A method for auxiliary driving force distribution of a double-hung train based on an electric trailer

Abstract

The application relates to the technical field of automobile train control, and discloses a double-hung train auxiliary driving force distribution method based on an electric trailer, which comprises the following steps: arranging multiple pressure sensors at a trailer traction device, and acquiring, in real time, longitudinal thrust and front side tension data reflecting the force received by the trailer; calculating the difference between the front side tension to determine the straight driving or turning state of the vehicle; in the straight driving state, comparing the sum of the front side tension, the longitudinal thrust and a preset traction force reference value, and independently controlling the working state of the trailer auxiliary driving system or the brake energy recovery system. The application breaks the barrier of the traditional main-hung communication protocol, can accurately judge the motion trend only by relying on the force state of the trailer, realizes intelligent distribution of the traction force without communication interaction, effectively avoids the instability risk of the double-hung train that the rear trailer pushes the front trailer, reduces the system cost, and greatly improves the comprehensive adaptability and safety of the combined operation of the multi-section double-hung automobile train.

Description

Technical Field

[0001] This invention relates to the field of automobile train control technology, and in particular to a method for distributing auxiliary driving force in a double-trailer train based on an electric trailer. Background Technology

[0002] Electric trailers are a new type of product proposed in recent years both domestically and internationally. They fundamentally change the "unpowered" nature of trailers by recovering braking energy and converting it into electrical energy, which is stored in a power battery and used for vehicle acceleration, hill climbing, and driving. This reshapes the power distribution, energy distribution, and braking force distribution between trailers and tractors, promoting innovation in vehicle train equipment and industrial upgrading through their energy-saving, safe, and stable advantages. Correspondingly, the matching technology between trailers and tractors in vehicle trains is still in its early stages of research both domestically and internationally. To achieve technological upgrading and industrial transformation in China's commercial vehicle industry, China is actively conducting research on electric trailer technology.

[0003] Double-trailer truck trains offer greater transport capacity and payload, significantly improving logistics efficiency. As a crucial mode of modern road transport, they are widely used in many countries and regions, handling far greater long-distance freight volumes than other modes. The automotive and transportation industries are undergoing a comprehensive green transformation, and in recent years have significantly increased their efforts in technical verification and feasibility studies of double-trailer truck trains.

[0004] For double-trailer truck trains, the transport capacity is greatly increased, for example, the total mass increases from 49 tons to 73 tons (or even higher), an increase of nearly 50%. In order to ensure the safe and stable operation of the truck train, it is necessary to increase the traction power accordingly. However, due to the limitation of high-power, high-performance vehicle engines, the supply of high-power tractors is insufficient. Therefore, the industry has proposed to use conventional tractors matched with electric trailers. For example, the auxiliary drive force of the trailer can ensure that the truck train can still provide sufficient operating power when the transport mass is increased. However, the problem with this approach is that the auxiliary power of the two trailers must be balanced and reasonable. In order to ensure operational safety, the phenomenon of "the rear vehicle pushing the front vehicle" must be absolutely avoided.

[0005] The operation of a truck train requires driving force to overcome the rolling resistance of the tires on the road and air resistance. For conventional truck trains, the driving force comes only from the output power of the engine. The driver can intuitively judge the control measures to be taken on the vehicle (such as increasing or decreasing the accelerator pedal) by sensing the speed and acceleration. However, for truck trains composed of electric trailers, the auxiliary drive of the trailer needs to follow the preceding vehicle as accurately as possible. For single-trailer truck trains, the common design approach is to connect the control system of the electric trailer to the control system of the tractor, directly reading the power control system signals of the preceding vehicle. For example, reading whether the preceding vehicle presses or releases the accelerator pedal or brake pedal (pressing speed, opening degree). The trailer is calibrated and accordingly follows to make auxiliary drive or regenerative braking actions, and controls the magnitude of the auxiliary drive force or the intensity of energy recovery (auxiliary braking effect) according to the acceleration or deceleration degree of the preceding vehicle.

[0006] However, for double-trailer truck trains composed of electric trailers, since the vehicle has three power sources (the tractor's main power source and the two trailers' auxiliary power sources), if the trailers still only read the tractor's signals, the signal feedback will become distorted due to the two auxiliary drives. Simultaneously, since both trailers communicate with the tractor, the control scheme becomes complex and costly. In particular, the tractor and trailers are manufactured by different companies, and buyers often purchase them separately and then assemble them themselves. Due to different signal protocols and information confidentiality issues between the trailers and tractor, communication between the tractor and trailers becomes difficult. If the double-trailer train adopts the more common combination of tractor, semi-trailer, and center-axle trailer, the number of manufacturers may even increase to three, making the scheme of controlling the trailer's auxiliary drives by reading the tractor's signals even more difficult, or even infeasible.

[0007] This invention is based on the trailer's own status monitoring. By analyzing its own acceleration, deceleration or smooth operation trend, it feeds feedback to the trailer control system and controls the auxiliary drive system to ensure reasonable power distribution and stable operation of the vehicle train. Summary of the Invention

[0008] The present invention aims to at least solve one of the technical problems existing in related technologies. To this end, the present invention provides a method for auxiliary drive force distribution in a dual-trailer train based on an electric trailer.

[0009] A method for distributing auxiliary drive force in a dual-trailer train based on an electric trailer includes: Obtain the mass parameters and driving resistance parameters of the target electric trailer, calculate and output the traction force benchmark value of the target electric trailer; Real-time acquisition of pressure data collected by multiple pressure sensors installed on the connection device of the target electric trailer; parsing and outputting longitudinal thrust data reflecting the longitudinal pushing action on the target electric trailer, as well as two front tension data from the pressure data. Receive the two front tension data and perform calculations, then output the front tension sum data and the front tension difference data; Receive the front tension difference data, compare the front tension difference data with the preset straight-line conditions, and if the absolute value of the front tension difference data meets the straight-line conditions, output a straight-line driving status signal. Upon receiving the straight-line driving status signal, and upon triggering the straight-line driving status signal, receiving and comparing the front pull and data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, the operating status of the auxiliary drive system or brake energy recovery system of the target electric trailer is controlled.

[0010] Furthermore, the connecting device includes a traction pin; the plurality of pressure sensors are mounted on the outer edge circumference of the traction pin, and the plurality of pressure sensors include one rear-side sensor and two front-side sensors; In the step of parsing and outputting longitudinal thrust data, the force value collected by the rear sensor is used as the output longitudinal thrust data. In the step of parsing and outputting the two front tension data, the first front tension value and the second front tension value collected by the two front sensors are respectively used as the front tension data output.

[0011] Furthermore, the step of obtaining the mass parameters and driving resistance parameters of the target electric trailer, and calculating and outputting the traction force reference value of the target electric trailer includes: The total mass data of the target electric trailer and other trailers attached to the target electric trailer are obtained as the mass parameter; a preset equivalent drag coefficient is obtained as the driving resistance parameter. The total mass data, the preset gravitational acceleration parameters, and the equivalent drag coefficient are used as input parameters to perform a product calculation, and the output product result is used as the traction force reference value.

[0012] Furthermore, in the step of receiving the two front tension data and calculating them, and outputting the front tension sum data and the front tension difference data, the difference between the first front tension value and the second front tension value is output as the front tension difference data. The straight-ahead conditions include: using the traction force reference value as a condition limit reference, the absolute value of the front tension difference data is less than or equal to the product of the traction force reference value and a preset percentage parameter, and the absolute value of the front tension difference data is less than a preset straight-ahead threshold.

[0013] Further, the step of receiving and comparing the frontal tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, includes: The front tension and data are numerically compared with the traction force reference value; When it is determined that the front tension and data are greater than the product of the traction force reference value and the preset large traction coefficient, a large traction force status signal is output. Upon receiving the high traction force status signal, an auxiliary drive start command is output to control the start of the auxiliary drive system of the target electric trailer.

[0014] Furthermore, after outputting the auxiliary driver startup command to start the auxiliary driver system, the method further includes: The system continuously receives the front tension and data, and compares the front tension and data with the traction force reference value. When it is determined that the front tension and data are less than the product of the traction force reference value and the preset small traction coefficient, a small traction force status signal is output. The system receives the small traction force status signal, generates a power reduction command, and outputs it to the auxiliary drive system to reduce the power output of the auxiliary drive system until the front traction force and data are adjusted and maintained within a preset traction force safety range.

[0015] Furthermore, the step of receiving and comparing the frontal tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, further includes: Obtain the operating status signal of the auxiliary drive system; When the working status signal indicates that the auxiliary drive system is in the off state, the front traction and data and the longitudinal thrust data are received, it is determined whether the front traction and data have dropped to zero, and it is determined whether the longitudinal thrust data is greater than or equal to the product of the traction reference value and the anti-push coefficient; If the conditions are met simultaneously, the vehicle is determined to be in a downhill or deceleration state, and a recovery start command is output to activate the brake energy recovery system of the target electric trailer.

[0016] Furthermore, after activating the regeneration system by outputting the regeneration activation command, the method further includes: The continuously acquired longitudinal thrust data is used as system feedback input, and a recovery intensity increase command is output to dynamically increase the recovery intensity of the braking energy recovery system until the longitudinal thrust data is monitored to decrease to zero. While dynamically increasing the recovery intensity, the front pull force and data of the input system are continuously monitored; when the front pull force and data increase and exceed the upper limit of the preset pull force safety range, a recovery shutdown command is output to shut down the braking energy recovery system. The method also includes system protection and alarm steps: Independent of the front tension and data and the longitudinal thrust data, the battery state of charge data and external braking trigger signal of the target electric trailer are acquired in real time. When the external braking trigger signal is received, the maximum recovery command is directly output over other control logic to control the braking energy recovery system to enter the maximum intensity working state. When the system receives a signal indicating that the regenerative braking system is operating at maximum intensity, or when the battery state-of-charge data indicates that the battery is fully charged and the longitudinal thrust data is determined to be continuously increasing beyond a preset safety push alarm threshold, an abnormal push alarm signal is output to the vehicle's driver's cabin.

[0017] Furthermore, the step of comparing the front tension difference data with preset straight-line conditions further includes: When the absolute value of the front tension difference data is greater than the preset turning threshold, a turning driving status signal is output. Upon receiving the turning driving status signal, the system outputs a drive cut-off command to forcibly shut down the auxiliary drive system of the target electric trailer.

[0018] Furthermore, the double-trailer truck train includes a tractor, a first electric trailer, and a second electric trailer that are articulated together in sequence; the target electric trailer is either the first electric trailer or the second electric trailer. In the control logic, the small traction coefficient set for the second electric trailer is smaller than the small traction coefficient set for the first electric trailer, so that the braking energy recovery system of the second electric trailer receives the start control command before the first electric trailer.

[0019] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: 1. The proposed trailer electric system control is completely independent of the communication protocol of the tractor or another trailer's control system, relying solely on its own mechanical force state for independent control. This fundamentally solves the compatibility and application problems caused by different signal protocols and technical confidentiality issues between tractors and trailers from different manufacturers on the market.

[0020] 2. This solution abandons expensive and complex accelerometers (for measuring acceleration and deceleration) and angle sensors (for measuring straight-line movement or turning), and innovatively utilizes an array of pressure sensors and a sum / difference calculation algorithm to determine the operating status. Pressure sensors are widely used and technologically mature in industry, significantly reducing system hardware costs while improving the overall reliability of the control system.

[0021] 3. By differentiating the control algorithms for the first electric trailer B and the second electric trailer C (e.g., prioritizing energy recovery for the second electric trailer C), dangerous folding or fishtailing phenomena caused by "the rear vehicle pushing the front vehicle" are effectively avoided. Simultaneously, thanks to the pre-monitoring settings for the squeezing thrust, the system can issue a warning to the driver before braking performance is completely lost, giving the system a very high degree of safety redundancy.

[0022] 4. To address potential sensor noise or road surface disturbances during straight-ahead and turning maneuvers, the system incorporates a state transition zone. This effectively prevents the control strategy from frequently "jumping" between straight-ahead and turning maneuvers, thus improving smoothness in practical engineering applications.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the system composition of a double-trailer truck train based on an electric trailer provided in an embodiment of the present invention; Figure 2 This is a schematic diagram (top view) of the pressure sensor arrangement provided in an embodiment of the present invention.

[0026] Figure label: A – Tractor; B – First electric trailer; C – Second electric trailer; B1 – First pressure sensor; B2 – Second pressure sensor; B3 – Third pressure sensor; C1 – Fourth pressure sensor; C2 – Fifth pressure sensor; C3 – Sixth pressure sensor; BL1 – Outer edge of the B-type towing pin of the first electric trailer; BL2 – Inner edge of the towing seat hole of tractor A; CL1 – Outer edge of the C-pin of the second electric trailer; CL2 – Inner edge of the connection hole of the first electric trailer B. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0028] This invention primarily targets the power distribution between the main trailer and trailer in double-trailer truck trains based on electric trailers, ensuring stable and safe driving during constant speed, acceleration, deceleration, uphill, and downhill driving. The main considerations are as follows: Feasibility: The dynamics of each moving unit of the vehicle train can be simplified to a hinged connection of multiple rigid bodies. By observing its own force state, the motion trend can be accurately determined, and relatively accurate following instructions can be provided to the trailer control system.

[0029] Suitability: Due to the lack of collaborative development between tractor units and trailers, and the different scrapping rates of tractor units and trailers in the market, this non-collaborative development model is further exacerbated. For non-collaboratively developed vehicle trains, given the objective background of the lack of a unified power system communication protocol, it is extremely difficult to achieve the response and following of the trailer's auxiliary drive system by reading the control system signals of the tractor unit. This is especially true when transportation users without development capabilities purchase tractor units and trailers separately for use. This invention, based on monitoring and judging the movement state of the trailer itself and controlling the operation of the auxiliary drive system, has broader adaptability.

[0030] Economic efficiency: This invention uses common and technologically mature pressure sensors to form control signal inputs, avoiding the need to request the tractor to open communication protocols, perform main-trailer matching calibration, and establish complex communication lines and interaction logic between the tractor and the two trailers. It can achieve power distribution of double-trailer truck trains based on electric trailers at a lower cost.

[0031] Autonomy: This method is an independent innovation. Based on the traditional control system signal interaction, it utilizes traction force monitoring to achieve train control.

[0032] A method for distributing auxiliary drive force in a dual-trailer train based on an electric trailer includes: Obtain the mass parameters and driving resistance parameters of the target electric trailer, calculate and output the traction force benchmark value of the target electric trailer; Real-time acquisition of pressure data collected by multiple pressure sensors installed on the connection device of the target electric trailer; parsing and outputting longitudinal thrust data reflecting the longitudinal pushing action on the target electric trailer, as well as two front tension data from the pressure data. Receive the two front tension data and perform calculations, then output the front tension sum data and the front tension difference data; Receive the front tension difference data, compare the front tension difference data with the preset straight-line conditions, and if the absolute value of the front tension difference data meets the straight-line conditions, output a straight-line driving status signal. Upon receiving the straight-line driving status signal, and upon triggering the straight-line driving status signal, receiving and comparing the front pull and data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, the operating status of the auxiliary drive system or brake energy recovery system of the target electric trailer is controlled.

[0033] Furthermore, the connecting device includes a traction pin; the plurality of pressure sensors are mounted on the outer edge circumference of the traction pin, and the plurality of pressure sensors include one rear-side sensor and two front-side sensors; In the step of parsing and outputting longitudinal thrust data, the force value collected by the rear sensor is used as the output longitudinal thrust data. In the step of parsing and outputting the two front tension data, the first front tension value and the second front tension value collected by the two front sensors are respectively used as the front tension data output.

[0034] Furthermore, the step of obtaining the mass parameters and driving resistance parameters of the target electric trailer, and calculating and outputting the traction force reference value of the target electric trailer includes: The total mass data of the target electric trailer and other trailers attached to the target electric trailer are obtained as the mass parameter; a preset equivalent drag coefficient is obtained as the driving resistance parameter. The total mass data, the preset gravitational acceleration parameters, and the equivalent drag coefficient are used as input parameters to perform a product calculation, and the output product result is used as the traction force reference value.

[0035] Furthermore, in the step of receiving the two front tension data and calculating them, and outputting the front tension sum data and the front tension difference data, the difference between the first front tension value and the second front tension value is output as the front tension difference data. The straight-ahead conditions include: using the traction force reference value as a condition limit reference, the absolute value of the front tension difference data is less than or equal to the product of the traction force reference value and a preset percentage parameter, and the absolute value of the front tension difference data is less than a preset straight-ahead threshold.

[0036] Further, the step of receiving and comparing the frontal tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, includes: The front tension and data are numerically compared with the traction force reference value; When it is determined that the front tension and data are greater than the product of the traction force reference value and the preset large traction coefficient, a large traction force status signal is output. Upon receiving the high traction force status signal, an auxiliary drive start command is output to control the start of the auxiliary drive system of the target electric trailer.

[0037] Furthermore, after outputting the auxiliary driver startup command to start the auxiliary driver system, the method further includes: The system continuously receives the front tension and data, and compares the front tension and data with the traction force reference value. When it is determined that the front tension and data are less than the product of the traction force reference value and the preset small traction coefficient, a small traction force status signal is output. The system receives the small traction force status signal, generates a power reduction command, and outputs it to the auxiliary drive system to reduce the power output of the auxiliary drive system until the front traction force and data are adjusted and maintained within a preset traction force safety range.

[0038] Furthermore, the step of receiving and comparing the frontal tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, further includes: Obtain the operating status signal of the auxiliary drive system; When the working status signal indicates that the auxiliary drive system is in the off state, the front traction and data and the longitudinal thrust data are received, it is determined whether the front traction and data have dropped to zero, and it is determined whether the longitudinal thrust data is greater than or equal to the product of the traction reference value and the anti-push coefficient; If the conditions are met simultaneously, the vehicle is determined to be in a downhill or deceleration state, and a recovery start command is output to activate the brake energy recovery system of the target electric trailer.

[0039] Furthermore, after activating the regeneration system by outputting the regeneration activation command, the method further includes: The continuously acquired longitudinal thrust data is used as system feedback input, and a recovery intensity increase command is output to dynamically increase the recovery intensity of the braking energy recovery system until the longitudinal thrust data is monitored to decrease to zero. While dynamically increasing the recovery intensity, the front pull force and data of the input system are continuously monitored; when the front pull force and data increase and exceed the upper limit of the preset pull force safety range, a recovery shutdown command is output to shut down the braking energy recovery system. The method also includes system protection and alarm steps: Independent of the front tension and data and the longitudinal thrust data, the battery state of charge data and external braking trigger signal of the target electric trailer are acquired in real time. When the external braking trigger signal is received, the maximum recovery command is directly output over other control logic to control the braking energy recovery system to enter the maximum intensity working state. When the system receives a signal indicating that the regenerative braking system is operating at maximum intensity, or when the battery state-of-charge data indicates that the battery is fully charged and the longitudinal thrust data is determined to be continuously increasing beyond a preset safety push alarm threshold, an abnormal push alarm signal is output to the vehicle's driver's cabin.

[0040] Furthermore, the step of comparing the front tension difference data with preset straight-line conditions further includes: When the absolute value of the front tension difference data is greater than the preset turning threshold, a turning driving status signal is output. Upon receiving the turning driving status signal, the system outputs a drive cut-off command to forcibly shut down the auxiliary drive system of the target electric trailer.

[0041] Furthermore, the double-trailer truck train includes a tractor, a first electric trailer, and a second electric trailer that are articulated together in sequence; the target electric trailer is either the first electric trailer or the second electric trailer. In the control logic, the small traction coefficient set for the second electric trailer is smaller than the small traction coefficient set for the first electric trailer, so that the braking energy recovery system of the second electric trailer receives the start control command before the first electric trailer.

[0042] The following are examples of specific implementation methods for the above scheme.

[0043] I. System Composition and Sensor Arrangement The specific structure of the device used in the present invention is described below, such as... Figure 1 The diagram illustrates the system composition of a double-trailer truck train based on electric trailers. The tractor A, together with the first electric trailer B and the second electric trailer C, forms the double-trailer truck train. The rear axle of the tractor A is the main drive axle, while the middle axle of the first electric trailer B and the front axle of the second electric trailer C are auxiliary drive axles.

[0044] For stable operation of a truck train, the tractor unit must provide the primary driving force, while the trailer unit provides the auxiliary driving force; that is, the tractor unit tows the trailer unit, and the trailer unit cannot push the tractor unit. Under any operating conditions (constant speed, acceleration / deceleration, uphill / downhill, etc.), all connecting devices should be kept taut, meaning the tractor unit applies a pulling force to the trailer unit, and the trailer unit does not apply a pushing force to the tractor unit, to avoid instability caused by the trailer unit pushing the tractor unit.

[0045] The tractor A is equipped with a towing seat; the front end of the first electric trailer B is equipped with a towing pin, which cooperates with the towing seat on the tractor A. BL1 is the outer edge of the towing pin of the first electric trailer B; BL2 is the inner edge of the towing seat hole of the tractor A.

[0046] The rear end of the first electric trailer B is provided with a connection hole that engages with the towing pin of the second electric trailer C. CL1 is the outer edge of the towing pin of the second electric trailer C; CL2 is the inner edge of the connection hole of the first electric trailer B.

[0047] Pressure sensors are installed between the connection devices of tractor A and first electric trailer B, and between the connection devices of first electric trailer B and second electric trailer C, such as... Figure 2 The diagram shows the arrangement of the pressure sensors in this embodiment.

[0048] Specific setup: In the straight-line direction of the double-trailer truck train, a pressure sensor, designated as first pressure sensor B1, is installed near the outer edge of the towing pin of the first electric trailer B. Two pressure sensors, designated as second pressure sensor B2 and third pressure sensor B3, are installed at 120° intervals from the first pressure sensor B1 on the outer circumference of the towing pin of the first electric trailer B. Consistent with the setup of the first electric trailer B, three pressure sensors, designated as fourth pressure sensor C1, fifth pressure sensor C2, and sixth pressure sensor C3, are installed on the outer circumference of the towing pin of the second electric trailer C.

[0049] In this embodiment, the pressure sensor is a pressure-type force sensor, installed on the outer circumference of the traction pin (i.e., on the load transmission path of the connecting device), used to sense the force distribution of the connecting device in the longitudinal (driving direction) and lateral (sideways) directions. Both sets of pressure sensors are installed in the same way. In engineering implementation, the correspondence between the force values ​​of each sensor and the actual longitudinal and lateral forces of the connecting device can be determined through bench calibration, and the control threshold can be calibrated accordingly.

[0050] Record the forces exerted on the six sensors during the movement of the car-train, and denot them as follows: , , , , , .in, , This is the longitudinal thrust signal at the rear. , , , This is the force signal on the front side.

[0051] The total mass of the first electric trailer B and the second electric trailer C are respectively , . , It can be obtained through methods such as preset vehicle mass parameters and estimation of weighing / air suspension pressure.

[0052] When the twin-trailer train accelerates or goes uphill, the first electric trailer B tends to be pulled backward relative to the second electric trailer C. At this time, the connection hole between the tractor A's traction seat and the first electric trailer B presses backward against the second pressure sensor B2, the third pressure sensor B3, the fifth pressure sensor C2, and the sixth pressure sensor C3, thus affecting the force signal at the front. , , , Consequently, when the twin-trailer train decelerates or goes downhill, the traction seat of tractor A and the connection hole of the first electric trailer B press forward against the first pressure sensor B1 and the fourth pressure sensor C1, generating a longitudinal force signal. , Consequently, when the twin-trailer train travels in a straight line, the coupling device remains taut to overcome the rolling resistance of the tires and the air resistance on the trailer, resulting in a longitudinal force signal. , It reflects the magnitude of the longitudinal traction force borne by the connecting device.

[0053] When the twin-trailer train is traveling in a straight line, because the connecting devices between the tractor A and the first electric trailer B, and between the first electric trailer B and the second electric trailer C, are cylindrical, spherical, or other symmetrical connections, the forces borne by the second pressure sensor B2 and the third pressure sensor B3 should be approximately equal in value, and the same applies to the forces borne by the fifth pressure sensor C2 and the sixth pressure sensor C3. However, when the twin-trailer train turns, because the tractor A tends to deviate from its original direction of travel relative to the first electric trailer B, and the first electric trailer B tends to deviate from its original direction of travel relative to the second electric trailer C, the forces borne by the second pressure sensor B2 and the third pressure sensor B3, and the fifth pressure sensor C2 and the sixth pressure sensor C3, change (and are no longer approximately equal). , Significantly increased.

[0054] The front sensor assembly (second pressure sensor B2 and third pressure sensor B3, fifth pressure sensor C2 and sixth pressure sensor C3): mainly used to detect the longitudinal traction force of the train under driving / acceleration / climbing conditions (by summation). (reflection), and detection of turning attitude (through difference) reflect); Rear sensors (first pressure sensor B1 and fourth pressure sensor C1): mainly used to directly detect the longitudinal compressive force exerted by the rear train on the front train during deceleration / downhill / braking conditions (via... (Reflection), serving as a key control signal for triggering trailer braking energy recovery and anti-push alarm.

[0055] II. Determination of Reference Force Double-trailer truck trains operate at lower speeds than passenger cars, trucks, and buses, have a greater carrying capacity, and use larger heavy-duty truck tires. Furthermore, the main air resistance of a double-trailer truck train is borne by the tractor unit A. Therefore, when traveling at a constant speed on a straight road, with the trailer auxiliary drive system not engaged, the force exerted by tractor unit A to pull the first electric trailer B is... ; in, , The unit is kg. The acceleration due to gravity is taken as 9.8 m / s². 2 , The unit is N; The equivalent drag coefficient, which integrates factors such as tire rolling resistance, trailer air resistance, and transmission losses, can be calibrated through real vehicle testing. In this embodiment... Take 0.15.

[0056] Similarly, the force used by the first electric trailer B to pull the second electric trailer C is: in The unit is N.

[0057] To ensure the driving stability of the double-trailer truck train and the driver's road feel, the electric trailer should not be driven in an auxiliary manner during turning to avoid lateral force from the rear trailer to the front trailer. Under any working condition, the front trailer should apply a pulling force to the rear trailer, and the rear trailer should not push the front trailer; that is, all connecting devices should be kept taut.

[0058] Reference power , It serves only as a baseline value for the control threshold. In actual control, the equivalent drag coefficient can be adjusted through calibration to adapt to different vehicle models.

[0059] III. First Electric Trailer B Auxiliary Drive Force Distribution Control Logic Based on the above principles, the electric control system of the first electric trailer B reads the pressure sensor data in real time.

[0060] For the first electric trailer B: Real-time reading , , and calculate and .

[0061] When detected , The forces are approximately equal (without turning), take and less than , The threshold for straight travel is used to determine that the double-trailer train is traveling in a straight line.

[0062] It should be noted that 0.05 is a proportional coefficient, which can be adjusted according to the vehicle model or weight. The specific value given in this embodiment is only a specific parameter used in a specific implementation case. The specific values ​​given in this solution below are also in this case, and will not be repeated one by one.

[0063] When the double-trailer train is traveling in a straight line, the driving status of the vehicles is further determined. When the train is judged to be in a state of high traction, the auxiliary drive function of the first electric trailer B can be activated.

[0064] After the auxiliary drive system is activated, the auxiliary drive system of the first electric trailer B outputs driving force, which partially undertakes the force required for the tractor A to pull the first electric trailer B. Therefore, the value collected by the front tension sensor will decrease accordingly.

[0065] After the auxiliary driver function is activated It will gradually decrease, but as long as it is greater than the preset lower limit (e.g.) For example, during acceleration or hill climbing, the auxiliary drive system can continue to work and increase power output until it reaches the maximum output power or does not meet the above conditions (whichever comes first).

[0066] When the double-trailer train is traveling in a straight line, the driving status of the vehicles is further determined. At this point, it is determined that the dual-trailer train is operating with relatively low traction. This indicates that the driving force output by the auxiliary drive system is approaching or exceeding the power required to maintain normal train operation. If the output power continues to increase, it may cause the first electric trailer B to exert thrust on the tractor A, leading to a risk of train instability. Therefore, the auxiliary drive function of the first electric trailer B should gradually reduce its power output to... Continue to maintain .

[0067] When the trailer auxiliary drive system is fully disengaged (off), and front traction is detected. The pressure dropped to near zero, while the reading of the rear sensor (first pressure sensor B1) reached... At this time, it is determined that the twin-trailer train has entered a downhill or deceleration state (the rear trailer begins to exert a pushing force on the front trailer). To ensure that the front trailer continues to exert a pulling force in the forward direction rather than a pressure force in the reverse direction on the rear trailer, the trailer's auxiliary drive system immediately switches to brake energy recovery mode, and according to... The reading is dynamically adjusted in real time to control the recovery intensity: to reduce the extrusion pressure The target is to keep the intensity close to zero; and gradually increase the intensity to ensure... Maintain at ,when When the system detects that the deceleration or downhill process has ended, the regenerative braking function is deactivated. Due to the lack of auxiliary drive assist, It will gradually increase until the conditions for the auxiliary driver function to be activated are met again.

[0068] Furthermore, regardless of the data collected by the sensors, when the trailer brake trigger signal appears (such as the trailer brake light illuminating, the trailer ABS activating, the trailer AEB activating, etc.), the control system should immediately switch to the brake energy recovery state and operate at maximum intensity.

[0069] When the trailer is in regenerative braking mode and operating at maximum intensity, and When a double-trailer truck is in a situation where the rear vehicle is pushing the front vehicle and cannot maintain the traction of the front vehicle on its own (e.g., mechanical braking system failure or functional thermal fade, steep slopes exceeding design capacity under heavy load, etc.), an alarm signal will be issued immediately (it can be sent to the tractor via a signal line; if there are difficulties in matching the main and trailer vehicles in the market where the double-trailer trucks can be freely combined, it can also be triggered by sound or by transmitting the signal wirelessly to the receiving terminal near the driver's seat and directly alarming the driver).

[0070] When the forces exerted on the second pressure sensor B2 and the third pressure sensor B3 are not equal, and , The turning threshold is used to determine if the dual-trailer truck train is turning. At this point, the trailer auxiliary drive system immediately stops working, and only if... Only then can the trailer's brake energy recovery system be activated, and its intensity should be increased slowly to allow for proper braking. Maintain at In other cases, to ensure safety during turning, the trailer's auxiliary drive function and brake energy recovery function should both be turned off.

[0071] To protect the power battery and avoid the fire risk caused by overcharging, the trailer's regenerative braking function cannot be activated when the first electric trailer B is operating at maximum regenerative braking intensity or when the power battery's SOC is 100% and regenerative braking cannot be initiated. In this case, if the sensor's force meets the alarm conditions: if the rear sensor (first pressure sensor B1) detects a continuous increase in compressive force and reaches... At this point, it means that the first electric trailer B has severely pushed the vehicle in front (tractor A) and cannot eliminate the danger by its own electric motor power. The driver should be alerted immediately to get out of the dangerous situation as soon as possible (e.g., find a relatively flat road, leave the steep slope, and stop for inspection).

[0072] and The value is adjusted systematically based on the specific weight of the tractor and trailer.

[0073] It should be noted that all the specific values ​​given in this embodiment are only specific parameters used in a specific implementation case and are not intended to limit the implementation. They can be adjusted according to the specific vehicle model and weight.

[0074] IV. Second Electric Trailer C Auxiliary Drive Force Distribution Control Logic Based on the above principles, the electric control system of the second electric trailer C reads the pressure sensor data of the second electric trailer C in real time.

[0075] For the second electric trailer C: Real-time reading , , and calculate and .

[0076] When detected , The forces are approximately equal (without turning), take and less than At this point, it is determined that the double-trailer train is traveling in a straight line; When the double-trailer train is traveling in a straight line, the driving status of the vehicles is further determined. When the system is determined to be operating under significant traction, the auxiliary drive function of the second electric trailer C can be activated. After the auxiliary drive system is activated, the auxiliary drive system of the second electric trailer C outputs driving force, which partially undertakes the force required for the first electric trailer B to pull the second electric trailer C. Therefore, the value collected by the front tension sensor will decrease accordingly.

[0077] After the auxiliary driver function is activated It will gradually decrease, but as long as it is greater than the preset lower limit (e.g.) For example, during acceleration or hill climbing, the auxiliary drive system can continue to work and increase power output until the maximum output power is reached or the above conditions are not met (whichever comes first).

[0078] When a dual-trailer train is traveling in a straight line, the driving status of the vehicles needs to be further determined. For dual-trailer truck trains, since the second electric trailer C pushing the lead trailer poses a more serious risk to driving stability than the first electric trailer B pushing the lead trailer, the auxiliary drive function of the second electric trailer C should be subject to stricter control. Logically, the tractor unit starts first to provide the main driving force. When the trigger condition is met, the auxiliary drive function of the first electric trailer B is activated. If the trigger condition is met again, the auxiliary drive function of the second electric trailer C is activated. When the vehicle is going downhill or decelerating, the regenerative braking function of the second electric trailer C is activated first. If the condition is met, the regenerative braking function of the first electric trailer B is activated. If the condition is met again, the auxiliary braking function of the tractor unit A is activated. When a braking signal is detected, each vehicle activates its own regenerative braking system. Therefore, when... When the train is judged to be in a state of low traction, it indicates that the driving force output by the auxiliary drive system has approached or exceeded the power required to maintain the normal operation of the train. If the output power is increased further, it may cause the second electric trailer to generate thrust on the first electric trailer B, which may lead to the risk of train instability.

[0079] Therefore, the auxiliary drive function of the second electric trailer C should gradually reduce its power output, so that... Continue to maintain , When the second electric trailer's C-assist drive system is fully disengaged (off), and detection is made... The pressure dropped to near zero, while the reading of the rear sensor (fourth pressure sensor C1) reached... At that time, it can be determined that the double-trailer train has entered a downhill or deceleration state.

[0080] To ensure that the vehicle in front continues to exert a pulling force in the forward direction rather than a pressure force in the reverse direction on the vehicle behind, the trailer's auxiliary drive system immediately switches to brake energy recovery mode, and according to... The reading is dynamically adjusted in real time to control the recovery intensity: to reduce the extrusion pressure Controlled to near 0 (or The goal is to achieve this; and the intensity is gradually increased to ensure... Maintain at ,when When the system detects that the deceleration or downhill process has ended, the regenerative braking function is deactivated. Due to the lack of auxiliary drive assist, It will gradually increase until the conditions for the auxiliary driver function to be activated are met again.

[0081] Furthermore, regardless of the sensor data, when a trailer brake trigger signal appears (e.g., the trailer brake light illuminates, the trailer ABS is activated, the trailer AEB is activated, etc.), the control system should immediately switch to the regenerative braking state and operate at maximum intensity.

[0082] When the second electric trailer C is in regenerative braking mode and operating at maximum intensity, and When this occurs, it means that the second electric trailer C is pushing the first trailer and is unable to maintain traction between the first and second trailers on its own, and an alarm signal will be issued immediately.

[0083] When the forces exerted on the fifth pressure sensor C2 and the sixth pressure sensor C3 are not equal, that is If the vehicle is determined to be turning, the trailer auxiliary drive system immediately stops working, and only when... Only then can the trailer's brake energy recovery system be activated, and its intensity should be increased slowly to allow for proper braking. Maintain at In other cases, to ensure safety during turning, the trailer's auxiliary drive function and brake energy recovery function should both be turned off.

[0084] Similar to the first electric trailer B, when the second electric trailer C is in its maximum regenerative braking operation state or the power battery SOC is 100% and regenerative braking cannot be initiated, the trailer's regenerative braking function cannot be activated. In this case, if the sensor's force meets the alarm conditions: If the fourth pressure sensor C1 detects that the squeezing pressure continues to increase and reaches... (or When the second electric trailer C is in a dangerous situation, it means that the second electric trailer C has seriously pushed the first electric trailer B and cannot eliminate the danger by its own electric motor power. The driver should be alerted immediately to get out of the dangerous situation as soon as possible (e.g., find a relatively flat road to leave the steep slope and stop to check).

[0085] V. State Determination and Hysteresis Control It should be noted that: to avoid frequent and repeated fluctuations in control state between "straight ahead" and "turning" at critical points (such as when just entering a slight turn) due to sensor noise or bumps, a transition zone is established: when or When the vehicle enters the aforementioned transition zone, the system maintains the current driving state of the previous cycle (straight or turning) and does not change the motor strategy; if a turning state is confirmed, the trailer auxiliary drive is immediately disengaged.

[0086] This invention aims to develop a high-efficiency double-trailer truck train product consisting of two electric trailers and one tractor unit. Without requiring the development of a dedicated high-power tractor unit, it utilizes the auxiliary drive function of the trailers to meet the power requirements of the double-trailer train. The invention focuses on the control logic of the trailer's auxiliary drive and regenerative braking functions. Through a rationally designed pressure sensor and a set of control logic methods, the invention aims to maximize the performance of the electric trailers in the double-trailer truck train, expanding the application scope of the technology and providing a supplementary solution to overcome the challenges of high-power tractor units in the trial operation of double-trailer truck trains in limited areas. The invention also protects the control method.

[0087] The sensor design and control methods specified in this invention cover the following aspects: 1. Under a specific management model, tractor units and trailers are developed, tested, produced, and approved for market application by different entities. Users purchase tractor units and trailers from different companies and combine them into truck trains. It is difficult to achieve more precise control of the trailer by reading the control system operation signals of the tractor unit, often involving commercial competition. The control method designed in this invention makes the function of the trailer's electric system independent of the control system protocol of the tractor unit or another trailer, avoiding the problem of system malfunction due to the inability to obtain the control protocol. It also helps users who purchase tractor units and trailers separately (or at different times, such as different product replacement cycles) to combine into truck trains, thus avoiding the problem of not being able to select electric trailers.

[0088] 2. By utilizing uniformly distributed pressure sensors and set control logic and algorithms, along with a high-performance controller, the vehicle's operating status can be determined without the need for additional acceleration sensors (to measure the vehicle's acceleration and deceleration) or angle sensors (to measure whether the vehicle is traveling in a straight line or turning), thus reducing system complexity and cost.

[0089] 3. By utilizing the differences in control algorithms between the first electric trailer B and the second electric trailer C, the power or braking performance of the dual-trailer train is kept in an orderly and safe state, reducing the risk of instability in the operation of the truck train.

[0090] 4. By utilizing the numerical acquisition and judgment conditions of the pressure sensor on the first electric trailer B, when the trailer is about to apply thrust to the tractor and the train's braking performance has not yet been lost, the system can sense the train's status before the driver or tractor and issue a warning signal in advance, thereby improving the operational safety of the double-trailer train.

[0091] This invention addresses the control of auxiliary drive and regenerative braking functions of two electric trailers when used in a double-trailer truck train, ensuring normal operation and preventing instability. The main advantages of this invention compared to existing methods are: 1. Compared to reading the communication protocol of the tractor control system, the trailer electric system involved in this invention only relies on its own monitoring data of the vehicle's operating status, which avoids the problem of system failure caused by different manufacturers' inability to obtain the control protocol, and expands the application scope of the technology (for example, users purchase tractors and trailers separately to combine into a car train).

[0092] 2. By utilizing uniformly distributed pressure sensors and set control logic and algorithms, along with a high-performance controller, the vehicle's operating status can be determined without the need for additional acceleration sensors (to measure the vehicle's acceleration and deceleration) or angle sensors (to measure whether the vehicle is traveling in a straight line or turning), thus reducing system complexity and cost.

[0093] 3. Pressure sensors are among the most widely used, technologically mature, and reliable sensors in the industrial field, and they play a vital role in improving the overall quality and reliability of trailer electric systems.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for distributing auxiliary driving force in a dual-trailer train based on an electric trailer, characterized in that, include: Obtain the mass parameters and driving resistance parameters of the target electric trailer, calculate and output the traction force benchmark value of the target electric trailer; Real-time acquisition of pressure data collected by multiple pressure sensors installed on the connection device of the target electric trailer; parsing and outputting longitudinal thrust data reflecting the longitudinal pushing action on the target electric trailer, as well as two front tension data from the pressure data. Receive the two front tension data and perform calculations, then output the front tension sum data and the front tension difference data; Receive the front tension difference data, compare the front tension difference data with the preset straight-line conditions, and if the absolute value of the front tension difference data meets the straight-line conditions, output a straight-line driving status signal. Upon receiving the straight-line driving status signal, and upon triggering the straight-line driving status signal, receiving and comparing the front pull and data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, the operating status of the auxiliary drive system or brake energy recovery system of the target electric trailer is controlled.

2. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 1, characterized in that, The connecting device includes a traction pin; the plurality of pressure sensors are mounted on the outer edge circumference of the traction pin, and the plurality of pressure sensors include one rear sensor and two front sensors; In the step of parsing and outputting longitudinal thrust data, the force value collected by the rear sensor is used as the output longitudinal thrust data. In the step of parsing and outputting the two front tension data, the first front tension value and the second front tension value collected by the two front sensors are respectively used as the front tension data output.

3. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 1, characterized in that, The steps of obtaining the mass parameters and driving resistance parameters of the target electric trailer, and calculating and outputting the traction force reference value of the target electric trailer include: The total mass data of the target electric trailer and other trailers attached to the target electric trailer are obtained as the mass parameter; a preset equivalent drag coefficient is obtained as the driving resistance parameter. The total mass data, the preset gravitational acceleration parameters, and the equivalent drag coefficient are used as input parameters to perform a product calculation, and the output product result is used as the traction force reference value.

4. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 2, characterized in that, In the step of receiving the two front tension data and calculating them, and outputting the front tension sum data and the front tension difference data, the difference between the first front tension value and the second front tension value is output as the front tension difference data. The straight-ahead conditions include: using the traction force reference value as a condition limit reference, the absolute value of the front tension difference data is less than or equal to the product of the traction force reference value and a preset percentage parameter, and the absolute value of the front tension difference data is less than a preset straight-ahead threshold.

5. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 1, characterized in that, The step of receiving and comparing the frontal tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, includes: The front tension and data are numerically compared with the traction force reference value; When it is determined that the front tension and data are greater than the product of the traction force reference value and the preset large traction coefficient, a large traction force status signal is output. Upon receiving the high traction force status signal, an auxiliary drive start command is output to control the start of the auxiliary drive system of the target electric trailer.

6. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 5, characterized in that, After starting the auxiliary driver system by outputting the auxiliary driver startup command, the method further includes: The system continuously receives the front tension and data, and compares the front tension and data with the traction force reference value. When it is determined that the front tension and data are less than the product of the traction force reference value and the preset small traction coefficient, a small traction force status signal is output. The system receives the small traction force status signal, generates a power reduction command, and outputs it to the auxiliary drive system to reduce the power output of the auxiliary drive system until the front traction force and data are adjusted and maintained within a preset traction force safety range.

7. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 6, characterized in that, The step of receiving and comparing the front tension data, the longitudinal thrust data, and the traction reference value, and outputting control commands based on the comparison results, further includes: Obtain the operating status signal of the auxiliary drive system; When the working status signal indicates that the auxiliary drive system is in the off state, the front traction and data and the longitudinal thrust data are received, it is determined whether the front traction and data have dropped to zero, and it is determined whether the longitudinal thrust data is greater than or equal to the product of the traction reference value and the anti-push coefficient; If the conditions are met simultaneously, the vehicle is determined to be in a downhill or deceleration state, and a recovery start command is output to activate the brake energy recovery system of the target electric trailer.

8. The auxiliary drive force distribution method for dual-trailer trains based on electric trailers according to claim 7, characterized in that, After the method outputs the recovery start command to activate the braking energy recovery system, it further includes: The continuously acquired longitudinal thrust data is used as system feedback input, and a recovery intensity increase command is output to dynamically increase the recovery intensity of the braking energy recovery system until the longitudinal thrust data is monitored to decrease to zero. While dynamically increasing the recovery intensity, the front pull force and data of the input system are continuously monitored; when the front pull force and data increase and exceed the upper limit of the preset pull force safety range, a recovery shutdown command is output to shut down the braking energy recovery system. The method also includes system protection and alarm steps: Independent of the front tension and data and the longitudinal thrust data, the battery state of charge data and external braking trigger signal of the target electric trailer are acquired in real time. When the external braking trigger signal is received, the maximum recovery command is directly output over other control logic to control the braking energy recovery system to enter the maximum intensity working state. When the system receives a signal indicating that the regenerative braking system is operating at maximum intensity, or when the battery state-of-charge data indicates that the battery is fully charged and the longitudinal thrust data is determined to be continuously increasing beyond a preset safety push alarm threshold, an abnormal push alarm signal is output to the vehicle's driver's cabin.

9. The auxiliary drive force distribution method for a dual-trailer train based on an electric trailer according to claim 1, characterized in that, The step of comparing the front tension difference data with preset straight-line conditions further includes: When the absolute value of the front tension difference data is greater than the preset turning threshold, a turning driving status signal is output. Upon receiving the turning driving status signal, the system outputs a drive cut-off command to forcibly shut down the auxiliary drive system of the target electric trailer.

10. The auxiliary drive force distribution method for a dual-trailer train based on an electric trailer according to any one of claims 1 to 9, characterized in that, The dual-trailer truck train includes a tractor, a first electric trailer, and a second electric trailer that are articulated together in sequence; the target electric trailer is either the first electric trailer or the second electric trailer. In the control logic, the small traction coefficient set for the second electric trailer is smaller than the small traction coefficient set for the first electric trailer, so that the braking energy recovery system of the second electric trailer receives the start control command before the first electric trailer.

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