DC motor anti-pinch control system and method based on PWM slope

Abstract

The invention discloses a DC motor anti-pinch control system and method based on PWM slope, and belongs to the technical field of motor control, and the system comprises an information collection module, a PWM slope calculation module, a PWM slope monitoring module, a current monitoring module, a speed monitoring module and a clamping state judgment module. The information acquisition module acquires a PWM signal, a current signal and a motor operation rotating speed for controlling the direct current motor; the PWM slope calculation module calculates the slope value of the PWM signal; the PWM slope monitoring module, the current monitoring module and the speed monitoring module are used for setting threshold values and monitoring data changes in real time; the clamping state judgment module judges whether the push rod is in a clamping state or not by analyzing monitoring results of the three data; the instantaneous change of the motor load is reflected by combining and analyzing current, rotating speed and PWM signal slope monitoring, the load change can be quickly detected, anti-pinch protection measures can be triggered in time, and the response speed and safety of the system are improved.

Description

Technical Field

[0001] The invention relates to the technical field of motor control, and in particular to a direct current motor anti-pinch control system and method based on PWM slope. Background Art

[0002] With the rapid development of automation and intelligent technology, push rod motors are widely used in smart homes, industrial automation and vehicle systems, such as electric curtains, electric door locks, car windows and industrial robotic arms. However, during the use of push rod motors, when the push rod encounters obstacles or clamps, it may cause equipment damage or personal injury. Therefore, anti-pinch protection has become a key issue in the design of these systems.

[0003] Traditional anti-pinch protection technologies mostly rely on mechanical limit switches, photoelectric sensors or other types of external sensors. Although these solutions can provide anti-pinch protection to a certain extent, they have some significant shortcomings. For example, external sensors have high installation and maintenance costs, are easily affected by environmental factors, and have slow response speeds. In addition, complex sensor systems increase the overall complexity of the equipment and reduce the system's reliability and anti-interference capabilities.

[0004] In order to solve the above problems, some studies in recent years have attempted to achieve anti-pinch protection by analyzing the operating status of the motor. Among them, monitoring methods based on current or voltage fluctuations have gradually attracted attention; however, these methods still have problems such as insufficient accuracy, slow response speed and false alarms in practical applications, especially in complex working environments. The effect is not ideal; therefore, there is an urgent need for a more efficient and reliable anti-pinch protection method that can monitor the operating status of the push rod in real time and respond in a timely manner without relying on external sensors. Summary of the invention

[0005] The object of the present invention is to provide a DC motor anti-pinch control system and method based on PWM slope to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: a DC motor anti-pinch control system based on PWM slope, the system includes an information acquisition module, a PWM slope calculation module, a PWM slope monitoring module, a current monitoring module, a speed monitoring module and a clamping state judgment module;

[0007] The information acquisition module is used to collect the PWM signal, motor speed and motor load current of the DC motor;

[0008] The PWM slope calculation module calculates the slope value of the PWM signal by performing differential processing on the PWM signals at consecutive time points;

[0009] The PWM slope monitoring module is used to set a PWM slope threshold and monitor in real time whether the calculated PWM slope exceeds the set PWM slope threshold;

[0010] The current monitoring module is used to set a current threshold and monitor in real time whether the collected motor load current exceeds the set threshold;

[0011] The speed monitoring module is used to set the motor speed threshold range and monitor in real time whether the motor speed is within the set range;

[0012] The clamping state judgment module judges whether the push rod is in a clamping state by comprehensively comparing the monitoring results of the PWM signal slope, the motor load current and the motor speed, and triggers corresponding anti-clamping protection measures after judging that it is in a clamping state.

[0013] Furthermore, the information acquisition module includes a PWM signal acquisition unit, a speed signal acquisition unit and a current signal acquisition unit;

[0014] PWM, or pulse width modulation, is a very effective technology that uses the digital output of a microprocessor to control analog circuits. It is widely used in many fields from measurement, communication to power control and conversion. The PWM signal acquisition unit acquires PWM signals in real time through a CCP interface, and converts the acquired PWM analog signals into digital signals through the CCP interface, or directly reads the duty cycle of the PWM signal through a microcontroller. The acquired signal data is stored in a data buffer of the system for subsequent processing. The acquired signal data includes the duty cycle of the PWM signal and the time point corresponding to the duty cycle. The duty cycle of the PWM signal is the ratio of the high-level signal pulse width to the entire pulse cycle within a pulse cycle of the acquired PWM pulse signal.

[0015] The speed signal acquisition unit acquires the motor running speed in real time through the Hall sensor;

[0016] The current signal acquisition unit is used to acquire the motor load current.

[0017] Furthermore, the PWM slope calculation module reads the PWM signal data collected twice in a row and stored in the buffer, performs differential processing on the duty cycle of each pair of adjacent sampling points to calculate a set of PWM signal slope values;

[0018] The sliding window technology is used to set the time window, and the calculated slope values ​​within the set time window are averaged to obtain a more stable slope signal. The length of the sliding window is determined by the response speed requirements of the system and is generally set to 20 to 50 sampling points.

[0019] A low-pass filter is used to remove high-frequency noise from the collected signal to make the slope signal smoother, which is beneficial for subsequent clamping detection; this process is repeated in each new sampling cycle to ensure that the system can continuously track changes in the PWM signal.

[0020] Furthermore, the information monitoring module includes a slope monitoring unit, a speed monitoring unit, a current monitoring unit and a threshold adjustment unit; the PWM slope monitoring module pre-sets a slope threshold T, the threshold value can be adjusted, and the PWM signal slope is monitored by comparing the PWM slope S calculated in real time with the slope threshold T;

[0021] The current monitoring module presets the current threshold I max , the threshold value can be adjusted, and the motor load current is monitored by comparing the motor load current I collected in real time with the current threshold;

[0022] The speed monitoring module pre-sets the speed threshold range [R min , R max ], the threshold value can be adjusted, and the motor speed is monitored to see if it is abnormal by comparing the real-time monitored motor speed r with the set speed threshold range;

[0023] The thresholds set by the system can be configured according to the needs of the specific application of the system to ensure the best anti-pinch protection effect under different load conditions.

[0024] Furthermore, the clamping state judgment module judges whether the push rod is in the clamping state at this moment by analyzing the detection results of the PWM slope S, the motor load current I and the motor speed r;

[0025] When any one of the three data items, PWM slope S, motor load current I and motor speed r, is in an abnormal state, the push rod is judged to be in a clamped state, and the anti-clamping protection measure is triggered after the push rod is judged to be in a clamped state;

[0026] The anti-pinch protection measures in the system include stopping the motor, driving the motor in reverse to release the clamped objects, and issuing an alarm signal to alert the user; stopping the motor means immediately stopping the motor drive signal to avoid further force applied by the push rod to prevent equipment damage or personal injury; driving the motor in reverse means that in some application scenarios, the system can drive the motor in reverse to make the push rod move in the opposite direction to release possible clamped objects; issuing an alarm signal means that the system can notify the user of the current clamping risk through sound and light alarms or other means, so that the user can take further measures in time;

[0027] The system selects the appropriate anti-pinch protection strategy based on the current application requirements; when the anti-pinch mechanism is triggered, the system can also set a delayed reset or automatic restart function according to actual needs to ensure the safety and continuity of the system.

[0028] A DC motor anti-pinch control method based on PWM slope includes the following steps:

[0029] S1, real-time acquisition and storage of the PWM signal of the DC motor, the load current of the motor and the speed of the motor during operation;

[0030] S2, performing differential processing on the collected PWM signal data to calculate the slope value of PWM;

[0031] S3, setting and storing the PWM signal slope threshold, the motor current threshold and the motor speed threshold range, and monitoring in real time whether the calculated PWM signal slope value, the collected motor load current and the motor speed exceed the set threshold;

[0032] S4. judging whether the push rod is in a clamping state according to the monitoring result, and triggering anti-clamping protection measures when the push rod is in the clamping state;

[0033] S5. After the anti-pinch protection measures are executed, the sampling and calculation process is resumed and the clamping status monitoring is continued.

[0034] Further, in step S2: after acquiring the continuous sampling data of the PWM signal, the acquired PWM signal is subjected to differential processing to calculate the slope value of the PWM. The slope calculation formula is as follows:

[0035]

[0036] Wherein, S is the slope of the PWM signal, t and t+Δt represent two adjacent time points respectively, Δt is a set fixed time interval, D(t) represents the duty cycle at time point t, and D(t+Δt) represents the duty cycle at time point t+Δt; the above formula represents the rate at which the duty cycle of the PWM signal changes over time through the changing slope of the PWM signal; the above formula describes the rate at which the duty cycle of the PWM signal changes over time, that is, the changing slope of the PWM signal.

[0037] Further, in step S3: the PWM slope S, the motor load current I and the motor speed R are analyzed:

[0038] a. Compare the calculated PWM slope value S with the slope threshold T;

[0039] b. Compare the collected motor load current I with the current threshold I max Make a comparison;

[0040] c. Compare the real-time collected motor speed r with the speed threshold [R min , R max ] for comparison;

[0041] According to the analysis results of the three data items of PWM slope S, motor load current I and motor speed r, it is judged whether the push rod is in the clamping state. If any of the data is abnormal, it is judged that the push rod is in the clamping state;

[0042] The comparison results of the PWM signal slope are divided into two cases:

[0043] When S>T, it is judged that there is a clamping risk, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered;

[0044] When S≤T, it is determined that there is no clamping risk at present, and the next set of PWM signals will continue to be monitored;

[0045] The comparison results of the motor load current in operation are divided into two cases:

[0046] When I≤I max When the motor load current is normal, there is no risk of clamping;

[0047] When I>I max When the motor load current is judged to be abnormal, there is a risk of clamping, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered;

[0048] The comparison results of the running motor speed are divided into two cases:

[0049] When R min ≤r≤R max When the motor is running at normal speed, it is judged that there is no risk of clamping;

[0050] When r<R min or r>R max When the motor running speed is abnormal, it is judged that there is a risk of clamping, and the speed adjustment measures and anti-clamping protection measures are triggered; the speed adjustment measures are to adjust the current speed by adjusting the PWM duty cycle output within 50ms through the PID algorithm;

[0051] The principle of the current anti-pinch algorithm is to synchronously sample the motor load current during motor operation, and set a current threshold slightly higher than the current threshold during motor operation in the program. When the motor encounters an obstacle during operation, the current will increase. When the current value is greater than or equal to the set current threshold, the system starts the anti-pinch function. However, the current anti-pinch algorithm has obvious disadvantages. For example, during the full stroke of the push rod, the resistance will change with the load gravity or the lever position. The motor must maintain the same movement speed, and the current will also change accordingly. As a result, the set current threshold must be greater than the maximum current that will appear during the entire push rod operation process, otherwise the anti-pinch function will be triggered during the push rod operation, which makes the anti-pinch trigger only under very large resistance and completely ineffective for small resistance.

[0052] The principle of the speed difference anti-pinch algorithm is that the program collects the motor running speed in real time through the Hall sensor integrated on the motor tail shaft. When the difference between the motor running speed and the program set speed exceeds the set range, the system starts the anti-pinch function; but the speed difference anti-pinch algorithm has obvious shortcomings. The speed error anti-pinch algorithm depends on the difference between the current motor expected speed and the motor actual speed to be too large before it is triggered; this will cause the algorithm to encounter resistance when it starts, and the system cannot determine whether it encounters resistance or the load itself is so large, and the speed difference anti-pinch algorithm will not be triggered;

[0053] The principle of PWM slope anti-pinch is that the program continuously adjusts the PWM duty cycle output through the PID algorithm to achieve control of the motor speed. When the motor encounters resistance or thrust causing the speed to be lower or higher than the set speed, the PID algorithm will adjust the PWM duty cycle output within 50ms to adjust the current speed. The response speed of PWM regulation is the fastest. When the PWM slope changes beyond the set slope threshold, the system starts the anti-pinch function.

[0054] The present invention determines whether the push rod is in a clamping state by collecting and monitoring three items of data, and combines the three algorithms of current anti-pinch algorithm, speed difference anti-pinch algorithm and PWM slope anti-pinch algorithm to form a combined anti-pinch algorithm, thereby ensuring that the system can have at least one algorithm that meets the usage conditions and can trigger anti-pinch protection in complex scenarios, thereby avoiding personal safety issues caused by failure of independent algorithms.

[0055] Furthermore, in step S4:

[0056] d. After the anti-pinch protection measure is triggered, the motor is first controlled to stop running;

[0057] e. Then reverse drive the motor to release the clamped object;

[0058] f. At the same time, an alarm signal is issued to remind users to pay attention to risks.

[0059] Further, in step S5:

[0060] g. After the anti-pinch protection measures are implemented, the system enters the recovery phase;

[0061] h. If the clamping risk has been eliminated, the system will resume the normal PWM signal monitoring and slope calculation process and continue to monitor the operation status of the actuator in real time;

[0062] i. If the clamping risk is not eliminated, the system will remain in the anti-pinch state until the user intervenes or the system recovers on its own; after each anti-pinch protection is executed, the system reinitializes the monitoring module and resumes the normal sampling and calculation process to ensure that the next clamping risk can be discovered and handled in time.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] The present invention can more accurately reflect the instantaneous change of motor load by analyzing the change slope of PWM signal, motor load current and motor speed, thereby improving detection accuracy; using existing PWM signal for monitoring and analysis simplifies hardware design and reduces system cost; adopting the real-time slope, current and speed monitoring method, can quickly detect load changes and timely trigger anti-pinch protection measures, thereby improving the response speed and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a structural schematic diagram of a DC motor anti-pinch control system based on PWM slope of the present invention;

[0066] Figure 2 A schematic diagram of the steps of a DC motor anti-pinch control method based on PWM slope of the present invention;

[0067] Figure 3 The invention provides a schematic diagram of the working process of a DC motor anti-pinch control method based on PWM slope. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the 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.

[0069] like Figure 1-Figure 3 As shown, the present invention provides a technical solution, a DC motor anti-pinch control system based on PWM slope, the system includes an information acquisition module, a PWM slope calculation module, a PWM slope monitoring module, a current monitoring module, a speed monitoring module and a clamping state judgment module;

[0070] The information acquisition module is used to collect the PWM signal, motor speed and motor load current of the DC motor;

[0071] The PWM slope calculation module calculates the slope value of the PWM signal by performing differential processing on the PWM signals at consecutive time points;

[0072] The PWM slope monitoring module is used to set a PWM slope threshold and monitor in real time whether the calculated PWM slope exceeds the set PWM slope threshold;

[0073] The current monitoring module is used to set a current threshold and monitor in real time whether the collected motor load current exceeds the set threshold;

[0074] The speed monitoring module is used to set the motor speed threshold range and monitor in real time whether the motor speed is within the set range;

[0075] The clamping state judgment module judges whether the push rod is in a clamping state by comprehensively comparing the monitoring results of the PWM signal slope, the motor load current and the motor speed, and triggers corresponding anti-clamping protection measures after judging that it is in a clamping state.

[0076] The information acquisition module includes a PWM signal acquisition unit, a speed signal acquisition unit and a current signal acquisition unit;

[0077] PWM, or pulse width modulation, is a very effective technology that uses the digital output of a microprocessor to control analog circuits. It is widely used in many fields from measurement, communication to power control and conversion. The PWM signal acquisition unit acquires PWM signals in real time through a CCP interface, and converts the acquired PWM analog signals into digital signals through the CCP interface, or directly reads the duty cycle of the PWM signal through a microcontroller. The acquired signal data is stored in a data buffer of the system for subsequent processing. The acquired signal data includes the duty cycle of the PWM signal and the time point corresponding to the duty cycle. The duty cycle of the PWM signal is the ratio of the high-level signal pulse width to the entire pulse cycle within a pulse cycle of the acquired PWM pulse signal.

[0078] The speed signal acquisition unit acquires the motor running speed in real time through the Hall sensor;

[0079] The current signal acquisition unit is used to acquire the motor load current.

[0080] The PWM slope calculation module reads the PWM signal data collected twice in a row and stores it in the buffer, performs differential processing on the duty cycle of each pair of PWM signals collected at adjacent sampling points, and calculates a set of PWM signal slope values;

[0081] The sliding window technology is used to set the time window, and the calculated slope values ​​within the set time window are averaged to obtain a more stable slope signal. The length of the sliding window is determined by the response speed requirements of the system and is generally set to 20 to 50 sampling points.

[0082] A low-pass filter is used to remove high-frequency noise from the collected signal to make the slope signal smoother, which is beneficial for subsequent clamping detection; this process is repeated in each new sampling cycle to ensure that the system can continuously track changes in the PWM signal.

[0083] The information monitoring module includes a slope monitoring unit, a speed monitoring unit, a current monitoring unit and a threshold adjustment unit; the PWM slope monitoring module pre-sets a slope threshold T, the threshold value can be adjusted, and monitors the PWM signal slope by comparing the PWM slope S calculated in real time with the slope threshold T;

[0084] The current monitoring module presets the current threshold I max , the threshold value can be adjusted, and the motor load current is monitored by comparing the motor load current I collected in real time with the current threshold;

[0085] The speed monitoring module pre-sets the speed threshold range [R min , R max ], the threshold value can be adjusted, and the motor speed is monitored to see if it is abnormal by comparing the real-time monitored motor speed r with the set speed threshold range;

[0086] The thresholds set by the system can be configured according to the needs of the specific application of the system to ensure the best anti-pinch protection effect under different load conditions.

[0087] The clamping state judgment module judges whether the push rod is in the clamping state at this moment by analyzing the detection results of the PWM slope S, the motor load current I and the motor speed r;

[0088] When any one of the three data items, PWM slope S, motor load current I and motor speed r, is in an abnormal state, the push rod is judged to be in a clamped state, and the anti-clamping protection measure is triggered after the push rod is judged to be in a clamped state;

[0089] The anti-pinch protection measures in the system include stopping the motor, driving the motor in reverse to release the clamped objects, and issuing an alarm signal to alert the user; stopping the motor means immediately stopping the motor drive signal to avoid further force applied by the push rod to prevent equipment damage or personal injury; driving the motor in reverse means that in some application scenarios, the system can drive the motor in reverse to make the push rod move in the opposite direction to release possible clamped objects; issuing an alarm signal means that the system can notify the user of the current clamping risk through sound and light alarms or other means, so that the user can take further measures in time;

[0090] The system selects the appropriate anti-pinch protection strategy based on the current application requirements; when the anti-pinch mechanism is triggered, the system can also set a delayed reset or automatic restart function according to actual needs to ensure the safety and continuity of the system.

[0091] A DC motor anti-pinch control method based on PWM slope includes the following steps:

[0092] S1, real-time acquisition and storage of the PWM signal of the DC motor, the load current of the motor and the speed of the motor during operation;

[0093] S2, performing differential processing on the collected PWM signal data to calculate the slope value of PWM;

[0094] S3, setting and storing the PWM signal slope threshold, the motor current threshold and the motor speed threshold range, and monitoring in real time whether the calculated PWM signal slope value, the collected motor load current and the motor speed exceed the set threshold;

[0095] S4. judging whether the push rod is in a clamping state according to the monitoring result, and triggering anti-clamping protection measures when the push rod is in the clamping state;

[0096] S5. After the anti-pinch protection measures are executed, the sampling and calculation process is resumed and the clamping status monitoring is continued.

[0097] In step S2: after acquiring the continuous sampling data of the PWM signal, the acquired PWM signal is differentially processed to calculate the slope value of the PWM. The slope calculation formula is as follows:

[0098]

[0099] Wherein, S is the slope of the PWM signal, t and t+Δt represent two adjacent time points respectively, Δt is a set fixed time interval, D(t) represents the duty cycle at time point t, and D(t+Δt) represents the duty cycle at time point t+Δt; the above formula represents the rate at which the duty cycle of the PWM signal changes over time through the changing slope of the PWM signal; the above formula describes the rate at which the duty cycle of the PWM signal changes over time, that is, the changing slope of the PWM signal.

[0100] In step S3: Analyze the PWM slope S, motor load current I and motor speed R:

[0101] a. Compare the calculated PWM slope value S with the slope threshold T;

[0102] b. Compare the collected motor load current I with the current threshold I max Make a comparison;

[0103] c. Compare the real-time collected motor speed r with the speed threshold [R min , R max ] for comparison;

[0104] According to the analysis results of the three data items of PWM slope S, motor load current I and motor speed r, it is judged whether the push rod is in the clamping state. If any of the data is abnormal, it is judged that the push rod is in the clamping state;

[0105] The comparison results of the PWM signal slope are divided into two cases:

[0106] When S>T, it is judged that there is a clamping risk, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered;

[0107] When S≤T, it is determined that there is no clamping risk at present, and the next set of PWM signals will continue to be monitored;

[0108] The comparison results of the motor load current in operation are divided into two cases:

[0109] When I≤I max When the motor load current is normal, there is no risk of clamping;

[0110] When I>I max When the motor load current is judged to be abnormal, there is a risk of clamping, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered;

[0111] The comparison results of the running motor speed are divided into two cases:

[0112] When R min ≤r≤R max When the motor is running at normal speed, it is judged that there is no risk of clamping;

[0113] When r<R min or r>R max When the motor running speed is abnormal, it is judged that there is a risk of clamping, and the speed adjustment measures and anti-clamping protection measures are triggered; the speed adjustment measures are to adjust the current speed by adjusting the PWM duty cycle output within 50ms through the PID algorithm;

[0114] The principle of the current anti-pinch algorithm is to synchronously sample the motor load current during motor operation, and set a current threshold slightly higher than the current threshold during motor operation in the program. When the motor encounters an obstacle during operation, the current will increase. When the current value is greater than or equal to the set current threshold, the system starts the anti-pinch function. However, the current anti-pinch algorithm has obvious disadvantages. For example, during the full stroke of the push rod, the resistance will change with the load gravity or the lever position. The motor must maintain the same movement speed, and the current will also change accordingly. As a result, the set current threshold must be greater than the maximum current that will appear during the entire push rod operation process, otherwise the anti-pinch function will be triggered during the push rod operation, which makes the anti-pinch trigger only under very large resistance and completely ineffective for small resistance.

[0115] The principle of the speed difference anti-pinch algorithm is that the program collects the motor running speed in real time through the Hall sensor integrated on the motor tail shaft. When the difference between the motor running speed and the program set speed exceeds the set range, the system starts the anti-pinch function; but the speed difference anti-pinch algorithm has obvious shortcomings. The speed error anti-pinch algorithm depends on the difference between the current motor expected speed and the motor actual speed to be too large before it is triggered; this will cause the algorithm to encounter resistance when it starts, and the system cannot determine whether it encounters resistance or the load itself is so large, and the speed difference anti-pinch algorithm will not be triggered;

[0116] The principle of PWM slope anti-pinch is that the program continuously adjusts the PWM duty cycle output through the PID algorithm to achieve control of the motor speed. When the motor encounters resistance or thrust causing the speed to be lower or higher than the set speed, the PID algorithm will adjust the PWM duty cycle output within 50ms to adjust the current speed. The response speed of PWM regulation is the fastest. When the PWM slope changes beyond the set slope threshold, the system starts the anti-pinch function.

[0117] The present invention determines whether the push rod is in a clamping state by collecting and monitoring three items of data, and combines the three algorithms of current anti-pinch algorithm, speed difference anti-pinch algorithm and PWM slope anti-pinch algorithm to form a combined anti-pinch algorithm, thereby ensuring that the system can have at least one algorithm that meets the usage conditions and can trigger anti-pinch protection in complex scenarios, thereby avoiding personal safety issues caused by failure of independent algorithms.

[0118] In step S4:

[0119] d. After the anti-pinch protection measure is triggered, the motor is first controlled to stop running;

[0120] e. Then reverse drive the motor to release the clamped object;

[0121] f. At the same time, an alarm signal is issued to remind users to pay attention to risks.

[0122] In step S5:

[0123] g. After the anti-pinch protection measures are implemented, the system enters the recovery phase;

[0124] h. If the clamping risk has been eliminated, the system will resume the normal PWM signal monitoring and slope calculation process and continue to monitor the operation status of the actuator in real time;

[0125] i. If the clamping risk is not eliminated, the system will remain in the anti-pinch state until the user intervenes or the system recovers on its own; after each anti-pinch protection is executed, the system reinitializes the monitoring module and resumes the normal sampling and calculation process to ensure that the next clamping risk can be discovered and handled in time.

[0126] Embodiment 1:

[0127] In this embodiment, the PWM signal acquisition module includes a high-precision ADC (analog-to-digital converter), whose main function is to convert the PWM signal from analog form to digital form to facilitate subsequent signal processing; the frequency of the collected PWM signal is generally set between 1kHz and 10kHz, and the specific frequency selection is based on the dynamic response requirements of the system and the operating characteristics of the motor;

[0128] The specific connection of the signal acquisition module is as follows: after the PWM signal is output from the motor control module, it enters the ADC through the voltage conditioning circuit; the function of the voltage conditioning circuit is to adjust the voltage range of the PWM signal to the acceptable range of the ADC, and at the same time filter the signal appropriately to eliminate high-frequency noise and transient interference; the collected PWM signal then enters the digital input port of the microprocessor; in order to improve the sampling accuracy and data reliability, the system adopts multi-channel parallel sampling technology, that is, PWM signals are collected simultaneously through multiple ADC channels, and the results are averaged to reduce the impact of single channel sampling errors.

[0129] The anti-pinch protection system of the present invention can be integrated into a variety of electric actuator systems that require anti-pinch functions; the following is a detailed description of two typical application scenarios:

[0130] Power window anti-pinch protection system: In the power window system, the motor drives the glass up and down through the push rod. If the window encounters resistance (such as fingers, foreign objects, etc.) during closing, the system will detect the abnormal change of the PWM signal slope and quickly start the anti-pinch protection, reversing the motor to move the window down to avoid pinching passengers or damaging objects.

[0131] Anti-pinch system for electric seat adjusters: Anti-pinch protection is particularly important in electric seat adjusters for cars. When an incompressible object (such as a passenger's body part) is encountered during seat adjustment, the system will detect a drastic change in the slope of the PWM signal, triggering the anti-pinch protection mechanism to immediately stop or reverse the movement of the seat to ensure the safety of the passengers.

[0132] In actual applications, the system integration process includes the construction of hardware circuits and the embedding of software algorithms; the system hardware mainly includes PWM signal acquisition module, microprocessor module, motor drive module and control signal sending module; the software mainly implements signal processing, slope calculation, threshold judgment, clamping detection and protection start-up functions; the system can adapt to a variety of different application requirements by configuring different slope monitoring thresholds, sliding window lengths and filtering parameters. For high-precision application scenarios, the system can increase the sensitivity by increasing the sampling frequency and shortening the sliding window length; and for scenarios with high anti-interference requirements, the system can enhance stability by increasing the order of the filter.

[0133] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A DC motor anti-pinch control system based on PWM slope, characterized in that: The system includes an information acquisition module, a PWM slope calculation module, a PWM slope monitoring module, a current monitoring module, a speed monitoring module and a clamping state judgment module; The information acquisition module is used to collect the PWM signal, motor speed and motor load current of the DC motor; The PWM slope calculation module calculates the slope value of the PWM signal by performing differential processing on the PWM signals at consecutive time points; The PWM slope monitoring module is used to set a PWM slope threshold and monitor in real time whether the calculated PWM slope exceeds the set PWM slope threshold; The current monitoring module is used to set a current threshold and monitor in real time whether the collected motor load current exceeds the set threshold; The speed monitoring module is used to set the motor speed threshold range and monitor in real time whether the motor speed is within the set range; The clamping state judgment module judges whether the push rod is in a clamping state by comprehensively comparing the monitoring results of the PWM signal slope, the motor load current and the motor speed, and triggers corresponding anti-clamping protection measures after judging that it is in a clamping state.

2. A DC motor anti-pinch control system based on PWM slope according to claim 1, characterized in that: The information acquisition module includes a PWM signal acquisition unit, a speed signal acquisition unit and a current signal acquisition unit; The PWM signal acquisition unit acquires PWM signals in real time through the CCP interface, converts the acquired PWM analog signals into digital signals through the CCP interface, and stores the acquired signal data in the data buffer of the system, wherein the acquired signal data includes the duty cycle of the PWM signal and the time point corresponding to the duty cycle; The speed signal acquisition unit acquires the motor running speed in real time through the Hall sensor; The current signal acquisition unit is used to acquire the motor load current.

3. The DC motor anti-pinch control system based on PWM slope according to claim 1, characterized in that: The PWM slope calculation module reads the PWM signal data collected twice in a row and stores it in the buffer, performs differential processing on the duty cycle of each pair of PWM signals collected at adjacent sampling points, and calculates a set of PWM signal slope values; The sliding window technique is used to set the time window, and the calculated slope values ​​within the set time window are averaged; And use a low-pass filter to remove high-frequency noise in the collected signal.

4. The DC motor anti-pinch control system based on PWM slope according to claim 1, characterized in that: The PWM slope monitoring module pre-sets a slope threshold T, the threshold value can be adjusted, and monitors the PWM signal slope by comparing the PWM slope S calculated in real time with the slope threshold T; The current monitoring module presets the current threshold I max , the threshold value can be adjusted, and the motor load current is monitored by comparing the real-time collected motor load current I with the current threshold; The speed monitoring module pre-sets the speed threshold range [R min , R max ], the threshold value can be adjusted, and the motor speed is monitored to see if it is abnormal by comparing the real-time monitored motor speed r with the set speed threshold range.

5. The DC motor anti-pinch control system based on PWM slope according to claim 1, characterized in that: The clamping state judgment module judges whether the push rod is in the clamping state at this moment by analyzing the detection results of the PWM slope S, the motor load current I and the motor speed r; When any one of the three data items, PWM slope S, motor load current I and motor speed r, is in an abnormal state, the push rod is judged to be in a clamped state, and the anti-clamping protection measure is triggered after the push rod is judged to be in a clamped state; The anti-pinch protection measures in the system include stopping the motor, driving the motor in reverse to release the clamped objects, and sending an alarm signal to alert the user.

6. A DC motor anti-pinch control method based on PWM slope, characterized in that: The following steps are involved: S1, real-time acquisition and storage of the PWM signal of the DC motor, the load current of the motor and the speed of the motor during operation; S2, performing differential processing on the collected PWM signal data to calculate the slope value of PWM; S3, setting and storing the PWM signal slope threshold, the motor current threshold and the motor speed threshold range, and monitoring in real time whether the calculated PWM signal slope value, the collected motor load current and the motor speed exceed the set threshold; S4. judging whether the push rod is in a clamping state according to the monitoring result, and triggering anti-clamping protection measures when the push rod is in the clamping state; S5. After the anti-pinch protection measures are executed, the sampling and calculation process is resumed and the clamping status monitoring is continued.

7. A DC motor anti-pinch control method based on PWM slope according to claim 6, characterized in that: In step S2: after acquiring the continuous sampling data of the PWM signal, the acquired PWM signal is differentially processed to calculate the slope value of the PWM. The slope calculation formula is as follows: Wherein, S is the slope of the PWM signal, t and t+Δt represent two adjacent time points respectively, Δt is a set fixed time interval, D(t) represents the duty cycle at time point t, and D(t+Δt) represents the duty cycle at time point t+Δt. The above formula represents the rate at which the duty cycle of the PWM signal changes with time through the changing slope of the PWM signal.

8. The DC motor anti-pinch control method based on PWM slope according to claim 6, characterized in that: In step S3: Analyze the PWM slope S, motor load current I and motor speed R: a. Compare the calculated PWM slope value S with the slope threshold T; b. Compare the collected motor load current I with the current threshold I max Make a comparison; c. Compare the real-time collected motor speed r with the speed threshold [R min , R max ] for comparison; According to the analysis results of the three data items of PWM slope S, motor load current I and motor speed r, it is judged whether the push rod is in the clamping state. If any of the data is abnormal, it is judged that the push rod is in the clamping state; The comparison results of the PWM signal slope are divided into two cases: When S>T, it is judged that there is a clamping risk, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered; When S≤T, it is determined that there is no clamping risk at present, and the next set of PWM signals will continue to be monitored; The comparison results of the motor load current in operation are divided into two cases: When I≤I max When the motor load current is normal, there is no risk of clamping; When I>I max When the motor load current is judged to be abnormal, there is a risk of clamping, the anti-pinch protection stage is entered, and the anti-pinch protection measures are triggered; The comparison results of the running motor speed are divided into two cases: When R min ≤r≤R max When the motor is running at normal speed, it is judged that there is no risk of clamping; When r<R min or r>R max When the motor running speed is judged to be abnormal and there is a risk of clamping, the speed adjustment measures and anti-pinch protection measures are triggered; the speed adjustment measures are to adjust the current speed by adjusting the PWM duty cycle output within 50ms through the PID algorithm.

9. The DC motor anti-pinch control method based on PWM slope according to claim 6, characterized in that: In step S4: d. After the anti-pinch protection measure is triggered, the motor is first controlled to stop running; e. Then reverse drive the motor to release the clamped object; f. At the same time, an alarm signal is issued to remind users to pay attention to risks.

10. The DC motor anti-pinch control method based on PWM slope according to claim 6, characterized in that: In step S5: g. After the anti-pinch protection measures are implemented, the system enters the recovery phase; h. If the clamping risk has been eliminated, the system will resume the normal PWM signal monitoring and slope calculation process and continue to monitor the operation status of the actuator in real time; i. If the risk of pinching is not eliminated, the system will remain in the anti-pinch state until the user intervenes or the system recovers on its own.

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