JP2009090421A - Sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that there are lots of merits on radio transmission of the information since a sensor for measuring conditions of a mechanical system driven by a motor is arranged at a moving section but there is disadvantage such as the lack of capacity of a battery and frequent exchanges of batteries when the battery is used for a power source supplying to the sensors and a radio circuit. <P>SOLUTION: In a robot sensor unit 111 for measuring conditions of a mechanical system 102, power is supplied to the sensor 103 and the radio circuit 106 by using a power generation module 104 for conveying kinetic energy into electric power. The lack of power can be compensated by using a battery 105 together with the power source. Thus, it can correspond to forgotten cutting-off of the power source and the lack of power by using a means for changing sources of service, and stable supply of the power and a stable operation of the mechanical system can be realized. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor attached to a mechanical device such as a robot, a machine tool, or an XY table, a wireless circuit that wirelessly transmits information from the sensor, a power generation module that drives these, and a sensor device that includes a battery.

An example of a sensor device used in a conventional mechanical device is a finger collision detection device used in a wafer transfer robot. (See Patent Document 1).
The apparatus shown in FIG. 8 includes a collision detection means 10 and a receiver 11 provided in a separately installed control device. The collision detection means 10 includes a detection circuit 12, a radio transmission circuit 13, an antenna 13a, and a battery 14. Consists of When the finger 4 collides with a carrier, boat, wafer or the like, the spring 8a as an elastic member is pushed, the limit switch 8b is activated, a signal is sent from the antenna 13a of the wireless transmission circuit 13 via the detection circuit 12, and is installed separately. Is received by the receiver 11 of the control device, and the robot is stopped by the control device by this signal.
In this manner, in the sensor device of FIG. 8, power is supplied by a single battery, and sensor signal output is performed by wireless communication.
JP-A-6-349930 (5th page, FIG. 1)

In the above-described conventional sensor device, a battery is required to make the sensor and the radio function. Since the power required for communication is large, if a single battery is used to supply all the power, the capacity required for the battery becomes large. In order to reduce the frequency of battery replacement, the battery volume may be increased, but it is difficult to attach the battery to the arm tip. If the battery volume is reduced, the battery life (replacement interval) is shortened, and the battery needs to be replaced frequently. Battery life (exchange interval) is determined by battery capacity. In addition, if the power switch is forgotten to be turned off, the battery life (replacement interval) becomes extremely short, and control using sensor information such as abnormality detection causes a safety problem.

Further, the detection circuit 12 and the wireless transmitter 13 in FIG. 8 are always turned on, and the battery 14 is consumed even when the controller power is turned off and the robot is not operating. Therefore, it can be considered that the power switch is turned on when the robot operates, and the power switch can be turned off when the robot is not working so that the power switch can be turned on / off every time the robot is started / stopped. The control circuit becomes complicated, and the man-hours for turning on and off the switch are large, and there is a problem in that the battery is consumed if forgetting to cut.

The present invention has been made in view of such problems, and provides a sensor device that supplies power to the sensor and the radio circuit by a power generation module attached to the sensor device and reduces consumption of the added battery. The purpose is to do.

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, in a mechanical device driven by a motor, a motion that is configured by a sensor that measures the state of the mechanical device and a wireless circuit that wirelessly transmits the sensor information to the mechanical device controller is added to the mechanical device. The sensor device includes a power generation module that converts energy into electric energy, and supplies the necessary power of the sensor and the wireless circuit using the power generated by the power generation module.
The invention described in claims 2 and 3 is characterized in that the power generation module is configured using a piezoelectric element.
According to a fourth aspect of the present invention, the mechanical device is an articulated robot.
The invention according to claim 5 is characterized in that a battery is provided as a power supply means together with the power generation module.
The invention according to claim 6 is characterized in that it has means for measuring the state of motion of the mechanical device from the sensor information on the sensor device and switching the power supply method according to the state of motion.
According to the seventh aspect of the present invention, the motion state of the mechanical device is estimated from the motion command of the mechanical device, the position signal of each axis motor of the mechanical device and the torque command value, and the power supply method is determined based on the estimated value of the motion state. It has the means to switch, It is characterized by the above-mentioned.
The invention described in claim 8 is characterized by comprising means for switching the power supply method according to the magnitude of the output voltage of the power generation module.
According to the ninth aspect of the present invention, it is possible to charge the battery with surplus power when the power generated in the power generation module is larger than the power consumption of the sensor device along with the selection of the power supply source to the sensor device depending on the operation state of the mechanical device It is characterized by.
The invention described in claim 10 is characterized in that the charging efficiency of the battery is improved by inserting a transformer between the power generation module and the battery to be charged and matching the impedance between the power generation module and the battery.

According to the first aspect of the present invention, since the power source is the power generation module 104 and the signal output is performed wirelessly between the wireless circuit 106 and the mechanical device controller 101, the sensor device and the mechanical device controller can be connected without wiring. Even when a multi-turn turning operation is performed, sensor information at the tip of the mechanical device can be measured.
Since electric power is supplied from the power generation module, the entire wireless sensor device can be configured to be small and light. Further, since the wiring can be eliminated, the degree of freedom of arrangement of the sensor device is improved, and even a machine such as a robot that moves around with a high degree of freedom can be easily attached to a necessary portion, and a sensor signal can be obtained.
According to the second and third aspects of the present invention, by using the power generation module using the piezoelectric element, the kinetic energy of the mechanical device can be efficiently converted into electric energy. Can be powered.
According to the invention described in claim 4, by mounting the sensor device on the articulated robot as the mechanical device, the kinetic energy of the robot operation can be efficiently converted into electric energy by the power generation module. Electric power can be supplied.
According to the fifth aspect of the present invention, since the power shortage in the power generation module can be supplied from the battery, the power generation module can be stably supplied even when the conditions are bad for power generation such as the beginning of machine movement or low speed / low acceleration. Electric power can be supplied.
According to the sixth aspect of the present invention, the power supply source can be switched between the power generation module and the battery, or the method of sharing both based on the information from the sensor attached to the mechanical device. Accordingly, an appropriate power supply source can be selected, and battery consumption can be minimized. Further, it is possible to perform more stable power supply without depending on the motion state of the mechanical device.
According to the seventh aspect of the present invention, the power supply source is the power generation module or the battery based on the motion command of the mechanical device controller and the motion state of the mechanical device estimated from the position signal and torque command value of each axis motor of the mechanical device. Alternatively, the method of sharing both can be switched, an appropriate power supply source can be selected according to the exercise state, and battery consumption can be minimized. Further, it is possible to perform more stable power supply without depending on the motion state of the mechanical device.
According to the eighth aspect of the present invention, the power supply source can be switched between the power generation module and the battery, or the method of sharing both based on the magnitude of the output voltage of the power generation module. A supply source can be selected, and battery consumption can be minimized. Further, it is possible to perform more stable power supply without depending on the motion state of the mechanical device.
According to the ninth aspect of the present invention, when electric power larger than the power consumption of the sensor device is generated in the power generation module, surplus power can be charged into the battery, so that battery consumption can be suppressed.
According to the invention described in claim 10, by inserting a transformer between the power generation module and the battery to be charged, it is possible to achieve impedance matching between the power generation module and the battery, and the power generated in the power generation module. Can be efficiently charged to the battery, so that battery consumption can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the principle diagram. In the figure, reference numeral 101 denotes a machine controller that generates a position command, a speed command, and the like for the motor based on the motion command. The motor is driven by the command, but the mechanical device 102 incorporating the motor generates motion. A sensor 103 is added to the mechanical device. For example, acceleration and vibration sensors are examples. The measured sensor information is transmitted to the machine controller using the information transmission means, and feedback control and safety functions can be realized. In the figure, a wireless method is shown as information transmission means. The sensor device 111 is desired to be small and light so as not to cause a load on the mechanical device 102 as much as possible. Further, since the mechanical device itself becomes complicated when the number of motors increases, it is desirable that the wiring connecting the sensor device 111 and the mechanical device controller 101 should be eliminated as much as possible. When there is no signal wiring, it is inevitably desired that the power supply means that are inevitably consumed by the sensor or wirelessly be wiring-free. In general, power is supplied by a battery or the like as a method of supplying electric power without wiring. However, in the present invention, a power generation module 104 that converts kinetic energy into electric power using a feature that motion is generated in the mechanical device 102 by a motor is provided. In addition, it is characterized by generating the necessary power by itself within the system.

In the embodiment, a case where a robot is used as a specific example of the mechanical device will be described.

FIG. 2 shows a block diagram of the robot sensor device according to the first embodiment of the present invention.
Power supply for the sensor 103 and the wireless circuit 106 is supplied from a module including the power generation module 104 and the battery 105. An example of the configuration of the power generation module 104 is shown in FIG. The power generation module includes a steel ball 302, a piezoelectric ceramic plate 301, and a support member 303. The steel ball 302 rolls inside the pipe of the support member 303 and collides with the piezoelectric ceramic plate 301 when the power generation module receives a speed change. Due to this impact, the piezoelectric ceramic plate 301 is deformed and a charge corresponding to the amount of strain is generated between the electrodes attached to both surfaces of the piezoelectric ceramic plate 301. The generated charge is taken out to the external circuit through the wiring 304 , rectified by the rectifier circuit, and the generated power is supplied to the external circuit.

2 includes a sensor 103, a power generation module 104, a battery 105, and a radio circuit 106. The sensor device 111 is attached to the articulated robot 204, and state quantities such as acceleration and vibration of the robot arm tip and the work tool 205 are measured by the built-in sensor 103, and the measurement data is wirelessly detected via the wireless circuit 106. The wireless signal 107 is transmitted to the robot controller 201.
The robot controller 201 includes a robot multi-axis control arithmetic unit 202 and a robot multi-axis amplifier 203. In the present invention, a wireless communication function with the wireless circuit 106 is added to the conventional robot multi-axis control arithmetic unit 202, and the control performance of the robot is improved based on the received sensor information. The robot operation program is executed in the robot multi-axis control arithmetic unit 202, and the robot multi-axis amplifier 203 controls the position and speed of the robot arm by supplying current to motors attached to the respective axes of the multi-joint robot 204.

A power generation module 104 and a battery 105 are used as a power source for the sensor 103 and the wireless circuit 106. When the power generation module 104 does not generate power, the power of the battery 105 is used as power consumption of the sensor device 111. When the power generation module 104 generates sufficient power generation, the power generation power of the power generation module 104 is used as power consumption of the sensor device 111. The sensor 103 and the wireless circuit 106 are operated by using them. Switching between the power generation module 104 and the battery 105 used for the power source of the sensor device is automatically performed according to the power generation state of the power generation module.
For example, when the sensor 103 acquires acceleration and vibration information of the arm tip and the work tool 205, the sensor information is used for the robot control calculation of the multi-axis control arithmetic device 202 for the robot to suppress the vibration of the arm tip, Is used as a detection signal for emergency stop when it collides with the surrounding environment.

Since the articulated robot 204 has a configuration in which an arm on which a motor is arranged is coupled in series, it is difficult to route the wiring. Since the point where the robot works is usually at the last end connected to the series, there is a high demand for no wiring. In addition, in order to attach the sensor 103, it is one of the requirements that the degree of freedom of attachment is high in order to cope with the shape of the work tool 205 at the tip of the work and the complicated movement direction for the work.
In order to satisfy these functional requirements and improve reliability, the wiring-less is a point having a great merit.
On the other hand, since the articulated robot 204 has an open link configuration, the tip of the robot performs a large motion region and frequent acceleration / deceleration motion. This feature is an effective characteristic when the kinetic energy is converted into electric power for use. This is an advantageous condition for reducing the size and weight of the battery.

FIG. 3 is a circuit block diagram showing a second embodiment of the sensor device of the present invention.
In this embodiment, a sensor trigger generation circuit 120 and a changeover switch 401 are provided. The sensor trigger generation circuit 120 outputs a switching trigger signal 402 according to the magnitude of the signal from the sensor 103. The switching trigger signal 402 indicates which of the three states of the power generation module 104, the battery 105, the power generation module 104, and the battery 105 is selected as a power supply source for the sensor 103 and the wireless circuit 106. The changeover switch 401 selects the power supply source of the sensor 103 and the wireless circuit 106 based on the switching trigger signal 402.

When a vibration sensor is used as the sensor 103, the vibration state of the robot can be monitored.
When the movement of the robot is small or when the posture change is small, the vibration applied to the vibration sensor 103 and the power generation module 104 attached to the robot body is small. The output voltage of the sensor 103 is small and the generated power of the power generation module 104 is small. Since the power consumption of the sensor 103 and the wireless circuit 106 cannot be supplied from the power generation module 104, the battery 105 is selected as the power supply source. The sensor trigger generation circuit 120 outputs a signal for selecting the battery 105 to the switching trigger signal 402, and the changeover switch 401 connects the battery 105 as a power supply source.
When the movement or posture change of the robot is large, vibration applied to the sensor 103 and the power generation module 104 becomes large. The output voltage of the sensor 103 increases and the generated power of the power generation module 104 also increases. If the output voltage of the sensor 103 exceeds a certain value, the power generation by the power generation module 104 becomes possible, and the sensor trigger generation circuit 120 outputs a signal for selecting the power generation module 104 as the switching trigger signal 402, and the changeover switch 401 Selects the power generation module 104 as a power supply source.
When power cannot be supplied only by the power generation module 104, the power supply source is both the power generation module 104 and the battery 105, so that the power consumption of the battery 105 is reduced. In this case, the selector switch 401 selects both the power generation module 104 and the battery 105 as power supply sources.

FIG. 4 is a circuit block diagram showing a third embodiment of the sensor device of the present invention.
The power generation amount of the power generation module 104 is small when the motion speed and the posture of the robot are estimated by calculating from the position command, position signal and torque command of the articulated robot, or when the motion speed estimated is low or the posture does not change. The power of the sensor device is supplied from the battery 105. When the estimated operating speed exceeds a certain value or when the posture change is large, the power generation module 104 is switched to use the power on the power generation module 104 assuming that the power generation module 104 can supply power to the sensor device. A signal for switching the power supply source is generated in the robot controller 201, this signal is transmitted to the wireless circuit 106, converted into a switching trigger signal 402 by the wireless circuit, and the changeover switch 401 is switched.
The sensor information may be transmitted to the robot controller 201 via the wireless circuit 106, and the sensor information and the controller information may be combined to estimate the robot operation speed and the robot posture to generate the switching trigger signal 402.

FIG. 5 is a circuit block diagram showing a fourth embodiment of the sensor device of the present invention.
The comparison result of the output voltage of the power generation module 104 and the reference voltage 404 by the comparator 403 is input to the changeover switch 401 to switch the power supply source. When the output voltage of the power generation module 104 is small, it is assumed that the amount of power generation is small, and the power of the sensor device is supplied from the battery 105, and when the output voltage is a certain value or higher, the power is supplied from the power generation module 104.

The power generation module 104 according to the second to fourth embodiments may be configured to charge the battery 105. The changeover switch 401 supplies the power of the sensor device 111 from the power generation module 104 and / or the battery 105 according to the operation state of the robot, and the power generation module 104 generates power larger than the power consumption of the sensor device 111. In this case, since the power generation module 104 has a circuit configuration for charging the battery 105, the life of the battery 105 can be extended.
A circuit configuration in which all of the electric power generated in the power generation module 104 is once charged in the battery 105 may be employed. With this circuit configuration, much of the power generated in the power generation module 104 can be used as the power consumption of the sensor 103 and the wireless circuit 106, and the power consumption of the battery 105 can be reduced.

FIG. 6 is a block diagram showing a fifth embodiment of the sensor device of the present invention. The power generation portion of the power generation module 104 is configured to generate power using kinetic energy such as vibration. In this embodiment, the transformer 110 is inserted between the power generation module 104 and the charging circuit including the battery 105 to match impedance between the power generation module and the charging circuit, and charging efficiency of the power generated by the power generation module 104 to the battery is increased. Raise. By improving the charging efficiency of the battery 105, the use of the electric power generated by the power generation module 104 for the sensor device can be increased, and the life of the battery can be extended.

Since the power generation module 104 supplies power to the robot sensor device 111, the battery 105 does not require a high-capacity battery and can be reduced in weight and volume.

By attaching the sensor device of the present invention to a mechanical device whose posture changes greatly and the wiring cannot be pulled out, or a mechanical device whose state changes due to the wiring, the measured value is transmitted to the mechanical device controller. The status can be monitored and the control performance can be improved.

Block diagram illustrating the principle of the present invention The block diagram of the robot sensor apparatus which shows the 1st Example of this invention. The block diagram of the sensor apparatus which shows the 2nd Example of this invention. The block diagram of the sensor apparatus which shows the 3rd Example of this invention. The block diagram of the sensor apparatus which shows the 4th Example of this invention. The block diagram of the sensor apparatus which shows the 5th Example of this invention. Example of power generation module using piezoelectric element of the present invention Conventional sensor device

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Mechanical device controller 102 Motor and mechanical device 103 Sensor 104 Power generation module 105 Battery 106 Wireless circuit 107 Sensor wireless signal 108 Movement command 109 Rectifier circuit 110 Transformer 111 Sensor device 120 Sensor trigger generation circuit

201 robot controller 202 multi-axis control arithmetic unit for robot 203 multi-axis amplifier 204 for robot multi-joint robot 205 work tool

301 Piezoelectric ceramic plate 302 Steel ball 303 Support member 304 Wiring 305 Adhesive 306 Cushion material

401 selector switch 402 switching trigger signal 403 comparator 404 reference voltage

Claims (10)

In a sensor device used in a mechanical device driven by a motor,
A sensor for measuring the state of the mechanical device;
A wireless circuit for wirelessly transmitting sensor information to the machine controller;
A power generation module that converts kinetic energy added to the mechanical device into electrical energy;
A sensor device that supplies necessary electric power of the sensor and the wireless circuit by electric power generated by the power generation module. The sensor device according to claim 1, wherein the power generation module is configured using a piezoelectric element. The power generation module using the piezoelectric element includes a piezoelectric ceramic plate, a steel ball, and a support member that accommodates the steel ball in a rollable manner, and the steel ball rolls and collides with the piezoelectric ceramic plate. The sensor device according to claim 2, wherein the piezoelectric ceramic plate is deformed to generate electric charges between electrodes attached to both surfaces of the piezoelectric ceramic plate.
The sensor device according to claim 1, wherein the mechanical device is an articulated robot. The sensor device according to claim 1, further comprising a battery as power supply means together with the power generation module. Measure the state of movement of the mechanical device from the sensor information on the sensor device,
6. The sensor device according to claim 5, further comprising means for switching a power supply method according to the state of movement. The motion state of the mechanical device is estimated from the motion command of the mechanical device in the mechanical device controller and the position signal and torque command value of each axis motor of the mechanical device,
6. The sensor device according to claim 5, further comprising means for switching a power supply method according to the estimated value of the motion state. The sensor device according to claim 5, further comprising means for switching a power supply method according to a magnitude of an output voltage of the power generation module. The sensor device according to claim 5, wherein the battery is charged with electric power generated by the power generation module according to a motion state of a mechanical device. The sensor device according to claim 9, wherein a transformer is inserted between the power generation module and the battery in order to improve the charging efficiency of the battery.

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