A control method for a cam-type continuous zoom system

Abstract

The present invention discloses a cam configuration continuous zoom system control method, firstly establishes a control device zero position reference, reads the focus pre-calibration initialization value in the peripheral memory; the controller unit receives the control command from the RS422 bus, and switches the field of view according to the command transmitted by the airborne device; when the controller performs a task, the PWM duty cycle is adjusted according to the position feedback value during the switching process to perform reliable control, and after the controller completes the task, the focus calibration value of each field of view is updated according to the instruction. The present invention can realize the rapid and accurate control of the cam configuration continuous zoom full stroke.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared imaging, and in particular relates to a cam configuration continuous zoom system control method. Background Art

[0002] Infrared imaging equipment can be used in small drones, unmanned helicopters, and reconnaissance vehicles to provide aircraft with target images for observation and search at night or in adverse weather conditions.

[0003] As the payload of UAV, the market demand for infrared sensors will grow in direct proportion to the growth of UAVs. At present, due to the restrictions on take-off weight, volume and space, most of the infrared sensors equipped on small and medium-sized UAVs are uncooled infrared thermal imagers, and their detection performance and imaging effects are limited by the devices. The use of cam variable magnification compensation control and structural design can meet the above needs. The advantage is that the number of motors can be reduced, but the disadvantage is that the structural design and control bring corresponding difficulties. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a cam configuration continuous zoom system control method, firstly establish the control device zero position reference, read the focus pre-calibration initialization value in the peripheral memory; the controller unit receives the control command from the RS422 bus, and switches the field of view according to the command transmitted by the airborne device; when the controller performs the task, the PWM duty cycle is adjusted according to the position feedback value during the switching process to perform reliable control, and after the controller completes the task, the focus calibration value of each field of view is updated according to the instruction. The present invention can realize the rapid and accurate control of the cam configuration continuous zoom full stroke.

[0005] The technical solution adopted by the present invention to solve the technical problem includes the following steps:

[0006] Step 1: The cam configuration continuous zoom system control device includes a controller unit, a driving unit, an actuator unit and a position feedback unit;

[0007] The target simulator calibrates the focus value of the field of view and stores it in the peripheral memory of the controller unit;

[0008] Step 2: The zero reference of the control device is established, and the focus pre-calibration initialization value in the peripheral memory is read;

[0009] Using a small field of view as a reference, the controller unit performs a power-on self-test when powered on, and the self-test completes the establishment of a reference, which is the position of the collimator determined during the optical machine adjustment. During the self-test, a sensing device is set on the reference, and after the sensing signal is read in the program, it is determined that the reference position has been moved, and the motor is self-locked at this position. The reference is established, the initial focus value is read, and initialization is completed, and then wait for control commands;

[0010] Step 3: The controller unit receives the control command from the RS422 bus and switches the field of view according to the command transmitted by the onboard device;

[0011] Step 4: When the controller executes the task:

[0012] (1) Performing first-order derivative on the mechanical cam curve to obtain the velocity curve, and performing second-order derivative on the mechanical cam curve to obtain the acceleration curve;

[0013] (2) According to the speed and acceleration curves, the position of the maximum speed value is obtained, and according to the encoder feedback value, the PWM duty cycle is adjusted to perform speed control;

[0014] Step 5: After completing the task, the controller updates the focus calibration value of each field of view according to the instruction.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention can realize rapid and accurate control of the full stroke of the cam configuration continuous zoom. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a flow chart of the method of the present invention.

[0018] Figure 2 This is a three-dimensional diagram of the double-link optical machine.

[0019] Figure 3 This is an interface diagram of the multi-mode control device of the present invention.

[0020] Figure 4 This is a principle block diagram of the control system of the present invention.

[0021] Figure 5 This is the relationship curve between the position, speed and acceleration of the mechanical cam of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] The purpose of the present invention is to provide a cam configuration continuous zoom system control method to quickly and accurately control the variable magnification focusing mechanism.

[0024] The solution of the present invention comprises a controller unit, a drive unit, an actuator unit and a position feedback unit, wherein the controller unit is the core, and the unit comprises a variable magnification and focus coordinated control algorithm and a variable PWM duty cycle control.

[0025] like Figure 1 As shown, a cam configuration continuous zoom system control method comprises the following steps:

[0026] Step 1: The cam configuration continuous zoom system control device includes a controller unit, a driving unit, an actuator unit and a position feedback unit;

[0027] The target simulator calibrates the focus value of the field of view and stores it in the peripheral memory of the controller unit;

[0028] Step 2: The zero reference of the control device is established, and the focus pre-calibration initialization value in the peripheral memory is read;

[0029] Using a small field of view as a reference, the controller unit performs a power-on self-test when powered on, and the self-test completes the establishment of a reference, which is the position of the collimator determined during the optical machine adjustment. During the self-test, a sensing device is set on the reference, and after the sensing signal is read in the program, it is determined that the reference position has been moved, and the motor is self-locked at this position. The reference is established, the initial focus value is read, and initialization is completed, and then wait for control commands;

[0030] Step 3: The controller unit receives the control command from the RS422 bus and switches the field of view according to the command transmitted by the onboard device;

[0031] Step 4: When the controller executes the task:

[0032] (1) Performing first-order derivative on the mechanical cam curve to obtain the velocity curve, and performing second-order derivative on the mechanical cam curve to obtain the acceleration curve;

[0033] (2) According to the speed and acceleration curves, the position of the maximum speed value is obtained, and according to the encoder feedback value, the PWM duty cycle is adjusted to perform speed control;

[0034] Step 5: After completing the task, the controller updates the focus calibration value of each field of view according to the instruction. Specific embodiment:

[0036] like Figure 2 The figure shows a three-dimensional diagram of the dual-link optical machine used in the present invention, wherein the zoom motor is a DC brushed motor, which drives the zoom optical machine structure to move through gear transmission. The focus motor is a DC brushed motor, which drives the focus optical machine structure to move through dimension transmission. According to the host computer instruction, the focus and zoom control is completed at the same time, and the PWM duty cycle is adjusted according to the position feedback value during the switching process to perform reliable control.

[0037] 1. Work process design

[0038] like Figures 3 to 5As shown, the present invention realizes the control of the mechanical cam through the controller unit. The controller unit includes a DSP controller, an RS422 communication interface and a motor drive circuit. The controller unit receives the field of view switching instruction through the RS422 interface chip, selects the full-stroke or partial electronic cam mode, compares the position signal fed back by the encoder with the target value, and controls the motor speed in real time after PID calculation to adapt to the control requirements of the mechanical cam, thereby realizing the field of view switching requirements.

[0039] According to the continuous zoom working requirements:

[0040] When the controller unit is powered on, it performs a power-on self-test to complete the zero calibration. The present invention uses a small field of view as the zero reference. The relative encoder used in this article is established through the zero reference to initialize the reference data of the focus and magnification, and the encoder can be used as the real-time position of the motor operation.

[0041] 2. Method and step design

[0042] 1) Control device benchmark establishment

[0043] For the continuous zoom system, the present invention adopts a small field of view as a reference. When the controller unit is powered on, a power-on self-detection is performed, and the self-detection completes the establishment of a reference. The reference is the position of the collimator determined during the optical machine assembly. During the self-detection process, a sensing device is set at the reference. After the sensing signal is read in the program, it is considered that the movement has reached the reference position, and the motor is self-locked at this position. The reference is established, and the initial focus value is read to complete the initialization and then wait for the control command.

[0044] 2) Receive control information

[0045] The controller unit receives control commands from the RS422 bus and switches the field of view according to the commands transmitted by the onboard equipment.

[0046] 3) Execute tasks

[0047] A) According to the mechanical cam curve, the first-order derivative can be taken to obtain the velocity curve, and the second-order derivative of the mechanical cam curve can be taken to obtain the acceleration curve;

[0048] B) According to the speed and acceleration curve, the position of the maximum speed value can be obtained, and according to the encoder feedback value, the PWM duty cycle is adjusted to control the speed.

[0049] When executing a task, zoom and focus are initialized at the same time:

[0050] (1) After the zoom adjustment is initialized, the zoom mechanism is blocked and controlled in the zoom sub-function, and the maximum running time is set. The condition for exiting the function is that the function runs to the set field of view or the running time reaches the maximum running time.

[0051] (2) The focus target position is judged and detected in real time during the timer interruption, and the focus adjustment is stopped when the error value from the target position is within the set range.

[0052] 4) After completing the task: the focus calibration value of each field of view can be updated according to the instructions.

Claims

1. A cam configuration continuous zoom system control method, characterized in that: The steps include: Step 1: The cam configuration continuous zoom system control device includes a controller unit, a driving unit, an actuator unit and a position feedback unit; The target simulator calibrates the focus value of the field of view and stores it in the peripheral memory of the controller unit; Step 2: The zero reference of the control device is established, and the focus pre-calibration initialization value in the peripheral memory is read; Using a small field of view as a reference, the controller unit performs a power-on self-test when powered on, and the self-test completes the establishment of a reference, which is the position of the collimator determined during the optical machine adjustment. During the self-test, a sensing device is set on the reference, and after the sensing signal is read in the program, it is determined that the reference position has been moved, and the motor is self-locked at this position. The reference is established, the initial focus value is read, and initialization is completed, and then wait for control commands; Step 3: The controller unit receives the control command from the RS422 bus and switches the field of view according to the command transmitted by the onboard device; Step 4: When the controller executes the task: (1) Performing first-order derivative on the mechanical cam curve to obtain the velocity curve, and performing second-order derivative on the mechanical cam curve to obtain the acceleration curve; (2) According to the speed and acceleration curves, the position of the maximum speed value is obtained, and according to the encoder feedback value, the PWM duty cycle is adjusted to perform speed control; Step 5: After completing the task, the controller updates the focus calibration value of each field of view according to the instruction.

Images