Two-degree-of-freedom follow-up platform

Abstract

The utility model discloses a two-degree-of-freedom follow-up platform which comprises a support, an outer-layer frame, an inner-layer platform, a laser range finder and a controller, the outer-layer frame and the inner-layer platform are respectively connected with a first motor and a second motor, the first motor and the second motor are both electrically connected with the controller, and the controller is electrically connected with an airborne gyroscope. According to the two-degree-of-freedom follow-up platform, the mounting platform of the laser range finder can be adjusted in real time along with the posture of the helicopter through the first motor and the second motor, it is ensured that the laser range finder is always in the vertical direction, and therefore low-height high-precision measurement under the maneuvering test flight state of the helicopter is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to airborne laser height measuring equipment field, concretely relates to a two degrees of freedom servo platform. BACKGROUND

[0002] Laser height measurement is a low height measurement means commonly used in helicopter hovering and small speed flight. UTILITY MODEL CONTENTS

[0003] The utility model provides a two degrees of freedom servo platform, the installation platform of laser range finder can follow real -time adjustment of helicopter posture through first motor and second motor, ensures that laser range finder always plumb to ground, thereby realizes low height high -precision measurement under the helicopter maneuvering flight state.

[0004] The technical solution provided by the utility model is as follows:

[0005] A two degrees of freedom servo platform is installed on a target helicopter, an airborne gyroscope is installed on the target helicopter, and the two degrees of freedom servo platform comprises a support installed on the target helicopter, an outer frame is arranged on the support, an inner platform is arranged in the outer frame, a laser range finder and a controller are installed on the inner platform.

[0006] The outer frame and the inner platform are respectively connected with first motor and second motor, and the first motor and the second motor are electrically connected with the controller.

[0007] The controller is electrically connected with the airborne gyroscope, and the controller controls the first motor and the second motor to work, so that the laser range finder always plumb to ground.

[0008] Further, the first motor and the second motor are respectively connected with speed reducer, the first motor controls the outer frame to move along the first direction, the second motor controls the inner platform to move along the second direction, and the first direction is perpendicular to the second direction.

[0009] Further, a navigation and attitude reference device is arranged on the side of the support, and the navigation and attitude reference device is electrically connected with the controller.

[0010] Further, the support comprises a mounting plate connected with the target helicopter and connecting ears arranged at the bottom of the mounting plate.

[0011] Further, the outer frame is arranged inside the connecting ears and has a square structure with an open bottom.

[0012] Further, the attitude and position reference device is arranged outside one of the connecting ears.

[0013] Further, absolute value photoelectric encoders are arranged on the mounting shafts of the connecting ears and the outer frame and the mounting shafts of the outer frame and the inner platform, respectively, and all the absolute value photoelectric encoders are electrically connected with the controller.

[0014] Further, the controller is an ARM7 single-chip microcomputer.

[0015] Further, the controller and the laser range finder are connected through an RS422 bus.

[0016] Further, the first motor and the second motor are both stepping motors.

[0017] Compared with the prior art, the platform has the following advantages:

[0018] 1. The two-degree-of-freedom servo platform comprises a support, an outer frame, an inner platform, a laser range finder and a controller, the outer frame and the inner platform are respectively connected with a first motor and a second motor, the controller is electrically connected with an airborne gyroscope, the controller controls the first motor and the second motor to work, so that the laser range finder is always perpendicular to the ground, thereby realizing high-precision measurement at a low height in a helicopter maneuvering flight state.

[0019] 2. The two-degree-of-freedom servo platform can reflect a real-time motion state through absolute value photoelectric encoders, provide negative feedback for the controller and correct a control angle.

[0020] 3. The two-degree-of-freedom servo platform is provided with an attitude and position reference device for calibrating installation errors of the platform, when the platform starts to work, a measurement value of the attitude and position reference device is taken as a system error, and the error is subtracted in subsequent attitude calculation, so that the platform can be calibrated.

[0021] 4. The utility model provides a two degrees of freedom servo platform, the outer frame can rotate in the horizontal roll direction, provides the mounting space for first motor and second motor, speed reducer and controller, the inner layer platform is installed on the central axis of outer frame, can rotate independently in the pitch direction, provides the mounting space for laser range finder;

[0022] 5. The utility model provides a two degrees of freedom servo platform, the platform draws the output signal of on -board gyro as the reference input ARM7 single-chip microcontroller's central controller, by central controller analysis pitch angle and roll angle signal, then the required movement reaches the drive circuit of first motor and second motor respectively, drive motor works to drive two degrees of freedom platform to reach the state of plumb to the ground. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is two degrees of freedom servo platform's structural schematic diagram in the utility model embodiment;

[0024] Figure 2 It is the flow chart of two degrees of freedom servo platform's control system in the utility model embodiment.

[0025] The signs are as follows:

[0026] 1 - support, 101 - mounting plate, 102 - connecting lug, 2 - outer frame, 3 - speed reducer, 4 - attitude reference device, 5 - first motor, 6 - controller, 7 - laser range finder, 8 - inner layer platform, 9 - second motor. DETAILED DESCRIPTION

[0027] To make the purpose, technical scheme and advantage of the embodiment of the application more clear, the technical scheme in the embodiment of the application will be clearly and completely described below in conjunction with the drawings in the embodiment of the application. Obviously, the following described embodiment is a part of the embodiment of the application, not all the embodiment. The components of the embodiment of the application described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the detailed description of the embodiment of the application provided below in conjunction with the drawings is only intended to represent the selected embodiment of the application, and not to limit the scope of the application claimed. Based on the embodiment in the application, all other embodiments obtained by the ordinary skill in the art without making creative efforts belong to the scope of the application.

[0029] It should be understood that, in the description of the embodiments of the utility model, the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the utility model. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the utility model, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0030] In the description of the embodiments of the utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected or can communicate with each other, it can be directly connected, or indirectly connected through an intermediate medium, it can be the communication or interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the embodiments of the utility model can be understood according to the specific circumstances.

[0031] As shown in Figure 1 The utility model provides a two degrees of freedom servo platform, this two degrees of freedom servo platform installs on target helicopter, target helicopter installs airborne gyroscope, including installing on target helicopter's support 1, support 1 is provided with outer frame 2, the inner layer platform 8 is provided in outer frame 2, the laser range finder 7 and controller 3 are installed on the inner layer platform 8, and the laser range finder 7 includes laser emitter and receiver. The target helicopter here refers to the randomly selected helicopter installing the two degrees of freedom servo platform, and the platform can be installed on other aircraft according to the need in addition to being used for the helicopter.

[0032] The outer frame 2 and the inner layer platform 8 are respectively connected with the first motor 5 and the second motor 9, and the first motor 5 and the second motor 9 are electrically connected with the controller 3.

[0033] The controller 3 is electrically connected with the airborne gyroscope, and the controller 3 controls the first motor 5 and the second motor 9 to work, so that the laser range finder 7 is always vertical to the ground.

[0034] Optionally, the first motor 5 and the second motor 9 are each connected to a reduction gear 3. The first motor 5 controls the movement of the outer frame 2 in a first direction, and the second motor 9 controls the movement of the inner platform 8 in a second direction, with the first direction and the second direction being perpendicular. During actual use, the outer frame 2 can rotate in the roll direction, providing installation space for the first and second motors 5, 9, the reduction gear 3, and the controller 3. The inner platform 8 is mounted on the central axis of the outer frame 2 and can rotate independently in the pitch direction, providing installation space for the laser rangefinder 7.

[0035] Optionally, a heading reference device 4 is provided on the side of the support 1 and is electrically connected to the controller 3. This device is used to calibrate the platform's installation errors. When the platform begins operating, the measurement value of the heading reference device 4 is sampled as the system error. This error is subtracted from subsequent attitude calculations to achieve platform calibration.

[0036] Optionally, the bracket 1 includes a mounting plate 101 and connecting ears 102. The mounting plate 1 is connected to the target helicopter. The connecting ears 102 are provided on both sides of the bottom of the mounting plate 101. The connecting ears 102 and the mounting plate 101 form an inverted U shape. The mounting plate 101 and the connecting ears 102 can be connected by welding or threading.

[0037] Optionally, the outer frame 2 is arranged on the inner side of the connecting ear 102, and the outer frame 2 is a square structure with an open bottom.

[0038] Optionally, the heading reference device 4 is arranged on the outside of one of the connecting ears 102 .

[0039] Optionally, an absolute value photoelectric encoder ( Figure 1 (not shown), all absolute value photoelectric encoders are electrically connected to the controller 3. The absolute value photoelectric encoder can reflect the real-time motion state of the platform, provide negative feedback to the controller 3, and correct the control angle.

[0040] Optionally, the controller 3 uses an ARM7 single-chip microcomputer, for example, an ARM7-LPC2148 model ARM7 single-chip microcomputer can be used.

[0041] Optionally, the controller and the laser rangefinder are connected via an RS422 bus.

[0042] Optionally, both the first motor 5 and the second motor 9 are stepper motors, such as the FHB31118 three-phase hybrid stepper motor. The platform utilizes a servo drive system, an automatic control system that controls mechanical position or angle. The drive motors used feature fast response, accurate positioning, and a large moment of inertia. Stepper motors are control motors that convert electrical pulse signals into corresponding angular or linear displacements. Position tracking systems based on stepper motors can effectively achieve all-around monitoring.

[0043] In actual use, the controller 6, laser rangefinder 7, heading reference device 4, first motor 5, and second motor 9 are all connected to a power module and powered by the power module. The power module can be installed on the target helicopter or separately installed on the two-degree-of-freedom tracking platform. The specific installation method can be selected according to actual conditions.

[0044] The control system flow chart of the present utility model is as follows: Figure 2 As shown, the platform draws the output signal of an onboard gyroscope as a reference input to an ARM7 single-chip central controller. The central controller then interprets the pitch and roll angle signals, then transmits the required motion to the driver circuits of the first and second motors, respectively, driving the motors to operate, thereby bringing the two-degree-of-freedom platform to a vertical position. An absolute photoelectric encoder is installed on each axis of the two-degree-of-freedom platform to reflect the platform's real-time motion state, providing negative feedback to the central controller and correcting the control angle. After the two-degree-of-freedom platform reaches the predetermined measurement position, the central controller reads the measurement signal from the laser rangefinder and outputs this data via the RS422 bus. A power module converts the onboard power to an appropriate voltage to power the central controller, attitude reference device 4, laser rangefinder 7, and motor drive circuits. The first and second motors 5 are stepper motors 9; the pitch and roll axis absolute encoders are absolute photoelectric encoders. The attitude reference device 4 utilizes a strapdown attitude reference system.

[0045] The two-degree-of-freedom platform provided by the utility model, after power on, the clock, phase-locked loop, interrupt vector, serial communication interface and I / O interface of the central controller are configured initially, and wait for the attitude reference device to calibrate itself; after self-calibration is completed, initialization is completed, and information of the airborne gyroscope is read, the pitch angle and roll angle signals are extracted, and the attitude information of the current carrier relative to the geographic coordinate system is solved; the alignment position preset by the system and the output value of the two-axis absolute value encoder are read in turn, the coordinate transformation is carried out in combination with the attitude information, the angles that the first motor 5 and the second motor 9 need to rotate in the current carrier coordinate system are calculated; according to the control frequency, the motor rotating position and the response characteristics of the motor itself, the acceleration and deceleration curve of the motor is planned and the real-time motor speed is calculated, and the two-degree-of-freedom platform is driven to move to the predetermined position. Once control is completed, the attitude signal is collected again to enter the next control process. In order to improve the start-stop characteristics of the stepping motor, the response speed of the stepping motor is accelerated, and the running is stable, the noise is reduced, and the PID control algorithm is adopted in the control system.

[0046] The product carrying the utility model is sensitive to the position of the height measurement system, and the installation error can introduce system error. The installation deviation of the heading direction can introduce the two rotating shafts of the servo platform in the form of sine and cosine components. The lifting buffer used in the general damping design cannot fix the platform base to the airplane, and the roll and pitch installation angles cannot be guaranteed. The airborne gyroscope as the attitude reference only detects the airplane state and cannot reflect the actual relationship between the height measurement system and the airplane. Therefore, the attitude reference device 4 is added to calibrate the installation error of the platform. When the platform starts to work, the measurement value of the attitude reference device 4 is taken as the system error, and the error is subtracted in the subsequent attitude operation, so that the calibration of the platform can be realized.

[0047] It should be noted that the ARM7 single-chip microcomputer used in the application controls the first motor 5 and the second motor 9 to reach the required rotating angle, and calibrates the error of the laser range finder 7 distance measurement by the ARM7 single-chip microcomputer, and the principles are all prior art. The application focuses on protecting the structural relationship of the two-degree-of-freedom servo platform, and the purpose of the application can be achieved through the structural design. The data and signals in the structure are not protected.

[0048] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, any change or replacement within the technical scope disclosed in the application should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A two-degree-of-freedom servo platform, the two-degree-of-freedom servo platform being mounted on a target helicopter, the target helicopter being equipped with an onboard gyroscope, characterized in that: It comprises a bracket mounted on the target helicopter, wherein the bracket is provided with an outer frame, an inner platform is provided within the outer frame, and a laser rangefinder and a controller are installed on the inner platform; The outer frame and the inner platform are respectively connected to a first motor and a second motor, and the first motor and the second motor are both electrically connected to the controller; The controller is electrically connected to the airborne gyroscope, and the controller controls the first motor and the second motor to operate so that the laser rangefinder is always vertical to the ground.

2. The two-degree-of-freedom servo platform according to claim 1, characterized in that: The first motor and the second motor are respectively connected to a reduction device. The first motor controls the outer frame to move along a first direction, and the second motor controls the inner platform to move along a second direction. The first direction is perpendicular to the second direction.

3. The two-degree-of-freedom servo platform according to claim 1 or 2, characterized in that: A heading reference device is provided on the side of the bracket, and the heading reference device is electrically connected to the controller.

4. The two-degree-of-freedom servo platform according to claim 3, characterized in that: The bracket includes a mounting plate and connecting ears. The mounting plate is connected to the target helicopter. The connecting ears are arranged on both sides of the bottom of the mounting plate. The connecting ears and the mounting plate form an inverted U shape.

5. The two-degree-of-freedom servo platform according to claim 4, characterized in that: The outer frame is arranged on the inner side of the connecting ear, and the outer frame is a square structure with an open bottom.

6. The two-degree-of-freedom servo platform according to claim 4 or 5, characterized in that: The heading reference device is arranged on the outside of one of the connecting ears.

7. The two-degree-of-freedom servo platform according to claim 6, characterized in that: Absolute value photoelectric encoders are respectively connected to the mounting shafts between the outer frame and the connecting ears and the mounting shafts between the outer frame and the inner platform. All the absolute value photoelectric encoders are electrically connected to the controller.

8. The two-degree-of-freedom servo platform according to claim 7, characterized in that: The controller uses an ARM7 single chip microcomputer.

9. The two-degree-of-freedom servo platform according to claim 7 or 8, characterized in that: The controller and the laser rangefinder are connected by an RS422 bus.

10. The two-degree-of-freedom servo platform according to claim 9, characterized in that: The first motor and the second motor are both stepping motors.

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