A system and method for adapting a mower engine throttle speed control
By combining visual recognition and dynamic armature resistance model with PID control, the problems of adjustment lag and poor matching accuracy of lawnmower engine throttle control system were solved, realizing stable voltage and current of power generation system and efficient operation of equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-06-08
- Publication Date
- 2026-07-14
AI Technical Summary
Traditional lawnmower engine throttle control systems lack quantitative data, resulting in inconsistent power output from the drive motor, delayed adjustments that fail to anticipate terrain changes, poor matching accuracy, high fuel consumption, and high noise levels. They also lack an active speed adjustment mechanism that anticipates terrain changes.
The system uses a visual communication module to identify terrain and grass conditions, combines data collected by the engine module, and calculates throttle output through a dynamic armature resistance model and a PID controller to achieve precise adjustment of engine speed, integrating a triple protection mechanism.
It achieves precise control of voltage and current stability in the power generation system, solves the problems of speed drop and engine stall during sudden load changes, and improves the operational stability and efficiency of the equipment.
Smart Images
Figure CN122383518A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of internal combustion power generation speed control technology for garden machinery, and in particular to a throttle speed control system and method adapted to lawnmower engines. Background Technology
[0002] Currently, large and medium-sized intelligent lawnmowers generally adopt an internal combustion engine with a generator as their power architecture. The generator supplies power to the walking motor and control system, giving them the advantages of unlimited range and high-power operation.
[0003] Traditional speed control schemes have the following drawbacks: Lack of quantitative basis: There is no basis for manually adjusting the throttle, the no-load voltage is too high and the load voltage drops severely, resulting in the power of the travel motor fluctuating.
[0004] Adjustment lag: Relying solely on the passive adjustment of speed based on the drop in generator output voltage, it cannot anticipate changes in terrain ahead. When the lawnmower enters complex working conditions such as steep slopes or tall grass areas, the load surges instantaneously, and the engine cannot respond in time, easily leading to malfunctions such as insufficient power or stalling.
[0005] Poor matching accuracy: In order to avoid stalling, traditional equipment generally adopts a constant high speed mode, which results in high fuel consumption, high noise, and severe equipment wear.
[0006] Existing technologies lack an active speed control mechanism that anticipates terrain conditions and a mathematical model for speed derivation based on generator electromotive force. Therefore, developing an engine throttle closed-loop speed control system based on visual prediction and an electromotive force model has significant engineering application value. Summary of the Invention
[0007] The purpose of this invention is to solve the above-mentioned problems by providing a control system and method for the throttle speed of a lawnmower engine.
[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A throttle speed control system adapted to a lawnmower engine, comprising: Power supply module, vision communication module, engine module, walking motor module and main control module; The visual communication module is used to identify terrain and vegetation conditions and output working condition level signals; The engine module is used to collect engine speed, generator bus voltage and throttle opening; The walking motor module is used to collect the load current of the walking motor; The main control module is connected to each module and configured as follows: Implement graded control based on operating condition level: lock the high speed range for complex operating conditions, and enter the speed reverse push for simple operating conditions; Under simple operating conditions, based on the target stable current With the target bus voltage Using a dynamic armature resistance model, the controlled rotational speed is calculated. : in, To adjust the rotational speed to the target, the unit is r / min. The target stable current is expressed in amperes (A). The target bus voltage is expressed in volts (V). The generator structure constant is... Φ is the current correction factor; Φ is the excitation flux, in Wb. K1 represents the static base resistance of the armature, in Ω / A; K2 represents the static base resistance of the dynamic armature resistance model, in Ω. Calculate speed deviation And calculate the throttle output according to the PID formula. : in, This represents the actual engine speed, expressed in r / min. This represents the rotational speed deviation, expressed in r / min. This represents the throttle control output during the k-th control cycle. , , These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.
[0009] Furthermore, the complex working conditions include steep slopes >12°, uneven ground, ditches, tree roots, dense weeds or shrubs; The simple working conditions include leveling grass or traveling without a load.
[0010] Furthermore, the target stable current The methods of obtaining it include: Any one of constant current command, constant power calculation, or load tracking; The constant instruction directly provides the controller with a current value; Constant power calculation is performed by setting a target output power. According to the formula calculate; The load tracking method is as follows: real-time detection of load-side voltage and dynamic calculation of output power. ; in For real-time output power, This is the generator bus voltage.
[0011] Furthermore, the main control module also integrates triple protection: monitoring bus voltage. Load current and engine speed When any parameter triggers the corresponding threshold, the target rotational speed is corrected. .
[0012] Furthermore, the walking motor module includes a three-phase half-bridge drive circuit, a MOS full-bridge circuit, and a current acquisition circuit; the engine module includes a Hall speed acquisition circuit, a voltage acquisition circuit, and a throttle execution circuit; the visual communication module adopts a CAN transceiver; and the power supply module includes a multi-channel voltage regulator unit.
[0013] Furthermore, the dynamic armature resistance model is as follows: .
[0014] Furthermore, this application also provides a method for controlling the throttle speed of a lawnmower engine, comprising the following steps: S1: Identify terrain and vegetation conditions, and classify complex and simple working conditions; S2: Collect engine speed, generator bus voltage and travel motor load current; S3: In complex operating conditions, lock the engine to the preset high RPM range; in simple operating conditions... Based on the target stable current With the target bus voltage Using a dynamic armature resistance model, the target is calculated. : in, To adjust the rotational speed to the target, the unit is r / min. The target stable current is expressed in amperes (A). The target bus voltage is expressed in volts (V). The generator structure constant is... Φ is the current correction factor; Φ is the excitation flux, in Wb. K1 represents the static base resistance of the armature, in Ω / A; K2 represents the static base resistance of the dynamic armature resistance model, in Ω. S4. Calculate speed deviation And calculate the throttle output according to the PID formula. : in, This represents the actual engine speed, expressed in r / min. This represents the rotational speed deviation, expressed in r / min. This represents the throttle control output during the k-th control cycle. , , These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively. S5: Real-time monitoring of operating parameters, and correction of speed or limitation of power when overvoltage, overload or overspeed protection is triggered; S6: Iterative steps S1 to S5.
[0015] The throttle speed control system for lawnmower engines disclosed in this invention has the following advantages compared with the prior art: 1. A speed regulation model based on the electromotive force mechanism of a generator is used to accurately back-calculate the target speed through the speed-voltage-current-internal resistance coupling formula, thereby achieving precise control of voltage and current stabilization in the power generation system.
[0016] 2. Combining visual terrain prediction with proactive speed adjustment, it solves the core pain points of speed drop and engine stalling when the load changes abruptly. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the principle module of a lawnmower engine throttle speed control system according to the present invention.
[0018] Figure 2 This is a circuit diagram of the three-phase half-bridge drive circuit in this invention.
[0019] Figure 3 This is a circuit diagram of the current sampling in this invention.
[0020] Figure 4 This is a circuit diagram for acquiring motor speed in this invention.
[0021] Figure 5 This is a schematic diagram of the sensorless brushless motor commutation signal acquisition circuit in this invention.
[0022] Figure 6 This is a circuit diagram of the engine module sampling in this invention.
[0023] Figure 7 This is a flowchart illustrating a method for controlling the throttle speed of a lawnmower engine according to the present invention. Detailed Implementation
[0024] The present invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic diagrams, illustrating only the basic structure of the invention in a schematic manner, and therefore only show the components relevant to the invention.
[0025] Example 1 like Figure 1 As shown, an adaptive lawnmower engine throttle speed control system includes: a power module, a vision communication module, an engine module, a travel motor module, and a main control module.
[0026] Power module: Connected to the main power supply of the whole machine, after reverse connection protection and LC filtering and voltage regulation, it outputs 12V, 5V and 3.3V regulated power supplies through multi-stage DC-DC conversion, which power the throttle drive, main control system, Hall sensor, CAN communication and high-precision sampling chip respectively.
[0027] refer to Figure 7 The circuit diagram of the visual communication module used in this application is shown. It is equipped with a TJA1050 high-speed CAN transceiver, and is matched with a 120Ω terminating resistor through the bus. It collects the terrain undulations and weed density characteristics in front in real time through the camera, and outputs the working condition level signal to the main control module through CAN communication.
[0028] In practical applications, the engine uses a flywheel Hall sensor to collect speed pulse signals, which are then input to the main control timer capture port to achieve high-frequency and high-precision sampling of engine speed. The throttle actuator uses a PWM brushed motor drive chip, and the main control outputs a PWM signal to continuously adjust the throttle opening. The generator bus voltage is divided by a 0.1% precision resistor and then sent to the main control ADC. The throttle position feedback Hall signal is divided and filtered before being sent to the main control ADC.
[0029] Furthermore, in practical applications, the walking motor module adopts a three-phase brushless DC motor drive. The three-phase brushless DC motor includes a three-phase half-bridge drive circuit, a power MOS full-bridge circuit, a sensorless brushless motor commutation signal acquisition circuit, a sensored brushless motor Hall sensor signal acquisition circuit, and an INA181 walking motor load current acquisition circuit, to achieve high-precision sampling of all system parameters.
[0030] The main control module is connected to the vision communication module, engine module, and walking motor module. It has an embedded mathematical model based on generator armature electromotive force, dynamic armature resistance, and closed-loop PID speed regulation. It calculates the engine target speed based on visual prediction of the working condition level and real-time electrical parameters, and outputs a PWM signal to adjust the throttle opening.
[0031] In this embodiment, an adaptive lawnmower engine throttle speed control system includes: a power module, a vision communication module, an engine module, a travel motor module, and a main control module. The vision communication module is used to identify terrain and grass conditions and output operating condition level signals. The engine module is used to collect engine speed, generator bus voltage, and throttle opening. The travel motor module is used to collect travel motor load current. The main control module is connected to each module and is configured to: perform graded control according to the operating condition level: lock the high speed range for complex operating conditions, and enter the speed reverse calculation mode for simple operating conditions; in simple operating conditions, calculate the throttle output according to the PID formula. : in, This represents the actual engine speed, expressed in r / min. This represents the rotational speed deviation, expressed in r / min. This represents the throttle control output during the k-th control cycle. , , These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.
[0032] In this embodiment, the main control module uses an STM32 series microcontroller with a complete mathematical speed regulation model embedded within it.
[0033] Specifically, the main control module performs hierarchical control based on the operating condition level signal output by the vision communication module. When the visual communication module identifies a steep slope (slope > 12°), continuous uneven ground, ditch, protruding tree roots, dense weeds, or shrubs ahead, it determines that the operating condition is complex and high-load. At this time, the main control module locks the engine to operate in a preset high-speed range (e.g., 3200-3600 rpm) to reserve electromotive force and power generation in advance to cope with sudden load changes and prevent engine stalling, insufficient electromotive force, and engine stalling from the root cause.
[0034] When the system detects that the road ahead is flat and sparsely grassy or that the vehicle is traveling unloaded, it is determined to be a simple light-load condition. At this time, the main control module enters the target speed reverse calculation step, dynamically calculating the optimal target speed using a formula to achieve energy-saving operation.
[0035] The steps for reverse-engineering the target rotational speed are as follows: Under simple light load conditions, the main control module determines the target stable current. With the target bus voltage (Usually set to rated voltage), the target control speed is calculated using a dynamic armature resistance model: The derivation of this formula is based on the following: Formula for generator armature electromotive force: ; Generator load voltage balance relationship: To achieve dynamic correction of temperature rise, armature reaction, and contact resistance changes, a dynamic model is used for armature resistance: ,in Φ is the current correction factor; Φ is the excitation flux, in Wb. This is the static base resistance of the armature, expressed in Ω / A. This is the static base resistance of the dynamic armature resistance model, in Ω.
[0036] Specifically, among them This is the generator structure constant, which is different for each generator and is uniquely determined by the generator's mechanical winding structure parameters. The factory parameters are given by the manufacturer, and the general calculation formula is as follows: .
[0037] Specifically, the armature resistance is related to the temperature rise of the copper winding. In practice, the temperature rise of the copper winding must be considered. The copper temperature rise coefficient is approximately 0.004 per degree Celsius. Actual theoretical calculations are related to power. Therefore, the armature resistance can also be expressed by the following formula using a dynamic model: in Generator rated power temperature rise, Generator rated current, Actual operating current.
[0038] Solve the above formulas to get the target rotational speed. Thus, the above reverse formula is obtained.
[0039] Based on the above formula derivation, the specific PID closed-loop regulation is as follows: the main control module collects the actual engine speed. Calculate the speed deviation And calculate the throttle output according to the PID formula. : The signal is converted into a PWM signal with the corresponding duty cycle by the PWM module and output to the throttle execution circuit of the engine module to drive the throttle motor to change the opening, thereby making the actual speed quickly converge to the target speed.
[0040] Furthermore, in this application, an industrial camera can be used to acquire environmental images in real time. The acquired images are then processed and analyzed, and image recognition algorithms are used to classify the terrain and vegetation conditions in front. Specific threshold settings are as follows: Complex working conditions (meeting any one of these conditions constitutes a complex working condition): terrain slope detection value > 12°; ground flatness detection shows continuous unevenness (height difference within an adjacent 10cm range > 5cm); ditches or tree root protrusions are identified; dense weeds with grass height detection value > 15cm and density > 70% coverage are identified; shrubs or continuous obstacles are identified (interval between obstacles < 50cm).
[0041] Simple working condition judgment conditions: flat lawn (height difference within 10cm between adjacent lawns <2cm); sparse grassland with grass height <8cm and coverage <50%; unloaded movement (walking motor current less than the unloaded threshold).
[0042] The main control module executes the corresponding speed regulation strategy based on the working condition level identifier bit output by the vision communication module (e.g., 0 indicates simple working condition, 1 indicates complex working condition).
[0043] Furthermore, in this application, the target stable current... There are multiple ways to obtain the value, and more than one method can be used in specific implementations. Specific methods include: constant current command, constant power calculation, and load tracking.
[0044] In the constant current command mode, the main control module directly receives the constant current command given by the upper-level controller. The constant current command can be set according to the experiment of working in different sites.
[0045] In constant power calculation mode, the main control module calculates the target output power given by the upper layer. ,according to calculate.
[0046] The load tracking method is as follows: real-time detection of load-side voltage and dynamic calculation of output power. ;in For real-time output power, This represents the real-time bus voltage.
[0047] In practical applications, the constant current instruction mode can be selected by default.
[0048] Furthermore, in this application, the main control module also integrates triple protection: monitoring bus voltage, load current and engine speed, correcting the target speed and limiting power output when the trigger threshold is reached.
[0049] In this embodiment, the main control module monitors the following three key parameters in real time and executes corresponding protection actions, as follows: 1. Overvoltage protection: When the bus voltage... When the overvoltage exceeds the preset overvoltage threshold (such as 120% of the rated voltage) and the duration exceeds 50ms, the main control module immediately reduces the throttle PWM duty cycle, reduces the engine speed, and reduces the power generation.
[0050] 2. Overload protection: Load current When the overload threshold is exceeded, the current limiting mode is triggered first, and the target speed is corrected in the reverse direction. This reduces the electromotive force and output power; if the current continues to exceed the threshold for more than 1 second, the throttle output power is limited.
[0051] 3. Overspeed protection: When the engine speed... When the mechanical safe speed is exceeded (e.g., 4000 rpm), the throttle PWM duty cycle is immediately and forcibly reduced to quickly decrease the speed.
[0052] The priority of the triple protection mechanism is: overspeed protection > overvoltage protection > overload protection.
[0053] Furthermore, as a specific implementation, the walking motor module in this application includes a three-phase half-bridge drive circuit, a MOS full-bridge circuit, and a current acquisition circuit; the engine module includes a Hall speed acquisition circuit, a voltage acquisition circuit, and a throttle execution circuit; the visual communication module adopts a CAN transceiver; and the power supply module includes a multi-channel voltage regulator unit.
[0054] refer to Figure 2 The three-phase half-bridge drive circuit uses three independent half-bridge drive chips to drive the A, B, and C phase bridge arms respectively. Each circuit includes a bootstrap power supply circuit, a gate drive circuit, and protection components. The specific operating mode is as follows: Power supply circuit: The VCC pin of each driver chip is connected to a +12V power supply, and the GND pin is connected to system ground. A filter capacitor (C44 / C55 / C58) is connected in parallel at the power supply end to filter out ripple. The bootstrap circuit consists of diodes (D23 / D29 / D30) and bootstrap capacitors (C45 / C56 / C59) to provide floating drive power for the upper bridge arm MOSFET.
[0055] Input / output: The HIN / LIN pin receives the upper and lower bridge arm drive signals sent by the master controller, and the HO / LO pin outputs the gate drive signals to control the conduction state of the upper bridge arm MOS (MOS1 / MOS3 / MOS5) and the lower bridge arm MOS (MOS2 / MOS4 / MOS6) respectively.
[0056] Gate protection: Each gate is connected in series with a current-limiting resistor (R54 / R55 / R61 / R62 / R63 / R64), and a freewheeling diode connected in reverse parallel (D21 / D22 / D24 / D25 / D26 / D28) to suppress switching spikes and prevent MOSFET gate breakdown.
[0057] refer to Figure 3 A standard three-phase full-bridge topology is formed by six N-channel power MOSFETs (Q13 / Q14 / Q15 / Q16 / Q17 / Q18). The drains of the upper bridge arm MOSFETs are uniformly connected to the high-voltage bus VCC, and the sources are respectively connected to the three-phase windings of the motor (MA / MB / MC). The drains of the lower bridge arm MOSFETs are connected to the motor windings, and the sources are connected to the system ground via sampling resistors (R56 / R57 / R58). The three-phase bridge arms are turned on in turn according to the master control timing, converting the DC bus voltage into three-phase alternating current to drive the motor to rotate. The sampling resistors in the lower bridge arm circuit also convert the phase current into a voltage signal, which is sent to the INA181 current sampling circuit to provide raw data for the load current speed regulation model.
[0058] refer to Figure 4This circuit is designed for acquiring motor speed and is suitable for sensor signal acquisition circuits of brushless motors with sensors, complementing the sensor circuits of brushless motors without sensors. The motor's built-in three Hall sensor signals (HA / HB / HC) are connected to the conditioning circuit through interfaces (H6 / H7): the Hall signals are powered by +5V and converted to 3.3V level through pull-up resistors (R78 / R79 / R80) to adapt to the main control I / O; the output is equipped with a filter capacitor (C52) to suppress interference, and the processed Hall signals are directly sent to the main control to determine the rotor position and achieve precise commutation. At the same time, the motor speed is calculated through the commutation frequency, providing speed feedback for the closed-loop control of the whole machine.
[0059] refer to Figure 5 This section is applicable to the commutation signal acquisition circuit of sensorless brushless motors, ensuring circuit versatility. A three-phase resistor network (R85 / R88 / R87, R86 / R89 / R70, R71 / R72 / R73) divides the three-phase terminal voltages (MA, MB, MC) of the motor, forming a virtual neutral point voltage at the MFA, MFB, and MFC nodes. The voltage divider network consists of resistors (R65 / R66 / R67 / R68 / R69 / R70 / R71 / R72 / R73 / R74). Using the bus midpoint potential as a reference, the resistor network can synthesize a reference voltage at the same potential as the actual neutral point of the motor, used for zero-crossing comparison. For example, the three-phase back electromotive force signals (MFA, MFB, MFC) of the brushless motor are sent to the non-inverting inputs (IN1+, IN2+, IN3+) of the LM339.
[0060] The virtual neutral point voltage (VM) is fed into the inverting input terminals (IN1-, IN2-, IN3-). When the back electromotive force voltage of a certain phase is higher than the virtual neutral point voltage, the comparator outputs a high level; when it is lower, it outputs a low level, forming a zero-crossing signal, thereby enabling the main control module to realize the commutation of the sensorless motor.
[0061] C6, C4, and C51 are RC low-pass filter capacitors, which, in conjunction with the motor phase line internal resistance / front-end resistor, filter out high-frequency interference from PWM chopping and motor noise, preventing false triggering. R76, R75, and R77 are output pull-up resistors, which pull the open-collector output of the LM339 high to +3.3V, forming a digital level that the main control module can recognize.
[0062] refer to Figure 6The engine module uses a flywheel Hall sensor to collect speed pulse signals, which are then input to the main control timer capture port to achieve high-frequency, high-precision sampling of engine speed. The throttle actuator uses a PWM brushed motor drive chip, and the main control outputs a PWM signal to continuously adjust the throttle opening, achieving fine and linear control of engine intake air volume and speed. The real-time throttle position feedback Hall signal is divided by a 0.1% precision resistor and fed to the analog input port of the main control module. The generator voltage VCC is also divided by a 0.1% precision resistor and fed to the analog input port of the main control module. The bidirectional TVS diode SMAJ3.3CA can withstand bidirectional transient peak voltages with a clamping voltage of 3.3V. Together with a 1kΩ current-limiting resistor R85, it limits the peak current. The filter capacitor C61 is 100nF, and together with R85, they form an RC low-pass filter that effectively filters out high-frequency ripple after generator rectification, improving sampling stability.
[0063] The throttle position feedback Hall signal WZ is divided by a 0.1% precision resistor and supplied to the analog input port of the main control module. One end of the current limiting resistor R88 (1kΩ) is connected to the output node of the voltage divider network, and the other end is connected to the sampling port (ADC2) of the main control ADC. One end of the filter capacitor C62 (100nF) is connected to the ADC2 port, and the other end is grounded, forming a first-order RC low-pass filter to filter out high-frequency noise and electromagnetic interference in the Hall signal and improve sampling stability.
[0064] Through the above methods, the main control module of this application establishes a mathematical model based on armature electromotive force, internal resistance loss, and speed-current coupling characteristics. Under no-load conditions, it maintains a minimum stable speed to reduce energy consumption; when the load increases, it automatically increases the speed to supplement power generation; when the load decreases, it automatically decreases the speed to stabilize the bus voltage and current within the rated range. During operation, the system strictly executes hierarchical control logic: facing complex conditions such as steep slopes, potholes, and dense weeds, the system locks in a high speed to reserve power; facing simple conditions such as flat open spaces and sparse grasslands, the system calculates the target speed in real-time using input parameters, and performs closed-loop precise speed regulation to ensure the engine always operates within its optimal efficiency range.
[0065] Meanwhile, the machine is equipped with triple safety protection logic, which monitors bus overvoltage, load overload, overcurrent, and engine overspeed in real time. Once the parameters exceed the standard, the system immediately reverses the target speed and limits the throttle power output to protect the safety of core components and significantly reduce the equipment failure rate. The system continuously cycles through operating condition identification, parameter acquisition, formula calculation, throttle adjustment, and fault protection processes, achieving adaptive, high-precision, high-reliability, and low-energy intelligent operation of the generator-type lawnmower under all operating conditions.
[0066] Example 2 refer to Figure 7This application also provides a method for controlling the throttle speed of a lawnmower engine, specifically including the following steps: S1: Identify terrain and vegetation conditions, and classify complex and simple working conditions.
[0067] Specifically, after the lawnmower is powered on, the vision communication module scans the working area in front in real time (the scanning distance is set to 3-5 meters in front). After processing by the vision algorithm, the working conditions are divided, and the working condition level signal is sent to the main control module through the CAN bus.
[0068] S2: Collect engine speed, generator bus voltage and travel motor load current.
[0069] Specifically, the main control module synchronously collects the actual engine speed. Generator bus and the load current of the walking motor All signals are filtered and shaped before being sent to the main control module.
[0070] S3: Locks in the high-speed range for complex operating conditions; calculates the target speed by reverse calculation using a formula for simple operating conditions.
[0071] Specifically, for complex operating conditions, a preset high speed value (such as 3500 rpm) is locked; for simple operating conditions, the target speed is calculated using a formula. : .
[0072] S4: Calculate the throttle output according to the PID formula, and adjust the PWM duty cycle to change the throttle opening.
[0073] Specifically, calculate the speed deviation. And calculate the throttle output according to the PID formula. : ;Will The output is mapped to the PWM duty cycle and sent to the throttle execution circuit to change the electronic throttle opening. The reverse derivation steps of the above formula are described in Example 1.
[0074] S5: Real-time monitoring of operating parameters, and correction of speed or limitation of power when overvoltage, overload, or overspeed protection is triggered.
[0075] Specifically, the bus voltage, load current and engine speed are monitored in real time throughout the process. When the protection threshold is triggered, overvoltage protection, overload protection and overspeed protection actions are executed. For specific protection actions, please refer to Example 1.
[0076] S6: Iterative steps S1 to S5.
[0077] Specifically, in actual operation, after completing one control cycle, the process immediately returns to step S1 for repeated execution, with the control cycle set to 10ms-20ms.
[0078] Furthermore, the target stable current There are multiple ways to obtain the value, and more than one method can be used in specific implementations. Specific methods include: constant current command, constant power calculation, and load tracking.
[0079] In the constant current command mode, the main control module directly receives the constant current command given by the upper-level controller. The constant current command can be set according to the experiment of working in different sites.
[0080] In constant power calculation mode, the main control module calculates the target output power given by the upper layer. According to the formula calculate.
[0081] The load tracking method is as follows: real-time detection of load-side voltage and dynamic calculation of output power. ;in For real-time output power, This represents the real-time bus voltage.
[0082] In practical applications, the constant current instruction mode can be selected by default.
[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A throttle speed control system adapted for lawnmower engines, characterized in that, include: Power supply module, vision communication module, engine module, walking motor module and main control module; The visual communication module is used to identify terrain and vegetation conditions and output working condition level signals; The engine module is used to collect engine speed, generator bus voltage and throttle opening; The walking motor module is used to collect the load current of the walking motor; The main control module is connected to each module and configured as follows: Implement graded control based on operating condition level: lock the high speed range for complex operating conditions, and enter the speed reverse push for simple operating conditions; Under simple operating conditions, based on the target stable current With the target bus voltage Using a dynamic armature resistance model, the target is calculated. : in, To adjust the rotational speed to the target, the unit is r / min. The target stable current is expressed in amperes (A). The target bus voltage is expressed in volts (V). The generator structure constant is... Φ is the current correction factor; Φ is the excitation flux, in Wb. K1 represents the static base resistance of the armature, in Ω / A; K2 represents the static base resistance of the dynamic armature resistance model, in Ω. Calculate speed deviation And calculate the throttle output according to the PID formula. : in, This represents the actual engine speed, expressed in r / min. The deviation is the rotational speed; the unit is r / min. This represents the throttle control output during the k-th control cycle. , , These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively.
2. The system according to claim 1, characterized in that, The complex working conditions include steep slopes >12°, uneven ground, ditches, tree roots, and dense weeds or shrubs; The simple working conditions include leveling grass or traveling without a load.
3. The system according to claim 1, characterized in that, The target stable current The methods of obtaining it include: Any one of constant current command, constant power calculation, or load tracking; The constant instruction directly provides the controller with a current value; Constant power calculation is performed by setting a target output power. ,according to calculate; The load tracking method is as follows: real-time detection of load-side voltage and dynamic calculation of output power. ; in For real-time output power, This represents the real-time bus voltage.
4. The system according to claim 1, characterized in that, The main control module also integrates triple protection: monitoring bus voltage. Load current and engine speed When any parameter triggers the corresponding threshold, the target rotational speed is corrected. .
5. The system according to claim 1, characterized in that, The walking motor module includes a three-phase half-bridge drive circuit, a MOS full-bridge circuit, and a current acquisition circuit; the engine module includes a Hall speed acquisition circuit, a voltage acquisition circuit, and a throttle execution circuit; the vision communication module uses a CAN transceiver; and the power supply module includes a multi-channel voltage regulator unit.
6. The system according to claim 1, characterized in that, The dynamic armature resistance model is as follows: 。 7. A method for controlling the throttle speed of a lawnmower engine, characterized in that, Includes the following steps: S1: Identify terrain and vegetation conditions, and classify complex and simple working conditions; S2: Collect engine speed, generator bus voltage and travel motor load current; S3: In complex operating conditions, lock the engine in the preset high speed range; For simple working conditions Based on the target stable current With the target bus voltage Using a dynamic armature resistance model, the target is calculated. : in, To adjust the rotational speed to the target, the unit is r / min. The target stable current is expressed in amperes (A). The target bus voltage is expressed in volts (V). The generator structure constant is... Φ is the current correction factor; Φ is the excitation flux, in Wb. K1 represents the static base resistance of the armature, in Ω / A; K2 represents the static base resistance of the dynamic armature resistance model, in Ω. S4. Calculate speed deviation And calculate the throttle output according to the PID formula. : in, This represents the actual engine speed, expressed in r / min. The deviation is the rotational speed; the unit is r / min. This represents the throttle control output during the k-th control cycle. , , These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively. S5: Real-time monitoring of operating parameters, and correction of speed or limitation of power when overvoltage, overload or overspeed protection is triggered; S6: Iterative steps S1 to S5.
8. The method according to claim 7, characterized in that, The target stable current The output power is obtained through constant power calculation, specifically by setting the target output power. According to the formula calculate.
9. The method according to claim 7, characterized in that, The target stable current The value is obtained through real-time detection of the load terminal voltage and dynamic calculation of the output power, specifically: ; in For real-time output power, This represents the real-time bus voltage.
10. The method according to claim 7, characterized in that, The dynamic armature resistance model is as follows: .