JP2016037051A - Control system of brake, adhesive coefficient calculation method, maximum brake force calculation method and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system of a brake which can be applied for high speed operation of a light weight vehicle of a short organization and prevent sliding.SOLUTION: A control system 1 is equipped with a brake force computing part 2 and a brake force adjustment part 3. A value of necessary brake force is inputted from the brake force computing part 2 into the brake force adjustment part 3, and the brake force adjustment part 3 outputs a value of a brake force of each shaft. The brake force adjustment part 3 has a storage part 4 in which an adhesive coefficient of each shaft to a combination of a vehicle speed and a wheel weight in a prescribed range is previously stored. A brake initial rate is inputted into the brake force adjustment part 3, and the brake force adjustment part 3 reads out an adhesive coefficient of each shaft to a combination of the inputted brake initial rate and the wheel weight of the vehicle from the storage part 4, calculates a maximum brake force of each shaft with no sliding on the basis of the adhesive coefficient of each shaft and the wheel weight, and adjusts a value of a brake force F of each shaft so that the brake force F of each shaft does not exceed the maximum brake force and a total sum of the brake force F of each shaft does not become lower than the necessary brake force for the vehicle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control system for controlling a brake of a railway vehicle, an adhesion coefficient calculation method used in the control system, a maximum brake force calculation method using the adhesion coefficient calculation method, and a computer program based on the adhesion coefficient calculation method About.

  In recent years, along with the opening of a new line of Shinkansen railway (the Shinkansen railway defined in Article 2 of the National Shinkansen Development Law), a parallel conventional trunk line has become a third from the passenger railway company that operated the line. It is succeeded by the sector railway. Since such third sector railway lines have high-standard tracks and electric facilities for express trains that were operated before the succession, high-speed operation as conventional lines is possible. On the other hand, the third sector railway operates instead of reducing the amount of transport per train by introducing a lighter and smaller railway vehicle compared to conventional railway vehicles for conventional lines and operating in a short train. Efforts will be made to reduce costs and maintain high-frequency operation. Therefore, in a third sector railway or the like, there is a possibility that a light rail vehicle (light vehicle) is operated at high speed with a short train.

  In a lightweight vehicle, since the force with which the wheel presses the rail from above, that is, the wheel load is small, the frictional force between the rail and the wheel is small, and sliding is likely to occur. The frictional force between the rail and the wheel is called adhesive force. Sliding is slippage between a wheel and a rail that occurs when a braking force exerted on the wheel is larger than an adhesive force between the wheel and the rail during braking (see number 13037 of Non-Patent Document 1). The ratio of the braking force and wheel load exerted on the limit wheel that does not cause sliding is referred to as the adhesion coefficient (see number 13017 in Non-Patent Document 1). The adhesion coefficient fluctuates due to inclusions between the wheel and the rail. Among these inclusions, the water film caused between the wheel and the rail by rain is known as an element that reduces the adhesion coefficient. If the adhesion coefficient is reduced by the water film, gliding tends to occur.

  Modeling based on elastohydrodynamic lubrication (EHL) theory is known for the adhesion coefficient between a rail and a wheel when a water film is interposed (see Non-Patent Document 2). Furthermore, based on this model, the correlation between the vehicle running speed (vehicle speed), the water film thickness between the rail and the wheel, and the adhesion coefficient has been clarified (see Non-Patent Document 3). In this correlation, as the water film thickness decreases, the adhesion coefficient increases, and as the vehicle speed increases, the adhesion coefficient decreases.

  The water film adhering to the rail surface is removed by the wheels when the vehicle passes. For this reason, the thickness of the water film in front of the succeeding second wheel (wheel of the second shaft) is smaller than that of the water film in front of the first first wheel (wheel of the first shaft). In such a situation where the water film thickness decreases for each axis, the adhesion coefficient also changes for each axis, and it is considered that the subsequent wheels approach the adhesion coefficient during drying.

  Such a phenomenon related to the adhesion coefficient for each axis is widely known. For example, data on the frequency of sliding for each axis in a train obtained from an actual business vehicle in a Shinkansen railway has been reported (non-patented). Reference 4). According to this sliding frequency data, the sliding frequency of the wheel of the shaft near the head is high.

  Based on the data of such a sliding frequency, the method of distributing different braking force for every vehicle in a formation was built (refer nonpatent literature 5). Such a brake force distribution method is actually used in Shinkansen vehicles. For example, in the first train of No. 1 to No. 16 (the Tokaido Shinkansen "700 series Shinkansen train"), the braking force of No. 1 and No. 16 is organized. Minimize the average value to 40% of the overall average, set the braking force of cars 2 and 15 to 95%, and increase the braking force of other cars to more than 100%, except for cars 8 and 9, which are non-electric vehicles. doing.

  Since this braking force distribution method (see Non-Patent Document 5) distributes different braking forces for each vehicle, it can be used only when there is a sufficient number of vehicles for knitting. On the other hand, light vehicles driven by the third sector railway usually have at most about two vehicles per train. Therefore, the method of allocating the braking force in units of vehicles cannot be applied to such a railway vehicle that is operated with a short train.

  Further, in this brake force distribution method (see Non-Patent Document 5), the braking force is set based on data on the frequency of Shinkansen vehicles (see Non-Patent Document 4). On the other hand, the light weight vehicles of the third sector railways are much smaller in weight than the Shinkansen vehicles, so the adhesive force is also small, and the sliding frequency by axis in the train is significantly different from the data obtained for the Shinkansen vehicles. It is thought that it is different. Therefore, it is difficult to apply such a brake force distribution method for Shinkansen vehicles to lightweight vehicles.

  In a railway vehicle, a control system has been proposed in which an independent braking force is applied to each shaft (see, for example, Patent Document 1). Such a control system can be applied to short train cars by allocating different braking forces for each shaft. In the control system described in Patent Document 1, the brake command is equalized by the number of axes of each vehicle, and the brake force command value of each axis is determined by multiplying each axis by a predetermined coefficient. Since the coefficient determined in advance does not consider the correlation between the vehicle speed and the adhesion coefficient (see Non-Patent Document 3), it is difficult to apply the control system described in Patent Document 1 to high-speed driving of a lightweight vehicle.

  As a prior study of measuring the adhesion coefficient for each wheel in a railway vehicle, a method for measuring the adhesion coefficient for each axis from brake information of a commercial vehicle has been proposed (see Non-Patent Document 6). Since this method measures the adhesion coefficient from the brake information, it is effective under the same wheel load and track conditions as those measured, but has not been applied to all railway vehicles.

  As described above, in the previous research on the change in the adhesion coefficient by axis, the theory for predicting the change in adhesion coefficient by axis for all railway vehicles, including the condition that the wheel load is small like a lightweight vehicle, has not yet been established. Not.

JP 2004-312918 A

JIS E4001: 2011 "Railway Vehicles-Terminology" Oyama Tadao, Chen Wei, Makoto Ishida "EHL between rails and wheels of railways", tripologist, Vol. 49, no. 4, pp. 316-322 2004 Chen, Ban Taku, Ishida Makoto, Nakahara Tsunamitsu "Factors affecting the adhesion coefficient between wheels and rails under wet conditions", Railway Research Institute, Vol. 26, no. 2, pp. 45-50 2012 Tadao Oyama "Study on the effect of contact conditions on the adhesion between wheels and rails of high-speed rail cars and the improvement of adhesion", Tohoku University Doctoral Dissertation 1986 Masayuki Ueno, Toshi Kikuno “Brake Adhesion Technology for Tokaido Shinkansen Vehicles: Understanding and Analyzing Adhesion Coefficient as Train Formation”, JREA, Vol. 47, no. 5, pp. 69-74 2004 Shinichi Tsuji, Satoshi Tsuruzaki, Ishihara Steel, Shinya Kawamura “Understanding of knitting adhesion characteristics using monitor information of commercial vehicles”, Proc. 105-108 2009

  The present invention solves the above-described problems, and an object of the present invention is to provide a brake control system for preventing sliding that can be applied to high-speed driving of a short-sized lightweight vehicle.

  The control system of the present invention is for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts, and is applied with a brake command and outputs a value of a necessary braking force of the vehicle. And a brake force adjustment unit that receives the value of the necessary brake force and outputs the value of the brake force of each axis, the brake force adjustment unit for a combination of vehicle speed and wheel load within a predetermined range. A storage unit in which the adhesion coefficient of each axis is stored in advance, a brake initial speed, which is a vehicle speed when a brake command is input, is input, and the input brake initial speed and the wheel load of the vehicle The sticking coefficient of each axis for the combination is read from the storage unit, and based on the sticking coefficient and the wheel load of each axis, the maximum braking force of each axis that does not slide is calculated. Without exceeding the maximum braking force, and the sum of the braking force of each axis to be no less than the required braking force of the vehicle, and adjusts the value of the braking force of each axis.

  The control system of the present invention is for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts. When a brake command is input, the average value per one axis of the required braking force of the vehicle is calculated. A brake force calculating unit for outputting, and a brake force adjusting unit for inputting the average value and outputting a value of the brake force of each axis, wherein the brake force adjusting unit is configured to obtain a vehicle speed and wheel load within a predetermined range. It has a storage unit in which the sticking coefficient of each axis for the combination is stored in advance, a brake initial speed, which is a vehicle speed when a brake command is input, is input, and the input brake initial speed and the wheel load of the vehicle The sticking coefficient of each axis with respect to the combination is read from the storage unit, and based on the sticking coefficient and the wheel load of each axis, the maximum braking force of each axis that does not slide is calculated, and the braking force of each axis Wherein not exceed the maximum braking force, and, as the sum of the braking force of each axis is not smaller than the required braking force of the vehicle, it may be characterized by adjusting the brake load factor of each axis.

  The control system of the present invention is for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts, and is applied with a brake command and outputs a value of a necessary braking force of the vehicle. And a brake force adjustment unit that receives the value of the necessary brake force and outputs the value of the brake force of each axis, the brake force adjustment unit for a combination of vehicle speed and wheel load within a predetermined range. The maximum braking force that does not slide for each axis is stored in advance, the brake initial speed that is the vehicle speed when the brake command is input is input, and the input brake initial speed and the wheel of the vehicle The maximum braking force of each axis for the combination with the weight is read from the storage unit, the braking force of each axis does not exceed the maximum braking force, and the sum of the braking forces of each axis is Wherein the not less than the required braking force of the two, it may be characterized in that adjusting the value of the braking force of each axis.

  The control system of the present invention is for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts. When a brake command is input, the average value per one axis of the required braking force of the vehicle is calculated. A brake force calculating unit for outputting, and a brake force adjusting unit for inputting the average value and outputting a value of the brake force of each axis, wherein the brake force adjusting unit is configured to obtain a vehicle speed and wheel load within a predetermined range. A storage unit that stores in advance the maximum braking force of each axis that does not slide with respect to the combination is input, a brake initial speed that is a vehicle speed when a brake command is input is input, and the input brake initial speed and the vehicle The maximum braking force of each axis for the combination with the wheel load of the axis is read from the storage unit, the braking force of each axis does not exceed the maximum braking force, and the total braking force of each axis is So as not to be less than the required braking force of the vehicle, it may be characterized by adjusting the brake load factor of each axis.

  In this control system, the brake force adjustment unit stores an empty vehicle weight value in advance, an increase amount of the vehicle weight with respect to the empty vehicle weight is input, and calculates the wheel load based on the empty vehicle weight value and the increase amount. It is preferable to do.

  In this control system, the brake force adjusting unit may receive a vehicle weight value and calculate the wheel load based on the vehicle weight value.

  An adhesion coefficient calculation method of the present invention is a method for calculating an adhesion coefficient of each axis for a combination of vehicle speed and wheel weight in a railway vehicle having a plurality of wheel shafts, and a water film exists between the rail and the wheel. A water film reduction rate, which is the ratio of the minimum water film thickness to the inlet water film thickness in the case of, and based on the vehicle speed and wheel load for each combination of vehicle speed and wheel load The minimum water film thickness after the second wheel is sequentially calculated based on the step of calculating the minimum water film thickness of the first wheel, the minimum water film thickness of the first wheel, and the water film reduction rate. And a step of calculating an adhesion coefficient of each axis based on the calculated minimum water film thickness of each wheel.

  The maximum braking force calculation method of the present invention is a method for calculating the maximum non-sliding braking force of each axis for a combination of the vehicle speed and the wheel load in a railway vehicle having a plurality of wheel shafts. The step of calculating the adhesion coefficient of each axis by the adhesion coefficient calculation method according to claim 7 for each combination, and the maximum brake that does not slide on each axis based on the wheel load and the number of adhesions of each axis And calculating a force.

  A computer program according to the present invention causes a computer to calculate an adhesion coefficient of each axis for a combination of vehicle speed and wheel weight in a railway vehicle having a plurality of wheel shafts, and a water film exists between the rail and the wheel. A water film reduction rate, which is the ratio of the minimum water film thickness to the inlet water film thickness in the case of, and based on the vehicle speed and wheel load for each combination of vehicle speed and wheel load The minimum water film thickness after the second wheel is sequentially calculated based on the step of calculating the minimum water film thickness of the first wheel, the minimum water film thickness of the first wheel, and the water film reduction rate. And causing the computer to execute a step and a step of calculating an adhesion coefficient of each axis based on the calculated minimum water film thickness of each wheel.

  According to the control system of the present invention, the braking force of each axis is controlled, so that the control system can be applied to a short train train. Further, since the value of the braking force of each axis is adjusted based on the adhesion coefficient of each axis with respect to the combination of the initial brake speed and the vehicle wheel load, the present invention can be applied to high-speed driving of a lightweight vehicle with a small wheel load. Since the value of the braking force of each axis is adjusted so as not to exceed the maximum braking force that does not slide, sliding is prevented. Since the value of the brake force of each axis is adjusted so that the sum of the brake force of each axis does not become smaller than the required brake force of the vehicle, the brake distance is prevented from increasing due to the adjustment of the brake force. Since this control system can be applied to high-speed driving of a light-weight short-knitted vehicle having the most severe conditions for preventing sliding, it can be widely applied regardless of knitting growth, driving speed, and vehicle weight of a railway vehicle.

The block block diagram of the control system which concerns on one Embodiment of this invention. The side view of the wheel on a rail at the time of water film intervention. The flowchart of the adhesion coefficient calculation in the adhesion coefficient calculation method of this invention. The side view which shows the relationship between the wheel in a continuation state, and a water film. Sectional drawing which expanded the contact surface of a rail and a wheel at the time of water film intervention. The flowchart of the minimum water film thickness calculation of the 1st ring | wheel in the same method. A graph showing an example of the speed dependence of the change in the sticking coefficient (coefficient of friction) axis calculated by the same method The graph which shows the vehicle weight dependence example of the change according to the sticking coefficient (friction coefficient) axis calculated by the same method A graph showing an example of water film reduction rate dependence of changes in the sticking coefficient (friction coefficient) axis calculated by the same method

  A control system according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the control system 1 is a system for controlling the braking force F of each axis in a railway vehicle having a plurality of wheel shafts. The brake device is controlled by the output of the control system 1. A brake device is a series of devices used to decelerate a vehicle, keep it at a constant speed, stop it, or hold it at a certain position (see number 71001 of Non-Patent Document 1).

  The product of the braking force F and the wheel radius is the braking torque T, and the radius of the wheel is constant. Therefore, controlling the braking force F and controlling the braking torque T are substantially the same. It is. That is, it can be said that the control system 1 is a system for controlling the braking torque T of each axis in a railway vehicle having a plurality of wheel shafts.

The control system 1 includes a brake force calculation unit 2 and a brake force adjustment unit 3. The brake force calculation unit 2 receives a brake command and outputs a value of a necessary brake force of the vehicle. The brake force adjusting unit 3 receives the value of the required brake force from the brake force calculating unit 2 and outputs the value of the brake force F (F ₁ , F ₂ , F ₃ ,...) Of each axis.

  The brake force calculation unit 2 receives a brake command, an empty vehicle weight value, and a variable load signal. The brake command is input to the brake force calculation unit 2 as a value of a brake notch designated by the driver's operation or an in-vehicle security device. The response load signal is a signal for correcting the braking force so that the deceleration during braking does not change even when the vehicle weight becomes heavier than the empty vehicle weight, and is generated by an on-vehicle response load device. In the present embodiment, the variable load signal is an increase amount of the vehicle weight with respect to the empty vehicle weight. The brake force calculation unit 2 outputs a value of a required brake force according to a brake notch value, an empty vehicle weight value, and a variable load signal.

In a conventional lightweight vehicle, the required braking force of the vehicle is evenly distributed to each axis. In the control system 1 of the present embodiment, the brake force adjusting unit 3 adjusts the value (F ₁ , F ₂ , F ₃ ,...) Of the brake force F of each axis.

The brake force adjustment unit 3 includes a storage unit 4. The storage unit 4 stores in advance the adhesion coefficient of each axis for a combination of vehicle speed and wheel load within a predetermined range. “Preliminary” means before the vehicle is operated as a train. The brake force adjusting unit 3 receives a brake initial speed that is a vehicle speed when a brake command is input. The brake force adjusting unit 3 reads out from the storage unit 4 the adhesion coefficient of each axis for the combination of the input brake initial speed and the wheel load of the vehicle. The brake force adjusting unit 3 calculates the maximum brake force F _μ that does not slide on each axis based on the adhesion coefficient of each axis and the wheel load of the vehicle. Braking force adjusting unit 3, for each axis braking force _{F i (F 1, F 2} , F 3, ...) the maximum braking force _{F μ (F μ1, F μ2} , F μ3, ...) does not exceed _{(F i} ≦ F _μi (i = 1, 2, 3,...)) And the total sum of the braking forces ΣF _i (i = 1, 2, 3,...) Of each axis is not smaller than the required braking force of the vehicle. Then, the brake force F value (F ₁ , F ₂ , F ₃ ,...) Of each axis is adjusted.

  Each configuration will be further described in detail. The railway vehicle has a plurality of wheel shafts on one vehicle. The wheel shaft is an assembly of a wheel and an axle (see number 22001 of Non-Patent Document 1). The number of axes controlled by the control system 1 is determined according to the railway vehicle on which the control system 1 is mounted. For example, when a railway vehicle on which the control system 1 is mounted has four wheel axles in one vehicle and is operated with one train and one set, the number of axes controlled by the control system 1 is four. When a railway vehicle is operated with two cars in one train, the number of axes controlled by the control system 1 is, for example, eight axes if all axes are controlled.

  The control system 1 includes, for example, a programmable controller, and the brake force calculation unit 2 and the brake force adjustment unit 3 are functional parts of the control system 1. The storage unit 4 is, for example, a nonvolatile semiconductor memory. In this embodiment, the adhesion coefficient of each axis for a combination of vehicle speed and wheel load within a predetermined range is stored as tabular data in the storage unit 4 and is called an adhesion coefficient table. In the adhesion coefficient table, for example, the parameter in the row direction is wheel load, the parameter in the column direction is the vehicle speed, and the data specified by the row and column is the adhesion coefficient of a specific axis. Have. Note that the adhesion coefficient of each axis for a combination of the vehicle speed and the wheel load within a predetermined range may be stored in the storage unit 4 as an approximate expression using the initial brake speed and the wheel load as parameters.

  In the present embodiment, the brake force adjusting unit 3 stores an empty vehicle weight value in advance. An increase amount of the vehicle weight with respect to the empty vehicle weight is input to the brake force adjusting unit 3 as an applied load signal from an on-vehicle applied load device. The brake force adjusting unit 3 calculates the wheel load of the vehicle based on the value of the empty vehicle weight and the amount of increase in the vehicle weight with respect to the empty vehicle weight. Since each wheel shaft has two wheels, for example, when one vehicle has four wheel shafts, the wheel weight is vehicle weight / 8 = (empty vehicle weight + increase amount) / 8.

  When the value of the vehicle weight is grasped outside the control system 1, the value of the vehicle weight may be input to the brake force adjustment unit 3. In this case, the brake force adjustment unit 3 receives the value of the vehicle weight and calculates the wheel weight of the vehicle based on the vehicle weight. Further, when the wheel load value is grasped outside the control system 1, the wheel load value may be input to the brake force adjusting unit 3.

  The adhesion coefficient of each axis for a combination of vehicle speed and wheel load within a predetermined range stored in the storage unit 4 is calculated by the adhesion coefficient calculation method of the present invention. Table 1 shows the parameters used in this method for calculating the adhesion coefficient.

As shown in FIG. 2, when the rail 5 and the wheel 6 are in contact with each other and a water film 7 is interposed between the rail 5 and the wheel 6, the water film behind the wheel 6 is more than the water film in front of the wheel 6. Even the thickness decreases. The water film thickness in front of the wheel 6 is referred to as an inlet water film thickness H, and the water film thickness in the rear of the wheel is referred to as a minimum water film thickness H _min . Water film thickness at the contact surface between the wheels 6 and the rail 5 is equal to the minimum water film thickness H _min. The water film thickness represented by the capital letter H is a dimensionless water film thickness obtained by making the water film thickness h represented by the unit of length [m] dimensionless (see Table 1).

In the adhesion coefficient calculation method of the present invention, first, as shown in FIG. 3 (flow chart), the minimum water film thickness H ¹ _min of the first wheel is calculated (step S101). The first wheel is the leading wheel to be controlled. The minimum water film thickness H ¹ _min of the ^first wheel is calculated based on the vehicle speed and wheel weight. The detailed calculation method will be described later.

Next, the minimum water film thickness H ² _min of the second wheel is calculated (i = 2 in step S102). A water film reduction rate a which is a ratio of the minimum water film thickness H _min to the inlet water film thickness H is given (H _min = a · H). The water film reduction rate a is obtained by experiment. The minimum water film thickness H ² _min of the second wheel is the product of the inlet water film thickness H ^{2 of} the second wheel and the water film reduction rate a (H ² _min = a · H ² ). As shown in FIG. 4, since the second wheel 62 is the wheel 6 that follows the first wheel 61, the inlet water film thickness H ² of the second wheel 62 is the minimum water film thickness of the first wheel 61. _Is equal to H ¹ _min (H ² = H ¹ _min ). Therefore, the minimum water film thickness H ² _min of the second wheel 62 is the product of the minimum water film thickness H ¹ _{min of} the first wheel 61 and the water film reduction rate a as shown in the following equation.

H ² _min = a · H ¹ _min

Similarly, the minimum water film thickness H ⁱ _min (i = 3,..., N) of each wheel up to the last wheel (n-th wheel) to be controlled is calculated by the following equation (i in step S102 of FIG. 3) = 3-n).

H ⁱ _min = a · H ⁱ⁻¹ _min (i = 3,..., N)

Thus, it is the inventor's idea to calculate the minimum water film thickness H ⁱ _min (i ≧ 2) after the second wheel by introducing the water film reduction rate a.

The water film reduction rate a may be changed for each wheel (i-wheel) (a: a ₂ , a ₃ ,...). The water film reduction rate a _i of each ring is obtained by experiments. The minimum water film thickness H ⁱ _min (i ≧ 2) of each wheel after the second wheel is calculated by the following equation using the water film reduction rate a _i of each wheel.

H ⁱ _min = a _i · H ⁱ⁻¹ _min (i = 2,..., N)

Finally, an adhesion coefficient for each axis is calculated based on the calculated minimum water film thickness H _min of each wheel (step S103). The calculation method will be described later.

According to Oyama et al., Each of the rail 5 and the wheel 6 has a surface roughness. As shown in FIG. 5, when the contact surface is enlarged, the tip portions of the fine protrusions are in contact with each other, and the other portions are voids. (See Non-Patent Document 2). When the water film 7 is interposed between the rail 5 and the wheel 6, the gap W is filled with water, so that the force W _c applied to the contact of the projection W with the wheel load W and the force W _h due to the water film pressure are shared. Will be received. At this time, the friction coefficient mu is expressed by Equation 1 using a shear stress coefficient mu _h the coefficient of friction mu _c and water during drying.

In Oyama et al model (see Non-Patent Document 2), the inlet water film thickness H and a minimum water film thickness Grubin fluid thick film type of the relationship between _{H min (D. Dowson, GR Higginson} : Elasto-Hydro- dynamic Lubrication, Pergamon Press (1966)). However, Grubin's fluid thick film type can be applied when the inlet water film thickness H is sufficiently thick, that is, only the first wheel. Is not applicable.

The adhesion coefficient calculating method of the present invention is based on the model shown in FIG. 5, without using the fluid thick type Grubin the calculation of the minimum water film thickness H _min.

Calculation of the minimum water film thickness of the first wheel in the adhesion coefficient calculation method of the present invention (step S101 in FIG. 3) will be described in detail. As shown in FIG. 6 (flow chart), the non-dimensional wheel load W is calculated from the wheel load (step S201). If the wheel weight is W _r and the radius of curvature of the wheel in the left-right direction is R _y , the wheel weight w per unit length is calculated by w = W _r / R _y . The dimensionless wheel load W is calculated as W = w / ER (see Table 1). In this equation, E is the equivalent Young's modulus and R is the wheel radius (see Table 1).

Next, the dimensionless speed U is calculated from the vehicle speed u (step S202). The dimensionless speed U is calculated by U = η ₀ u / ER (see Table 1). In this equation, η ₀ is the viscosity of water at 0 ° C. and 1 atmosphere (see Table 1).

Next, an initial value of the minimum water film thickness H _min is set (step S203). The initial value of H _min is, for example, a value obtained by making 0.3 μm dimensionless, and is not limited to this value.

Next, the non-dimensional load W _c (see FIG. 5) received by the protrusions is calculated (step S204 in FIG. 6). This non-dimensional load W _c is the non-dimensional formula obtained by Patir, Cheng (Nadir Patir, HS Cheng: Effect of surface roughness orientation on the central film thickness in EHD contacts, Elastohydrodynamics and Related Topics, pp.15-21 (1978)).

In Formula 2, H ^* is a value obtained by dividing the water film thickness h by the surface roughness σ, and there is a relationship of Formula 4 with the dimensionless water film thickness H.

Here, dimensionless Kamizumaku thickness H in equation 4 is the minimum water film thickness H _min, which is dimensionless.

In Equation 2, _Kc is a roughness directionality parameter, and in the adhesion coefficient calculation method of the present invention, Equation 5 used in the calculation by Oyama et al. Is used (see Non-Patent Document 2).

In Equation 2, _{P H} is the Hertz maximum pressure (see Table 1).

In Formula 3, X _in is a position where the contact between the wheel 6 and the rail 5 starts, and X _out is a position where the contact between the wheel 6 and the rail 5 is separated (see FIG. 2).

Next, the load W _h (see FIG. 5) received by the water film is calculated (step S205 in FIG. 6). This dimensionless load W _h is equal to Herrebrugh's equation of viscosity (K. Herrebrugh: Solving the Incompressible and Isothermal Problem in Elastohydrodynamic Lubrication through an Integral Equation, Transactions ASME, Ser.F, Vol.90, No.1, pp. .262-270 (1968)).

  In Equation 6, U is the dimensionless speed (calculated in step S202).

  Instead of Equation 6, the more general Dowson-Higginson equation (D. Dowson, GR Higginson: Elasto-Hydro-dynamic Lubrication, Pergamon Press (1966) ) May be calculated by Equation 7.

  In Equation 7, G is a material parameter represented by G = αE. α is a coefficient of viscosity with respect to the pressure of the fluid, and E is a Young's modulus.

  Although it is known that the viscosity of a fluid changes under the influence of both temperature and pressure, Herrebrugh expresses Equation 6 as an iso-viscosity conditional expression in which the target is limited to water and the change in pressure is ignored. expressed. Oyama et al. Compared the results of using both Formula 6 and Formula 7 in calculating the coefficient of friction between the wheel and the rail during water intervention, and found that there was no difference between the two. For this reason, in the method for calculating the adhesion coefficient of the present invention, Equation 6 which is simpler than Equation 7 is used only for the calculation during water intervention.

Next, (W _c + W _h ) is compared with W (step S206 in FIG. 6), and if the difference exceeds a predetermined error ε (No in step S206), the minimum water film thickness H _min is changed. is (step S207), returns to the calculation of the dimensionless load _{W c} of the protrusion portions is subjected (step S204). The method of changing the minimum water film thickness H _min is performed according to the change state of (W _c + W _h ). When comparing (W _c + W _h ) and W, if the difference is within a predetermined error ε (Yes in step S206), the minimum water film thickness H _min at that time is set to the minimum water film thickness of the first wheel. H ¹ _min is set (step S208).

As described above, the minimum water film thickness H ⁱ _min (i = 2 to n) after the second wheel uses the water film thickness H ¹ _min of the first wheel calculated as described above. It calculates sequentially using the rate a (step S102 of FIG. 3).

The calculation of the adhesion coefficient (friction coefficient) of each axis based on the minimum water film thickness H ⁱ _min (i = 1 to n) of each wheel will be described (step S103).

First, H ^{* of} the i-th wheel is calculated by substituting the minimum water film thickness H ⁱ _min of the i-th wheel into Equation 4.

Next, W _c is calculated by Equation 2, Equation 3, and Equation 5.

W _h is calculated by Equation 6.

Substituting W _c and W _h into Equation 1 to calculate the friction coefficient μ of the i-th wheel. The i-th axis adhesion coefficient μ is the same as the friction coefficient of the i-th wheel. Incidentally, in Equation 1, the shear stress coefficient mu _h of dry friction coefficient mu _c and water are known coefficients (see Table 1).

  Such calculation is performed for each axis from the first axis to the nth axis, and the adhesion coefficient μ of each axis for the combination of the vehicle speed and the wheel load is calculated. The actual calculation is performed by causing a computer to execute a computer program.

  The adhesion coefficient μ of each axis for the combination of the vehicle speed and the wheel load calculated in this way is stored in the storage unit 4 (see FIG. 1).

  The brake force adjustment unit 3 reads the adhesion coefficient μ of each axis for the combination of the input brake initial speed and the vehicle wheel load from the storage unit 4. That is, the brake force adjusting unit 3 reads out the adhesion coefficient μ of each axis for the combination of the vehicle speed and the vehicle wheel load when the vehicle speed is the brake initial speed from the storage unit 4.

The brake force adjusting unit 3 determines the maximum brake force F _μ (non-sliding) for each axis based on the adhesion coefficient μ (μ _i : μ ₁ , μ ₂ ,..., Μ _n ) of each axis and the wheel load W _r of the vehicle. F _μi : F _μ1 , F _μ2 ,..., F _μn ) are calculated by the following equation.

F _μi = 2μ _i W _r (i = 1, 2,..., N)

This maximum brake force F _μi calculation method uses the adhesion coefficient μ _i calculation method. In the control system 1, instead of storing in advance the adhesion coefficient μ _i of each axis for a combination of the vehicle speed and the wheel load W _r within a predetermined range in the storage unit 4, the vehicle speed and the wheel load W within a predetermined range. _The maximum braking force F _μi that does not slide on each axis for the combination with _r may be stored in the storage unit 4 in advance. In this case, the maximum braking force F _μi of each axis for a combination of the vehicle speed and wheel load W _r within a predetermined range is stored in the storage unit 4 as tabular data. The tabular data, for example, a row direction of the parameter is wheel load W _r, the maximum braking force F _.mu.i the data does not glide particular axis column parameters are specified in the vehicle speed, rows and columns, such Each matrix (i-axis, i = 1 to n). Note that the maximum braking force F _μi of each axis that does not slide for a combination of the vehicle speed and the wheel load W _r within a predetermined range is stored in the storage unit 4 as an approximate expression using the brake initial speed and the wheel load W _r as parameters. May be.

The adjustment of the brake force F _i of each axis (first axis to n-th axis) by the brake force adjustment unit 3 will be described. The brake force before adjustment is a value F ₀ in which the required brake force of the vehicle is evenly distributed to each axis.

Braking force adjusting section 3 is, for example, as follows, adjusting the braking force F _i of each axis (the i-axis) from the first axis in order.

At the wheel shaft close to the head when the water film is interposed, the adhesion coefficient μ _i decreases, and the maximum braking force F _μi that does not slide decreases. When the brake force F ₀ before the adjustment is up braking force F _.mu.i or not sliding, to prevent sliding, as shown in the following equation, it is limited to a maximum braking force F _.mu.i without sliding the braking force F _i after adjustment .

F _μi ≦ F ₀ ⇒ F _i = F _μi

As the sticking coefficient μ _i gradually approaches the sticking coefficient at the time of drying from the leading wheel axle to the succeeding wheel axle, the maximum braking force F _μi that does not slide is adjusted before the adjustment on the rear wheel axle (m <i ≦ n). It becomes larger than the brake force _{F 0} of _(F μi> F 0). Therefore, instead of limiting the brake force F _i after adjustment on the wheel shaft close to the head (i ≦ m), the brake force F after adjustment on the other shafts (number of axes nm) as in the following equation: _i is made larger than the brake force F ₀ before adjustment, and the deficiency (Σ [j = 1,..., m] (F ₀ −F _μj )) is compensated.

F _μi > F ₀ ⇒ F _i = F ₀ + (Σ [j = 1,..., _M ] (F ₀ −F _μj )) / (n−m)
m: Number of axes _satisfying F _μi ≦ F ₀ However, when F _i > F _μi , F _i = F _μi, and the deficiency due thereto is further distributed to the rear wheel shaft.

Incidentally, the method comprising controlling the braking force F, to control the braking torque T are substantially the same, instead of the braking force F _i of the i axis, the braking torque T _i of the i-axis similarly You may adjust it.

Further, since the brake load ratio of the i-th axis is F _i / F ₀ , adjusting the brake force F _i of each axis means that the brake force calculation unit 2 does not adjust the brake force F ₀ before the adjustment (required for the vehicle This is substantially the same as the brake force adjusting unit 3 adjusting the brake load ratio F _i / F ₀ of each axis.

As described above, according to the control system 1 according to the present embodiment, the brake force F _{i of} each axis is controlled, so that the control system 1 can be applied to a short train train. Also, since the brake force value F _i of each axis is adjusted based on the adhesion coefficient μ _i of each axis with respect to the combination of the initial brake speed and the vehicle wheel load, it is applicable to high-speed driving of a lightweight vehicle with a small wheel load. Is possible. Since the value F _i of the braking force of each axis is adjusted so as not to exceed the maximum braking force F _μi that does not slide, sliding is prevented. The brake force value F _i of each axis is adjusted so that the sum of the brake forces of each axis (Σ [i = 1,..., N] F _i ) does not become smaller than the required brake force (n · F ₀ ) of the vehicle. Therefore, it is possible to prevent the brake distance from being increased by adjusting the braking force.

  The prevention of sliding in a railway vehicle is easier when the formation is longer, easier when the vehicle weight is larger, and easier when the vehicle speed is lower. Since the control system 1 can be applied to high-speed driving of a short-sized lightweight vehicle having the strictest conditions for preventing sliding, it can be widely applied regardless of the knitting growth of the railway vehicle, the driving speed, and the vehicle weight.

  During braking, the vehicle speed gradually decreases from the initial brake speed. As the vehicle speed decreases, the minimum water film thickness decreases (see Equation 6), and as a result, the adhesion coefficient increases. Such an increase in the adhesion coefficient during braking is a change in a direction in which sliding is less likely to occur. Therefore, by adjusting the value of the braking force based on the initial braking speed, sliding is prevented even if the vehicle speed decreases during braking. Since the adhesion coefficient used for adjusting the braking force is not changed in time based on the initial brake speed, rather than changing in real time following the change in the vehicle speed during braking, the processing in the control system 1 is simplified. The reliability of the control system 1 is improved. Reliability is extremely important in brake control.

According to the adhesion coefficient calculation method used in the control system 1, since the water film reduction rate a is introduced, the minimum water film thickness H ⁱ _min (i ≧ 2) after the second wheel can be calculated. The adhesion coefficient μ _i for each axis can be calculated. This adhesion coefficient calculation method can calculate the change in the adhesion coefficient for each axis for all railway vehicles including the condition that the wheel load is included in the calculation condition and the condition that the wheel load is small such as a lightweight vehicle. .

  As an example of the adhesion coefficient calculation method of the present invention, the adhesion coefficient (friction coefficient between rails and wheels) of each axis in a railway vehicle was calculated. The railway vehicle was a two-car train. Since one vehicle has four axles, the knitting has 4 × 2 = 8 axles. Table 2 shows the parameters used for the calculation.

  First, the relationship between the vehicle speed and the change in the sticking coefficient (friction coefficient) for each axis was examined. The vehicle speed was set to 8 conditions of 20 km / h from 20 km / h (5.56 m / s) to 160 km / h (44.44 m / s).

The calculation results are shown in FIG. According to FIG. 7, the adhesion coefficient at the leading axis decreases as the vehicle speed increases, and gradually approaches μ _c = 0.3 set as the adhesion coefficient during drying as the vehicle speed decreases. When attention is paid to the change for each axle, the adhesion coefficient gradually approaches the adhesion coefficient at the time of drying from the first wheel axis to the subsequent wheel axis, and the adhesion coefficient μ _c at the time of drying is almost the same at the 8th wheel axis at the end of the second car. = Converges to the same value as 0.3.

  Next, the relationship between the vehicle weight and the change in the sticking coefficient (friction coefficient) for each axis was examined. The vehicle weight was set to 8 conditions in increments of 10 t from 10 t (tons) to 80 t. The vehicle speed was 120 km / h.

The calculation results are shown in FIG. According to FIG. 8, the adhesion coefficient in the first wheel decreases as the vehicle weight decreases. When the vehicle weight decreases, the wheel weight that presses the wheel against the rail from the top decreases, so that the wheel floats on the water film even under the same speed condition. As a result, the adhesion coefficient is reduced. When attention is paid to the change for each wheel shaft, the adhesion coefficient μ _c at the time of drying converges to the same value as the subsequent wheel shaft.

  The water film reduction rate a is set by experiment or the like. In Example 1 and Example 2, the water film reduction rate a was set to 1/2 as a provisional value for examining the change in the sticking coefficient for each axis (see Table 2). In Example 3, a parameter study on the water film reduction rate a was performed. As the water film reduction rate a, a total of 5 conditions of 1/3, 1/4, 1/5, and 1/8 were set in addition to a = 1/2. The wheel load was 36750 N, and the vehicle speed was 120 km / h (33.33 m / s) (see Table 2).

The calculation results are shown in FIG. According to FIG. 9, the adhesion coefficient of the leading wheel shaft is the same for all the water film reduction rates a, and the adhesion coefficient converges to the same value as the adhesion coefficient μ _c = 0.3 at the time of the subsequent wheel shaft. Yes. Focusing on the difference in the water film reduction rate a, the smaller the water film reduction rate a, the faster the convergence to the adhesion coefficient during drying. More water film decrease rate a is small, because the water film thickness of the rear wheels is reduced relative to the front wheels, and converges to 0 early water film thickness at the wheels of the continuing state, as a result, adhesion coefficient as early mu _c Is considered to have converged to 0.3.

  According to the calculation results of Examples 1 to 3, the change model for each axis of the water film thickness into which the water film reduction rate a is introduced is applied to the model of Oyama et al. (See Non-Patent Document 2). Thus, it was shown that the change by axis of the adhesion coefficient can be modeled.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. The control system 1 of the present invention is not limited to control of braking force in a railway vehicle of a short knitted lightweight vehicle that is operated at high speed, and is widely applied to low to high speed operation of a railway vehicle having a general vehicle weight. The Moreover, you may apply the control system 1 to a Shinkansen vehicle.

DESCRIPTION OF SYMBOLS 1 Control system 2 Brake force calculation part 3 Brake force adjustment part 4 Memory | storage part 6 Wheel 7 Water film a Water film decrease rate F Brake force H _min Minimum water film thickness (Dimensionless minimum water film thickness)
μ Cohesion coefficient (coefficient of friction)

Claims (9)

A control system for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts,
A brake force calculation unit that receives a brake command and outputs a value of a required brake force of the vehicle;
A brake force adjusting unit that receives the value of the required brake force and outputs the value of the brake force of each axis;
The brake force adjustment unit has a storage unit in which an adhesion coefficient of each axis for a combination of vehicle speed and wheel load within a predetermined range is stored in advance.
The brake initial speed, which is the vehicle speed when the brake command is input, is input,
Read the adhesion coefficient of each axis for the combination of the input brake initial speed and wheel load of the vehicle from the storage unit,
Based on the adhesion coefficient and wheel load of each axis, calculate the maximum braking force that does not slide on each axis,
The value of the braking force of each axis is adjusted so that the braking force of each axis does not exceed the maximum braking force and the total braking force of each axis does not become smaller than the necessary braking force of the vehicle. And control system. A control system for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts,
A brake force calculation unit that receives a brake command and outputs an average value per one axis of the required brake force of the vehicle;
A brake force adjusting unit that receives the average value and outputs a brake force value of each axis;
The brake force adjustment unit has a storage unit in which an adhesion coefficient of each axis for a combination of vehicle speed and wheel load within a predetermined range is stored in advance.
The brake initial speed, which is the vehicle speed when the brake command is input, is input,
Read the adhesion coefficient of each axis for the combination of the input brake initial speed and wheel load of the vehicle from the storage unit,
Based on the adhesion coefficient and wheel load of each axis, calculate the maximum braking force that does not slide on each axis,
Adjusting the brake load ratio of each axis so that the braking force of each axis does not exceed the maximum braking force and the total braking force of each axis does not become smaller than the required braking force of the vehicle. Control system. A control system for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts,
A brake force calculation unit that receives a brake command and outputs a value of a required brake force of the vehicle;
A brake force adjusting unit that receives the value of the required brake force and outputs the value of the brake force of each axis;
The brake force adjusting unit has a storage unit in which a maximum brake force that does not slide for each axis for a combination of vehicle speed and wheel load within a predetermined range is stored in advance.
The brake initial speed, which is the vehicle speed when the brake command is input, is input,
Read the maximum braking force of each axis for the combination of the input brake initial speed and wheel load of the vehicle from the storage unit,
The value of the braking force of each axis is adjusted so that the braking force of each axis does not exceed the maximum braking force and the total braking force of each axis does not become smaller than the necessary braking force of the vehicle. And control system. A control system for controlling the braking force of each axis in a railway vehicle having a plurality of wheel shafts,
A brake force calculation unit that receives a brake command and outputs an average value per one axis of the required brake force of the vehicle;
A brake force adjusting unit that receives the average value and outputs a brake force value of each axis;
The brake force adjusting unit has a storage unit in which a maximum brake force that does not slide for each axis for a combination of vehicle speed and wheel load within a predetermined range is stored in advance.
The brake initial speed, which is the vehicle speed when the brake command is input, is input,
Read the maximum braking force of each axis for the combination of the input brake initial speed and wheel load of the vehicle from the storage unit,
Adjusting the brake load ratio of each axis so that the braking force of each axis does not exceed the maximum braking force and the total braking force of each axis does not become smaller than the required braking force of the vehicle. Control system.   The brake force adjustment unit stores an empty vehicle weight value in advance, receives an increase amount of the vehicle weight relative to the empty vehicle weight, and calculates the wheel load based on the empty vehicle weight value and the increase amount. The control system according to any one of claims 1 to 4.   5. The brake force adjusting unit according to claim 1, wherein a vehicle weight value is input to the brake force adjusting unit, and the wheel load is calculated based on the vehicle weight value. 6. Control system. An adhesion coefficient calculation method for calculating an adhesion coefficient of each axis for a combination of vehicle speed and wheel load in a railway vehicle having a plurality of wheel axes,
Water film reduction rate is given as the ratio of the minimum water film thickness to the inlet water film thickness when a water film exists between the rail and the wheel,
For each combination of vehicle speed and wheel load,
Calculating a minimum water film thickness of the first wheel based on the vehicle speed and wheel weight;
Sequentially calculating the minimum water film thickness after the second wheel based on the minimum water film thickness of the first wheel and the water film reduction rate;
And a step of calculating an adhesion coefficient of each axis based on the calculated minimum water film thickness of each wheel. A maximum brake force calculating method for calculating a maximum non-sliding brake force of each axis for a combination of vehicle speed and wheel load in a railway vehicle having a plurality of wheel shafts,
For each combination of vehicle speed and wheel load,
Calculating the adhesion coefficient of each axis by the adhesion coefficient calculation method according to claim 7;
And a step of calculating a maximum braking force of each shaft that does not slide based on the wheel load and the number of sticking cases of each shaft. A computer program for causing a computer to calculate an adhesion coefficient of each axis for a combination of vehicle speed and wheel load in a railway vehicle having a plurality of wheel axes,
Water film reduction rate is given as the ratio of the minimum water film thickness to the inlet water film thickness when a water film exists between the rail and the wheel,
For each combination of vehicle speed and wheel load,
Calculating a minimum water film thickness of the first wheel based on the vehicle speed and wheel weight;
Sequentially calculating the minimum water film thickness after the second wheel based on the minimum water film thickness of the first wheel and the water film reduction rate;
A computer program for causing a computer to execute a step of calculating an adhesion coefficient of each axis based on the calculated minimum water film thickness of each wheel.

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