Illumination intensity detection method and system based on light kinetic energy

Abstract

The invention provides an illumination intensity detection system and method based on light kinetic energy. The system comprises a photovoltaic cell, a controller and a ceiling lamp. The photovoltaic cell converts light energy into electric energy to supply power to the system. The controller monitors the current and voltage generated by the photovoltaic cell, determines the current illumination intensity according to the pre-established corresponding relation, and controls the working state of the ceiling lamp. And the system sends the illumination intensity data to a whole vehicle network through the CAN bus. The invention further comprises a system calibration process, an illumination intensity calculation method, ceiling lamp control logic optimization and a system integration scheme. The system integrates illumination intensity detection, system power supply and ceiling lamp control functions, and has the advantages of low cost, high integration level, high energy utilization efficiency and the like. The system can be widely applied to the fields of automobiles, buildings and the like, and provides reliable technical support for intelligent illumination control and environment monitoring.

Description

Technical Field

[0001] The present invention relates to the field of automotive electronic technology, and in particular to a light intensity detection method and system based on light kinetic energy. Background Art

[0002] At present, the illumination sensors on the whole vehicle all measure the current light intensity through photosensors, and then send the light intensity to the CAN network. The whole vehicle adjusts the brightness of the headlights, the central control screen and the instrument according to the light intensity value. This solution requires a special illumination sensor and corresponding wiring harness, which increases the cost of the whole vehicle. Therefore, a new light intensity detection solution is needed that can not only achieve accurate measurement of light intensity but also reduce the cost of the whole vehicle. Summary of the invention

[0003] The purpose of the present invention is to provide a light intensity detection method and system based on photokinetic energy, which evaluates the light intensity by calculating the current generated by photokinetic energy, and uses photokinetic energy to power the system and the ceiling light, thereby eliminating the special light intensity sensor and the ceiling light power supply harness, reducing the cost of the entire vehicle while ensuring the functionality.

[0004] To achieve the above object, in a first aspect, the present invention provides a method for detecting light intensity based on light kinetic energy, comprising:

[0005] Photovoltaic cells absorb light energy and convert it into electrical energy;

[0006] monitoring the current and voltage generated by the photovoltaic cell;

[0007] Determine the current light intensity based on the pre-established relationship between current, voltage and light intensity;

[0008] The current light intensity is sent to the entire vehicle network.

[0009] Preferably, the pre-established correspondence between current, voltage and light intensity includes:

[0010] A first corresponding relationship curve is established when the ceiling light is turned off, and a second corresponding relationship curve is established when the ceiling light is turned on.

[0011] Further preferably, the process of establishing the first correspondence curve and the second correspondence curve includes:

[0012] When the ceiling light is turned off, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, and the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, and the corresponding relationship between the current, voltage, and light intensity is established to establish the first corresponding relationship curve;

[0013] When the ceiling light is on, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, the current value is tested within the light intensity range of 0 to 50000Lux, the system current is measured, the corresponding relationship between current, voltage and light intensity is established, and the second corresponding relationship curve is established.

[0014] Preferably, the ceiling light is turned on and off according to the light intensity; and the control of the ceiling light includes an automatic control mode and a manual control mode.

[0015] Further preferably, the automatic control mode includes:

[0016] When the light intensity value is less than the preset threshold and the vehicle speed is less than the preset speed, the ceiling light is automatically turned on;

[0017] When the light intensity value is greater than or equal to the preset threshold or the vehicle speed is greater than or equal to the preset speed, the ceiling light is automatically turned off.

[0018] Still further preferably, the preset threshold value of light intensity is 100 Lux, and the preset speed is 3 km / h.

[0019] Further preferably, the manual control mode includes: responding to a switch operation by a user, manually turning the ceiling light on or off.

[0020] In a second aspect, the light intensity detection system based on light kinetic energy designed by the present invention comprises:

[0021] Photovoltaic cells, used to convert light energy into electricity to power the control system and ceiling lights;

[0022] A controller, electrically connected to the photovoltaic cell, for monitoring the current and voltage generated by the photovoltaic cell, controlling the working state of the ceiling light, determining the current light intensity according to a pre-established correspondence between the current, voltage and light intensity, and sending the light intensity to the vehicle network;

[0023] A ceiling light is electrically connected to the controller and is used to provide lighting when needed.

[0024] Preferably, the control system comprises:

[0025] A voltage monitoring module is used to monitor the voltage generated by the photovoltaic cell;

[0026] A current monitoring module for monitoring the current generated by the photovoltaic cell;

[0027] A light intensity calculation module is used to determine the current light intensity according to the pre-established corresponding relationship between current, voltage and light intensity;

[0028] A communication module, used to send the determined light intensity to the vehicle network;

[0029] The ceiling light control module is used to control the on / off status of the ceiling light.

[0030] Further preferably, the light intensity calculation module stores a first corresponding relationship curve established when the ceiling light is turned off, and a second corresponding relationship curve established when the ceiling light is turned on.

[0031] Still further preferably, the first corresponding relationship curve and the second corresponding relationship curve are obtained by:

[0032] When the ceiling light is turned off, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, and the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, and the corresponding relationship between the current, voltage, and light intensity is established to establish the first corresponding relationship curve;

[0033] When the ceiling light is on, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, the current value is tested within the light intensity range of 0 to 50000Lux, the system current is measured, the corresponding relationship between current, voltage and light intensity is established, and the second corresponding relationship curve is established.

[0034] Further preferably, the ceiling light control module includes automatic control logic and manual control logic; wherein,

[0035] The automatic control logic is: when the light intensity value is less than the preset threshold and the vehicle speed is less than the preset speed, the ceiling light is automatically turned on; when the light intensity value is greater than or equal to the preset threshold or the vehicle speed is greater than or equal to the preset speed, the ceiling light is automatically turned off;

[0036] The manual control logic is: when a manual opening command is received, the ceiling light is turned on; when a manual closing command is received, the ceiling light is turned off.

[0037] Still further preferably, the preset threshold is 100 Lux, and the preset speed is 3 km / h.

[0038] The beneficial effects of the present invention are: the dedicated light intensity sensor is eliminated, thereby reducing the cost of the entire vehicle; the power supply wiring harness of the ceiling light system is eliminated, thereby simplifying the wiring harness layout of the entire vehicle; light kinetic energy is used to power the system, thereby improving energy utilization efficiency; accurate detection of light intensity and intelligent control of the ceiling light are achieved; the integration of light intensity detection, system power supply and ceiling light control is achieved, thereby improving system integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a logic block diagram of a light intensity detection method based on light kinetic energy provided by an embodiment of the present invention;

[0040] Figure 2It is a structural block diagram of a light intensity detection system based on light kinetic energy provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The present invention proposes a light intensity detection system and method based on photokinetic energy. The system integrates light intensity detection, system power supply and ceiling light control functions, and has the advantages of low cost, high integration, high energy utilization efficiency, etc.

[0043] Example 1: Basic system structure and working principle

[0044] like Figure 1 As shown, the light intensity detection system based on light kinetic energy proposed by the present invention includes a photovoltaic cell 1, a controller 2 and a ceiling light 3. The controller 2 includes a voltage monitoring module 21, a current monitoring module 22, a light intensity calculation module 23, a communication module 24 and a ceiling light control module 25.

[0045] Photovoltaic cell 1 is used to convert light energy into electrical energy to power controller 2 and ceiling light 3. Photovoltaic cell 1 generates electron-hole pairs by absorbing photons, and generates electric potential at both ends of the PN junction, thereby converting light energy into electrical energy. Photovoltaic cell 1 provides power for the entire system, including powering controller 2 and ceiling light 3.

[0046] In this embodiment, the photovoltaic cell 1 is a flexible thin-film solar cell to adapt to the curved surface of the roof. Flexible thin-film solar cells have the characteristics of light weight, thin thickness, and bendability, and are very suitable for use in the roof of a car.

[0047] The controller 2 is electrically connected to the photovoltaic cell 1, and is used to monitor the current and voltage generated by the photovoltaic cell 1, control the working state of the ceiling light 3, determine the current light intensity according to the pre-established correspondence between current, voltage and light intensity, and send the light intensity data to the vehicle network.

[0048] The controller is the core of the entire system and is mainly responsible for the following functions: monitoring the current and voltage generated by photovoltaic cells; controlling the on / off state of the ceiling lights; determining the current light intensity based on the pre-established correspondence between current, voltage and light intensity according to the current and voltage generated by photovoltaic cells; and sending the light intensity data to the vehicle network via the CAN bus.

[0049] The ceiling light 3 is electrically connected to the controller 2 and is used to provide lighting when needed. In this embodiment, an LED ceiling light is used to provide soft white light. The ceiling light 3 is the executive component of the system and provides lighting when needed. Its working state (on or off) is controlled by the controller according to the light intensity and the vehicle state.

[0050] The voltage monitoring module 21 is used to monitor the voltage generated by the photovoltaic cell 1. In specific implementation, a voltage divider circuit and an analog-to-digital converter (ADC) may be used to achieve voltage measurement.

[0051] The current monitoring module 22 is used to monitor the current generated by the photovoltaic cell 1. In specific implementation, a low-resistance sampling resistor and a differential amplifier can be used to achieve current measurement.

[0052] The illumination intensity calculation module 23 is used to determine the current illumination intensity according to the pre-established correspondence between current, voltage and illumination intensity. The module stores a first correspondence curve established when the ceiling light is off and a second correspondence curve established when the ceiling light is on. These curve data are stored in the flash memory in the form of a lookup table for quick query and calculation.

[0053] The first corresponding relationship curve and the second corresponding relationship curve are obtained in the following way:

[0054] When the ceiling light is turned off, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, and the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, and the corresponding relationship between the current, voltage, and light intensity is established to establish the first corresponding relationship curve;

[0055] When the ceiling light is on, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, the current value is tested within the light intensity range of 0 to 50000Lux, the system current is measured, the corresponding relationship between current, voltage and light intensity is established, and the second corresponding relationship curve is established.

[0056] The communication module 24 is used to send the determined light intensity to the vehicle network. In this embodiment, the CAN bus communication protocol is used to send the light intensity data to the vehicle network. The CAN controller built into the STM32L476RG and the TJA1050CAN transceiver are used to implement CAN communication. The communication rate is set to 500kbps, and the light intensity data is sent every 100ms.

[0057] The ceiling light control module 25 is used to control the on / off state of the ceiling light 3. The module includes automatic control logic and manual control logic.

[0058] The automatic control logic is:

[0059] When the light intensity value is less than the preset threshold (100 Lux) and the vehicle speed is less than the preset speed (3 km / h), the ceiling light will be automatically turned on;

[0060] When the light intensity value is greater than or equal to the preset threshold or the vehicle speed is greater than or equal to the preset speed, the ceiling light is automatically turned off.

[0061] The manual control logic is:

[0062] When receiving a manual opening command, turn on the ceiling light;

[0063] When a manual shutdown command is received, the ceiling light is turned off.

[0064] Example 2: Basic logic of detection method

[0065] like Figure 2 As shown, the light intensity detection method based on light kinetic energy of the present invention comprises the following steps:

[0066] S1: absorbs light energy through photovoltaic cell 1 and converts it into electrical energy;

[0067] S2: Controller 2 monitors the current and voltage generated by photovoltaic cell 1;

[0068] S3: The controller 2 determines the current light intensity according to the pre-established corresponding relationship between current, voltage and light intensity;

[0069] S4: The controller 2 sends the current light intensity to the vehicle network through the communication module 24.

[0070] In practical applications, the system of the present invention can be integrated on the roof of a vehicle. The photovoltaic cell 1 can be a flexible thin-film solar cell to adapt to the curved surface of the roof. The controller 2 can be a low-power microcontroller, such as the STM32L series. The ceiling light 3 can be an LED light to improve energy efficiency.

[0071] The system of the present invention not only realizes accurate detection of light intensity, but also realizes intelligent control of ceiling lights. By eliminating the special light intensity sensor and the power supply harness of the ceiling light system, the cost of the whole vehicle is reduced and the layout of the whole vehicle harness is simplified. At the same time, the system is powered by light kinetic energy, which improves energy utilization efficiency. In addition, the present invention realizes the integration of light intensity detection, system power supply and ceiling light control, and improves the system integration.

[0072] Example 3: System calibration process

[0073] In order to ensure the accuracy of light intensity calculation, it is necessary to calibrate the system before use to establish the corresponding relationship between current, voltage and light intensity. The specific calibration process is as follows:

[0074] 1. Preparation:

[0075] Prepare standard light sources (such as halogen lamps), light meters, DC power supplies, electronic loads and other equipment. Install the system on an angle-adjustable bracket to simulate different lighting conditions.

[0076] 2. Establish the first corresponding relationship curve (ceiling light off state):

[0077] a) Control the output voltage of the photovoltaic cell to 3V (using electronic load regulation);

[0078] b) Adjust the light source so that the light intensity starts from 0 Lux, and a point is taken every 100 Lux (the specific interval value can be selected according to different requirements) until 50,000 Lux, for a total of 510 points;

[0079] c) At each light intensity point, record the current value measured by the system and the light meter reading;

[0080] d) repeating steps ac to adjust the output voltage of the photovoltaic cell to 4V and 5V respectively;

[0081] e) Based on the recorded data, the three-dimensional surface equation of current, voltage and light intensity was fitted using the least squares method.

[0082] 3. Establish the second corresponding relationship curve (ceiling light on state):

[0083] Repeat the process in step two, but keep the overhead light on throughout the process.

[0084] 4. Data processing and storage:

[0085] The two three-dimensional surface equations obtained by fitting are discretized to generate a lookup table, which is stored in the flash memory of the controller.

[0086] None, accuracy verification:

[0087] Select several light intensity points that are not involved in the fitting, compare the system measurement results with the light meter readings, and ensure that the measurement error is within ±5%.

[0088] Through this calibration process, we established an accurate correspondence between current, voltage and light intensity, providing a reliable data basis for subsequent light intensity calculations.

[0089] Through the above calibration process, we get two sets of corresponding curves: Curve 1 is applicable to the state where the ceiling light is off, and Curve 2 is applicable to the state where the ceiling light is on. These two sets of curves will be stored in the control system and used for the calculation of light intensity during actual working process.

[0090] Example 4: Light intensity calculation method

[0091] In actual operation, the control system calculates the light intensity according to the following steps:

[0092] 1. Real-time monitoring of system current and voltage;

[0093] 2. Determine whether the ceiling light is on;

[0094] 3. If the ceiling light is off, select curve 1; if the ceiling light is on, select curve 2;

[0095] 4. According to the current current and voltage values, linear interpolation is performed on the selected curve to obtain the current light intensity value.

[0096] The specific calculation process can be done by table lookup or polynomial fitting. Taking the table lookup method as an example, a three-dimensional table containing current, voltage and corresponding light intensity values ​​is stored in the control system. When calculating, first select the corresponding table according to the state of the ceiling light, then find the table item closest to the current current and voltage, and calculate the accurate light intensity value through linear interpolation.

[0097] In some optional embodiments of the present invention, based on the corresponding relationship established during the calibration process, the present invention calculates the light intensity using the following method:

[0098] 1. Data collection:

[0099] Data is collected every 100ms to measure the output voltage V and current I of the photovoltaic cell.

[0100] 2. Determine the status of the ceiling light:

[0101] Check the switch status of the ceiling light and select the corresponding lookup table (the first corresponding relationship curve or the second corresponding relationship curve).

[0102] 3. Table lookup calculation:

[0103] a) In the selected lookup table, find the four points closest to the measured value (V1, I1, L1), (V1, I2, L2), (V2, I1, L3), (V2, I2, L4);

[0104] b) Calculate the light intensity L using bilinear interpolation:

[0105] First, perform linear interpolation in the V direction:

[0106] La=L1+(L2-L1)*(I-I1) / (I2-I1)

[0107] Lb=L3+(L4-L3)*(I-I1) / (I2-I1)

[0108] Then perform linear interpolation in the I direction:

[0109] L=La+(Lb-La)*(V-V1) / (V2-V1)

[0110] 4. Filtering:

[0111] In order to reduce the impact of instantaneous fluctuations, the calculated light intensity value is subjected to sliding average filtering, and the average value of the most recent 10 calculation results is taken as the final output.

[0112] 5. Result output:

[0113] The filtered light intensity value is sent to the vehicle network via the CAN bus.

[0114] This calculation method makes full use of the precise correspondence established during the calibration process, while taking into account real-time performance and stability, and can obtain a more accurate light intensity value.

[0115] Example 5: Ceiling light control logic

[0116] The ceiling light control of this system includes two modes: automatic control logic and manual control logic.

[0117] 1. Automatic control logic:

[0118] a) The system enters automatic control mode by default when it is powered on for the first time;

[0119] b) When the calculated light intensity value is less than 100 Lux (this threshold can be adjusted according to user needs):

[0120] If the vehicle speed is less than 3km / h, the top light will be automatically turned on;

[0121] If the vehicle speed is greater than or equal to 3km / h, the top light will be automatically turned off;

[0122] c) When the light intensity value is greater than or equal to 100 Lux, keep the ceiling light off.

[0123] 2. Manual control logic:

[0124] a) When the user starts the manual control mode through the key switch, the system exits the automatic control logic;

[0125] b) In manual mode:

[0126] When the ceiling light switch is turned on, the system turns on the ceiling light;

[0127] When the ceiling light switch is turned off, the system turns off the ceiling light;

[0128] c) Each time the system is powered on again, it will default back to the automatic control mode.

[0129] Example 6: Light intensity data transmission

[0130] After calculating the light intensity, the control system needs to transmit this information to the vehicle network for use by other systems. The specific steps are as follows:

[0131] 1. The control system packages the calculated light intensity value into a data frame that complies with the CAN protocol;

[0132] 2. Send the data frame to the vehicle network through the CAN bus;

[0133] 3. The sending frequency can be set according to actual needs, such as sending once per second or sending when the light intensity changes significantly;

[0134] 4. Other vehicle systems (such as headlight control system, central control screen, instrument panel, etc.) can obtain real-time light intensity information by subscribing to this CAN message and adjust their respective working status accordingly.

[0135] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for detecting light intensity based on light kinetic energy, characterized in that: The method includes: absorbing light energy through photovoltaic cells and converting it into electrical energy; monitoring the current and voltage generated by the photovoltaic cells; determining the current light intensity based on a pre-established relationship between current, voltage, and light intensity; and sending the current light intensity to the vehicle network.

2. The method for detecting light intensity based on light kinetic energy according to claim 1, characterized in that: The pre-established corresponding relationship between current, voltage and light intensity includes: A first corresponding relationship curve is established when the ceiling light is turned off, and a second corresponding relationship curve is established when the ceiling light is turned on.

3. The method for detecting light intensity based on light kinetic energy according to claim 2, characterized in that: The process of establishing the first correspondence curve and the second correspondence curve includes: When the ceiling light is turned off, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, and the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, and the corresponding relationship between the current, voltage, and light intensity is established to establish the first corresponding relationship curve; When the ceiling light is on, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, the corresponding relationship between current, voltage and light intensity is established, and the second corresponding relationship curve is established.

4. The method for detecting light intensity based on light kinetic energy according to claim 1, 2 or 3, characterized in that: The ceiling light is turned on and off according to the light intensity; the ceiling light control includes an automatic control mode and a manual control mode.

5. The method for detecting light intensity based on light kinetic energy according to claim 4, characterized in that: Automatic control modes include: When the light intensity value is less than the preset threshold and the vehicle speed is less than the preset speed, the ceiling light is automatically turned on; When the light intensity value is greater than or equal to the preset threshold or the vehicle speed is greater than or equal to the preset speed, the ceiling light is automatically turned off.

6. The method for detecting light intensity based on light kinetic energy according to claim 5, characterized in that: The preset threshold of light intensity is 100 Lux, and the preset speed is 3 km / h.

7. A light intensity detection system based on light kinetic energy, characterized in that: The system comprises: Photovoltaic cells, used to convert light energy into electricity to power the control system and ceiling lights; A controller, electrically connected to the photovoltaic cell, for monitoring the current and voltage generated by the photovoltaic cell, controlling the working state of the ceiling light, determining the current light intensity according to a pre-established correspondence between the current, voltage and light intensity, and sending the light intensity to the vehicle network; A ceiling light is electrically connected to the controller and is used to provide lighting when needed.

8. The light intensity detection system based on light kinetic energy according to claim 7, characterized in that: The control system comprises: A voltage monitoring module is used to monitor the voltage generated by the photovoltaic cell; A current monitoring module for monitoring the current generated by the photovoltaic cell; A light intensity calculation module is used to determine the current light intensity according to the pre-established corresponding relationship between current, voltage and light intensity; A communication module, used to send the determined light intensity to the vehicle network; The ceiling light control module is used to control the on / off status of the ceiling light.

9. The light intensity detection system based on light kinetic energy according to claim 8, characterized in that: The illumination intensity calculation module stores a first corresponding relationship curve established when the ceiling light is turned off and a second corresponding relationship curve established when the ceiling light is turned on. The first corresponding relationship curve and the second corresponding relationship curve are obtained in the following manner: When the ceiling light is turned off, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, and the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, and the corresponding relationship between the current, voltage, and light intensity is established to establish the first corresponding relationship curve; When the ceiling light is on, the voltage of the photovoltaic cell is controlled to be 3V, 4V, and 5V respectively, the current value is tested within the light intensity range of 0 to 50000 Lux, the system current is measured, the corresponding relationship between current, voltage and light intensity is established, and the second corresponding relationship curve is established.

10. The light intensity detection system based on light kinetic energy according to claim 8, characterized in that: The ceiling light control module includes automatic control logic and manual control logic; wherein, The automatic control logic is: when the light intensity value is less than the preset threshold and the vehicle speed is less than the preset speed, the ceiling light is automatically turned on; when the light intensity value is greater than or equal to the preset threshold or the vehicle speed is greater than or equal to the preset speed, the ceiling light is automatically turned off; The manual control logic is: when a manual opening command is received, the ceiling light is turned on; when a manual closing command is received, the ceiling light is turned off.

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