JPH1053119A - Method and apparatus for determining coupling force in coupled vehicle - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To accurately determine a connection force in a connected vehicle based on a measurement value already existing in a connected vehicle, particularly a tractor, without using a force sensor. SOLUTION: A brake device of a connected vehicle is controlled based on a driver's braking request and a required connection force, and a deceleration of the connected vehicle and an axle load of a tractor of the connected vehicle are measured. With the parameter evaluation method, the longitudinal and / or vertical connecting forces between the partial vehicles of the connected vehicle are evaluated based on the measured values (deceleration of the connected vehicle, axle load of the tractor).
By this parameter evaluation, mathematical parameters are first calculated from the measured values, and the physical parameters of the trailer are determined from the mathematical parameters. The longitudinal and / or vertical connecting forces between the partial vehicles of the connected vehicle are then calculated from the measured values and the evaluated physical parameters of the trailer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for determining a connecting force of a connected vehicle.

[0002]

2. Description of the Related Art German Offenlegungsschrift 4405709 describes a braking device for an articulated vehicle in which the forces generated between partial vehicles of the articulated vehicle during the braking process are kept as low as possible. For this purpose, this force is measured by a sensor and the braking device is controlled in such a way that the determined force is minimized by changing the braking force on the partial vehicle of the coupled vehicle as a function of the measurement signal.

Measuring this connecting force between the individual sub-vehicles of the connected vehicle by means of a measuring device is costly and requires that this force be determined from existing measurement signals.

[0004] In EP-A-621161 a method is proposed for determining the longitudinal force between partial vehicles of a connected vehicle without using a force sensor at the fifth wheel connection point. In this case, it is assumed that the braking force, i.e. the force between the wheels and the road in the longitudinal direction of the vehicle, is known, and the longitudinal force between the partial vehicles of the connected vehicle is calculated from this braking force and other measured values. Is done. However, in general, the braking force is not known and is based on many influence factors that change with time (for example, road characteristics, tire characteristics, brake characteristic values, etc.). Thus, the premise that this braking force is known will severely limit the accuracy with which the force is determined.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for accurately determining a coupling force in a coupled vehicle based on measured values already present in the coupled vehicle, especially in a tractor, without using a force sensor. It is an issue of.

[0006]

In order to solve the above-mentioned problems, in the method for determining a connecting force in a connected vehicle according to the present invention, a brake device of the connected vehicle is configured to operate based on a driver's braking request and at least a determined connecting force. At least the deceleration of the connected vehicle and the axle load of the tractor of the connected vehicle are measured. The method according to the present invention is characterized in that the connection force in the longitudinal direction and / or the vertical direction between the partial vehicles of the connected vehicle is evaluated based on the measured value by the parameter evaluation method.

[0007] In order to solve the above problems, the apparatus for determining a connection force in a connected vehicle according to the present invention includes a control device for controlling at least a brake device of the tractor, and the control device includes at least a deceleration of the connected vehicle and a tractor. Receive measurements on axle load. And the device of the present invention is characterized in that the control device evaluates, based on the supplied measurement values, the connection force in the longitudinal direction or the vertical direction or both of the partial vehicles of the connected vehicle by a parameter evaluation method. I do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows a control device 10 having an input circuit 12, at least one microcomputer 14 and an output circuit 16. These elements are interconnected via a bus system 18 to exchange information and data with the other party. Various input lines are supplied to the input circuit 12, and operating variables necessary for controlling the brake device are supplied to the control device 10 via these input lines. The input line 20 is connected to the control device 10 by a measuring device 22 for measuring the degree of operation of the brake pedal by the driver.
Is combined with Further, input lines 24 to 26 are provided, and the input lines 24 to 26
Exiting from 8 to 30, the control unit 10 is supplied with other operating variables such as, for example, wheel speed, brake pressure or moment values, axle load values and the like. Furthermore, the control device 10 is connected via output lines 32 to 34 to a vehicle brake device 36. In a preferred embodiment, a pneumatic braking device is used in the braking device 36, which can regulate the braking pressure in each wheel brake via an electrically operable setting element. In another advantageous embodiment, the braking device 36 is a hydraulic braking device with a corresponding setting element or an electric braking device in which the braking moment applied to the wheel brakes is generated by an electric motor. The control device 10 adjusts the brake pressure or the brake moment at the wheel brakes 38 to 40 by correspondingly manipulating the setting elements via output lines 32 to 34.

[0010] Such a braking device is connected to a measuring device 22.
As a function of the degree of brake pedal operation determined by
It is known from the prior art to control while taking into account functions such as anti-lock protection control, drive slip control and the like.
In this case, the control device 10 is usually incorporated in the tractor and controls the tractor brake device 36 by a control program executed in at least one microcomputer 14. At least one output line 42 is provided in addition to the output lines 32 to 34 for the braking of the tractor, and the control device is connected via the output line 42, for example by means of a so-called trailer control valve, to a braking device 44 and thus to a trailer wheel brake 46. The braking pressure supplied or the braking moment to be generated.

One example for such a control program is shown in the flowchart of FIG. The program shown here is started at a predetermined time, for example, every 10 to 100 milliseconds. In a first step 100, measured values such as pedal operation, wheel rotation speed, tractor axle load and the like are read. In a subsequent step 102, the coupling force G determined as described below L is read. In a subsequent step 104, the desired brake pressure psollz on the tractor is determined as a function of the pedal actuation, the wheel speed, the axle load value and possibly other operating variables and is output to the braking device. Here, the target brake pressure psollz is set, for example, within the range of the pressure control circuit. Accordingly, in a subsequent step 106, a target brake pressure psollA for the trailer is determined based on the pedal actuation and in particular the determined coupling force (for example in a range in which the coupling force is controlled to approach the target value), Output to adjust the brake pressure in the trailer brake. In this case, the brake pressure in the brake of the trailer is determined such that the force between the partial vehicles takes a predetermined target value. After step 106, the program ends and repeats after a predetermined time has elapsed.

An evaluation method is used according to the present invention to determine the coupling force, and the principle process of the evaluation method is shown in FIG. The program shown here is started at predetermined times (for example, every 10 to 100 milliseconds) during the braking process. In a first step 200, the measurements used for the parameter evaluation are: the deceleration of the connected vehicle, the axle load of the tractor,
The brake pressure in the wheel brakes of the tractor and possibly the retarder braking (traction) moment are read. In a following step 202, the semi-trailer mathematical parameters are evaluated, as described below, and in a subsequent step 204, the semi-trailer physical parameters are calculated. Subsequent step 20
At 6, the longitudinal and / or vertical coupling forces are determined based on the physical parameters, and the program portion is terminated and repeated after a predetermined time.

According to the basic method, only the main physical parameters of the semi-trailer (or trailer) are generated by an evaluation algorithm, which evaluates the measured values already present in the tractor (speed of the connected vehicle, speed at the rear axle of the tractor). Axle load and pressure in the brake cylinder). Next, the connection force is calculated by the balance equation using the physical parameters.

In a semi-trailer-coupled vehicle, brake pressure (control pressure) required for brake operation is supplied to the semi-trailer via a pneumatic line. The control pressure should ideally be set such that the semitrailer is decelerated at the same deceleration as the tractor. By matching this deceleration,
A stable braking process is formed in the braking operation as a function of the axle load of the semi-trailer vehicle.

However, when the semi-trailer's inherent braking action is less than the tractor's braking action, the longitudinal force generated at the fifth wheel connection (pushed by the semi-trailer) will cause the tractor to break when the brake is applied, for example, on a curve Pushing out of the curve, the whole connected car tries to form a bend. When the semi-trailer's inherent braking action is large, the semi-trailer wheels will be locked and the semi-trailer will slide sideways from the curve.

As a function of the force determined at the fifth wheel connection, a correction of the control pressure for the semi-trailer takes place via a control algorithm, whereby the brake output of the semi-trailer is increased or decreased. Control of the brake output of the semi-trailer is only possible when the coupling force is known.

It should be noted here that only longitudinal dynamics are of interest for determining the coupling force. As a result, the effects of lateral dynamics are ignored. Thus, the coupling between the tractor and the semi-trailer can only transmit longitudinal and vertical forces.

The determination of the connecting forces (longitudinal and supporting forces) between the semi-trailer tractor and the semi-trailer is transferred to a parameter evaluation for the semi-trailer. A further examination of the evaluation algorithm described below shows that only the mathematical parameters are evaluated, from which the required physical parameters of the semitrailer as well as the braking characteristic values of the semitrailer tractor are calculated. The above parameters are not generally known for semitrailer-coupled vehicles used to replace and transport semitrailers due to environmental changes, so parameter evaluation is required. As a result, the brake characteristic values of the semi-trailer may be significantly different, so that the setting of the distribution of the brake output to the semi-trailer tractor and the semi-trailer will change. Using the physical parameters and with the aid of momentum conservation and moment balancing for the semi-trailer vehicle, the connection force can subsequently be determined.

To illustrate the dynamic behavior of a semi-trailer vehicle, simple models for the tractor and semi-trailer (FIGS. 4 and 5) are used to derive basic equations for parameter estimation. The simple model is also sufficient for a detailed study of the system, since the model parameters as a function of the operating point, in particular the brake characteristic values of the semi-trailer tractor, are evaluated online during operation.

The following assumptions have been applied to parameter estimation based on linear elementary equations containing parameters.

The braking action takes place on level ground; the retarder is not used or the braking moment applied from it is known; the engine traction moment is the vehicle variable used. The actuation (engagement) pressure and the release pressure of the braking device are time-invariant and known, and the distance R from the connection point to the axle relative to the semi-trailer.
A and the distance L between the connection point and the rear axle of the tractor K
Is known.

The variables used and the directions and directions of movement of the force vectors are defined in FIGS. For clarity, the time argument has been omitted from the formula below.

The determination of the basic equations for parameter evaluation is performed on the tractor using the law of conservation of momentum as follows.

[0024]

[Equation 1] m Z * (x¨) = G LB 1-B 2-F M (1) where (x¨) indicates the deceleration of the semi-trailer connected vehicle,
F M indicates the force provided by the retarder and / or engine traction moment. The deceleration of the semi-trailer vehicle is calculated as the quotient of the speed difference from the speed signal of the ABS function, so that the deceleration of the semi-trailer vehicle can be used as a measurement for determining the coupling force. Using the assumptions for the determination of the coupling force (the engine traction moment and / or the retarder moment are known), the known value F Since M can be calculated on the left side of Equation (1), Equation (1) can be simplified as follows. This is insignificant for the following deformation and therefore the value F M is deleted from equation (1) without changing the left side of equation (1).

[0025]

[Equation 2] m Z * (x¨) = G LB 1-B 2 (2) The braking force of one axle of the simple model is
Pressure in cylinder p approximated as a linear function of i, where
To change the braking force by increasing the pressure
Force p Ai is taken into account, and braking force changes due to pressure drop.
Release pressure p Li is considered.

[0026]

(Equation 3) B i = c ip (p ip Ai) where i = 1,2 (pressure rise) (3) B i = c im (p ip Li) where i = 1,2 (pressure drop) (4) When the braking force is changed by pressure increase or pressure drop, it should be understood that the pressure range is a range that is not affected by the brake hysteresis. In this range, no matter how small the change in brake pressure, a corresponding change in brake force is provided.

In order to derive the basic equations for the calculation of the coupling force, first, for the sake of simplicity, the operating pressure p
Ai and release pressure p Li is equal for each axle, while the proportional amplification factor c i is the pressure rise that changes the braking force c ip or pressure drop c The additional assumption that the match also applies independently of im applies. Physical parameter c ip (pressure rise) and c im (pressure drop) indicates that the braking force has a linear functional relationship with the pressure in the wheel brake cylinder. Therefore, in the following equation, the variable c i and p A
A corresponding substitution is made only for i. This indicates that the brake hysteresis is not first considered to form the equation of motion. The characteristic of the wheel brake is a proportional amplification coefficient c It is modeled as a dead zone with i outside.

The relational expression of the moment around the support point of the fifth wheel axle (the point of contact between the semi-trailer wheel and the road) is the support force G The term for S is represented by the longitudinal force G at the fifth wheel connection point for the simple model. It is expressed as a function of L.

[0029]

(Equation 4) In a multi-axle semitrailer, all axles are combined into an alternative system with only one axle. At this time, the combined axle load and combined braking force on the semi-trailer are engaged at the axle support point. The relational expression of the moment about the support point of the front axle of the semi-trailer tractor is the longitudinal force G at the fifth wheel connection point. L and bearing capacity G Another expression is given to S.

[0030]

(Equation 5) Using equations (6) and (7), the longitudinal force G at the fifth wheel connection point One formula is given for L, which is the measured value (x¨) and N 2. The product of unknown semi-trailer physical parameters m A * H A and m A
* S A is a function of only the known parameters of the tractor.

[0031]

(Equation 6) When equations (3) or (4) and (8) are substituted into equation (2), a linear elementary equation for the parameters for parameter evaluation is obtained therefrom.

[0032]

(Equation 7) The mathematical parameters for the basic equations are calculated as follows.

[0033]

(Equation 8) The mathematical parameters for calculating the coupling force can be determined by parameter evaluation. Hereinafter, an evaluation equation for forming a parameter will be described in detail. Using the mathematical parameters (formulas (10) to (13)) obtained by the evaluation, the necessary physical parameters of the semitrailer are calculated as follows.

[0034]

(Equation 9) Thereby, the physical parameters of the semitrailer necessary for calculating the coupling force are obtained. To determine the longitudinal force at the fifth wheel connection point, Equation (2) is used in consideration of Equations (3) through (4) or Equation (8), where (x¨), N 2, p 1 and p 2 is a measured value.

[0035]

(Equation 10) When the parameter estimates converge, the results of equations (18) and (8) are equal. At this time, the supporting force at the fifth wheel connection point is given as follows using the longitudinal force according to Equation (6) and Equation (8) or (18).

[0036]

[Equation 11] By using inductive parameter evaluation, the physical parameter m can be obtained in online driving without additional detuning of the braking device, while giving the desired deceleration by the driver.
A * H A, m A * S A, c 1 and c 2 can be determined. As an alternative to this, offline parameter evaluation is also conceivable. Detuning of the braking device means the integrated change of the target pressure for the front and rear axles of the semitrailer tractor and the fifth wheel axle of the semitrailer.

In order to inductively perform the algorithm for parameter evaluation, a time argument is temporarily introduced here.

In the linear basic equation (9) for parameter evaluation, the measured data vector Ψ (k), parameter vector Θ (k) (vector of mathematical parameters) and measured value y (k) = (x¨) are generally The format is as follows:

[0039]

(Equation 12) Here, the elements of the measurement vector are expressed as follows.

[0040]

(Equation 13) The correction vector γ (k) for weighting the evaluation error is calculated as follows by the covariance matrix P (k) of the evaluation error.

[0041]

[Equation 14] The evaluation error is determined as follows.

[0042]

(Equation 15) This gives a new parameter vector due to the recursive relationship.

[0043]

(Equation 16) Various algorithms exist for the calculation of the evaluation error value μ (k + 1) and the covariance matrix P (k). For example:-least squares

[Equation 17] − Stochastic approximation

Μ (k + 1) = 1 (31) P (k + 1) = α * (k + 1) ⁻¹ * 1, where α> 0 (32) The weight of the covariance matrix P (k) of the evaluation error is A very large and very rapid reduction of the elements is prevented, thereby preventing too small correction values for the mathematical parameters. If the correction value is too small,
The number of iterations required to reduce the effectiveness criterion to an acceptable value increases. Furthermore, for values larger than the case without weighting, the evaluation result may be affected by newly generated measurement values. This has important implications for the time-varying parameter for the convergence of the evaluation. The simplest weighting of the covariance matrix is performed by a constant amplification factor ρ. Taking into account the constant weighting of the covariance matrix, the following equation is given by, for example, the least squares method (Equation (28)).

[0044]

[Equation 19] For linear parameter estimation, the weighting factors should be chosen as follows to achieve a stable estimation.

0.95 <ρ <0.99 (34) The selection of the scanning time for the formation of a time series for the measured values is particularly important. Scan time T If A is too small, there will be little change in the measured value from one scan time to the next, and the parameter evaluation will be less stimulated by the measured value. Empirically, the scan time T for parameter evaluation A is determined by the transient response as follows.

[0046]

(Equation 20) Time constant T 63 gives the time interval to reach 63% of the steady state final value of the transient response.

The starting values for the parameter evaluation are determined on the one hand from the physical parameters of the semi-trailer vehicle and, on the other hand, on the basis of empirical values and by a preliminary selection which gives a suitable compromise on the convergence characteristics. A simple preselection is applied to the start value of the covariance matrix of the evaluation error.

[0048]

(Equation 21) If the start value for the covariance matrix is too large, the parameter estimation may be unstable, but larger start values cause the algorithm to converge more quickly. An effective improvement of the convergence characteristic consists in setting the covariance matrix back to the start value after a predetermined number of evaluations (30 ≦ repetition number ≦ 100). Repetition for parameter evaluation is performed at each scanning time.

In addition, attention should be paid to the measured value matrix over all N scan times. The column vectors of this matrix show the time series of measurements over all N scan times. The rows of the matrix must be maximal so that the parameter estimates are unique and converge (row defects must not occur).

The two evaluations to determine the parameters
Must be switched between
Higher-level methods for meter evaluation are important. This method
Will be described in detail below. The actual braking device is
By rake (drum or disc brake)
There is a characteristic that hysteresis appears. Therefore, it works
Pressure p Ai and release pressure p If you know Li
And amplification coefficient c i is the pressure rise that changes the braking force
c Pressure drop that changes ip and braking force c im
Must be evaluated separately (Figure 6).
reference).

The braking force has a positive pressure gradient (pressure rise).
Is calculated by the following equation after overcoming the hysteresis.

[0052]

[Mathematical formula-see original document] B i = c ip (p ip Ai) Here, i = 1,2 (37) Then, for the negative pressure gradient (pressure drop), after overcoming the hysteresis, it is calculated by the following equation.

[0053]

[Expression 23] B i = c im (p ip Li) where i = 1,2 (38) This means that the two parameter evaluations must be performed in parallel. Algorithm 1 is used for parameter evaluation when the braking force is changed by pressure increase, and algorithm 2 is used only for parameter evaluation when the braking force is changed by pressure drop. At this time, switching must be performed between the algorithms according to the respective pressure gradients and the gradients of the braking force, so that the algorithm 1 shows a positive pressure gradient and a positive braking force gradient for parameter evaluation. Only measurement data is given. Similarly, Algorithm 2 processes only data indicating a pressure drop when the braking force gradient is negative.

After the mathematical parameters have been evaluated, the physical parameters are calculated, and subsequently the coupling force is calculated for the range in which the braking force is changed by increasing or decreasing the pressure (equation (39) and subsequent equations). . In the middle of both ranges, a change in brake pressure as desired by the driver does not significantly change the braking force. This is because the braking force is almost constant due to hysteresis (ranges B and D in FIG. 6). As a result, the coupling force at the fifth wheel connection point cannot be calculated for the ranges B and D as a function of the actual deceleration and the actual pressure in the wheel brake cylinder.

For ranges B and D characterized by a positive pressure gradient (Range D) or a negative pressure gradient (Range B) and having a zero value for the braking force, the following method is applied. .

The respective brake pressure p in the wheel brake cylinder Hysteresis p for i (change in braking force due to pressure increase, range A) Hi is known.

[0057]

(Equation 24) Here, when the sign of the pressure gradient changes from plus to minus as desired by the driver, the pressure is reduced after passing through the brake hysteresis. Brake pressure is reference pressure p braking force B on each axle as long as it is greater than im i is calculated by the following equation using this reference pressure.

[0058]

(Equation 25) B i = c im (p im-p Li) where i = 1,2 (40) Reference pressure p im is the hysteresis p Him and the brake pressure p at which the sign of the pressure gradient switches ips.

[0059]

[Mathematical formula-see original document] p im = p ips-p Him where i = 1,2 (41) In this case, the hysteresis p Him takes the following value.

[0060]

[Equation 27] Separate calculations to calculate the longitudinal force at the fifth wheel connection at negative pressure gradients under the influence of hysteresis which will likely be different for the front and rear axles of the semi-trailer tractor Must be performed.

Case 1.1: Pressure p in the wheel brake cylinder of the tractor axle i are both the corresponding reference pressures p calculated via hysteresis im (range B) and pressure p less than ips.

Case 1.2: Wheel block of tractor axle
Both pressures p in the rake cylinder pressure of one of i
Is the corresponding reference pressure p calculated via hysteresis i
m (range C) and the other pressure is the reference pressure p i
m (range B) and both pressures are pressure p i
smaller than ps.

When divided into the above cases, Case 1.1
Is determined by the following equation from the equation (2) at the fifth wheel connection point.

[0064]

[Equation 28] And, for example, pressure p 1 is first the reference pressure p 1m
, The longitudinal force at the fifth wheel connection point for case 1.2 is determined by:

[0065]

(Equation 29) Pressure p 2 is the reference pressure p When it falls below 2m,
The longitudinal force at the fifth wheel connection point is calculated similarly.

At this time, the supporting force at the fifth wheel connection point is given by Expression (6) regardless of the case.

[0067]

[Equation 30] Both brake pressures p i is the reference pressure p When the value of im falls below the value of im, the parameter evaluation by the algorithm 2 starts (change in braking force due to output reduction, range C). However, when the sign of the pressure gradient changes from negative to positive again in this case, the reference pressure p
ip is the hysteresis p Hip and brake pressure p at which the sign of the pressure gradient switches again ims.

[0068]

[Mathematical formula-see original document] p ip = p ims + p Hip (45) In this case, the hysteresis p Hip takes the following values.

[0069]

(Equation 32) Brake pressure p i is the reference pressure p brake pressure B for each axle as long as it is less than ip (range D)
i is calculated by the following equation using the reference pressure.

[0070]

[Expression 33] B i = c ip (p ip-p Ai) where i = 1,2 (47) The longitudinal direction at the fifth wheel connection point at a positive pressure gradient under the influence of hysteresis which will probably be different for the front and rear axles of the semitrailer tractor In order to calculate the force, the calculations must be performed in a similar manner.

Case 2.1: Pressure p in the wheel brake cylinder of the tractor axle i are both the corresponding reference pressures p calculated via hysteresis ip (range D) and both pressures are pressure p greater than ims.

Case 2.2: Wheel block of tractor axle
Both pressures p in the rake cylinder pressure of one of i
Is the corresponding reference pressure p calculated via hysteresis i
p (range A) and the other pressure is equal to the reference pressure p i
p (range D) and both pressures are i
ms.

When divided into the above cases, Case 2.1
Is determined by the following equation at the fifth wheel connection point.

[0074]

(Equation 34) And, for example, pressure p 1 is first the reference pressure p 1m
Is assumed, the longitudinal force at the fifth wheel connection point for Case 2.2 is determined by:

[0075]

(Equation 35) Pressure p 2 is the reference pressure p Above 2p, the longitudinal force at the fifth wheel connection point is calculated similarly.

At this time, the supporting force at the fifth wheel connection point is similarly given by equation (6) regardless of the case.

[0077]

[Equation 36] Both brake pressures p i is the reference pressure p After exceeding ip, the parameter evaluation by algorithm 1 is performed again (change in braking force due to increase in output, range A).

Here, the parameter evaluation method is described for a pneumatic brake system and operates on the basis of the measured pressure in the wheel brake cylinder. The advantageous effect of this method for determining the coupling force is also achieved in electric brake systems. In this case, the corresponding control variables (brake moment, operating current, etc.) are used instead of the brake pressure. The latter (use of control variables) also applies to hydraulic or pneumatic brake systems.

The method described above is used not only for semitrailers, but also for trailers (connected via connecting rods).

The reference numerals shown in FIGS. 4 and 5 represent the following items, respectively.

B 1 Brake force of front axle B 2 Rear axle braking force B 3 Wheel brake axle N 1 Axle load of front axle N 2 Rear axle axle load N 3 Axle load G of the fifth wheel axle L Longitudinal force at the fifth wheel connection point G S Supporting force at the fifth wheel connection point m Z Mass of tractor H Z Height of center of gravity of tractor L K Distance between fifth wheel connection point and rear axle R Z Distance between front and rear axles S Z Distance between tractor center of gravity and rear axle H K Height of fifth wheel connection point m A Mass of semi-trailer H A Semi trailer center of gravity height R A Distance between fifth wheel connection point and fifth wheel axle S A Distance between the center of gravity of the semi-trailer and the fifth wheel axle

[0082]

According to the solution of the invention, the determination of the connection force at the fifth wheel connection point is made based on the parameter evaluation without using a force sensor.

Therefore, when using this method, it is not necessary to use a force sensor at the fifth wheel connection point. Since the force sensor is correspondingly expensive since it measures forces generated in very heavy structures, the solution according to the invention significantly reduces equipment costs and costs.

When determining the coupling force between the partial vehicles of a coupled vehicle, it is particularly advantageous that the brake pressure on the semitrailer is adjustable such that the semitrailer is decelerated at the same deceleration as the tractor.

The connection force is an important state variable for observing the running dynamics of the whole connected vehicle and determining the force between the wheels and the road in the longitudinal direction of the vehicle in the braking process by determining the connection force. Thus, it is advantageous to determine the connection force.

In the solution according to the invention, it is advantageous that the evaluation parameters evaluate the mathematical parameters from which the required physical parameters of the semi-trailer as well as the tractor brake characteristic values are calculated. Subsequently, the coupling force is determined with the help of momentum conservation and moment balancing. This method of parameter estimation has the advantage that the hysteresis and / or the traction or retarding moment of the individual wheel brakes can be taken into account.

Furthermore, it is particularly advantageous that the parameter evaluation can be performed online, ie during the braking process.

[Brief description of the drawings]

FIG. 1 is an overall circuit diagram of a control device for a brake device.

FIG. 2 is a flow chart showing a control principle of a brake device in consideration of a longitudinal force between respective vehicle portions of the connected vehicle.

FIG. 3 is a flowchart illustrating determination of a connection force according to the present invention.

FIG. 4 is a schematic view of a connected vehicle showing the forces in the connected vehicle considered in determining the connecting force according to the present invention.

FIG. 5 is a schematic view of a connected vehicle showing dimensions of the connected vehicle to be considered in determining the connecting force according to the present invention.

FIG. 6 is a braking force diagram for selected wheel brakes versus brake pressure, showing the hysteresis present in each wheel brake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Control device 12 Input circuit 14 Microcomputer 16 Output circuit 18 Bus system 22 Measurement device of brake pedal operation degree 36 Tractor brake device 38, 40 Tractor wheel brake 44 Trailer brake device 46 Trailer wheel brake

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hans Feil Germany 71735 Eberdingen, Theodore-Heus-Strasse 68

Claims (10)

[Claims] 1. A coupled vehicle, wherein a brake device of the coupled vehicle is controlled based on a driver's braking request and at least a determined coupling force, and at least a deceleration of the coupled vehicle and an axle load of a tractor of the coupled vehicle are measured. Wherein the longitudinal or vertical coupling force between the partial vehicles of the coupled vehicle or both of them is evaluated based on a measured value by a parameter evaluation method. How to determine the power. 2. The method according to claim 1, wherein the determined longitudinal coupling force is taken into account in the control of the brake device of the trailer. 3. The method according to claim 1, wherein the connection force is taken into account in the control of the brake device of the trailer such that the longitudinal force between the tractor and the trailer assumes a predetermined target value. the method of. 4. The method according to claim 1, wherein mathematical parameters are first calculated from the measured values by parameter evaluation, and physical parameters of the trailer are determined from the mathematical parameters. 5. The connecting force in a longitudinal direction and / or a vertical direction between partial vehicles of the coupled vehicle is calculated from the measured values and the evaluated physical parameters of the trailer. The method according to any one of claims 4 to 7. 6. The method according to claim 1, wherein the parameter evaluation is such that the braking is performed on level ground, the retarder is not used or the braking moment to be applied is known, and the engine traction moment is used for the vehicle to be used. Variables, the operating pressure and the release pressure of the brake system are time-invariant and known, and the distance between the trailer axle and the distance between the connection point and the rear axle of the tractor are known. The method according to any one of claims 1 to 5, wherein the method is performed on the assumption that: 7. The method as claimed in claim 1, wherein a switch is made between the two evaluation algorithms as a function of the pressure change characteristic in order to determine the coupling force. 8. The method of claim 7, wherein the first evaluation algorithm is activated on a positive pressure gradient and the second evaluation algorithm is activated on a negative pressure gradient. 9. The longitudinal and / or vertical forces between the partial vehicles of the articulated vehicle are calculated from the evaluated parameters as a function of the hysteresis width as a function of the pressure change characteristics and the wheel brake pressure. The method according to claim 7 or 8, wherein: 10. An apparatus for determining a coupling force in a coupled vehicle, comprising at least a control device for controlling a tractor braking device, the control device receiving at least measurements of deceleration of the coupled vehicle and axle load of the tractor. Is a device for determining a connecting force in a connected vehicle, wherein the connecting force in a longitudinal direction and / or a vertical direction between partial vehicles of the connected vehicle is evaluated by a parameter evaluation method based on the supplied measurement values.