Intelligent bed brushless motor partition drive and anti-pinch linkage system
Patent Information
- Application Number
- CN202611137400.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-29
- Publication Date
- 2026-09-15
Smart Images
Figure CN122764074A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of intelligent furniture drive control technology, specifically to a smart bed brushless motor zone drive and anti-pinch linkage system. Background Technology
[0002] Modern smart beds often use multi-segment push rods (backrest, legrests, lumbar support, etc.) to achieve zoned posture adjustment. Existing solutions mostly use brushed motors in conjunction with a main controller for centralized drive, with multiple push rods communicating and coordinating via bus. This results in poor adjustment flexibility and insufficient synchronization. In addition, existing anti-pinch functions are mostly based on single current threshold detection. When the push rod encounters a soft obstacle (such as clothing or soft human tissue), the current change is not obvious, and it is easy to miss the trigger. When encountering a rigid small obstacle, the current changes suddenly, which can easily trigger the wrong thing. Furthermore, the inherent defects of brushed motors (noise, lifespan, impact) and the mechanical failure risk of limit switches further affect product performance.
[0003] According to existing technical data, the intelligent bed multi-push rod adjustment system adopts centralized drive of brushed motors, and controls multiple brushed motors to operate in coordination through the main controller. The anti-pinch function is based on fixed current threshold detection and relies on limit switches. The multi-push rod adjustment system has problems such as poor flexibility of zone adjustment, low reliability of anti-pinch, insufficient synchronization, high noise, short life and complex structure.
[0004] Therefore, a smart bed brushless motor zone drive and anti-pinch linkage system is needed to solve the problems mentioned above. Summary of the Invention
[0005] The purpose of this invention is to provide a smart bed brushless motor zoned drive and anti-pinch linkage system to solve the problems mentioned in the background art.
[0006] The smart bed brushless motor zoned drive and anti-pinch linkage system includes a user interaction unit, a central control unit, and multiple sets of push rod actuators arranged in different zones of the bed. Each set of push rod actuators is connected to a zoned brushless motor assembly, and each zoned brushless motor assembly is set in the back, leg, and lumbar areas of the smart bed respectively.
[0007] Each partitioned brushless motor assembly integrates an independent drive board, which has a built-in FOC drive circuit and three Hall sensors. The central control unit communicates with the independent drive boards of each partitioned brushless motor assembly via a LIN bus. Each partitioned brushless motor assembly also integrates an anti-pinch detection module.
[0008] Furthermore, the anti-pinch detection module is simultaneously connected to the motor power supply circuit and the signal output terminal of the Hall sensor. The system eliminates the mechanical limit switch, using the accumulated position count of the Hall sensor as the basis for determining the electronic limit, and the motor stall current detection serves as the limit redundancy protection.
[0009] The central control unit integrates a multi-push rod drive control module, which includes: an instruction parsing unit for distinguishing between independent adjustment instructions and coordinated adjustment instructions; a synchronous speed planning unit for generating initial speed instructions proportionally based on the remaining stroke of each push rod during coordinated adjustment; and a position synchronization correction unit for receiving position feedback during operation and calculating the remaining stroke based on the ideal synchronous trajectory.
[0010] The multi-push rod drive control module of the central control unit can output independent adjustment commands to a single partition brushless motor assembly or synchronously output coordinated adjustment commands to multiple partition brushless motor assemblies. Each partition brushless motor assembly can operate independently or synchronously in conjunction with the corresponding command.
[0011] Furthermore, the independent drive board has a built-in three-phase full-bridge FOC drive circuit composed of 6 MOS transistors. The PWM carrier frequency of the FOC drive circuit is set to 16kHz. Three Hall sensors are arranged at 120° electrical angle intervals along the circumference of the motor rotor. The signal output terminal of the Hall sensor is connected to the position calculation unit of the independent drive board. The rotor position signal output by the position calculation unit is connected to the control input terminal of the FOC drive circuit.
[0012] The anti-pinch detection module has a built-in dynamic current threshold calculation unit. The dynamic current threshold is updated synchronously with the real-time load of the motor, and the calculation formula is:
[0013] ,in This is the reference current of the motor load obtained by moving average filtering within the current sampling period. The anti-pinch margin coefficient is set to a value between 0.2 and 0.4. The reference current increases synchronously with the increase of the push rod load, and the corresponding dynamic threshold is adjusted upward synchronously. When the load decreases, the threshold is adjusted downward synchronously.
[0014] Furthermore, the anti-pinch detection module has a built-in speed and position change rate calculation unit, and the formula for calculating the real-time running speed of the push rod is:
[0015] In the formula Unit sampling duration The pulse increment output by the NeHall sensor This represents the total number of Hall pulses per revolution of the motor. The system detects the stroke of the push rod driven by the motor after each revolution of the motor through the reduction transmission. The system performs detection during the steady-state operation of the motor. When the ratio of the decrease in motor speed within 1 second to the steady-state speed is greater than or equal to 0.3, or when the change rate of push rod position is lower than the preset minimum value and the duration reaches the set threshold, the anti-pinch detection module outputs a trigger signal.
[0016] Furthermore, the central control unit has a built-in synchronization correction calculation unit. In the cooperative operation mode, one of the partitions is set as the reference partition, and the synchronization correction calculation unit calculates the positional deviation between the remaining driven partitions and the reference partition in real time.
[0017] ,in The real-time position value of the reference zone push rod. Given the real-time position value of the i-th driven zone push rod, the central control unit outputs a speed correction command based on the position deviation, and the real-time running speed of the corresponding driven zone is adjusted as follows:
[0018] In the formula The baseline speed for coordinated operation, This is the proportional adjustment coefficient. The total journey is for the goal of coordinated operation.
[0019] Furthermore, the system has a limit learning mode, in which the judgment condition when the push rod reaches the mechanical limit position is satisfied:
[0020] ,in This is the real-time operating current of the motor. To preset the stall current threshold, To set the change in the position of the push rod within a set time period, As the minimum position change threshold, when both conditions are met simultaneously and the duration reaches the set value, the system calibrates the current Hall pulse cumulative value as the limit position parameter in the corresponding direction and stores it. In normal operation mode, the push rod uses the stored limit position parameter as the electronic limit trigger point.
[0021] Furthermore, the LIN bus uses the central control unit as the master node, and each partition brushless motor component is configured with an independent slave node address. The instruction frame output by the central control unit includes a node address segment, an instruction type segment, a target position segment, and a speed parameter segment. Each partition brushless motor component matches the corresponding instruction through the node address segment. The status frame returned by the independent drive board to the central control unit includes real-time position, operating current, and fault status information.
[0022] Furthermore, the output end of the partitioned brushless motor assembly is connected to a reduction gear set, and the output end of the reduction gear set is connected to the lead screw pair of the push rod actuator. A Hall sensor is installed at the rotor end of the brushless motor, and the accumulated Hall pulse value corresponding to the total stroke of the push rod satisfies the following:
[0023] In the formula This represents the total number of Hall pulses between the upper and lower limit positions. This represents the stroke of the push rod after each revolution of the motor through the reduction gear transmission. This represents the number of Hall pulses per revolution of the motor.
[0024] Furthermore, the independent drive board has a built-in retraction control register, which stores the number of reverse pulses corresponding to the preset retraction distance. After the anti-pinch detection module outputs a trigger signal, the independent drive board immediately cuts off the forward drive output and outputs the corresponding number of reverse drive pulses, causing the push rod to retract in the opposite direction. In the independent adjustment mode, only the anti-pinch partition is triggered to perform the retraction action. In the coordinated adjustment mode, while the anti-pinch partition is triggered to perform the retraction action, the central control unit suspends all partition brushless motor components in the coordinated operation state and pushes alarm information to the user interaction unit.
[0025] Furthermore, the user interaction unit is a fixed control panel or a mobile terminal with a control application installed, used to set the independent target angle and independent running speed of each push rod, and to define and store multiple push rod target angle parameter groups corresponding to the cooperative mode;
[0026] The user interaction unit has a built-in attitude storage unit. The attitude storage unit has multiple sets of target position parameters for each partition corresponding to fixed attitude modes. The user interaction unit supports custom target position and running speed parameters for a single partition, and supports custom attitude parameters for multiple partition combinations and storing them in the attitude storage unit. When called, the corresponding parameter combination is directly sent to the central control unit.
[0027] By adopting the above technical solutions, multi-dimensional anti-pinch detection of three parameters—current, rotation speed, and position change rate—is achieved. The dynamic current threshold can be adjusted synchronously with the real-time load to adapt to scenarios with fluctuating bed load under different postures, reducing false triggers caused by load changes. Rotation speed and position change rate detection can capture the phenomenon of rotation speed drop and position stagnation caused by soft obstacles, making up for the deficiency of single current detection in the sensitivity of soft obstacle identification, reducing the probability of missed anti-pinch triggers. After anti-pinch triggering, the push rod automatically reverses and retreats. In the collaborative operation mode, all linkage zones are synchronously paused, which can fully ensure the safety of the use process.
[0028] Compared with the prior art, the beneficial effects of the present invention are: the intelligent bed's brushless motor zoned drive and anti-pinch linkage system...
[0029] Each section of the bed is equipped with an independent brushless motor and drive board, replacing the traditional centralized brushed motor drive architecture. Each section can independently set the target position and running speed, and the adjustment process does not interfere with each other. It can adapt to the personalized posture needs of different users. The brushless motor, together with the FOC drive circuit, realizes soft start and stop operation. There is no carbon brush wear or commutation sparks during operation, the whole machine has lower noise, longer service life, and can eliminate the maintenance costs caused by the inherent defects of brushed motors.
[0030] The multi-zone coordinated adjustment adopts a master-slave position synchronization correction logic. Based on the real-time position feedback of the Hall sensor, the running speed is dynamically adjusted according to the position deviation between the slave zone and the reference zone. This can effectively reduce the positioning deviation of multiple push rods and improve the coordination and synchronization of multi-zone actions. The LIN bus master-slave communication architecture provides stable transmission and can simultaneously carry independent adjustment commands and coordinated synchronization commands, taking into account both the flexibility of the zones and the consistency of coordination.
[0031] The mechanical limit switch has been eliminated, and Hall pulse cumulative counting is used as the main basis for electronic limit determination. Combined with stall current detection as redundant protection, the number of vulnerable mechanical parts has been reduced, the overall installation structure has been simplified, the risk of mechanical failure has been reduced, and the limit parameters can be calibrated through self-learning mode. It can adapt to position deviations caused by different installation tolerances and mechanical wear, resulting in more stable limit accuracy and lower maintenance costs in the later stage. Attached Figure Description
[0032] Figure 1 This is a block diagram of the overall system architecture of the present invention;
[0033] Figure 2 This is a flowchart illustrating the independent adjustment process for each partition in this invention.
[0034] Figure 3 This is a hardware block diagram of the partitioned brushless motor assembly of the present invention;
[0035] Figure 4 This is a flowchart of the multi-zone coordinated adjustment and synchronous correction process of the present invention;
[0036] Figure 5 This is a flowchart of the multi-dimensional anti-pinch detection logic of the present invention;
[0037] Figure 6 This is a flowchart of the electronic limit learning and operation process of the present invention. Detailed Implementation
[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Please see Figure 1-6 This invention provides a technical solution: a smart bed brushless motor zoned drive and anti-pinch linkage system. This system is applied to a smart bed with multi-zone adjustable posture. The bed body is divided into three independently movable zones: the backrest, the legs, and the waist. Each zone is equipped with a set of push rod actuators. The power input end of each set of push rod actuators is connected to a zoned brushless motor assembly.
[0040] Each partitioned brushless motor assembly integrates an independent drive board, which is equipped with a three-phase full-bridge FOC drive circuit and three Hall sensors. The drive circuit is built with six MOSFETs, and the PWM carrier frequency is set to 16kHz. The three Hall sensors are arranged at 120° electrical angle intervals along the circumference of the motor rotor. The signal output is connected to the position calculation unit of the independent drive board. The calculated rotor position signal is connected to the control input of the FOC drive circuit to support field-oriented control operation. The output of the partitioned brushless motor assembly is connected to the reduction gear set, and the output of the reduction gear set is connected to the lead screw pair of the push rod actuator. The Hall sensors are installed at the rotor end of the brushless motor to directly collect the rotation signal of the motor rotor.
[0041] The central control unit is installed inside the bed frame and communicates with the independent drive boards of each section's brushless motor assembly via a LIN bus. The LIN bus uses the central control unit as the master node, and each section's brushless motor assembly is configured with an independent slave node address. The slave node addresses for the backrest, legs, and waist are set to 0x01, 0x02, and 0x03, respectively. The command frame output by the central control unit includes a node address segment, a command type segment, a target position segment, and a speed parameter segment. Each section's brushless motor assembly matches the corresponding command through the node address segment and only receives command data that matches its own address. The status frame returned by the independent drive board to the central control unit includes real-time position, operating current, and fault status information. The central control unit can obtain the operating status of all sections in real time.
[0042] The central control unit integrates a multi-push rod drive control module, which includes an instruction parsing unit, a synchronous speed planning unit, and a position synchronization correction unit. The instruction parsing unit receives instructions from the user interaction unit and distinguishes whether the instructions are for independent or coordinated adjustment. In coordinated adjustment mode, the synchronous speed planning unit calculates the remaining stroke based on the current position and target position of each push rod, and generates the initial speed instructions for each push rod according to the proportion of the remaining stroke, so that the multiple push rods have the basic conditions for synchronous positioning. During operation, the position synchronization correction unit continuously receives the position feedback signals of each push rod and calculates the remaining stroke deviation in real time based on the ideal synchronous trajectory.
[0043] The central control unit can output independent adjustment commands to a single zone brushless motor assembly, or synchronously output coordinated adjustment commands to multiple zone brushless motor assemblies. Each zone brushless motor assembly operates independently or synchronously according to the corresponding command. Each zone brushless motor assembly integrates an anti-pinch detection module. The sampling input terminal is simultaneously connected to the motor power supply circuit and the signal output terminal of the Hall sensor. The module has a built-in dynamic current threshold calculation unit. The dynamic current threshold is updated synchronously with the real-time load of the motor. The calculation formula is:
[0044] ,in This is the reference current of the motor load obtained by moving average filtering within the current sampling period. The anti-pinch margin coefficient is set to a value of 0.2-0.4. The reference current increases synchronously with the increase of the push rod load, and the corresponding dynamic threshold is adjusted upward synchronously. When the load decreases, the threshold is adjusted downward synchronously, which can adapt to the reference current fluctuation caused by the change of bed load under different postures.
[0045] The anti-pinch detection module has a built-in unit for calculating the rotational speed and position change rate. The formula for calculating the real-time running speed of the push rod is:
[0046] In the formula Unit sampling duration The pulse increment output by the NeHall sensor This represents the total number of Hall pulses per revolution of the motor. This refers to the stroke of the push rod driven by the motor after each revolution of the reduction gear. The system only performs anti-pinch detection during the steady-state operation of the motor to avoid current surges and speed fluctuations during startup. When the ratio of the decrease in motor speed within 1 second to the steady-state speed is greater than or equal to 0.3, or when the rate of change of push rod position is lower than the preset minimum value and the duration reaches a set threshold, the anti-pinch detection module outputs a trigger signal. The independent drive board has a built-in retraction control register, which stores the number of reverse pulses corresponding to the preset retraction distance. After the anti-pinch detection module outputs the trigger signal, the independent drive board immediately cuts off the forward drive output and outputs the corresponding number of reverse drive pulses. A pulse triggers the push rod to reverse and retract. In independent adjustment mode, only the anti-pinch zone is triggered to retract, while the other zones remain in their original state. In coordinated adjustment mode, while the anti-pinch zone is triggered to retract, the central control unit suspends all brushless motor components in coordinated operation and pushes alarm information to the user interaction unit. The system does not have mechanical limit switches; the position count accumulated by the Hall sensor is used as the main basis for electronic limit determination. Motor stall current detection serves as limit redundancy protection. The system has a limit learning mode. In the learning mode, the determination condition when the push rod reaches the mechanical limit position is met:
[0047] ,in This is the real-time operating current of the motor. To preset the stall current threshold, To set the change in the position of the push rod within a set time period, To minimize position change threshold, when both conditions are met simultaneously and the duration reaches a set value, the system calibrates the current accumulated Hall pulse value as the limit position parameter in the corresponding direction and stores it in the non-volatile storage unit. In normal operation mode, the push rod uses the stored limit position parameter as the electronic limit trigger point, and automatically stops output when the limit position is reached. The accumulated Hall pulse value corresponding to the total stroke of the push rod satisfies the following:
[0048] In the formula This represents the total number of Hall pulses between the upper and lower limit positions. This represents the stroke of the push rod after each revolution of the motor through the reduction gear transmission. To determine the number of Hall pulses per motor revolution, in cooperative operation mode, the synchronous correction calculation unit built into the central control unit enters the working state, setting one partition as the reference partition and the remaining partitions as driven partitions. The synchronous correction calculation unit calculates the positional deviation between the remaining driven partitions and the reference partition in real time.
[0049] ,in The real-time position value of the reference zone push rod. Given the real-time position value of the i-th driven zone push rod, the central control unit outputs a speed correction command based on the position deviation, and the real-time running speed of the corresponding driven zone is adjusted as follows:
[0050] In the formula The baseline speed for coordinated operation, This is the proportional adjustment coefficient. To achieve the target total travel for coordinated operation, when the position of the driven partition lags behind the reference partition, the position deviation is positive, and the running speed of the driven partition increases accordingly; when the position of the driven partition leads the reference partition, the position deviation is negative, and the running speed of the driven partition decreases accordingly. This achieves position synchronization of multiple push rods. The user interaction unit can be a fixed control panel or a mobile terminal with a control application installed. It is used to set the independent target angle and independent running speed of each push rod, as well as define and store multiple push rod target angle parameter groups corresponding to the coordinated mode. The user interaction unit has a built-in attitude storage unit, which has multiple sets of target position parameters for each partition corresponding to fixed attitude modes, including common modes such as lying down, leisure, reading, and zero gravity. The user interaction unit supports custom target position and running speed parameters for a single partition, and also supports custom attitude parameters for multiple partition combinations and storing them in the attitude storage unit. When calling the corresponding mode, the corresponding parameter combination is directly sent to the central control unit.
[0051] Example 1
[0052] In the scenario of adjusting a single zone individually, the user selects to adjust the headboard zone individually through the user interaction unit, sets the target angle corresponding to a push rod travel of 60mm, and the running speed of 5mm / s. The command parsing unit of the central control unit recognizes it as an independent adjustment command and sends the target position and speed parameters to the brushless motor assembly of the headboard zone at address 0x01. The leg and waist zones do not receive commands and remain stationary.
[0053] In this scenario, the total number of Hall pulses per revolution of the brushless motor in the headboard section is... The value is 6, and the corresponding push rod stroke per revolution of the motor after reduction transmission is 6. The sampling period is 0.1 mm. The reference current after moving average filtering is set to 10ms during the motor's no-load steady-state operation. The anti-pinch allowance is 0.7A. Taking 0.3, the dynamic current threshold can be calculated using the above formula. =0.7×1.3=0.91A, during the operation of the push rod, the real-time speed is calculated using the corresponding formula, and the pulse increment collected every 10ms during steady-state operation. The value is 3. Substituting it in, we get... =3×0.1 / (6×0.01)=5mm / s, matching the set operating speed. When the push rod reaches the 30mm position, soft fabric gets stuck in the gap of the bed board, and the load on the push rod slowly increases. At this time, the motor operating current rises to 0.85A, which does not reach the dynamic current threshold of 0.91A. Single current detection cannot trigger the anti-pinch function. At the same time, the motor speed drops from the steady-state value of 3000rpm to 2000rpm. The ratio of the speed drop within 1 second to the steady-state speed is (3000-2000) / 3000≈0.33, which is greater than or equal to the trigger threshold of 0.3. When the rapid detection conditions are met, the anti-pinch detection module outputs a trigger signal. After the anti-pinch is triggered, the independent drive board immediately cuts off the forward drive output and calculates the number of reverse pulses according to the preset 5mm retraction distance. The 5mm retraction corresponds to a motor speed of 5 / 0.1=50 revolutions, which corresponds to a Hall pulse count of 50×6=300. The independent drive board outputs 300 reverse drive pulses, which drive the push rod to retract 5mm in the opposite direction and then stop. In this scenario, it is an independent adjustment mode, where only the backrest area performs the retraction action, while the leg and waist areas remain stationary. The user interaction unit simultaneously displays the prompt information of the backrest area anti-pinch trigger.
[0054] Example 2
[0055] In a multi-zone coordinated operation scenario, when the user selects the relaxation mode, the headboard zone is raised by 30° and the legroom zone by 20°. The target total travel of the headboard push rod is 120mm, and the target total travel of the legroom push rod is 80mm. The central control unit recognizes this as a coordinated adjustment command, sets the headboard zone as the reference zone, the legroom zone as the driven zone, and the reference speed for coordinated operation. The speed is 6 mm / s, and the proportional adjustment coefficient is... Take 0.6 as the target total travel distance for coordinated operation. The reference zone is 120mm.
[0056] In the initial stage of operation, the synchronous speed planning unit allocates the initial speed proportionally according to the target travel of the two zones. The initial speed of the leg push rod is adjusted accordingly to (80 / 120)×6=4mm / s to ensure that the two zones have the basis for synchronous positioning. At a certain moment, the real-time position of the reference zone, i.e., the headboard zone, is determined. The real-time position of the driven zone, i.e., the leg zone, is 60mm. The value is 38mm. Substituting this into the position deviation formula, we can obtain... =60-38=22mm. Substituting the parameters into the speed correction formula, we can obtain the running speed after the driven partition correction. =6×(1+0.6×22 / 120)=6×1.11=6.66mm / s, the running speed of the leg push rod increases, gradually reducing the positional deviation from the reference zone. During subsequent operation, the position synchronization correction unit performs deviation calculation and speed correction every 10ms. As the position of the driven zone gradually catches up with the reference zone, the positional deviation continues to decrease, and the corresponding correction speed gradually returns to the reference speed. Finally, the positioning deviation of the push rods of the two zones is controlled within 0.5mm, achieving synchronous positioning. If any zone triggers the anti-pinch detection during operation, the central control unit will immediately stop all cooperating zone motors, trigger the anti-pinch zone to perform reverse retreat, and push alarm information to the user interaction unit. After troubleshooting, operation can be manually resumed.
[0057] Example 3
[0058] In the application scenario of limit calibration, after the system is first installed or reset, it enters the limit learning mode to calibrate the upper and lower limit positions of the waist section push rod;
[0059] In this scenario, the stall current threshold of the waist-mounted push rod motor Set to 2.5A, minimum position change threshold The pulse rate is set to 0.1mm every 200ms, the Hall pulse count P is 6, and the corresponding push rod stroke per motor revolution is... The thickness is 0.1mm. After the learning mode is activated, the push rod first moves to its upper limit position. When it approaches the mechanical limit position, the push rod is blocked by the mechanical structure, and the motor load continues to increase. When the motor's real-time operating current... Rising to 2.7A, meeting the requirements. The conditions; simultaneously detect the change in the position of the push rod within 200ms. The value is 0.08mm, which meets the requirements. When both conditions are met simultaneously and the duration reaches 200ms, the system determines the current position as the upper limit position, records the current Hall pulse cumulative value as 6667, calibrates this value as the upper limit position parameter and stores it. Subsequently, the push rod moves downward, and the same logic is used to calibrate the lower limit position. Finally, the Hall pulse cumulative value at the calibrated lower limit position is 0, and the total number of Hall pulses between the upper and lower limit positions is... The value is 6667. Substituting this into the total travel formula, we get... =6667×0.1 / 6≈111.12mm, that is, the effective total stroke of the waist push rod is about 111.12mm. After calibration, the system enters the normal operation mode. During daily adjustment, the stored pulse accumulation value is used as the electronic limit trigger point. When the push rod runs to the limit position and the corresponding number of pulses, it will automatically stop. The stall current detection is used as a redundant protection. When the pulse count is deviated and the push rod does not stop when it reaches the limit position, the stall current detection will trigger the protection, stop the motor output, and avoid damage to the mechanism.
[0060] Example 4
[0061] Alternative Scenario 1: Use CAN bus instead of LIN bus to improve the communication rate between multi-zone motors and the central control unit, which is suitable for scenarios with a larger number of zones;
[0062] Alternative condition two: Each independent driver board uses dual Hall sensors instead of three Hall sensors to reduce costs, while ensuring position detection accuracy through algorithm optimization;
[0063] Alternative condition three: Add a pressure sensor (installed at the end of the push rod) to the anti-pinch detection to achieve contact-type anti-pinch detection and improve the recognition rate of soft obstacles;
[0064] Alternative condition four: Replace the partitioned brushless motor assembly with a stepper motor to improve positioning accuracy;
[0065] Substitute one or a combination of the above alternative conditions one, two, three and four into this system for implementation.
Claims
1. A smart bed brushless motor partition driving and anti-pinch linkage system, characterized in that, include: The user interaction unit, the central control unit, and multiple sets of push rod actuators arranged in different sections of the bed are connected to a partition brushless motor assembly. Each partition brushless motor assembly is set in the back, leg, and waist areas of the smart bed. Each partitioned brushless motor assembly integrates an independent drive board, which has a built-in FOC drive circuit and three Hall sensors. The central control unit communicates with the independent drive boards of each partitioned brushless motor assembly via a LIN bus. Each partitioned brushless motor assembly also integrates an anti-pinch detection module.
2. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The anti-pinch detection module is connected to both the motor power supply circuit and the signal output terminal of the Hall sensor. The system eliminates the mechanical limit switch and uses the cumulative position count of the Hall sensor as the basis for determining the electronic limit. The motor stall current detection is used as the limit redundancy protection. The central control unit integrates a multi-push rod drive control module, which includes: an instruction parsing unit for distinguishing between independent adjustment instructions and coordinated adjustment instructions; a synchronous speed planning unit for generating initial speed instructions proportionally based on the remaining stroke of each push rod during coordinated adjustment; and a position synchronization correction unit for receiving position feedback during operation and calculating the remaining stroke based on the ideal synchronous trajectory. The multi-push rod drive control module of the central control unit can output independent adjustment commands to a single partition brushless motor assembly or synchronously output coordinated adjustment commands to multiple partition brushless motor assemblies. Each partition brushless motor assembly can operate independently or synchronously in conjunction with the corresponding command.
3. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The independent drive board has a built-in three-phase full-bridge FOC drive circuit composed of 6 MOS transistors. The PWM carrier frequency of the FOC drive circuit is set to 16kHz. Three Hall sensors are arranged at 120° electrical angle intervals along the circumference of the motor rotor. The signal output terminal of the Hall sensor is connected to the position calculation unit of the independent drive board. The rotor position signal output by the position calculation unit is connected to the control input terminal of the FOC drive circuit. The anti-pinch detection module has a built-in dynamic current threshold calculation unit. The dynamic current threshold is updated synchronously with the real-time load of the motor, and the calculation formula is: ,in This is the reference current of the motor load obtained by moving average filtering within the current sampling period. The anti-pinch margin coefficient has a value range of 0.2-0.
4. The reference current increases synchronously with the increase of the push rod load, and the corresponding dynamic threshold is adjusted upward synchronously. When the load decreases, the threshold is adjusted downward synchronously.
4. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The anti-pinch detection module has a built-in speed and position change rate calculation unit. The formula for calculating the real-time running speed of the push rod is: In the formula Unit sampling duration The pulse increment output by the NeHall sensor This represents the total number of Hall pulses per revolution of the motor. The system detects the stroke of the push rod driven by the motor after each revolution of the motor through the reduction transmission. The system performs detection during the steady-state operation of the motor. When the ratio of the decrease in motor speed within 1 second to the steady-state speed is greater than or equal to 0.3, or when the change rate of push rod position is lower than the preset minimum value and the duration reaches the set threshold, the anti-pinch detection module outputs a trigger signal.
5. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The central control unit has a built-in synchronization correction calculation unit. In the cooperative operation mode, one of the partitions is set as the reference partition, and the synchronization correction calculation unit calculates the positional deviation between the remaining driven partitions and the reference partition in real time. ,in The real-time position value of the reference zone push rod. Given the real-time position value of the i-th driven zone push rod, the central control unit outputs a speed correction command based on the position deviation, and the real-time running speed of the corresponding driven zone is adjusted as follows: In the formula As the reference speed for coordinated operation, This is the proportional adjustment coefficient. The total journey is for the goal of coordinated operation.
6. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The system has a limit learning mode. In the learning mode, the judgment condition when the push rod reaches the mechanical limit position is met: ,in This is the real-time operating current of the motor. To preset the stall current threshold, To set the change in position of the push rod over a set time period, As the minimum position change threshold, when both conditions are met simultaneously and the duration reaches the set value, the system calibrates the current Hall pulse cumulative value as the limit position parameter in the corresponding direction and stores it. In normal operation mode, the push rod uses the stored limit position parameter as the electronic limit trigger point.
7. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The LIN bus uses the central control unit as the master node, and each brushless motor component in each partition is configured with an independent slave node address. The instruction frame output by the central control unit includes a node address segment, an instruction type segment, a target position segment, and a speed parameter segment. Each brushless motor component in each partition matches the corresponding instruction through the node address segment. The status frame returned by the independent drive board to the central control unit includes real-time position, operating current, and fault status information.
8. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The output end of the partitioned brushless motor assembly is connected to a reduction gear set, and the output end of the reduction gear set is connected to a lead screw pair of the push rod actuator. A Hall sensor is installed at the rotor end of the brushless motor, and the cumulative value of the Hall pulse corresponding to the total stroke of the push rod satisfies the following: In the formula This represents the total number of Hall pulses between the upper and lower limit positions. This represents the stroke of the push rod after each revolution of the motor through the reduction gear transmission. This represents the number of Hall pulses per revolution of the motor.
9. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The independent drive board has a built-in retraction control register, which stores the number of reverse pulses corresponding to the preset retraction distance. After the anti-pinch detection module outputs a trigger signal, the independent drive board immediately cuts off the forward drive output and outputs the corresponding number of reverse drive pulses, causing the push rod to retract in the opposite direction. In the independent adjustment mode, only the anti-pinch partition is triggered to perform the retraction action. In the coordinated adjustment mode, while the anti-pinch partition is triggered to perform the retraction action, the central control unit suspends all partition brushless motor components in the coordinated operation state and pushes alarm information to the user interaction unit.
10. The intelligent bed brushless motor zoned drive and anti-pinch linkage system according to claim 1, characterized in that, The user interaction unit is a fixed control panel or a mobile terminal with a control application installed. It is used to set the independent target angle and independent running speed of each push rod, and to define and store multiple push rod target angle parameter groups corresponding to the cooperative mode. The user interaction unit has a built-in attitude storage unit. The attitude storage unit has multiple sets of target position parameters for each partition corresponding to fixed attitude modes. The user interaction unit supports custom target position and running speed parameters for a single partition, and supports custom attitude parameters for multiple partition combinations and storing them in the attitude storage unit. When called, the corresponding parameter combination is directly sent to the central control unit.