An electromechanical-coordinated disturbance rejection control method simulating multi-stage variable valve timing and lift

Abstract

This invention provides an electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift. The method includes the following steps: controller power-on initialization, drive the motor to rotate the incremental encoder, real-time acquisition of the encoder output pulse signal, calculation of motor speed, and establishment of a speed-pulse phase correlation mapping. Through the above implementation process, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by this invention can stably achieve simulated control of two-stage variable valve lift within a motor speed range of 1000-3000 r / min, with valve timing control error ≤ ±1° and lift control error ≤ ±0.5 mm. Under conditions of ±10% air source pressure fluctuation, the feedforward compensation strategy can control the lift error within ±1 mm.

Description

Technical Field

[0001] This invention relates to the field of electromechanical control technology, and in particular to an electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift. Background Technology

[0002] In automotive engineering teaching, verification of engine variable valve timing (VVA) control strategies, and hardware-in-the-loop simulation testing, ordinary DC motors are often used to simulate engine crankshafts, combined with solenoid valves or relays to simulate valve actuators.

[0003] The existing test bench control system has significant defects:

[0004] First, traditional closed-loop speed control is usually based on a fixed time period (such as every 200 milliseconds) for speed measurement and control output. When simulating the engine working in multiple frequency cycles (such as 7 consecutive 2520-degree working cycles), time-based control cannot accurately match the mechanical phase of the physical equipment, resulting in phase lag in the actuator action.

[0005] Second, when inductive loads such as solenoid valves engage and disengage instantaneously, they generate extremely large surge currents and back electromotive forces. In systems with shared power supplies, this can lead to instantaneous voltage drops on the bus and electromagnetic interference in the space, directly causing encoder pulse distortion and microcontroller miscalculation of speed, resulting in severe speed fluctuations and poor system robustness.

[0006] Therefore, it is necessary to provide an electromechanical cooperative anti-disturbance control method that simulates multi-stage variable valve timing and lift to solve the above-mentioned technical problems. Summary of the Invention

[0007] This invention provides an electromechanical cooperative anti-disturbance control method that simulates multi-stage variable valve timing and lift, solving the problems of speed fluctuation and control phase lag caused by periodic abrupt inductive loads in the prior art.

[0008] To solve the above-mentioned technical problems, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention includes the following steps:

[0009] S1: The controller is powered on and initialized. The drive motor drives the incremental encoder to rotate. The pulse signal output by the encoder is collected in real time, the motor speed is calculated, and the correlation mapping between speed and pulse phase is established.

[0010] S2: Record the current global cumulative pulse of the encoder as the phase zero point, activate the valve control state machine, and establish the mapping relationship between the valve phase and the encoder pulse;

[0011] S3: Calculate the relative number of pulses for motor rotation, and take the modulus of the pulse number as 238. Divide the phase into two control zones based on the modulus value.

[0012] S4: Low lift or late opening range: The controller outputs a control signal to disconnect the solenoid valve, the cylinder is not driven by pressure, and the valve is in a low lift state, simulating the valve opening strategy under low speed conditions; High lift or early opening range: The controller outputs a control signal to close the solenoid valve, and the high-pressure gas in the cylinder drives the cylinder to move, realizing high valve lift output; At the same time, feedforward compensation control is superimposed to correct the solenoid valve action timing in advance based on the current speed and phase signal, to offset the disturbance caused by system response lag and gas source pressure fluctuation.

[0013] S5: After completing a single phase control, return to the signal acquisition step to continuously monitor speed and phase changes, thereby achieving closed-loop anti-disturbance control.

[0014] Preferably, when the speed is ≤1000rpm, it is determined to be an idling condition. All solenoid valves are forcibly de-energized and disconnected, the cylinder is in a reset state, and the valve simulation mechanism remains in the initial closed position to avoid false phase triggering at low speeds. If the speed is >1000rpm, it is determined to be a normal operating condition. The controller records the current global cumulative pulse value as the phase zero point, activates the state machine control process, and establishes a relative phase calculation benchmark based on the zero point.

[0015] Preferably, the controller calculates the relative phase based on the encoder pulse signal. The calculation method is: relative phase = current cumulative pulse value - zero-point cumulative pulse value mod 238, to obtain the modulus value in the range of 0~237, thereby realizing the discretized phase mapping of the 360-degree crankshaft rotation angle.

[0016] Preferably, the incremental encoder has 200-500 lines, and the modulus parameter 238 corresponds to the discretization of the crankshaft angle in the four-stroke cycle of a simulated engine. The modulus parameter and threshold Y can be adjusted according to different experimental requirements to adapt to the phase range of different engine models.

[0017] Preferably, in the two control zones, when the modulus value is <119, it is determined to be a low lift / late opening control zone; when the modulus value is ≥119, it is determined to be a high lift or early opening control zone.

[0018] Compared with related technologies, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention has the following beneficial effects:

[0019] This invention provides an electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift. Through the above implementation process, this method can stably achieve simulated control of two-stage variable valve lift within a motor speed range of 1000-3000 r / min, with valve timing control error ≤ ±1° and lift control error ≤ ±0.5 mm. Under the condition of air source pressure fluctuation of ±10%, the feedforward compensation strategy can control the lift error within ±1 mm, effectively improving the system's anti-disturbance capability and meeting the verification requirements of variable valve technology in the laboratory stage. By introducing phase zero-point calibration, speed zone forced control, and feedforward compensation strategies, the influence of factors such as speed fluctuation, solenoid valve response lag, and power supply disturbance on valve action phase and lift is effectively suppressed, improving control accuracy and stability, and providing reliable platform support for teaching experiments and control strategy verification. Attached Figure Description

[0020] Figure 1 A schematic diagram of the structure of the first embodiment of the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention;

[0021] Figure 2 This is a schematic diagram of the second embodiment of the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] First Embodiment

[0024] Please refer to the following: Figure 1 ,in, Figure 1 This is a schematic diagram of the first embodiment of the electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift provided by the present invention. The electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift includes the following steps:

[0025] S1: The controller is powered on and initialized. The drive motor drives the incremental encoder to rotate. The pulse signal output by the encoder is collected in real time, the motor speed (i.e., simulated engine crankshaft speed) is calculated, and the correlation mapping between speed and pulse phase is established.

[0026] Power unit: 24V DC motor, rated speed 3000r / min, coaxial incremental encoder with a resolution of 1000 lines.

[0027] S2: Record the current global cumulative pulse of the encoder as the phase zero point, activate the valve control state machine, and establish the mapping relationship between the valve phase and the encoder pulse;

[0028] Pneumatic unit: miniature air pump, 500mL air cylinder, two-position two-way solenoid valve, miniature cylinder, cylinder piston rod diameter 5mm, stroke 10mm, simulating valve lift;

[0029] S3: Calculate the relative number of pulses for motor rotation, and take the modulus of the pulse number as 238 (simulating the valve phase interval within one working cycle of the engine), and divide the phase into two control zones according to the modulus value;

[0030] S4: Low lift or late opening range: The controller outputs a control signal to disconnect the solenoid valve, the cylinder is not pressure driven, and the valve is in a low lift state, simulating the valve opening strategy under low speed conditions; High lift or early opening range: The controller outputs a control signal to close the solenoid valve, and the high-pressure gas in the cylinder drives the cylinder to move, realizing high valve lift output; At the same time, feedforward compensation control is superimposed to correct the solenoid valve action sequence in advance based on the current speed and phase signal, to offset the disturbance caused by system response lag and gas source pressure fluctuation;

[0031] Control unit: STM32 controller, relay module, power supply module. The controller controls the relay to switch on and off via PWM signals, thereby controlling the switching of the solenoid valve.

[0032] S5: After completing a single phase control, return to the signal acquisition step to continuously monitor speed and phase changes, thereby achieving closed-loop anti-disturbance control.

[0033] When the speed is ≤1000rpm, it is determined to be an idling condition. All solenoid valves are forcibly de-energized and disconnected, the cylinder is in a reset state, and the valve simulation mechanism remains in the initial closed position to avoid phase mis-triggering at low speeds. If the speed is >1000rpm, it is determined to be a normal operating condition. The controller records the current global cumulative pulse value as the phase zero point, activates the state machine control process, and establishes a relative phase calculation benchmark based on the zero point.

[0034] The controller calculates the relative phase based on the encoder pulse signal. The calculation method is: relative phase = (current cumulative pulse value - zero-point cumulative pulse value) mod 238, which yields the modulus value in the range of 0 to 237, realizing the discretized phase mapping of the 360-degree crankshaft rotation angle.

[0035] The incremental encoder has 200-500 lines, and its modulus parameter of 238 corresponds to the discretization of crankshaft angle in a simulated four-stroke cycle of an engine. The modulus parameter and threshold can be adjusted according to different experimental requirements to adapt to the phase range of different engine models.

[0036] In the two control zones, when the modulus value is <119, it is determined to be a low lift / late opening control zone; when the modulus value is ≥119, it is determined to be a high lift or early opening control zone.

[0037] The working principle of the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by this invention is as follows:

[0038] When the motor is powered on, the controller initializes peripherals such as encoders, solenoid valves, and cylinders, and sets the speed threshold to 1000 r / min, phase modulus to 238, and zone threshold to 119.

[0039] The controller calculates the real-time motor speed through encoder pulses. When the speed is <1000 r / min, the solenoid valve remains open and the cylinder does not move, simulating the low-speed operation of the engine with low valve lift. When the speed is ≥1000 r / min, the controller enters the valve adjustment control process, records the current cumulative encoder pulse value as the phase zero point, switches the state machine to the working state, and establishes a mapping relationship of "motor rotation angle - encoder pulse - valve phase". The controller reads the encoder pulse count in real time, calculates the relative pulse count and takes the modulus of 238 to obtain the current phase modulus value. When the modulus is less than 119, it is determined to be in the low lift range. The controller outputs a low-level signal to disconnect the solenoid valve, and the cylinder is not pressure-driven, maintaining the valve at a low lift. When the modulus is greater than or equal to 119, it is determined to be in the high lift range. The controller outputs a high-level signal to close the solenoid valve, and compressed gas from the cylinder enters the cylinder, pushing the piston rod to extend, thus achieving a high lift valve action. The controller calculates the motor angular velocity based on the current speed, predicts the phase position of the next control cycle, and outputs the solenoid valve control signal 10ms in advance to compensate for the mechanical action delay of the solenoid valve. At the same time, the controller uses the cylinder pressure sensor to provide feedback. When the pressure is lower than the set threshold, the solenoid valve opening time is extended to ensure stable cylinder output pressure and offset the lift error caused by gas source pressure fluctuations. After completing a single phase control, the controller returns to the signal acquisition step, continuously monitoring speed and phase changes to achieve closed-loop control. When the speed fluctuation exceeds ±200 r / min or the solenoid valve action feedback is abnormal, the controller triggers fault protection, disconnects the solenoid valve control signal, maintains the valve in a low lift state, and issues an alarm.

[0040] Compared with related technologies, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention has the following beneficial effects:

[0041] Through the above implementation process, this method can stably achieve simulated control of two-stage variable valve lift within the motor speed range of 1000-3000 r / min, with valve timing control error ≤ ±1° and lift control error ≤ ±0.5 mm. Under the condition of air source pressure fluctuation of ±10%, the feedforward compensation strategy can control the lift error within ±1 mm, effectively improving the system's anti-disturbance capability and meeting the verification requirements of variable valve technology in the laboratory stage. By introducing phase zero-point calibration, speed zone forced control, and feedforward compensation strategies, the influence of factors such as speed fluctuation, solenoid valve response lag, and power supply disturbance on valve action phase and lift is effectively suppressed, improving control accuracy and stability, and providing reliable platform support for teaching experiments and control strategy verification.

[0042] Second Embodiment

[0043] Please refer to the following: Figure 2 , Figure 2 This is a schematic diagram of the second embodiment of the electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift provided by the present invention. Based on the electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift provided in the first embodiment of this application, the second embodiment of this application proposes another electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift. The second embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the second embodiment will not affect the individual implementation of the first embodiment.

[0044] Specifically, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided in the second embodiment of this application differs in that the controller is further divided into low-speed VVA mode and high-speed VVA mode based on the engine speed. In the low-speed VVA mode (1000rpm < speed ≤ 1800rpm), the second solenoid valve is forcibly disconnected, and only the first solenoid valve is activated to control the valve, simulating the small valve lift mode at low speed. In the high-speed VVA mode (speed > 1800rpm), the first solenoid valve is forcibly disconnected, and only the second solenoid valve is activated to control the valve, simulating the large valve lift mode at high speed.

[0045] Low-speed VVA mode: If the modulus value is <119, it is determined to be the valve closing phase interval. The first solenoid valve is de-energized and disconnected, and the cylinder retracts to simulate the small-lift valve closing state. If the modulus value is ≥119, it is determined to be the valve opening phase interval. The first solenoid valve is energized and closed. At the same time, a feedforward compensation signal based on the speed change rate is superimposed to compensate for the solenoid valve response lag. The cylinder extends to simulate the small-lift valve opening state.

[0046] High-speed VVA mode: If the modulus value is less than the preset threshold Y (Y < 119, optimized and calibrated according to high-speed operating conditions), it is determined to be the valve closing phase interval, and the second solenoid valve is de-energized and disconnected, and the cylinder retracts; if the modulus value is greater than or equal to the preset threshold Y, it is determined to be the valve opening phase interval, and the second solenoid valve is energized and closed, while a long-stroke feedforward compensation signal is superimposed to drive the cylinder to extend to the maximum stroke, simulating the large valve lift valve opening state.

[0047] Compared with related technologies, the electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift provided by the present invention has the following beneficial effects:

[0048] By combining speed partitioning with the coordinated control of two solenoid valves, two VVA modes, namely low speed and small lift, and high speed and large lift, can be simulated simultaneously. Combined with encoder phase feedback, VVT timing control is realized, which fully reproduces the working logic of the multi-stage variable valve mechanism and adapts to the intake characteristic simulation requirements under different operating conditions.

[0049] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for electromechanical cooperative disturbance rejection control simulating multi-stage variable valve timing and lift, characterized in that, Includes the following steps: S1: The controller is powered on and initialized. The drive motor drives the incremental encoder to rotate. The pulse signal output by the encoder is collected in real time, the motor speed is calculated, and the correlation mapping between speed and pulse phase is established. S2: Record the current global cumulative pulse of the encoder as the phase zero point, activate the valve control state machine, and establish the mapping relationship between the valve phase and the encoder pulse; S3: Calculate the relative number of pulses for motor rotation, and take the modulus of the pulse number as 238. Divide the phase into two control zones based on the modulus value. S4: Low lift or late opening range: The controller outputs a control signal to disconnect the solenoid valve, the cylinder is not driven by pressure, and the valve is in a low lift state, simulating the valve opening strategy under low speed conditions; High lift or early opening range: The controller outputs a control signal to close the solenoid valve, and the high-pressure gas in the cylinder drives the cylinder to move, realizing high valve lift output; At the same time, feedforward compensation control is superimposed to correct the solenoid valve action timing in advance based on the current speed and phase signal, to offset the disturbance caused by system response lag and gas source pressure fluctuation. 2.S5: After completing a single phase control, return to the signal acquisition step to continuously monitor speed and phase changes, thereby achieving closed-loop anti-disturbance control.

3. The electromechanical cooperative disturbance rejection control method for simulating multi-stage variable valve timing and lift according to claim 1, characterized in that, When the speed is ≤1000rpm, it is determined to be an idling condition. All solenoid valves are forcibly de-energized and disconnected, the cylinder is in a reset state, and the valve simulation mechanism remains in the initial closed position to avoid phase mis-triggering at low speeds. If the speed is >1000rpm, it is determined to be a normal operating condition. The controller records the current global cumulative pulse value as the phase zero point, activates the state machine control process, and establishes a relative phase calculation benchmark based on the zero point.

4. The electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift according to claim 1, characterized in that, The controller calculates the relative phase based on the encoder pulse signal. The calculation method is: relative phase = current cumulative pulse value - zero-point cumulative pulse value mod 238, to obtain the modulus value in the range of 0~237, realizing the discretized phase mapping of the 360-degree crankshaft rotation angle.

5. The electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift according to claim 1, characterized in that, The incremental encoder has 200 to 500 lines, and the modulus parameter of 238 corresponds to the discretization of the crankshaft angle in the four-stroke cycle of the simulated engine. The modulus parameter and threshold Y can be adjusted according to different experimental requirements to adapt to the phase range of different engine models.

6. The electromechanical cooperative anti-disturbance control method for simulating multi-stage variable valve timing and lift according to claim 1, characterized in that, In the two control zones, when the modulus value is <119, it is determined to be a low lift / late opening control zone; when the modulus value is ≥119, it is determined to be a high lift or early opening control zone.

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