A method and system for emergency braking control of a modular trolleybus

Abstract

The application discloses a kind of emergency brake control method and system of trackless trolleybus, method includes: if receiving brake signal, detect current speed v and target distance relative to target position;If the target distance is less than the first threshold value of pre-set and current speed v is greater than the second threshold value of pre-set, function relationship of brake distance s and brake force distribution coefficient is constructed as target function according to target strategy, also obtain the instability working condition information of each carriage, configure the local constraint of the target function according to the instability working condition information;Optimal value is solved to the target function configured with local constraint, and the brake force distribution coefficient of each carriage is obtained, and the corresponding carriage is braked according to the brake force distribution coefficient, until the vehicle stops running.The application guarantees that trackless trolleybus is safely and stably braked, and the shortest brake distance is reached.

Description

Technical Field

[0001] This invention relates to the field of trolleybus control, and more particularly to an emergency braking control method and system for trolleybuses that can be assembled. Background Technology

[0002] With rapid urban development and a growing population, the rationalization of urban public transportation has become a key issue restricting urban development. Intelligent Rail Transit (IRT) trains are a type of trolleybus that can be assembled from multiple carriages and articulated to change passenger capacity, effectively addressing problems such as traffic congestion, inconvenience, and environmental pollution in modern transportation.

[0003] The trolleybus employs "virtual track" following control technology. Based on signals collected by various sensors installed around the vehicle, it accurately analyzes the virtual track information of the current route and issues appropriate control signals. Through actions such as pantograph movement, braking, and steering, it ensures the train travels precisely on the predetermined "virtual track." When unavoidable obstacles or tunnels appear on the "virtual track," a braking strategy or emergency braking strategy is required. The former is generally used when the distance to the braking endpoint is relatively far, while the latter is generally used when the distance is relatively short. The conventional braking strategy is: first stage, linear increase in braking force; second stage, maintaining braking force until the vehicle comes to a complete stop. The conventional emergency braking strategy is: without an anti-lock braking system (ABS), locking the wheels until the vehicle comes to a complete stop; with an ABS, intermittently locking the wheels until the vehicle comes to a complete stop.

[0004] With increasing vehicle speeds and more complex road conditions, when trolleybuses undergo emergency braking, the inter-vehicle forces and significant braking forces quickly push the tire adhesion to its limit, making them more prone to instability during emergency braking and increasing the likelihood of fishtailing, folding, and other instability events. Furthermore, conventional braking strategies and emergency braking strategies cannot simultaneously guarantee vehicle braking stability and reduce braking distance. Therefore, developing an emergency braking strategy suitable for the instability conditions of trolleybuses is urgently needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is: in view of the technical problems existing in the prior art, this invention provides an emergency braking control method and system for trolleybuses that can be assembled, so as to ensure safe and stable braking of trolleybuses while achieving the shortest braking distance.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] An emergency braking control method for a trolleybus that can be assembled includes the following steps:

[0008] S1) If a braking signal is received, detect the current speed v and the target distance relative to the target position;

[0009] S2) If the target distance is less than a preset first threshold and the current speed v is greater than a preset second threshold, construct a functional relationship between the braking distance s and the braking force distribution coefficient as the target function according to the target strategy. Also obtain the instability condition information of each car, configure the local constraints of the target function according to the instability condition information. The target strategy is: after the reaction time t1, the braking force increases linearly from t1 to t2, increases linearly from t2 to t4 and then decreases, and remains constant from t4 to t5. At t5, the vehicle speed is less than a preset third threshold, the braking force increases linearly from t5 to t6, causing the vehicle wheels to lock up, and remains constant from t6 to t7. At t7, the vehicle stops running.

[0010] S3) Solve for the optimal value of the objective function with local constraints to obtain the braking force distribution coefficient of each car. Brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

[0011] Furthermore, step S2) involves constructing the objective function based on the relationship between the braking distance s and the braking force distribution coefficient in the target strategy, including the following steps:

[0012] S21) Calculate the ground normal reaction force of the front and rear axles of each carriage. The expression is as follows:

[0013]

[0014]

[0015] In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. For the ground normal reaction force of the rear axle of carriage Mi, k S The equivalent stiffness of the front and rear axle suspensions of the passenger compartment Mi is given. This represents the deformation of the front axle suspension of the passenger compartment (Mi). Let m be the deformation of the rear axle suspension of the passenger compartment. Mi Let Mi be the total mass of the carriage, and g be the acceleration due to gravity.

[0016] S22) The functional relationship between the braking force distribution coefficient and the braking deceleration is constructed by the ground normal reaction forces of the front and rear axles of each carriage as follows:

[0017]

[0018] In the above formula, a is the braking deceleration, i is the serial number of the carriage Mi, and n is the total number of carriages. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. The braking force distribution coefficient for the rear axle of the carriage Mi;

[0019] S23) Based on the configuration of each car, the braking deceleration when the vehicle locks up is calculated using the ground normal reaction force of the front and rear axles of each car and the rolling adhesion coefficient or the maximum ground adhesion coefficient. The expression is as follows:

[0020] If each carriage lacks a braking anti-lock device

[0021] If each carriage is equipped with a braking anti-lock device

[0022] In the above formula, i is the serial number of carriage Mi, and n is the total number of carriages. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. Let Mi be the rolling adhesion coefficient of the front axle of the carriage. Let Mi be the rolling adhesion coefficient of the rear axle of the carriage. The maximum ground adhesion coefficient of the carriage Mi;

[0023] S24) Using the current speed v as the initial speed, simplify the target strategy to obtain the relationship between braking deceleration and time. Based on the relationship between braking deceleration and time, construct the braking distance s and braking deceleration a, as well as the braking deceleration a when the vehicle locks up. s The functional relationship is as follows:

[0024]

[0025] In the above formula, v0 is the initial velocity, a is the braking deceleration, and a s v1 is the braking deceleration when the vehicle locks up, v2 is the speed corresponding to the third threshold, t3 is the brake response time in the linear function of braking force and time, and t4 is the moment when the braking deceleration is at its maximum in the linear function of braking force and time.

[0026] Furthermore, in step S24), the relationship between braking deceleration and time is as follows: after a reaction time t1, the braking deceleration a increases linearly from t1 to t3, t2 < t3 < t4, and remains constant from t3 to t5. At t5, the vehicle speed is less than the preset third threshold, and the braking deceleration a increases linearly from t5 to t6. sThis causes the vehicle to lock up, remaining constant between times t6 and t7, and stopping at time t7.

[0027] Furthermore, in step S2), configuring the local constraints of the objective function based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. Mi The lateral reaction force from the ground on the rear axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product of.

[0028] Furthermore, in step S2), configuring local constraints based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. Mi The lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of.

[0029] Furthermore, in step S2), configuring local constraints based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. MiThe lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of the ... Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product of.

[0030] Furthermore, the braking deceleration a of the carriage Mi. Mi The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows:

[0031]

[0032] In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. The braking force distribution coefficient for the rear axle of the carriage Mi is given. Let X be the force along the X-axis at the hinge of the front of the carriage Mi. The force along the X-axis is the force at the rear hinge of carriage Mi, with the direction of travel of carriage Mi being the positive direction of the X-axis.

[0033] Furthermore, the lateral reaction force from the ground acting on the rear axle of the carriage Mi. The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows:

[0034]

[0035] In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. L is the braking force distribution coefficient of the rear axle of the carriage Mi. Mi L is the horizontal distance between the front and rear axles of the carriage, Mi. T L is the length of the hinge between the carriages. t m is the distance from the hinge to the nearest axle. Mi For the overall vehicle weight of carriage Mi, The average braking deceleration from the first car to the car Mi is... Let Mi be the angle between the front hinge of the carriage and the horizontal plane. The angle between the rear hinge of the carriage Mi and the horizontal plane is defined as follows:

[0036] Furthermore, the lateral reaction force from the ground acting on the rear axle of the carriage Mi. The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows:

[0037]

[0038] In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. L is the braking force distribution coefficient of the rear axle of the carriage Mi. Mi L is the horizontal distance between the front and rear axles of the carriage, Mi. T L is the length of the hinge between the carriages. t m is the distance from the hinge to the nearest axle. Mi For the overall vehicle weight of carriage Mi, The average braking deceleration from the first car to the car Mi is... Let Mi be the angle between the front hinge of the carriage and the horizontal plane. The angle between the rear hinge of the carriage Mi and the horizontal plane is defined as follows:

[0039] This invention also proposes an emergency braking control system for troop-type trolleybuses, comprising:

[0040] The information acquisition unit is used to detect the current speed v and the target distance relative to the target position if a braking signal is received.

[0041] The braking distance calculation unit is used to construct a functional relationship between the braking distance s and the braking force distribution coefficient as the objective function according to the objective strategy if the target distance is less than a preset first threshold and the current speed v is greater than a preset second threshold. It also obtains the instability condition information of each car and configures the local constraints of the objective function according to the instability condition information. The objective strategy is as follows: after the reaction time t1, the braking force increases linearly from t1 to t2, increases linearly from t2 to t4 and then decreases, and remains constant from t4 to t5. At t5, the vehicle speed is less than a preset third threshold, and the braking force increases linearly from t5 to t6, causing the vehicle wheels to lock up. It remains constant from t6 to t7, and the vehicle stops running at t7.

[0042] The braking unit is used to solve for the optimal value of the objective function with local constraints, obtain the braking force distribution coefficient of each car, and brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

[0043] Compared with the prior art, the advantages of the present invention are as follows:

[0044] This invention constructs an objective function for the relationship between braking distance and braking force distribution coefficient. The optimal solution for braking force distribution coefficient is obtained by simultaneously solving the objective function and constraint functions. Under the condition of optimal braking force distribution coefficient, the corresponding braking distance is also the shortest braking distance, thereby making the braking process more gentle. While achieving the shortest braking distance, it ensures the vehicle's stability and smoothness under emergency braking conditions. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the braking process without considering load transfer in an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the braking process considering load transfer in an embodiment of the present invention.

[0047] Figure 3 This is a diagram showing the stress analysis of the suspension in an embodiment of the present invention.

[0048] Figure 4 This is a schematic diagram of a vehicle experiencing emergency braking instability due to a deflection angle at the front hinge in an embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram of a vehicle experiencing emergency braking instability due to a deflection angle at the rear hinge in an embodiment of the present invention.

[0050] Figure 6 This is a schematic diagram of a vehicle in an emergency braking instability situation where both the front and rear hinges produce deflection angles, as described in an embodiment of the present invention.

[0051] Figure 7 This is a curve showing the relationship between braking force and time in an embodiment of the present invention.

[0052] Figure 8 This is a curve showing the relationship between braking deceleration and time in an embodiment of the present invention.

[0053] Figure 9 This is a flowchart of the method in an embodiment of the present invention.

[0054] Figure 10 The values ​​of each parameter in the simulation process of this embodiment of the invention are shown.

[0055] Figure 11 The figures show the braking distance and braking deceleration curves when the target carriage suspension deformation changes under ideal conditions in this embodiment of the invention.

[0056] Figure 12 The figures show the braking distance and braking deceleration curves when the center of gravity of the target carriage changes in an embodiment of the present invention.

[0057] Figure 13 This is the curve showing the shortest braking distance as a function of the hinge angle when the center of gravity of the target carriage changes in an embodiment of the present invention. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0059] Parameter meaning explanation:

[0060] m Mi —The total mass (kg) of the i-th carriage;

[0061] g — acceleration due to gravity (m / s²) 2 );

[0062] a Mi — Braking deceleration of the i-th carriage (m / s) 2 );

[0063] —The average braking deceleration from car 1 to car i (m / s²) 2 );

[0064] —The average braking deceleration from car 1 to car m (m / s²) 2 );

[0065] —The average braking deceleration from car m+1 to car n (m / s²) 2 );

[0066] —The ground braking force (N) on the front axle and rear axle of the i-th car;

[0067] — The lateral ground reaction force (N) on the front axle and rear axle of the i-th car;

[0068] —The ground normal reaction force (N) of the front axle and the rear axle of the i-th car;

[0069] — The X-force (N) experienced at the hinge between the front and rear of the i-th car;

[0070] —Y-direction force (N) at the hinge between the front and rear of the i-th car;

[0071] —The Z-force (N) experienced at the hinge between the front and rear of the i-th car;

[0072] F μ —Total ground braking force (N) from car 1 to car i;

[0073]

[0074] —The vertical angle (°) between the front and rear hinges of the i-th carriage and the horizontal plane;

[0075] —The left and right angles (°) between the front and rear hinges of the i-th carriage and the horizontal plane;

[0076] —The braking force distribution coefficients of the front axle and the rear axle of the i-th car;

[0077] μ S —Rolling adhesion coefficient;

[0078] μ P —Maximum ground adhesion coefficient;

[0079] k S —Equivalent stiffness of the axle suspension (N / m);

[0080] L Mi — The horizontal distance (m) between the two axles of the i-th carriage;

[0081]

[0082] L T —Length of hinge between carriages (m);

[0083] L t —From the hinge point to the nearest adjacent axis (m);

[0084] — The distance from the center of gravity of the i-th car to the ground (m);

[0085] H T — The distance from the front hinge to the ground and the distance from the rear hinge to the ground (m);

[0086]

[0087] Compared to trams, the operating conditions of trolleybuses, which are assembled from multiple sections, lack the Y-axis force constraint of the tracks on the wheels, making them more prone to instability conditions such as yaw and folding. Compared to trailers, trolleybuses have more sections, and each section is more severely affected by inter-vehicle forces. During braking on the road, axle load transfer inevitably occurs due to factors such as acceleration, inter-vehicle forces, and road conditions. Consequently, the ground normal reaction forces on each axle differ. When braking force is applied, the wheel pair with the smallest ground normal reaction force is more likely to lock up, meaning the sum of the braking force applied to that axle and the articulation force on that section exceeds the ground adhesion constraint, causing severe wheel abrasion and even yaw, folding, and other instability conditions. To fully utilize the vehicle's braking effect and avoid instability conditions, controlling the vehicle's ground normal reaction force, articulation force, braking force distribution coefficient, and articulation angle is crucial.

[0088] Because classic multi-axle vehicle dynamics models oversimplify the vehicle during calculations, the constraints are insufficient, the number of independent equations for force analysis is inadequate, and the model exhibits static indeterminacy. Therefore, to transform the model into a statically determinate one, some necessary constraints should be retained during the dynamic simplification of multi-axle vehicles, allowing the model to be used more effectively for force analysis of multi-axle vehicles. This embodiment introduces an approximate solution method for multi-axle vehicle loads, namely, incorporating suspension deformation compatibility equations and force relationships at hinge points into the multi-axle vehicle emergency braking dynamics model, such as... Figure 1 and Figure 2 As shown. Assuming the chassis is considered a constant rigid body, and each suspension element is simplified to a spring with a stiffness equal to the equivalent stiffness of the suspension; simultaneously, the deformation of the suspension is constrained by the chassis, and the forces acting on the suspension are as follows... Figure 2 As shown. Since the hinge plate at the vehicle connection is made of rubber, and in order to enable multi-axle vehicles to travel on sloping roads, the hinge can swing up and down at a larger angle than the up and down swing angle caused by load transfer during braking. Therefore, the situation of the hinge getting stuck during braking is not considered. Thus, each car is treated as an individual rigid body for force analysis, and the force at the hinge is used to represent the pressure or tension from the front and rear car compartments.

[0089] according to Figure 1 The force balance equations for a vehicle braking on a level road surface can be obtained as follows:

[0090]

[0091]

[0092] according to Figure 2 The torque balance equation for the vehicle during load transfer during braking on a level road surface can be obtained as follows:

[0093]

[0094]

[0095] In formulas (3) and (4), when i = 1, When i = n

[0096] pass Figure 3 The independent force equations of the suspension caused by load transfer can be obtained:

[0097]

[0098]

[0099] The geometric angle equation for the rear hinge of the i-th car can be obtained by using the vertical deflection angle caused by load transfer at the rear hinge of the i-th car and the front hinge of the (i+1)-th car:

[0100]

[0101] Force equations at the hinge:

[0102]

[0103]

[0104]

[0105]

[0106] During braking, due to the different distribution of braking force, the braking deceleration of each carriage is different, resulting in forces acting at the articulation points between the carriages. Under the action of the articulation force, the braking deceleration of a single carriage is the same as the overall braking deceleration of the multi-car trolleybus. When the articulation force is too large, due to the deflection angle, the carriage is subjected to lateral forces, which can easily lead to instability. Therefore, it is necessary to solve for the magnitude of the force at the articulation points.

[0107] Let the direction of travel be defined as positive, and let i ∈ [1, n]. The force balance equations for the entire vehicle's X-axis are as follows:

[0108]

[0109] Taking i=m as an example, in solving... At that time, considering the first to m carriages as a whole, the force balance equations in the X-axis direction are as follows:

[0110]

[0111] The following carriages (m+1) to n are considered as a whole, and their force balance equations along the X-axis are as follows:

[0112]

[0113] Calculate the hinge force along the X-axis at the hinge joint of the m-th carriage.

[0114]

[0115]

[0116] When a trolleybus undergoes emergency braking, a larger braking force is distributed to achieve better braking effect, resulting in a very small lateral force that can be distributed to the tires. Under emergency braking conditions, the force on the tires can easily exceed the maximum ground adhesion, leading to serious instability phenomena such as skidding, tail-swing, and carriage folding. Therefore, trolleybuses require higher control over factors that may cause instability, such as articulation force, braking force distribution coefficient, the maximum lateral force that the tires can withstand during braking, and the left and right sway angles at the front and rear articulations. Analysis of the factors that may cause instability during emergency braking of trolleybuses reveals that when a carriage is affected by instability factors, the tires will generate lateral force, and the front and rear articulations may develop left and right sway angles. These can be categorized into three types: sway angle at the front articulation and no sway angle at the rear articulation; no sway angle at the front articulation and sway angle at the rear articulation; and sway angles at both the front and rear articulations. Figures 4 to 6 As shown, according to Figures 4 to 6 The force balance equation for a single carriage can be obtained as follows:

[0117]

[0118]

[0119] Single-car torque balance equation:

[0120]

[0121]

[0122]

[0123] Tire force balance equation:

[0124]

[0125]

[0126] Equation of forces acting on a hinge:

[0127]

[0128]

[0129] Because trolleybuses prone to angle changes and body swaying during emergency braking, resulting in lateral forces, it is necessary to calculate the maximum lateral forces on each axle tires during emergency braking. The critical condition for instability. The angle η of the deflection at the front and rear hinges and the braking deceleration α are related, and it is necessary to find the relationship between them and perform optimization.

[0130] Formulas (13) and (16) can be used to obtain formulas (26) and (27), which are the joints of the (m-1)th car section. The articulation point with the m-th carriage The force equations are:

[0131]

[0132]

[0133] The hinge point T2 of the (m-1)th car and the hinge point T1 of the mth car are the same hinge point:

[0134]

[0135] During the process of being subjected to force at the hinge, the force in the Y-axis direction caused by the swing angle is:

[0136]

[0137]

[0138] From formulas (18), (20), (21), (30), and (31), the magnitude of the lateral force on the tires caused by the Y-axis force at the hinge of the i-th car section can be obtained:

[0139]

[0140]

[0141] This yields the general formula for calculating the lateral forces acting on the tires of the front and rear axles of the i-th section of the carriage:

[0142]

[0143]

[0144] Based on the maximum braking force provided by the ground adhesion coefficient and the braking force distributed to each axle, calculate the maximum lateral force that each axle tire can provide under this condition:

[0145]

[0146]

[0147] That is, the maximum value of the lateral force of the front and rear axles of the i-th carriage is:

[0148]

[0149]

[0150] Based on formulas (32), (33), (36), and (37), the condition for determining instability in a multi-axle vehicle under emergency braking conditions is as follows:

[0151]

[0152]

[0153] Since braking deceleration is the derivative of vehicle speed with respect to time during braking, that is... It reflects the magnitude of the ground braking force.

[0154] On different road surfaces, the ground braking force is:

[0155]

[0156] Therefore, the deceleration that can be achieved by assembling trolleybuses (m / s²) 2 )for:

[0157]

[0158] If both front and rear wheels lock up simultaneously, and there is no anti-lock braking system (ABS) to control the vehicle's braking, the braking deceleration will be:

[0159]

[0160] When both front and rear wheels lock up simultaneously, if an ideal anti-lock braking system (ABS) is in place to control the vehicle's braking, the braking deceleration will be:

[0161]

[0162] The braking distance and driving safety of a trolleybus are closely related. In this embodiment, the linear function of braking force over time is:

[0163]

[0164] like Figure 7 As shown, 0 to t1 represents the brake's reaction time. The brake begins to engage from t1, and the braking force F during the time interval t1 to t2... μIt continues to increase with a slope of k1. When it reaches time point t2, due to the effect of the core shift on each car, F μ The growth rate of [something] begins to decrease. Because the braking deceleration increases with the braking force, the trolleybus detects a potential yaw and sideslip risk at time t3. To avoid this risk, the braking force is appropriately reduced. During times t4 to t5, the braking force F [something]. μ The train is in a stable state. When the speed drops to 10 km / s, the trolleybuses begin to lock (i.e., all wheels stop turning during time t5 to t6), until the entire train locks at time t6, at which point F... μ3 Smoothly decelerate to a stop; at this point, μ3 is the coefficient of sliding adhesion. s .

[0165] Due to braking force F μ The changes due to core transfer and safety considerations are small in magnitude and short in duration. Therefore, the linear function of braking force versus time is simplified, resulting in the braking deceleration versus time curve as shown below. Figure 8 As shown, 0–t1 represents the brake's reaction time, t1–t3 represents the period during which braking deceleration continuously increases with increasing braking force, and t3–t5 represents the braking duration. When the speed drops to 10 km / h, the trolleybus begins to lock up. At time t5, the speed is 10 km / h, and at time t6, all wheels of the trolleybus are locked up. t6–t7 represents the time required for the trolleybus to come to a stop after locking up and sliding.

[0166] During the time interval t1 to t3:

[0167]

[0168]

[0169] Integrating over time, since v = v1 at t1, therefore...

[0170]

[0171] Integrating again

[0172]

[0173] Therefore, the velocity v3 at time t3 is

[0174]

[0175]

[0176] Therefore, from formulas (45) and (48), the braking distance during the time interval t1 to t3 is:

[0177]

[0178] Substitute formula (50) into formula (51),

[0179]

[0180] During the duration from t3 to t5, the braking deceleration a remains constant, allowing the trolleybuses to undergo uniformly decelerated motion. The initial velocity is v3, and the final velocity is v5 = 10 km / s.

[0181]

[0182] During the time interval t5 to t6, the deceleration continuously increases, and the distance can be obtained by solving the problem during the time interval t1 to t3.

[0183]

[0184] During the duration from t6 to t7, the braking deceleration is a. s And remain constant, undergo uniform deceleration, with an initial velocity of v6 and a final velocity of 0, therefore

[0185]

[0186] Therefore, the total braking distance is

[0187] s = s1 + s2 + s3 + s4 (56)

[0188] Substituting formulas (52), (53), (54), and (55) into formula (56), therefore...

[0189]

[0190] Because the time intervals from t1 to t3 and from t5 to t6 are very short, v1≈v3 and v5≈v6, therefore...

[0191]

[0192] Substituting formula (47) into formula (56), and since v1 equals the initial velocity v0, we have:

[0193]

[0194] Based on the above derivation process, this embodiment proposes an emergency braking control method for trolleybuses based on the relationship between the speed and braking distance of the trolleybuses. Figure 9 As shown, it includes the following steps:

[0195] S1) If a braking signal is received, receive driving information, including the total mass of each car, the angle between the hinges of each car, the rolling adhesion coefficient, the maximum ground adhesion coefficient, the current speed v, and the target distance relative to the target position. Compare the current speed v with the speed threshold v. c The size of the distance is compared with the target distance and the distance threshold s. c The size; in this embodiment, the target location is the location of the obstacle, tunnel, or depression;

[0196] S2) If the current speed v is less than the speed threshold v c And the target distance is greater than the distance threshold s c Alternatively, the current speed v is greater than the speed threshold v. c And the target distance is greater than the distance threshold s c If so, then the conventional braking strategy is executed, such as gradually increasing the braking force and then keeping the braking force constant.

[0197] If the current speed v is less than the speed threshold v c And the target distance is less than the distance threshold s c If so, then the conventional emergency braking strategy will be executed, such as locking all the wheels of the trolleybus.

[0198] If the current speed v is greater than the speed threshold v c And the target distance is less than the distance threshold s c Then the target strategy is executed, and the target strategy is as follows: Figure 7 As shown, after a reaction time t1, the braking force increases linearly from t1 to t2, increases linearly from t2 to t4 and then decreases, remaining constant from t4 to t5. At t5, the vehicle speed is less than 10 km / h, and the braking force increases linearly from t5 to t6, causing the vehicle wheels to lock up. It remains constant from t6 to t7, and the vehicle stops running at t7. Correspondingly, a functional relationship between the braking distance s and the braking force distribution coefficient is constructed as the objective function based on the objective strategy. Instability condition information of each compartment is also obtained, and local constraints of the objective function are configured based on the instability condition information.

[0199] S3) Solve for the optimal value of the objective function with local constraints to obtain the braking force distribution coefficient of each car. Brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

[0200] In step S2) of this embodiment, constructing the objective function based on the relationship between the braking distance s and the braking force distribution coefficient in the target strategy includes the following steps:

[0201] S21) Calculate the ground normal reaction force of the front and rear axles of each carriage. The expressions are shown in formulas (5) and (6) above, where i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. For the ground normal reaction force of the rear axle of carriage Mi, k S Let Mi be the equivalent stiffness of the front and rear axle suspensions of the passenger compartment, and let be a constant. Let Mi be the deformation of the front axle suspension of the passenger compartment, and let Mi be the measured value. Let Mi be the deformation of the rear axle suspension of the passenger compartment, and m be the measured value. Mi Let Mi be the total mass of the carriage, which is constant; g is the acceleration due to gravity, which is constant.

[0202] S22) The braking force distribution coefficient and braking deceleration are constructed by the ground normal reaction forces of the front and rear axles of each car. The functional relationship is shown in the formula (41) above, where a is the braking deceleration, i is the serial number of car Mi, and n is the total number of cars. The ground normal reaction force of the front axle of the carriage Mi, calculated in step S21), The ground normal reaction force of the rear axle of the carriage Mi, calculated in step S21), Let Mi be the braking force distribution coefficient of the front axle of the carriage, which needs to be determined. Let Mi be the braking force distribution coefficient of the rear axle of the carriage to be determined;

[0203] S23) Based on the configuration of each car, the braking deceleration when the vehicle locks up is calculated by the ground normal reaction force of the front and rear axles of each car and the rolling adhesion coefficient or the maximum ground adhesion coefficient. The expression is shown in formula (42) and formula (43) above, where i is the serial number of car Mi and n is the total number of cars. The ground normal reaction force of the front axle of the carriage Mi, calculated in step S21), The ground normal reaction force of the rear axle of the carriage Mi, calculated in step S21), Let be the rolling adhesion coefficient of the front axle of the carriage Mi, and be a measured quantity. Let be the rolling adhesion coefficient of the rear axle of the carriage Mi, and be a measured quantity. Let Mi be the maximum ground adhesion coefficient of the carriage, and let Mi be the measured quantity.

[0204] S24) Using the current velocity v as the initial velocity, the target strategy is simplified to obtain the relationship between braking deceleration and time, such as... Figure 8 As shown, after a reaction time t1, the braking deceleration a increases linearly from t1 to t3, t2 < t3 < t4, and remains constant from t3 to t5. At t5, the vehicle speed is less than the preset third threshold, and the braking deceleration a increases linearly from t5 to t6. sThe vehicle locks up, remaining constant between times t6 and t7, and stops moving at time t7. Based on the relationship between braking deceleration and time, a braking distance s and braking deceleration a, as well as the braking deceleration a when the vehicle locks up, are constructed. s The functional relationship is shown in the formula (59) above, where v0 is the initial velocity, a is the braking deceleration, and a s v5 is the braking deceleration when the vehicle locks up, v5 is 10 km / h, t1 is the brake reaction time, and t3 is the moment when the braking deceleration a is at its maximum.

[0205] In step S2) of this embodiment, the instability condition information includes three cases: the left-right angle between the front hinge of the car body Mi and the horizontal plane is 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0; the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is 0; and the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0. Correspondingly, configuring the local constraints of the objective function according to the instability condition information includes:

[0206] If the left-right angle between the front hinge of carriage Mi and the horizontal plane is 0, and the left-right angle between the rear hinge of carriage Mi and the horizontal plane is not 0, the local constraint is configured as follows: the braking force distribution coefficient of the front axle of carriage Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. Mi The lateral reaction force from the ground on the rear axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product;

[0207] If the angle between the front hinge of carriage Mi and the horizontal plane is not 0, and the angle between the rear hinge of carriage Mi and the horizontal plane is 0, the local constraint is configured as follows: the braking force distribution coefficient of the front axle of carriage Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. Mi The lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ PBraking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of.

[0208] If the angle between the front hinge of car body Mi and the horizontal plane is not 0, and the angle between the rear hinge of car body Mi and the horizontal plane is not 0, the local constraint is configured as follows: the braking force distribution coefficient of the front axle of car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient μ P The braking deceleration a of the previous carriage Mi-1 The braking deceleration a of the carriage Mi is less than that of the carriage Mi. Mi The lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of the ... Less than or equal to the maximum ground adhesion coefficient μ P Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product of.

[0209] In this embodiment, the braking deceleration a of the carriage Mi Mi The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is shown in formula (17) above, where i is the serial number of the carriage Mi. The ground normal reaction force of the front axle of the carriage Mi, calculated in step S21), The ground normal reaction force of the rear axle of the carriage Mi, calculated in step S21), Let Mi be the braking force distribution coefficient of the front axle of the carriage, which needs to be determined. Let Mi be the braking force distribution coefficient of the rear axle of the carriage, which needs to be determined. The force along the X-axis at the hinge of the front of the carriage Mi is a measured quantity. The force along the X-axis at the rear hinge of carriage Mi is a measurable quantity, and the direction of travel of carriage Mi is the positive X-axis direction.

[0210] In this embodiment, the lateral reaction force from the ground acting on the rear axle of the carriage Mi The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is shown in formula (32) above, and the lateral reaction force of the ground on the rear axle of the car body Mi is... The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is shown in formula (33) above, where i is the serial number of the carriage Mi. The ground normal reaction force of the front axle of the carriage Mi, calculated in step S21), The ground normal reaction force of the rear axle of the carriage Mi, calculated in step S21), Let Mi be the braking force distribution coefficient of the front axle of the carriage, which needs to be determined. Let L be the braking force distribution coefficient of the rear axle of the carriage Mi to be determined. Mi Let Mi be the horizontal distance between the front and rear axles of the carriage, which is a constant, and L be the horizontal distance between the front and rear axles of the carriage. T L is the length of the hinge between the carriages, which is a constant. t Let m be the distance from the hinge to the nearest axle, which is a constant. Mi Let Mi be the total mass of the carriage, and let be a constant. The average braking deceleration from the first car to the car Mi is... The angle between the front hinge of the carriage Mi and the horizontal plane is the left and right angle, and is a measured value. The angle between the rear hinge of the carriage Mi and the horizontal plane is the measured value.

[0211] This embodiment also proposes an emergency braking control system for a troopable trolleybus, including an information acquisition unit for detecting the current speed v and the target distance relative to the target position if a braking signal is received.

[0212] The braking distance calculation unit is used to construct a functional relationship between the braking distance s and the braking force distribution coefficient as the objective function according to the objective strategy if the target distance is less than a preset first threshold and the current speed v is greater than a preset second threshold. It also obtains the instability condition information of each car and configures the local constraints of the objective function according to the instability condition information. The objective strategy is as follows: after the reaction time t1, the braking force increases linearly from t1 to t2, increases linearly from t2 to t4 and then decreases, and remains constant from t4 to t5. At t5, the vehicle speed is less than a preset third threshold, and the braking force increases linearly from t5 to t6, causing the vehicle wheels to lock up. It remains constant from t6 to t7, and the vehicle stops running at t7.

[0213] The braking unit is used to solve for the optimal value of the objective function with local constraints, obtain the braking force distribution coefficient of each car, and brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

[0214] The effectiveness of the method in this embodiment will be illustrated through simulation below.

[0215] Based on the preceding content, a dynamic model of a three-car trolleybus under emergency braking conditions is established, and the numerical settings of each simulation parameter are as follows: Figure 10As shown, the deformation of the suspension of axles 1 and 2 of the i-th carriage is... As input, the braking force distribution coefficient under this deformation condition is obtained through simulation. Vehicle braking distance s, ground lateral reaction force and maximum ground lateral reaction force To ensure the stability of the trolleybus during high-speed emergency braking, the shortest braking distance and the optimal braking force distribution coefficient are achieved.

[0216] Under ideal conditions, the braking force distribution coefficients of axles 1 and 2 in the i-th car are... and The sum equals 1, that is First, based on the global constraint λ Mi <μ p The range of values ​​for the brake force distribution coefficient is (0.25, 0.75). The value of the brake force distribution coefficient must be within this range; otherwise, the wheels will slip, and the brakes will not be able to brake properly.

[0217] The deflection angle at the front and rear hinge points of adjacent carriages is fixed at 15°. The study investigates the emergency braking conditions of trolleybuses that can be assembled at different initial speeds (30, 60, 90 km / h), such as... Figure 11 As shown, Figure 11 From top to bottom, the chart shows the shortest braking distance and braking deceleration curves of a trolleybus with different initial speeds (30, 60, 90 km / h). It can be observed that when the speed is fixed... For any value, When it varies within the range of 0 to 0.8, as As the value of λ increases, the shortest braking distance s gradually decreases, and the corresponding optimal braking force distribution coefficient λ gradually increases. With an initial speed of 30 km / h, when... At that time, the shortest braking distance without vehicle instability was found to be 4.581m, and the corresponding optimal braking force distribution coefficient was λ1. M1 =0.746,λ1 M2 =0.485,λ1 M3 =0.75. At this time, λ1 M1 and λ1 M3 It approaches 0.75, which is close to the maximum ground adhesion coefficient μ. p Continue to increase The value, This will cause the vehicle to become unstable, so This represents the braking limit value under conditions where the vehicle remains stable. Simultaneously, under ideal conditions—that is, when the vehicle mass does not move forward or backward and the deflection angle at the vehicle's articulation is fixed—the shortest braking distance *m* corresponding to different initial velocities of the vehicle is calculated. i Since the deformation and braking force distribution coefficients of the suspensions on axles 1 and 2 are the same, the suspension deformation corresponding to the shortest braking distance under the premise of ensuring stability during emergency braking can be directly obtained regardless of the initial velocity of the vehicle. and braking force distribution coefficient

[0218] The simulation conditions remain unchanged (the deflection angle at the front and rear hinges is 15°, and the initial velocity is 30 km / h). The emergency braking situation of the vehicle when the center of gravity moves forward by 0.08m and 0.05m, and backward by 0.08m, 0.1m, and 0.15m is as follows: Figure 12 As shown (where "-" indicates the particle moves forward, "+" indicates the particle moves backward, and "0" indicates the particle's position remains unchanged). It can be observed that the shortest braking distance and deceleration achievable by the vehicle differ depending on the position of the center of mass, roughly manifesting as follows: (in This indicates the shortest braking distance that can be achieved when the vehicle's center of gravity moves forward or backward. This indicates the shortest braking distance achievable without the vehicle's center of gravity shifting. Although shifting the center of gravity backward can reduce the braking distance, the distance the vehicle's center of gravity shifts forward or backward cannot be too large, otherwise it will cause the train to become unstable during emergency braking.

[0219] The deflection angle at the front and rear articulations caused by emergency braking of a vehicle is not fixed. It may be random due to factors such as different road conditions, different braking force distribution coefficients, and passenger distribution. Because of these different deflection angles, the braking effect also varies. Therefore, studying the emergency braking conditions of a vehicle under different articulation deflection angles is particularly important. The simulation conditions are: initial speed 30 km / h. Simulation results are as follows Figure 13 As shown, it can be observed that when other conditions remain unchanged, the shortest braking distance s that the vehicle can achieve generally decreases as the left and right deflection angle η at the vehicle's articulation point decreases. In other words, the smaller the deflection angle η is, the smaller the braking distance will be.

[0220] Therefore, by optimizing the emergency braking dynamics model of the troopable vehicle established using the suspension deformation coordination equation, hinge force relationship equation, and tire force balance equation mentioned above, we can determine the suspension deformation amount that enables the vehicle to maintain stability during emergency braking while achieving the shortest braking distance *s*. and optimal braking force distribution coefficient

[0221] In summary, to address the serious problem of yaw and bending instability that easily occurs in trolleybuses during emergency braking, this embodiment, based on an in-depth analysis of the yaw instability risk and its formation mechanism under emergency braking conditions, introduces mathematical relationships such as axle load transfer, suspension deformation coordination equations, hinge force relationship equations, and tire adhesion balance equations to construct a dynamic analysis model applicable to emergency braking conditions of arbitrarily expanded intelligent rail transit vehicles. With the shortest braking distance as the optimization objective, an emergency braking operation control strategy for trolleybuses is proposed, and general calculation formulas for ground braking force, braking deceleration, and braking distance are derived. The braking force distribution coefficient is optimized, thereby ensuring vehicle stability and smoothness under emergency braking conditions while meeting the shortest braking distance requirement.

[0222] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for emergency braking control of a trolleybus capable of being assembled, characterized in that, Includes the following steps: S1) If a braking signal is received, detect the current speed v and the target distance relative to the target position; S2) If the target distance is less than a preset first threshold and the current speed v is greater than a preset second threshold, a functional relationship between the braking distance s and the braking force distribution coefficient is constructed as the target function according to the target strategy. Instability condition information for each carriage is also obtained, and local constraints of the target function are configured based on the instability condition information. The target strategy is: after reaction time... Afterwards, the braking force from to The time increases linearly, from to After the time increases linearly, it decreases. to Keep constant at all times When the vehicle's speed is less than the preset third threshold, the braking force... to As time increases linearly, the vehicle's wheels lock up. to Keep constant at all times When the vehicle is stationary, constructing the objective function based on the relationship between the braking distance *s* and the braking force distribution coefficient in the objective strategy includes the following steps: S21) Calculate the ground normal reaction force of the front and rear axles of each carriage. The expression is as follows: In the above formula, i For carriage M i Serial number ( i =1,2,3…n), The ground normal reaction force on the front axle of the current carriage. For carriage M i The ground normal reaction force of the rear axle, For carriage M i The equivalent stiffness of the front and rear axle suspensions. For carriage M i Deformation of the front axle suspension. For carriage M i The amount of deformation of the rear axle suspension. For carriage M i The overall vehicle quality It is the acceleration due to gravity; S22) The functional relationship between the braking force distribution coefficient and the braking deceleration is constructed by the ground normal reaction forces of the front and rear axles of each carriage as follows: In the above formula, Let i be the braking deceleration, and M be the car body speed. i The sequence number, where n is the total number of carriages. For carriage M i The ground normal reaction force on the front axle, For carriage M i The ground normal reaction force of the rear axle, For carriage M i Front axle braking force distribution coefficient, For carriage M i The braking force distribution coefficient of the rear axle; S23) Based on the configuration of each car, calculate the braking deceleration when the vehicle locks up by using the ground normal reaction force of the front and rear axles of each car and the rolling adhesion coefficient or the maximum ground adhesion coefficient. The expression is as follows: If each carriage lacks a braking anti-lock device If each carriage is equipped with a braking anti-lock device In the above formula, i is the serial number of carriage Mi, and n is the total number of carriages. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. Let Mi be the rolling adhesion coefficient of the front axle of the carriage. Let Mi be the rolling adhesion coefficient of the rear axle of the carriage. The maximum ground adhesion coefficient of the carriage Mi; S24) Using the current velocity v as the initial velocity, simplify the target strategy to obtain the relationship between braking deceleration and time. Based on the relationship between braking deceleration and time, construct the braking distance s and braking deceleration. and braking deceleration when the vehicle locks up. The functional relationship is as follows: In the above formula, The initial velocity, For braking and deceleration, The braking deceleration when the vehicle locks up. The speed corresponding to the third threshold. The reaction time of the brake. For braking deceleration The biggest moment; S3) Solve for the optimal value of the objective function with local constraints to obtain the braking force distribution coefficient of each car. Brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

2. The emergency braking control method for a trolleybus capable of being assembled according to claim 1, characterized in that, In step S24), the relationship between braking deceleration and time is as follows: after reaction time... Afterwards, braking deceleration from to The time increases linearly. ,exist to Keep constant at all times When the vehicle's speed is less than the preset third threshold, braking deceleration... from to The time increases linearly to This caused the vehicle to lock up. to Keep constant at all times The vehicle must stop running at that time.

3. The emergency braking control method for a trolleybus capable of being assembled according to claim 1, characterized in that, Step S2) configuring the local constraints of the objective function based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient Carriage M i -1 braking deceleration Less than the braking deceleration of the carriage Mi The lateral reaction force from the ground on the rear axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product of.

4. The emergency braking control method for a trolleybus capable of being assembled according to claim 1, characterized in that, Step S2) configuring local constraints based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient Carriage M i -1 braking deceleration Less than the braking deceleration of the carriage Mi The lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient Braking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of.

5. The emergency braking control method for a trolleybus capable of being assembled according to claim 1, characterized in that, Step S2) configuring local constraints based on the instability condition information includes: if the left-right angle between the front hinge of the car body Mi and the horizontal plane is not 0, and the left-right angle between the rear hinge of the car body Mi and the horizontal plane is not 0, the local constraint is configured as: the braking force distribution coefficient of the front axle of the car body Mi. and the braking force distribution coefficient of the rear axle All are less than the maximum ground adhesion coefficient Carriage M i -1 braking deceleration Less than the braking deceleration of the carriage Mi The lateral reaction force from the ground on the front axle of the carriage Mi Less than or equal to the maximum ground adhesion coefficient Braking force distribution coefficient with front axle of the carriage Mi The vector difference and the ground normal reaction force of the front axle of the carriage Mi The product of the ... Less than or equal to the maximum ground adhesion coefficient Braking force distribution coefficient with the rear axle of the carriage Mi The vector difference and the ground normal reaction force of the rear axle of the carriage Mi The product of.

6. The emergency braking control method for a trolleybus capable of being assembled according to any one of claims 3 to 5, characterized in that, Carriage Mi braking deceleration The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows: In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. The braking force distribution coefficient for the rear axle of the carriage Mi is given. Let X be the force along the X-axis at the hinge of the front of the carriage Mi. The force along the X-axis is the force at the rear hinge of carriage Mi, with the direction of travel of carriage Mi being the positive direction of the X-axis.

7. The emergency braking control method for a trolleybus capable of being assembled according to claim 3 or 5, characterized in that, Lateral reaction force from the ground on the rear axle of the carriage Mi The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows: In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. The braking force distribution coefficient for the rear axle of the carriage Mi is given. For M i The horizontal distance between the front and rear axles of the carriage Mi. This refers to the length of the hinge between the carriages. This is the distance from the hinge to the nearest axle. For the overall vehicle weight of carriage Mi, For the first carriage to M i The average braking deceleration of carriage Mi, For M i The angle between the front hinge of the carriage Mi and the horizontal plane. For M i The angle between the rear hinge of the carriage Mi and the horizontal plane.

8. The emergency braking control method for a trolleybus capable of being assembled according to claim 4 or 5, characterized in that, Lateral reaction force from the ground on the rear axle of the carriage Mi The functional relationship between the braking force distribution coefficient and the braking force distribution coefficient is as follows: In the above formula, i is the serial number of carriage Mi. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. The braking force distribution coefficient for the front axle of the carriage Mi is [value missing]. The braking force distribution coefficient for the rear axle of the carriage Mi is given. Mi is the horizontal distance between the front and rear axles of the carriage. This refers to the length of the hinge between the carriages. This is the distance from the hinge to the nearest axle. For the overall vehicle weight of carriage Mi, The average braking deceleration from the first car to the car Mi is... Let Mi be the angle between the front hinge of the carriage and the horizontal plane. The angle between the rear hinge of the carriage Mi and the horizontal plane is defined as follows:

9. An emergency braking control system for a troop-type trolleybus, characterized in that, include: The information acquisition unit is used to detect the current speed v and the target distance relative to the target position if a braking signal is received. The braking distance calculation unit is used to construct a functional relationship between the braking distance *s* and the braking force distribution coefficient as the objective function if the target distance is less than a preset first threshold and the current speed *v* is greater than a preset second threshold. It also acquires instability condition information for each carriage and configures local constraints on the objective function based on this information. The objective strategy is: after reaction time... Afterwards, the braking force from to The time increases linearly, from to After the time increases linearly, it decreases. to Keep constant at all times When the vehicle's speed is less than the preset third threshold, the braking force... to As time increases linearly, the vehicle's wheels lock up. to Keep constant at all times When the vehicle is stationary, constructing the objective function based on the relationship between the braking distance *s* and the braking force distribution coefficient in the objective strategy includes the following steps: S21) Calculate the ground normal reaction force of the front and rear axles of each carriage. The expression is as follows: In the above formula, i For carriage M i Serial number ( i =1,2,3…n), The ground normal reaction force on the front axle of the current carriage. For carriage M i The ground normal reaction force of the rear axle, For carriage M i The equivalent stiffness of the front and rear axle suspensions. For carriage M i Deformation of the front axle suspension. For carriage M i The amount of deformation of the rear axle suspension. For carriage M i The overall vehicle quality It is the acceleration due to gravity; S22) The functional relationship between the braking force distribution coefficient and the braking deceleration is constructed by the ground normal reaction forces of the front and rear axles of each carriage as follows: In the above formula, Let i be the braking deceleration, and M be the car body speed. i The sequence number, where n is the total number of carriages. For carriage M i The ground normal reaction force on the front axle, For carriage M i The ground normal reaction force of the rear axle, For carriage M i Front axle braking force distribution coefficient, For carriage M i The braking force distribution coefficient of the rear axle; S23) Based on the configuration of each car, calculate the braking deceleration when the vehicle locks up by using the ground normal reaction force of the front and rear axles of each car and the rolling adhesion coefficient or the maximum ground adhesion coefficient. The expression is as follows: If each carriage lacks a braking anti-lock device If each carriage is equipped with a braking anti-lock device In the above formula, i is the serial number of carriage Mi, and n is the total number of carriages. The ground normal reaction force is the force on the front axle of the carriage Mi. The ground normal reaction force is the force acting on the rear axle of carriage Mi. Let Mi be the rolling adhesion coefficient of the front axle of the carriage. Let Mi be the rolling adhesion coefficient of the rear axle of the carriage. The maximum ground adhesion coefficient of the carriage Mi; S24) Using the current velocity v as the initial velocity, simplify the target strategy to obtain the relationship between braking deceleration and time. Based on the relationship between braking deceleration and time, construct the braking distance s and braking deceleration. and braking deceleration when the vehicle locks up. The functional relationship is as follows: In the above formula, The initial velocity, For braking and deceleration, The braking deceleration when the vehicle locks up. The speed corresponding to the third threshold. The reaction time of the brake. For braking deceleration The biggest moment; The braking unit is used to solve for the optimal value of the objective function with local constraints, obtain the braking force distribution coefficient of each car, and brake the corresponding car according to the braking force distribution coefficient until the vehicle stops running.

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