JP5825900B2 - Signal transmission device - Google Patents

Description

  The present invention relates to a signal transmission device that transmits a signal via a slip ring.

  A rotating surveillance camera or the like includes a fixed portion fixed to a wall or the like and a rotating portion that can rotate with respect to the fixed portion, and an optical system and an image sensor for photographing are accommodated in the rotating portion. A slip ring is used for signal transmission between the rotating part and the fixed part. By using the slip ring, the fixed part and the rotating part can be electrically connected, and the rotating part can be rotated with respect to the fixed part while supplying power and signals.

  This type of slip ring is composed of a combination of a ring-shaped conductor and a brush-like contact so that electrical contact is maintained regardless of rotation. That is, in the slip ring, the ring-shaped conductor and the brush-shaped contact are always in electrical contact at any rotational position.

  Contact with the slip ring contact is caused by contact between the ring-shaped conductor and the brush-shaped contact due to wear powder or foreign matter adhering, or the contact state changes due to changes in the surface condition of the ring-shaped conductor or brush-shaped contact. The resistance changes, and as a result, the error rate of the transmission signal may deteriorate. FIG. 8 shows an example of the temporal change of the contact resistance and error rate of the slip ring.

  FIG. 8A shows an example of change in contact resistance. The horizontal axis represents time, and the vertical axis represents the contact resistance value. The reason why the contact resistance temporarily increases is that wear powder or foreign matter adheres to the contact portion of the slip ring. When attached wear powder or foreign matter is removed by driving the slip ring or the like, the original contact resistance is restored. The contact resistance starts to increase with the passage of a certain time or with a certain rotation. This is because the surface state of the ring-shaped conductor and the brush-shaped contact changes due to oxidation or the like.

  FIG. 8B shows an example of a change in error rate when a high-speed signal is transmitted through a slip ring. The horizontal axis represents time, and the vertical axis represents the error rate. Similar to the contact resistance shown in FIG. 8A, in the initial state where the contact resistance is below a certain level, the error rate is low and there is no significant change. When wear powder or foreign matter adheres to the contact portion of the slip ring and the contact resistance increases beyond a certain level, the error rate also increases accordingly. When the wear powder or foreign matter adhering to the contact portion of the slip ring is removed and the contact resistance is restored, the error rate is generally restored. As the drive continues and the contact resistance gradually increases, the error rate increases rapidly.

  Patent Document 1 describes a technique for improving the reliability of a contact point of a slip ring without causing a contact failure. Specifically, a cleaning operation for removing impurities on the rotating contact by rotating the rotating contact in the forward direction or the reverse direction by 360 degrees or more is performed. Also, means for detecting an abnormality of the signal passing through the rotating contact is provided, and a cleaning operation is performed in response to the abnormality detection.

JP 2001-103457 A

  In the method of removing impurities on the rotating contact by rotating the rotating contact in the forward direction or the reverse direction by 360 degrees or more, signal transmission may not be recovered. For example, when the surface state of the ring-shaped conductor and the brush-shaped contact changes due to oxidation or the like and the contact resistance increases, the cleaning operation described in Patent Document 1 does not improve the contact failure.

  The present invention relates to a sliding contact such as a contact formed by a ring-shaped conductor of a slip ring and a brush-shaped contact, the contact state changes due to adhesion of wear powder or foreign matter, change of the surface state of the conductor or brush contact, etc. An object of the present invention is to provide a signal transmission device capable of suppressing an increase in the number of signals.

A signal transmission device according to the present invention is a signal transmission device having a slip ring that transmits a signal via a rotating contact between a fixed portion and a rotating portion, and a rotation driving means for rotating the rotating portion; A signal transmitting means provided in one of the fixed part and the rotating part, and a signal provided in the other of the rotating part and the fixed part for receiving a signal transmitted from the signal transmitting means via the slip ring A receiving means; an error detecting means for detecting an error in a signal received by the signal receiving means; and an error rate is calculated according to a detection result of the error detecting means, and a period of a cleaning operation of the rotating contact according to the error rate And a control means for shortening .
The signal transmission device according to the present invention is also a signal transmission device having a slip ring that transmits a signal between a fixed portion and a rotating portion via a rotating contact, and a rotation driving unit that rotates the rotating portion. A signal sending means provided on one of the fixed part and the rotating part, and a signal sent from the signal sending means provided on the other of the rotating part and the fixed part, via the slip ring. An error rate is calculated according to a detection result of the signal receiving unit, an error detecting unit that detects an error of the signal received by the signal receiving unit, and the error detecting unit, and the cleaning operation of the rotating contact is performed according to the error rate. And control means for equalizing the waveform of the signal sent from the signal sending means and inputted via the slip ring, and the control means comprises the error Depending on the rate, and adjusting the waveform equalization of the waveform equalization means in a direction in which the error rate is reduced.

  According to the present invention, since the rotary contact of the slip ring is appropriately cleaned against an increase in signal error, an increase in transmission error due to an increase in contact resistance can be prevented.

It is a schematic block diagram of one Example of this invention. It is an operation | movement flowchart of a present Example. It is a schematic block diagram of the second embodiment of the present invention. It is a schematic block diagram of a waveform equalization unit. It is an operation | movement flowchart of 2nd Example. It is another operation | movement flowchart of 1st Example. It is another operation | movement flowchart of 2nd Example. It is a graph which shows a time-dependent change of the contact resistance and error rate of a slip ring.

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

  An embodiment applied to a rotary surveillance camera using a slip ring will be described. In this embodiment, the error rate of signal transmission through the slip ring is calculated, and when this error rate exceeds a predetermined error rate, the cleaning operation is performed and the cleaning cycle periodically changed is changed. To do.

  FIG. 1 is a schematic block diagram of the first embodiment of the present invention. Reference numeral 100 denotes a rotating part of the surveillance camera, and 300 denotes a fixed part of the surveillance camera. The rotating unit 100 and the fixed unit 300 are mechanically coupled by a slip ring 200 having a rotating contact for connecting a signal and a power source between the rotating unit 100 and the fixed unit 300.

  In the rotation unit 100, 110 is a lens, 120 is an image sensor, and 130 is a signal processing unit that processes an image signal from the image sensor 120. Reference numeral 140 denotes a serializer that serializes the video signal processed by the signal processing unit 130 for transmission to the fixed unit 300. The serializer 140 is a signal transmission unit that transmits a signal to the fixed unit 300. A CPU 150 controls the rotating unit 100. A motor driver 160 drives the tilt motor 170. Reference numeral 180 denotes a motor driver that drives the lens 110. A power supply unit 190 supplies power to each unit of the rotating unit 100.

  In the fixing unit 300, 320 is a deserializer that returns the serialized video signal to parallel. The deserializer 320 is a signal receiving unit that receives and processes a signal sent from the rotating unit 100. Reference numeral 330 denotes an error detection unit. Reference numeral 340 denotes a network processing unit. Reference numeral 350 denotes a CPU that controls each unit of the fixed unit 300. Reference numeral 360 denotes a motor driver that drives the pan motor 370. Reference numeral 380 denotes a power source that supplies power to each unit of the fixed unit 300.

  The imaging sensor 120 in the rotation unit 100 converts an optical image from the lens 110 into an electrical image signal and outputs the electrical image signal to the signal processing unit 130. The signal processing unit 130 converts the image signal from the imaging sensor 120 into a video signal having a predetermined format. The serializer 140 serializes the video signal output from the signal processing unit 130 and supplies the video signal to the fixing unit 300 via the slip ring 200.

  In the fixing unit 300, the deserializer 320 converts the serial video signal from the slip ring 200 into a parallel format and supplies it to the error detection unit 330 and the network processing unit 340. The error detection unit 330 detects an error in the output of the deserializer 320. For error detection, the signal processing unit 130 or the serializer 140 adds an error detection code (for example, CRC code) for each data block of a predetermined size. The error detection unit 330 detects the presence / absence of an error for each block using an error detection code in the input data, and supplies the detection result to the CPU 350. The CPU 350 calculates an error rate from the number of errors detected by the error detection unit 330.

  The CPU 350 controls the deserializer 320 and the network processing unit 340 and controls the pan motor 370 via the motor driver 360 to rotate the rotating unit 100 relative to the fixed unit 300.

  In this embodiment, the rotating part 100 is driven to rotate forward or backward by a certain angle or more by the pan motor 370 to clean the sliding contact part of the slip ring 200. By this cleaning operation, abrasion powder and impurities attached to the sliding contact portion of the slip ring 200 can be removed. It may be continuously rotated 360 ° or more, or may be driven little by little in the forward and reverse directions, or continuously several times. This cleaning operation is performed periodically. Instead of cleaning the sliding contact portion of the slip ring 200 by driving the rotating portion 100, a cleaning method is adopted in which the rotating portion 100 is driven to rotate while the cleaning member is applied to the ring-shaped conductor or the brush-shaped contact. May be. Of course, both cleaning methods may be used in combination.

  In this embodiment, in addition to the periodic cleaning operation, as shown in FIG. 2, the cleaning is executed depending on the error rate of signal transmission, and the period of the periodic cleaning operation is controlled.

  The rotating unit 100 transmits a signal to the fixed unit 300 via the slip ring 200 (S100). The transmitted signal is input to the error detection unit 330 via the deserializer 320, and the error detection unit 330 detects an error in the received signal. The CPU 350 calculates an error rate from the error detection result by the error detection unit 330 and the transmission data amount (S110).

  The CPU 350 determines whether or not the calculated error rate exceeds a predetermined error rate E1 (S120). When the error rate is equal to or less than the predetermined error rate E1 (S120), the process returns to signal transmission (S100). When the error rate exceeds the predetermined error rate E1 (S120), the CPU 350 cleans the sliding contact portion of the slip ring 200 by the method described above (S130). Further, the CPU 350 shortens the period of the regular cleaning operation with a certain standard (S140).

  In this embodiment, the error rate of signal transmission through the slip ring 200 is calculated, and when the predetermined error rate is exceeded, cleaning is performed and the periodic cleaning cycle is shortened, so that the contact state of the slip ring is improved. It can be maintained in a state.

  Although the embodiment has been described in which the signal transmitting unit is provided in the rotating unit 100 which is one of the fixed unit 300 and the rotating unit 100 and the signal receiving unit is provided in the other, the reverse may be possible. That is, the present invention can also be applied to a configuration in which a signal transmitting unit is provided in the fixed unit 300 and a signal receiving unit is provided in the rotating unit 100.

  FIG. 3 shows a schematic block diagram of the second embodiment of the present invention. In this embodiment, an error rate of signal transmission via a slip ring is calculated, and when the error rate exceeds a predetermined error rate, waveform equalization is performed to reduce the error rate. Constituent elements having the same functions as those in FIG.

  The fixed unit 300 a includes a waveform equalizer 310 that equalizes a waveform received from the rotating unit 100 via the slip ring 200. The CPU 350a controls the waveform equalization of the waveform equalizer 310 according to the error rate of the received signal. The deserializer 320 samples and serial-parallel converts the output signal of the waveform equalizer 310, and outputs the sampled signal to the error detection unit 330 and the network processing unit 340.

FIG. 4 is a schematic block diagram of the waveform equalizer 310. The output signal of the serializer 140 is input to the waveform equalizer 310 via the slip ring 200. The waveform equalizer 310 includes a switch 311 and terminators 312 to 319 having impedances Z _{0 to} Z _n . Impedance _Z 0 to Z _n terminator 312-319 are generally different from each other. By selecting one of the terminators 312 to 319 by the switch 311, the characteristic impedance of the transmission line including the slip ring 200 can be adjusted. The CPU 350a causes the switch 311 to select the terminators 312 to 319 that have the lowest error rate according to the error rate calculated from the error detection result of the error detection unit 330.

FIG. 5 is a flowchart of the control operation of this embodiment. Signal transmission from the rotating unit 100 to the fixed unit 300a is performed via the slip ring 200 (S500). The switch 311 of the waveform equalizer 310 initially selects any one of the terminators 312 to 319 (for example, the terminator 312). The waveform equalizer 310 applies the waveform equalization according to the impedance Z ₀ of the terminator 312 selected by the switch 311 to the signal from the slip ring 200.

  The deserializer 320 parallelizes the output signal of the waveform equalizer 310, and the error detection unit 330 detects an error in the received signal from the output signal of the deserializer 320. The CPU 350a calculates an error rate from the error detection result by the error detection unit 330 and the transmission data amount (S510).

  The CPU 350a determines whether or not the calculated error rate exceeds a predetermined error rate E1 (S520). When the error rate is equal to or less than the predetermined error rate E1 (S520), the process returns to the signal transmission (S500). When the error rate exceeds the predetermined error rate E1 (S520), the CPU 350a controls the switch 311 of the waveform equalizer 310 to select another terminator 312 to 319 (S530), and returns to signal transmission (S500). . With this control flow, the input impedance of the waveform equalizer 310 is adjusted so that the error rate is equal to or less than the predetermined error rate E1.

  As an example of the waveform equalizer 310, the configuration for adjusting the input impedance is illustrated, but other methods of waveform equalization may be employed. Of course, various methods are conceivable for the configuration for switching the terminating resistor. For example, considering that the signal waveform is distorted by the contact resistance and the error rate increases, the value of the termination resistor is switched step by step so as to correspond to the increased impedance of the transmission line according to the error rate.

  Further, a filter for correcting the distortion waveform may be provided as the waveform equalizer 310, and the constant of this filter may be changed.

  As described above, by performing waveform equalization on the received signal according to the error rate of the signal received via the slip ring, the signal transmission error rate can be reduced.

  FIG. 6 shows a flowchart of another control operation of the embodiment shown in FIG. The rotating unit 100 transmits a signal to the fixed unit 300 through the slip ring 200 (S600). The CPU 350 determines whether to perform panning or tilting driving or cleaning (S610). When the rotary unit 100 is driven to rotate, the contact state of the slip ring 200 changes, and as a result, the contact resistance or the signal transmission error rate changes. Therefore, if there is no driving, normal signal transmission is continued as it is, and if there is a plan to perform rotation driving of the rotating unit 100, the following processing such as error rate calculation is performed after the driving. That is, if neither pan / tilt driving nor cleaning is scheduled (S610), the process returns to signal transmission (S600).

  When it is necessary to perform driving for panning or tilting, or rotational driving for cleaning (S610), the CPU 350 causes a necessary operation to be performed (S620). There is a possibility that the contact state of the slip ring 200 changes due to the rotational drive (S620) of the rotating unit 100, and the contact resistance or the signal transmission error rate changes. Therefore, signal transmission is performed (S630), and the CPU 350 calculates an error rate according to the output of the error detection unit 330 (S640).

  The CPU 350 determines whether or not the calculated error rate exceeds a predetermined error rate E1 (S650). When the error rate is equal to or lower than the predetermined error rate E1 (S650), the process returns to signal transmission (S600). When the error rate exceeds the predetermined error rate E1 (S650), the CPU 350 cleans the sliding contact portion of the slip ring 200 by the method described above (S660). Further, the CPU 350 shortens the period of the periodic cleaning operation by a certain standard (S670).

  The contact state of the slip ring 200 is changed by the rotation operation for pan / tilt driving or cleaning, and as a result, the contact resistance or the signal transmission error rate may be changed. Therefore, in this embodiment, after these rotational operations, the error rate of signal transmission through the slip ring 200 is calculated, and when the error rate exceeds a predetermined error rate, cleaning is performed and the periodic cleaning cycle is shortened. Thereby, the contact state of a slip ring can be maintained in a favorable state.

  FIG. 7 shows a flowchart of another control operation of the embodiment shown in FIG.

  The rotating unit 100 transmits a signal to the fixed unit 300 via the slip ring 200 (S700). The CPU 350a determines whether to perform panning or tilting driving or cleaning (S710). When the rotary unit 100 is driven to rotate, the contact state of the slip ring 200 changes, and as a result, the contact resistance or the signal transmission error rate changes. Therefore, if there is no driving, normal signal transmission is continued as it is, and if there is a plan to perform rotation driving of the rotating unit 100a, the following processing such as error rate calculation is performed after the driving. That is, if neither pan / tilt driving nor cleaning is scheduled (S710), the process returns to signal transmission (S700).

  When it is necessary to perform driving for panning or tilting, or rotational driving for cleaning (S710), the CPU 350a performs a required driving operation (S720). There is a possibility that the contact state of the slip ring 200 changes due to the rotation driving of the rotating unit 100 (S720), and the contact resistance or the signal transmission error rate changes. Therefore, signal transmission is performed (S730), and the CPU 350a calculates an error rate according to the output of the error detection unit 330 (S740).

  The CPU 350a determines whether or not the calculated error rate exceeds a predetermined error rate E1 (S750). When the error rate is equal to or less than the predetermined error rate E1 (S750), the process returns to signal transmission (S700). When the error rate exceeds the predetermined error rate E1 (S750), the CPU 350a controls the switch 311 of the waveform equalizer 310 to select other terminators 312 to 319 (S760), as in the second embodiment. Return to signal transmission (S700). With this control flow, the input impedance of the waveform equalizer 310 is adjusted so that the error rate is equal to or less than the predetermined error rate E1.

  The contact state of the slip ring 200 is changed by the rotation operation for pan / tilt driving or cleaning, and as a result, the contact resistance or the signal transmission error rate may be changed. Therefore, in this embodiment, the error rate of signal transmission through the slip ring 200 is calculated after these rotational operations, and the waveform equalization is adjusted when the error rate exceeds a predetermined error rate. Thereby, the signal transmission of a slip ring can be maintained in a favorable state.

  Although the preferable implementation of this invention was demonstrated, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

Claims (5)

A signal transmission device having a slip ring that transmits a signal via a rotating contact between a fixed part and a rotating part,
A rotation driving means for rotating the rotating part;
Signal sending means provided on one of the fixed part and the rotating part;
A signal receiving means which is provided on the other of the rotating part and the fixed part and receives a signal sent from the signal sending means via the slip ring;
An error detecting means for detecting an error of a signal received by the signal receiving means;
A signal transmission apparatus comprising: a control unit that calculates an error rate according to a detection result of the error detection unit and shortens a cycle of the cleaning operation of the rotary contact according to the error rate. Between the fixed portion and the rotating portion, a signal transmission device having a slip ring for transmitting a signal through the rotary contact,
A rotation driving means for rotating the rotating part;
Signal sending means provided on one of the fixed part and the rotating part;
A signal receiving means which is provided on the other of the rotating part and the fixed part and receives a signal sent from the signal sending means via the slip ring;
An error detecting means for detecting an error of a signal received by the signal receiving means;
Control means for calculating an error rate according to the detection result of the error detection means, and for performing a cleaning operation of the rotating contact according to the error rate;
Waveform equalizing means for equalizing the waveform of the signal sent from the signal sending means and inputted through the slip ring
And
The control means adjusts the waveform equalization of the waveform equalization means in a direction in which the error rate decreases according to the error rate.
A signal transmission device characterized by that. 3. The signal transmission device according to claim 1, wherein the cleaning operation is an operation of rotating the rotating unit in a forward direction or a reverse direction by a predetermined angle or more by the rotation driving unit.   The said control means calculates the said error rate from the result detected by the said error detection means, after driving the said rotation part by the said rotation drive means, The any one of Claim 1 to 3 characterized by the above-mentioned. The signal transmission device described. A signal transmission device having a slip ring that transmits a signal via a rotating contact between a fixed part and a rotating part,
A rotation driving means for rotating the rotating part;
Signal sending means provided on one of the fixed part and the rotating part;
A waveform equalizing means provided on the other of the rotating part and the fixed part, for equalizing the waveform of the signal sent from the signal sending means;
Signal receiving means for receiving and processing the output signal of the waveform equalizing means;
An error detecting means for detecting an error of a signal received by the signal receiving means;
Control means for calculating an error rate according to the detection result of the error detection means, and for controlling the waveform equalization of the waveform equalization means so that the error rate decreases when the error rate exceeds a predetermined error rate A signal transmission device comprising:

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