Patent Application
20180031074
The present disclosure relates to a spatial stabilization apparatus and a spatial stabilization method, and in particular to a spatial stabilization apparatus including a vibration suppression mechanism for preventing propagation of trembling and/or vibrations and a spatial stabilization method.
A spatial stabilization apparatus is an apparatus for stabilizing a pointing direction of a payload (an installed apparatus) such as a sensor, a camera, a communication antenna installed in a moving body such as an airplane, a vehicle, a ship, and an artificial satellite with respect to an inertial space even under a condition in which the pointing direction of the payload is affected by trembling and/or vibrations of the moving body. As a technique for improving the performance of such a spatial stabilization apparatus, a method in which a vibration suppression mechanism for preventing trembling and/or vibrations from propagating from an airframe is incorporated in a pointing mechanism for controlling the pointing direction of a payload has been known. For example, related techniques are disclosed in Patent Literature 1 to 6, etc. Note that trembling may be included in vibrations and vibrations may be included in trembling.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. H10-132018
Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2009-19674
Patent Literature 3: Japanese Unexamined Patent Application Publication No. 2000-46977
Patent Literature 4: Japanese Unexamined Patent Application Publication No. H06-105189
Patent Literature 5: Japanese Unexamined Patent Application Publication No. H11-308604
Patent Literature 6: Japanese Unexamined Patent Application Publication No. 2004-205411
The inventor of the present disclosure has found that there are cases in which vibrations cannot be sufficiently suppressed by the related technique such as the technique disclosed in Patent Literature 1. Specifically, when an installed apparatus is installed in a moving body, vibrations of the moving body are transferred to the installed apparatus and hence the installed apparatus vibrates. Depending on the frequency of the vibrations, the vibrations could lead to large shaking due to a resonance or the like. Therefore, it is necessary to suppress the vibrations transferred from the moving body as much as possible.
However, in the related technique, a predetermined transfer characteristic including a resonance frequency is used. Therefore, there is a problem that, depending on the frequency of occurring vibrations, there are cases in which the vibrations cannot be effectively suppressed.
In view of the above-described problem, an object of the present disclosure is to provide a spatial stabilization apparatus and a spatial stabilization method capable of effectively suppressing vibrations.
A spatial stabilization apparatus according to the present disclosure includes: a vibration suppression mechanism unit configured to suppress vibrations occurring in an installed apparatus installed in a moving body; an attitude angle detection unit configured to detect an attitude angle of the installed apparatus; a characteristic change unit configured to change a transfer characteristic of vibrations transferred from the moving body to the installed apparatus; and an attitude correction unit configured to control the vibration suppression mechanism unit based on the changed transfer characteristic so that the detected attitude angle is corrected.
A spatial stabilization method according to the present disclosure is a spatial stabilization method for controlling a vibration suppression mechanism unit configured to suppress vibrations occurring in an installed apparatus installed in a moving body, including: detecting an attitude angle of the installed apparatus; changing a transfer characteristic of vibrations transferred from the moving body to the installed apparatus; and controlling the vibration suppression mechanism unit based on the changed transfer characteristic so that the detected attitude angle is corrected.
According to the present disclosure, it is possible to provide a spatial stabilization apparatus and a spatial stabilization method capable of effectively suppressing vibrations.
By changing the transfer characteristic of vibrations and controlling the vibration suppression mechanism unit as described above, it is possible to cope with various types of vibrations and thereby effectively suppress vibrations.
A first embodiment is explained hereinafter with reference to the drawings. In this embodiment, an example in which in a moving body with a radar apparatus installed therein, vibration suppression control for an antenna of the radar apparatus is performed is explained.
The radar apparatus 100 includes, as main components, an antenna unit 101 including an antenna, and a signal processing unit 102 that performs signal processing for a radio wave transmitted/received by the antenna. For example, the antenna unit 101 is disposed in a lower part of an airframe 31 of the moving body 30 and emits a radio wave from the antenna toward the earth's surface located below the airframe 31. The signal processing unit 102 is disposed inside the airframe 31 of the moving body 30 and displays an observation image observed through the antenna in real time.
The transmission unit 110 generates a transmission signal for carrying out an observation by using an SAR. The circulator 113 transmits the transmission signal generated by the transmission unit 110 from the antenna 201 and outputs a reception signal received by the antenna 201 to the reception unit 111. The antenna driving mechanism 202 drives the antenna 201 so that the antenna 201 has an optimal direction and an optimal position according to control by the control unit 120. The antenna 201 transmits a transmission wave (i.e., a transmission signal) to an object to be observed and receives a reception wave (i.e., a reception signal) reflected on the object to be observed. The vibration suppression mechanism 203 suppresses trembling and/or vibrations occurring in the antenna 201 according to control by the control unit 120.
The antenna sensor 103 detects an amount of displacement of the antenna 201, which has been displaced according to the driving of the antenna driving mechanism 202, and detects trembling and/or vibrations of the antenna 201. The antenna sensor 103 is an attitude angle sensor that detects an attitude angle of the antenna 201. Alternatively, the antenna sensor 103 may be a GPS (Global Positioning System), a speed sensor, an acceleration sensor, a gyroscopic sensor, a resolver, a displacement sensor, a rate sensor, or the like.
The reception unit 111 performs signal processing for the reception signal received by the antenna 201 and thereby generates a signal that the image processing unit 112 can process. The image processing unit 112 performs image processing for the reception signal processed by the reception unit 111, detects an object to be observed, generates an observation image, and displays the generated observation image.
The control unit 120, which is a control unit that controls each unit of the radar apparatus, controls the antenna driving mechanism 202, the vibration suppression mechanism 203, and so on based on the detection result of the antenna sensor 103 and the observation result of the image processing unit 112. The control unit 120 is an antenna driving control unit that controls the driving of the antenna driving mechanism 202, and also serves as a vibration suppression control unit that controls a vibration suppression operation performed by the vibration suppression mechanism 203.
For example, in the case of a spotlight mode in which a specific object to be observed is observed, the control unit 120 controls the antenna driving mechanism 202 so that a radio wave is emitted from a flight path toward the object to be observed all the time. Further, in the case of a strip-map mode in which an area along a flight path is observed, the control unit 120 controls the antenna driving mechanism 202 so that a radio wave is emitted to the flight path at a specific angle. In this embodiment, the control unit 120 changes a transfer characteristic including a resonance frequency of vibrations and controls the vibration suppression mechanism 203 based on the changed transfer characteristic.
A spatial stabilization apparatus 20 according to this embodiment is an apparatus that stabilizes the attitude of the antenna 201 against trembling and vibrations of the moving body 30, and includes, for example, the antenna 201, the antenna driving mechanism 202, the vibration suppression mechanism 203, the antenna sensor 103, and the control unit 120.
The vibration suppression mechanism 203 is disposed between the airframe 31 and an assembled unit of the antenna driving mechanism 202 and the antenna 201, and supports the antenna driving mechanism 202 and the antenna 201. When the airframe 31 vibrates (Δx), the vibrations are transferred and hence the antenna driving mechanism 202 and the antenna 201 vibrate (Δy). The vibration suppression mechanism 203 suppresses the vibrations (Δy) that occur in the antenna driving mechanism 202 and the antenna 201 according to the transfer of the vibrations (Δx) of the airframe 31.
The vibration suppression mechanism 203 is an active vibration suppression apparatus and includes a vibration suppression spring 211 and a vibration suppression actuator 212. One end of the vibration suppression spring 211 is fixed to the airframe 31 and the other end is fixed to the antenna driving mechanism 202 (and the antenna 201). For example, the bottom of the antenna driving mechanism 202 has a circular shape in a plan view and a plurality of vibration suppression springs 211 are arranged near the outer circumference of the bottom of the antenna driving mechanism 202 so that the antenna driving mechanism 202 is supported in a well-balanced manner. The vibration suppression springs 211 suppress vibrations that are transferred from the airframe 31 to the antenna driving mechanism 202 and the antenna 201 by elasticity corresponding to their spring constant.
Similarly to the vibration suppression spring 211, one end of the vibration suppression actuator 212 is fixed to the airframe 31 and the other end is fixed to the antenna driving mechanism 202 (and the antenna 201). For example, a plurality of vibration suppression actuators 212 are arranged near the outer circumference of the bottom of the antenna driving mechanism 202 so that they correspond to the plurality of vibration suppression springs 211. The vibration suppression actuators 212 are driven according to control of the control unit 120 and generate a vibration suppression force for suppressing vibrations of the antenna 201. The vibration suppression force is a reactive force that acts in an opposite direction to the direction of the vibration transferred from the airframe 31 to the antenna 201.
The control unit 120 includes a characteristic change unit 121 and an attitude correction unit 122. Note that other configurations may be used, provided that a vibration suppression operation (a spatial stabilization method) according to this embodiment can be realized. The characteristic change unit 121 changes a characteristic (a transfer characteristic) of vibrations that transferred from the airframe 31 to the antenna 201 and hence occur in the antenna 201. In this embodiment, the characteristic change unit 121 controls the driving of the vibration suppression actuator 212 so that the resonance frequency and/or the peak value of vibrations are changed.
The attitude correction unit 122 controls the driving of the vibration suppression actuator 212 so that vibrations of the antenna 201 detected by the antenna sensor 103 are corrected by the changed characteristic (the transfer characteristic) of the vibrations. For example, the attitude correction unit 122 drives the vibration suppression actuator 212 according to a signal (a value) that is obtained by adding a detection result of the antenna sensor 103 to a target attitude angle of the antenna 201.
It can also be considered that the sensor processing unit 130 and the control calculation unit 140 constitute a control unit that generates a driving signal(s) (a drive command value(s)) for driving the antenna driving mechanism 202 and the vibration suppression mechanism 203.
The sensor processing unit 130 processes the detection signal detected by the antenna sensor 103. For example, the sensor processing unit 130 includes a noise reduction unit 131 and a coupled control calculation unit 132. The noise reduction unit 131 removes noises from the detection signal detected by the antenna sensor 103. For example, the noise reduction unit 131 is a low-pass filter or the like.
The coupled control calculation unit 132 performs a coordinate conversion and/or a target value calculation necessary for driving the antenna driving mechanism 202 and the vibration suppression mechanism 203 based on the detection signal of the antenna sensor 103. The target value calculation is preferably performed so that the antenna driving mechanism 202 and the vibration suppression mechanism 203 are both controlled in a coupled manner (a corresponding manner), rather than making them operate independently of each other. In particular, for the vibration suppression control, a target value is generated while incorporating the attitude of the bi-axial gimbal (the attitude in the AZ and EL directions) into the calculation.
The coupled control calculation unit 132 determines the target value based on an observation mode, an attitude and an amount of movement of the airframe, an attitude and an amount of displacement of the antenna, and so on. The coupled control calculation unit 132 generates an AZ (azimuth) target angle, an AZ angle, and an AZ angular speed as AZ control parameters, generates an EL (elevation) target angle, an EL angle, and an EL angular speed as EL control parameters, and generates a vibration suppression target value and a vibration suppression control amount as vibration suppression control parameters. For example, it can be considered that the output of the coupled control calculation unit 132 corresponds to a signal (a value), shown in
The control calculation unit 140 performs control by using PID (Proportional Integral Derivative) controller, a phase lead/delay controller, an optimal controller, and so on so that detected values follow the respective target values. The control calculation unit 140 includes an AZ control unit 141, an EL control unit 142, and a vibration suppression control unit 143.
The AZ (azimuth) control unit 141 generates an AZ drive command value for driving the antenna 201 in an azimuth direction based on the input AZ target angle, the AZ angle, and the AZ angular speed so that the antenna 201 moves to the AZ target angle. The EL (elevation) control unit 142 generates an EL drive command value for driving the antenna 201 in an elevation direction based on the input EL target angle, the EL angle, and the EL angular speed so that the antenna 201 moves to the EL target angle.
The vibration suppression control unit 143 generates a vibration suppression command value for performing vibration suppression driving of the antenna 201 based on the input vibration suppression target value and the vibration suppression control amount so that the antenna 201 moves to the vibration suppression target value. For example, it can be considered that the vibration suppression control unit 143 corresponds to the characteristic change unit 121 and the attitude correction unit 122 shown in
The driver unit 150 generates a driving signal for driving the antenna driving mechanism 202 and the vibration suppression mechanism 203. The driver unit 150 includes a motor driver 151 and a vibration suppression driver 152. The motor driver 151 is a drive unit for driving the antenna driving mechanism 202.
The motor driver 151 generates an AZ driving voltage based on the input AZ drive command value and supplies the generated AZ driving voltage to the antenna driving mechanism 202 (a motor for azimuth). The motor driver 151 generates an EL driving voltage based on the input EL drive command value and supplies the generated EL driving voltage to the antenna driving mechanism 202 (a motor for elevation).
The vibration suppression driver 152 is a drive unit for driving the vibration suppression mechanism 203. The vibration suppression driver 152 generates a vibration suppression driving voltage for driving the antenna 201 based on the input vibration suppression command value and supplies the generated vibration suppression driving voltage to the vibration suppression actuator 212 of the vibration suppression mechanism 203.
Next, a vibration suppression operation (a spatial stabilization method) according to this embodiment is explained with reference to
As shown in
For example, the characteristic change unit 121 acquires a transfer characteristic 300 as shown in
The characteristic change unit 121 changes the acquired transfer characteristic 300 to transfer characteristics 301 to 303. The characteristic change unit 121 may change the transfer characteristic to one of the transfer characteristics 301 to 303, or may change the transfer characteristic to a characteristic that is obtained by combining the transfer characteristics 301 to 303. For example, the characteristic change unit 121 changes the characteristic by changing a parameter of the transfer function.
In the example of the transfer characteristic 301, control is performed so that a peak value at a resonance frequency f1 is lowered. In the case of the transfer characteristic 301, it is possible to prevent the largest vibration from occurring. In the example of the transfer characteristic 302, control is performed so that the resonance frequency f1 is lowered to a resonance frequency f2. In the case of the transfer characteristic 302, it is possible to prevent vibrations having frequencies higher than the resonance frequency f2 from occurring by lowering the resonance frequency to the resonance frequency f2. In the example of the transfer characteristic 303, control is performed so that the characteristic in frequencies lower than the resonance frequency f1 is lowered. In the case of the transfer characteristic 303, it is possible to prevent vibrations from occurring at the start of shaking.
Next, the antenna sensor 103 detects the attitude of the antenna (S103) and the attitude correction unit 122 of the control unit 120 corrects the attitude of the antenna (S104). The attitude correction unit 122 performs control so that the attitude of the antenna 201 is corrected by the transfer characteristic that has been changed as shown in
As described above, in this embodiment, the attitude of the antenna mounted on the moving body is corrected by changing the transfer characteristic for the vibration suppression mechanism for the antenna. In this way, vibrations can be suppressed more effectively compared to the case where the transfer characteristic is fixed. It is possible to considerably suppress vibrations that are transferred from the moving body to the antenna by changing the peak value of the transfer characteristic, the resonance frequency, and/or the transfer ratio in a low-frequency band. Vibrations are different depending on the moving body. For example, while a large airplane vibrates slowly with a long period, a small airplane or a helicopter vibrates quickly with a short period. It is possible to suppress such various types of vibrations by changing the transfer characteristic as explained in this embodiment.
A second embodiment is explained hereinafter with reference to the drawings. In this embodiment, an example in which vibration suppression control is performed based on an active attitude change in addition to the vibration suppression control in the first embodiment is explained.
The airframe sensor 104 is disposed in the airframe 31 and detects the attitude (displacements in roll, pitch and yaw) of the airframe 31, vibrations thereof, and so on. Similarly to the antenna sensor 103, the airframe sensor 104 is an attitude angle sensor. For example, the airframe sensor 104 may be a GPS, a speed sensor, an acceleration sensor, a gyroscopic sensor, a resolver, a displacement sensor, a rate sensor, or the like.
The active attitude change extraction unit 160 extracts an active attitude change from the attitude angle of the moving body and sets (adds) this extracted active attitude change in the target attitude angle of the vibration suppression mechanism. The active attitude change means a large active change in the attitude of a moving body that occurs when the moving body changes its trajectory such as when it turns in the horizontal direction or in the vertical direction. Further, the active attitude change does not include any change caused by vibrations or trembling. For example, the active attitude change extraction unit 160 can be formed by using a low-pass filter.
For example, the airframe sensor 104 generates a detection signal shown in
In
In the related technique, only the target attitude angle of the vibration suppression mechanism is supplied in advance. Therefore, there is a problem that when the attitude angle of the moving body considerably changes due to the change in the trajectory or the like, the attitude angle of the vibration suppression mechanism becomes unstable and/or the attitude angle gets closer to the limit of the operating range.
Therefore, this embodiment includes means for detecting an attitude angle of a moving body and means for extracting an active attitude change from the attitude angle of the moving body, and the attitude angle extracted by this extraction means is set (added) in the target attitude angle of the vibration suppression mechanism.
In this way, at the time of an active attitude change of the moving body such as a change in the trajectory, the correction is made so as to follow this attitude change. Therefore, it is possible to prevent propagation of trembling/vibrations without making the attitude angle of the vibration suppression mechanism unstable. Therefore, it is possible to stabilize the pointing direction of a payload with respect to an inertial space throughout the entire moving path including a trajectory change.
Note that the present disclosure is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit and scope of the present disclosure.
For example, in the above-described embodiment, an example in which vibrations of an antenna mounted on a moving body are suppressed is explained. However, vibrations of other installed apparatuses installed in the moving body such as a sensor or a camera may be suppressed.
Each structure in the above-described embodiment may be constructed by software, hardware, or both of them. Further, each structure may be constructed by one hardware device or one software program, or a plurality of hardware devices or a plurality of software programs. Each function (each process) in the embodiment may be implemented by a computer including a CPU, a memory, and so on. For example, a control program for performing a control method according to the embodiment may be stored in a storage device (a storage medium) and each function may be implemented by having a CPU execute the control program stored in the storage device.
Although the present disclosure is explained above with reference to embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure.
This application is based upon and claims the benefit of priority from Japanese patent applications No. 2015-033903, filed on Feb. 24, 2015, the disclosure of which is incorporated herein in its entirety by reference.
10 SPATIAL STABILIZATION APPARATUS
11 MOVING BODY
12 VIBRATION SUPPRESSION MECHANISM UNIT
13 INSTALLED APPARATUS
14 ATTITUDE ANGLE DETECTION UNIT
15 CHARACTERISTIC CHANGE UNIT
16 ATTITUDE CORRECTION UNIT
20 SPATIAL STABILIZATION APPARATUS
30 MOVING BODY
31 AIRFRAME
100 RADAR APPARATUS
101 ANTENNA UNIT
102 SIGNAL PROCESSING UNIT
103 ANTENNA SENSOR
104 AIRFRAME SENSOR
110 TRANSMISSION UNIT
111 RECEPTION UNIT
112 IMAGE PROCESSING UNIT
113 CIRCULATOR
120 CONTROL UNIT
121 CHARACTERISTIC CHANGE UNIT
122 ATTITUDE CORRECTION UNIT
130 SENSOR PROCESSING UNIT
131 NOISE REDUCTION UNIT
132 COUPLED CONTROL CALCULATION UNIT
140 CONTROL CALCULATION UNIT
141 AZ (AZIMUTH) CONTROL UNIT
142 EL (ELEVATION) CONTROL UNIT
143 VIBRATION SUPPRESSION CONTROL UNIT
150 DRIVER UNIT
151 MOTOR DRIVER
152 VIBRATION SUPPRESSION DRIVER
160 ACTIVE ATTITUDE CHANGE EXTRACTION UNIT
201 ANTENNA
202 ANTENNA DRIVING MECHANISM
203 VIBRATION SUPPRESSION MECHANISM
211 VIBRATION SUPPRESSION SPRING
212 VIBRATION SUPPRESSION ACTUATOR
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-033903 | Feb 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/006476 | 12/25/2015 | WO | 00 |
