invention, the simulated load according to the first aspect of the invention is connected in parallel with the main battery circuit.
According to a third aspect of the present invention, the simulated load according to the first aspect of the invention is a refresh circuit having a connection switch and a load that are electrically movable, or a manual operation having a connection switch and a load that are manually movable. It is a refresh circuit.
According to a fourth aspect of the present invention, the electrically movable connection switch according to the third aspect of the present invention is movable during normal operation of the control device.
According to a fifth aspect of the present invention, the manually movable connection switch according to the third aspect of the present invention is movable during normal operation of the control device or when the control device is not energized.
According to a sixth aspect of the present invention, the manually movable connection switch according to the third aspect of the invention is installed on the front surface of the control device.
According to a seventh aspect of the invention, the refresh circuit according to the third aspect of the invention is connected in parallel to the main battery circuit or the manual refresh circuit.
According to an eighth aspect of the invention, the main battery circuit according to the first aspect of the invention has a lithium battery as a battery, and the auxiliary battery circuit has an alkaline battery as a battery.

According to the first aspect of the present invention, even when the main battery circuit is not used for a long time, it is possible to reduce the voltage drop and prevent the sensor position information from disappearing when the main battery circuit is reused. The position information storage period can be extended and the battery remaining period can be accurately grasped. In addition, the main battery circuit can be used without worrying about the installation environment of the manipulator and the number of axes.
According to the second or seventh aspect of the invention, the main battery circuit can be easily refreshed, and a voltage drop can be reduced and the sensor position information can be prevented from disappearing when the main battery circuit is reused. In addition, the reliability of the system can be improved.
According to the third aspect of the present invention, the main battery circuit can be easily refreshed regardless of whether the control device is energized or not energized, and can be provided when the main battery circuit is reused.
According to the fourth aspect of the present invention, the main battery circuit can be easily refreshed during normal operation when the control device is energized.
According to the fifth aspect of the invention, the main battery circuit can be refreshed regardless of whether the control device is energized or not energized, and can be provided when the main battery circuit is reused.
According to the sixth aspect of the present invention, the refresh operation can be easily performed whenever the operator needs.
According to the eighth aspect of the present invention, the sensor position information storage period can be extended and the battery remaining period can be accurately grasped.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram illustrating a configuration of a robot system according to the first embodiment of the present invention. In the figure, 1 is a control device, 2 is a control power supply, 3 is a manipulator, 4-1 to 4-6 are sensors, 5-1 to 5-6 are motors, 6 is a main battery circuit, and 7 and 8 are power supply preventions. 10 is an auxiliary battery circuit, 11 is a power supply prevention means, and 12 is a refresh circuit. As the voltage sneaking prevention means 7, 8, 11, it is common to use a backflow prevention element such as a diode, transistor, FET or the like having a voltage unidirectional transmission.
Note that only the components related to the present invention are described, and the motor driving device and the like in the control device 1 are omitted. Moreover, although the manipulator 3 shows an example of 6 axes, the number of axes is not limited thereto. The control device 1 and the manipulator 3 are connected by wiring cables such as power supply and drive commands from the control device 1 and joint information signals from the manipulator 3 so that signals can be exchanged with each other.

The portion of the present invention different from the general robot system as the first prior art is a portion provided with the auxiliary battery circuit 10, the power sneak prevention means 11, and the refresh circuit 12.
Further, portions different from the backup power supply device of the second prior art (Patent Document 1) or the third prior art (Patent Document 2) are different in that they are applied to the robot system. It is a part with.
Further, the part different from the encoder device of the fourth prior art (Patent Document 3) is different in that it is applied to a robot system, and in particular is a part provided with a refresh circuit 12.

In the case of normal operation, the sensors 4-1 to 4-6 operate while being supplied with power from the control power supply 2 in the control device 1, and store and hold position information of the sensors 4-1 to 4-6.
In this case, by operating the refresh circuit 12, it is possible to refresh the main battery circuit 6 that does not need to supply power to the sensor. That is, a connection switch (not shown) in the refresh circuit 12 is operated based on a control signal from a control unit (not shown) in the control device 1, and a main battery circuit is connected to a load (not shown) in the refresh circuit 12. 6 is connected. Thereby, even when the main battery circuit 6 does not need to supply power to the sensor, the power supply state to the sensor can be virtually created, and even when the unused period of the main battery circuit 6 is long, the main battery It is possible to reduce the voltage drop when the circuit 6 is reused and prevent the disappearance of sensor position information. The refresh operation is not always performed during normal operation, but is performed periodically with a certain period of time. The refresh here refers to a power supply state from the main battery circuit 6 to the virtual sensor when there is no power supply from the main battery circuit 6 to the sensor. The refresh circuit 12 corresponds to a sensor simulated load for the main battery circuit 6.
The load is a load through which a current corresponding to the current consumed by the sensor flows. For example, the load can be easily configured with a small size and a low price. Further, a semiconductor element such as a transistor or FET may be used for the electrically movable connection switch, and a current may be passed through a load such as a resistor.

  On the other hand, there are two methods for supplying power to the sensor when the control device 1 is not operating, such as relocation of the robot system and maintenance of the control device 1 and the manipulator 3. That is, when power is not supplied from the control power supply 2 in the control device 1 to the sensors 4-1 to 4-6, a method of supplying power from the battery (not shown) in the main battery circuit 6 to the sensors 4-1 to 4-6. The position information is stored and held by a method of supplying power to the sensors 4-1 to 4-6 from a battery (not shown) in the main battery circuit 6 and a battery (not shown) in the auxiliary battery circuit 10.

The former is a case where there is no operation of the control device 1 and there is no connection between the control device 1 and the manipulator 3 with a wiring cable. In this case, if a lithium battery having high voltage, high energy density, and long-term stability is used for the battery (not shown) in the main battery circuit 6 in consideration of mounting on the manipulator 3, the first conventional technique is used. There is concern about the same voltage drop as a general robot system that is a technology. However, since the above-described refresh operation during normal operation is performed, even when the unused period of the main battery circuit 6 is long, there is a risk of voltage drop and loss of sensor position information when the main battery circuit 6 is reused. Will disappear.
The latter is a case where there is no operation of the control device 1 and there is a connection with a wiring cable between the control device 1 and the manipulator 3. In this case, since power can be supplied to the sensor by two batteries, the position information storage period of the sensor can be extended.

In the present invention, a battery (not shown) in the main battery circuit 6 uses a lithium battery having a high voltage, a high energy density, and a long-term stability in consideration of mounting on the manipulator 3. An internal battery (not shown) uses an alkaline battery.
FIG. 4 is a schematic diagram showing terminal voltage characteristics of a lithium battery and an alkaline battery. In the figure, the voltage characteristic of a lithium battery generally decreases abruptly at the end of its life, and the voltage characteristic of an alkaline battery decreases relatively slowly. By utilizing this difference in voltage characteristics, the battery life can be accurately grasped.

  Generally, the control device monitors the battery voltage, and there is a battery alarm that is output when the battery voltage reaches a certain drop level, and a backup alarm that is output when the position information holdable voltage drop level is reached. The operator replaces the battery based on the battery alarm and the backup alarm. Here, when the terminal voltage characteristic is steep, the time between the battery alarm and the backup alarm is short, so it is necessary to replace the battery for a short time.For example, the battery life is exhausted during the long holiday of the operator, There is a high possibility that the position information of the sensor will disappear. On the other hand, if the terminal voltage characteristics are gradual, the time between the battery alarm and the backup alarm is long, and it is easy to grasp the progress of the voltage drop. The battery life can be accurately grasped.

Here, a method for supplying power to the sensors of the two batteries will be described. An alkaline battery whose voltage is slightly higher than that of a lithium battery usually serves as a power supply to the sensor. When the alkaline battery is consumed, a voltage drop starts and the voltage of the lithium battery becomes higher (point A in FIG. 4). When the power is supplied to the sensor, and when the voltage starts to drop due to the consumption of the lithium battery and the voltage of the alkaline battery becomes higher (point B in FIG. 4), the alkaline battery becomes the power supply to the sensor again. That is, the higher voltage based on the voltage difference between the sensors serves as a power supply to the sensor. This also applies to the voltage relationship between the control power source 2 and the lithium battery or alkaline battery when the control device 1 is in operation. The voltage of the control power source 2 during normal operation is slightly higher than the voltage of the lithium battery or alkaline battery. Therefore, the control power supply 2 is a power supply for the sensor.
In addition, although the example provided with two battery circuits was shown in the Example, you may make it provide three or more battery circuits by the structure of a control apparatus, a manipulator, the whole system, etc.

  FIG. 2 is a schematic diagram illustrating a configuration of a robot system according to the second embodiment of the present invention. In the figure, 1 is a control device, 2 is a control power source, 3 is a manipulator, 4-1 to 4-6 are sensors, 5-1 to 5-6 are motors, 6 is a main battery circuit, and 7, 8, and 11 are power sources. A wraparound prevention means, 10 is an auxiliary battery circuit, 12 is a refresh circuit, and 13 is a manual refresh circuit. The portion different from the first embodiment is a portion provided with a manual refresh circuit 13 in parallel with the refresh circuit 12, and the components having the same reference numerals as those in FIG.

  In the first embodiment, the refresh operation of the main battery circuit 6 is performed by the connection in the refresh circuit 12 based on a control signal from a control unit (not shown) in the control device 1 during normal operation in which the control device 1 is energized. A switch (not shown) is operated to connect the main battery circuit 6 to a load (not shown) in the refresh circuit 12. In this case, since the connection switch (not shown) in the refresh circuit 12 is electrically operated (for example, a relay operated by an excitation current), the main battery circuit 6 can be refreshed only during normal operation. It will be.

  Therefore, by providing the manual refresh circuit 13 in parallel with the refresh circuit 12, the refresh operation of the main battery circuit 6 can be performed even when the control device 1 is not in operation. The manual refresh circuit 13 includes a connection switch (for example, a toggle switch) that is mechanically operated manually and a load similar to that of the refresh circuit 12. The manual refresh circuit 13 is installed in a place where it is easy for the operator of the control device 1 to operate. The refresh here refers to a power supply state from the main battery circuit 6 to the virtual sensor when there is no power supply from the main battery circuit 6 to the sensor. In addition, the refresh circuit 12 and the manual refresh circuit 13 correspond to a simulated sensor load for the main battery circuit 6.

  In the first and second embodiments, the main battery circuit has a lithium battery as the battery and the auxiliary battery circuit has an alkaline battery as the battery. However, the type of the battery is not limited to this. That is, the refresh operation is effective, there is a difference in the terminal voltage characteristics between the battery corresponding to the lithium battery and the battery corresponding to the alkaline battery, and the terminal voltage characteristic of the battery corresponding to the alkaline battery is a battery corresponding to the lithium battery. As long as it compensates for the terminal voltage characteristics of the terminal. Possible types of batteries include secondary batteries such as alkaline storage batteries, lead storage batteries, silver oxide batteries, nickel cadmium batteries, nickel metal hydride batteries, lithium ion secondary batteries, manganese batteries, alkaline batteries, lithium batteries, air A primary battery such as an alkaline battery may be used, and a supercapacitor, that is, an electric double layer capacitor or a large capacity capacitor such as an aluminum electrolytic capacitor may be used instead of the battery. The proper use of these combinations may depend on the application and the convenience of the system.

  A robot system is a typical system of a multi-axis servo control system, and other fields of the multi-axis servo control system may include machine tools, mounting machines, semiconductors, liquid crystal manufacturing apparatuses, and the like. Although the robot system has been described in the embodiments, the control system is separated from the mechanism system having a drive source such as a motor and a sensor, and other general fields such as machine tools that require backup of sensor position information are used. It can also be applied to typical multi-axis servo control system applications.

It is the schematic which shows the structure of the robot system in Example 1 of this invention. It is the schematic which shows the structure of the robot system in Example 2 of this invention. It is the schematic which shows the structure of the robot system of a 1st prior art. It is the schematic which shows the terminal voltage characteristic of a lithium battery and an alkaline battery. It is the schematic which shows the closed circuit voltage characteristic of a lithium battery. DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Control power supply 3 Manipulator 4-1 to 4-6 Sensors 5-1 to 5-6 Motor 6 Main battery circuit 7, 8, 11 Power supply circuit 10 Auxiliary battery circuit 12 Refresh circuit 13 Manual refresh circuit

Claims (8)

In a robot system comprising: a manipulator having a main battery circuit for supplying power to a sensor; and a control device for driving the manipulator having a main power supply for supplying power to the sensor.
An auxiliary battery circuit for supplying power to the sensor; and a simulated load for the main battery circuit.
A robot system, wherein power is supplied to the sensor based on a plurality of power supplies, and the main battery circuit and the simulated load are connected to refresh the main battery circuit.   The robot system according to claim 1, wherein the simulated load is connected in parallel with the main battery circuit.   2. The robot system according to claim 1, wherein the simulated load is a refresh circuit having an electrically movable connection switch and a load, or a manual refresh circuit having a manually movable connection switch and a load.   The robot system according to claim 3, wherein the electrically movable connection switch is movable during normal operation of the control device.   The robot system according to claim 3, wherein the manually movable connection switch is movable during normal operation of the control device or when the control device is not energized.   The robot system according to claim 3, wherein the manually movable connection switch is installed on a front surface of the control device.   4. The robot system according to claim 3, wherein the refresh circuit is connected in parallel with the main battery circuit or the manual refresh circuit. The main battery circuit has a lithium battery as a battery,
The robot system according to claim 1, wherein the auxiliary battery circuit includes an alkaline battery as a battery.

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