Patent Application
20240157918
The present invention relates generally to deceleration control of rail vehicles. Especially, the invention relates to a braking system for a rail vehicle containing two or more railroad cars, and a computer-implemented method of decelerating such a rail vehicle. The invention also relates to a computer program and a non-volatile data carrier storing such a computer program.
A rail vehicle's brakes are employed to control the deceleration of the rail vehicle and to implement a parking brake function. Typically, the same brakes are used both for service braking and emergency braking. Traditional rail vehicle brakes are dependent on a load input, i.e. data reflecting the weights of each railroad car. Today's rail vehicles are often regulated using compressed air, known as pneumatically regulated brakes. One disadvantage of such pneumatic brakes is that they cannot be regulated quickly. Due to the slow regulation, the system is dependent on knowing a gross weight reflecting the load on the individual bogies of the rail vehicle. The brakeforce is applied in relation to the load, and inter alia represents an important input to various anti-slip and anti-wheel-lock mechanisms. Nevertheless, in general, more load translates into a higher brake force.
US 2002/0088673 discloses an apparatus and method for incorporating a feedback mechanism into a train railcar wheel braking system to regulate applied braking force. The feedback mechanism provides information to an electronically controlled pneumatic braking system sufficient to detect impending wheel slip or skid. Responsive to the wheel slip/skid information, a brake control processor modulates the braking force applied to the train railcar wheel system to enable the braking system to apply a braking force without damaging the railcar wheel system or rails over which the railcar wheels are traveling.
US 2010/0078991 describes a brake device for braking a vehicle has a brake surface which is rotationally fixedly connected to a wheel axle of the vehicle, a brake lining which can be pressed with a braking force against the brake surface and an actuating element coupled to a control unit, for generating the braking force. The control unit is connected to a speed sensor for measuring a speed of the vehicle and is set up to adjust the braking force in dependence on the speed. The brake device has as high a braking force as possible which is introduced into the brake surfaces. The control unit is coupled to the actuating element via a device for continuous pressure adjustment, so as to enable a continuous adaptation of the braking force to the present speed in each case. The braking force is advantageously adjusted inversely proportionally to the speed of the vehicle.
US 2020/0198605 shows a microcomputer-controlled electromechanical braking system comprises an electromechanical braking control device and an electromechanical braking unit. The electromechanical braking control device comprises a braking microcomputer control unit, an electromechanical control unit and a standby power supply module. The braking microcomputer control unit receives a braking instruction signal sent by a driver or an automatic driving system, performs the calculation of a target braking force and braking management, and at the same time, can communicate with braking microcomputer control units of other vehicles in a train group.
Thus, solutions are known for producing continuously adapted braking forces during braking, for instance aiming at avoiding wheel slip. The prior art also contains examples of braking systems where control units in different railroad cars of a train vehicle communicate with one another to improve the braking performance. Common for the known solutions is that they all rely on load information to control the braking operations. This means that, in one way or the other, the weight of each railroad car forms a basis for how different brakes are applied. However, the load information is an unreliable parameter because imperfect scales provide inaccurate measures, and the bogie loads may vary during travel as passengers may walk between the railroad cars.
The object of the present invention is therefore to offer a solution that solves the above problem and enables efficient, safe and reliable braking of a rail vehicle without having to consider load information.
According to one aspect of the invention, the object is achieved by a braking system for a rail vehicle having at least two railroad cars, which braking system contains a number of control units, a number of brake actuators and a number of brake units. At least one control unit is arranged in each one of the railroad cars. Each of the control units is configured to receive a brake input signal, and in response thereto generate a respective control signal. The brake input signal may for example be generated in response to a service brake command issued by an operator, an emergency brake command issued manually or automatically, or a parking brake command issued manually or automatically. Further, at least one brake actuator is arranged in each railroad car, and each brake actuator is configured to receive the control signal generated by a control unit in the same railroad car as the brake actuator. Based on the received control signal, the brake actuator is configured to produce a brake-force signal. Each brake unit contains a pressing member and a rotatable member being mechanically linked to at least one wheel of one of the railroad cars. Each brake unit is configured to receive the brake-force signal produced by the brake actuator in the same railroad car as the brake unit. In response to the brake-force signal, the brake unit is configured to cause the pressing member to apply a braking force to the rotatable member so as to reduce a rotation speed of the at least one wheel. Moreover, in addition to the brake input signal, each control unit is configured to generate the control signal on the basis of at least one motion parameter expressing a respective movement of each of the railroad cars.
The above braking system is advantageous because it enables fast and individually adapted control of the brakes in each railroad car. Not only does this, in turn, translate into a low degree of jerk in the rail vehicle, it also allows each individual railroad car to utilize its full brake potential. Consequently, a shortest possible brake distance is attainable. The system further obtains a faster response time than a traditional load-based system, which results in less wheel flats. Since the braking system is well suited for electric/optic control, it is lighter than a traditional brake system being controlled based on pneumatic/hydraulic control. It should be noted, however, that nothing precludes that the braking system according to the invention is applied to pneumatically/hydraulically controlled brakes.
According to one embodiment of this aspect of the invention, the rail vehicle contains a first communication bus, e.g. of an electronic or optic format, configured to feed the brake input signal to each of the railroad cars. The first communication bus may either be fed in parallel to all the control units, be fed in series from one control unit to the other, or be fed to the control unit according to a hybrid series and parallel format, such as in parallel to each railroad car and in series between different control units within a railroad car. Nevertheless, the first communication bus enables reliable and speedy distribution of the brake input signal in the entire rail vehicle.
According to another embodiment of this aspect of the invention, each of the railroad cars contains at least one accelerometer configured to produce at least one vector signal representing an acceleration in at least one dimension of the railroad car in which the at least one accelerometer is placed, for example lengthwise the railroad car. The at least one vector signal expresses the respective movement of the railroad car on the further basis upon which the brake input signal is produced. Consequently, the at least one control unit is configured to receive the at least one vector signal, and based thereon generate the control signal. This is advantageous because such acceleration data form a solid basis for assigning adequate braking forces in the respective railroad cars.
According to yet another embodiment of this aspect of the invention, alternatively or in addition to producing the above-mentioned at least one vector signal, each of the least two railroad cars contains at least one a rotational speed sensor configured to produce at least one speed signal representing a respective speed of a wheel of the railroad car containing the at least one a rotational speed sensor. Thus, the rotational speed sensor may for example be arranged on a wheel and/or an axle of the railroad car. In any case, the at least one speed signal expresses the movement of the railroad car; and analogous to the above, the control unit is configured to receive the at least one speed signal, and based thereon generate the control signal. Such speed measurements are advantageous because the wheel speed constitutes a firm basis for assigning adequate braking forces in the respective railroad cars.
According to still another embodiment of this aspect of the invention, each of the control units is configured to: receive at least one of the at least one motion parameter expressing the respective movement of each other railroad car comprised in the rail vehicle; determine an average motion parameter based on the at least one received motion parameter and an own motion parameter expressing the movement the railroad car in which said respective one control unit is comprised; and generate the control signal such that it causes the brake actuator controlled by the respective one control unit to produce a respective brake-force signal to the at least one brake unit causing the at least one pressing member to apply an increased braking force, if the own motion parameter expresses that the movement of the railroad car has a magnitude larger than what is expressed by the average motion parameter. In other words, the braking force will be increased for a railroad car having an above-average magnitude of motion. Provided that the applied braking force is repeatedly updated at short intervals, this vouches for a short braking distance and a relatively low degree of jerk.
Preferably, each of the control units is further configured to generate the control signal such that it causes the brake actuator controlled by the respective one control unit to produce a respective brake-force signal to the at least one brake unit causing the at least one pressing member to apply a decreased braking force, if the own motion parameter expresses that the movement of the railroad car has a magnitude smaller than what is expressed by the average motion parameter. Thereby, the overall degree of jerk may be reduced further.
Moreover, it is preferable if each of the control units is configured to generate the control signal such that it causes the brake actuator controlled by the respective one control unit to produce a respective brake-force signal to the at least one brake unit causing the at least one pressing member to apply a maintained braking force, should the own motion parameter express that the movement the railroad car has a magnitude equal to what is expressed by the average motion parameter. Although, in practice, this may be unusual, such a strategy is likewise beneficial with respect to attaining a low degree of jerk during braking.
According to another embodiment of this aspect of the invention, the rail vehicle contains a second communication bus configured to exchange the motion parameters between the railroad cars, which motion parameters express the respective movements of the railroad cars included in the rail vehicle. The second communication bus may either be separate from the first communication bus physically and/or logically, or form a physically integrated part thereof and/or form a logically integrated part thereof. In any case, a bus format is generally preferred because it provides an efficient means of exchanging data between the different railroad cars.
According to yet another embodiment of this aspect of the invention, each of the railroad cars in the rail vehicle contains at least one respective battery unit, which is configured to provide electric energy to the control units and the brake actuators positioned in the same railroad car as the least one respective battery unit. A respective one of the least one battery unit may be comprised in or be co-located with each control unit, or two or more control units and/or two or more brake actuators may share a common battery unit. In the latter case, the battery unit is preferably not integrated into a control unit. However, from a technical point-of view, this is not excluded either. In any case, the battery units provide an important back-up source of energy for effecting the braking functionality in case a main electric supply to the braking system is broken.
Preferably, each of the railroad cars also contains at least one battery charger configured to charge the at least one respective battery unit during operation of the rail vehicle so as to ensure that the at least battery unit is operative when needed.
In a braking system comprising pneumatically/hydraulically controlled brakes, accumulator tanks holding pressurized gas/fluid may serve as replacements for batteries to provide emergency brake functionality in case of a malfunctioning brake control system.
According to still another embodiment of this aspect of the invention, each of the at least one wheel whose rotation speed one of the brake actuators is configured to cause to reduce is a wheel whose rotation is monitored by a measurement module configured to produce a slip signal reflecting a degree of slip of the at least one wheel. Each of the brake actuators is configured to receive the slip signal, and if the degree of slip exceeds a threshold value, the brake actuator is configured to produce the brake-force signal such that the brake unit causes the pressing member to apply a braking force to the rotatable member, which braking force is lower than a braking force designated by the received control signal. Consequently, the risk of wheel slip/lock may kept low. This, in turn, is beneficial with respect to braking distance as well as to avoid so-called flat spots or wheel flats.
According to another aspect of the invention, the object is achieved by a computer-implemented method of decelerating a rail vehicle including at least two railroad cars, each of which contains: at least one control unit, at least one brake actuator and at least one brake unit. The method involves: receiving a brake input signal in each of the control units; generating, in each of the control units, a respective control signal in response to the brake input signal; and receiving each of the respective control signals in one of the brake actuators in the same railroad car as the control unit which produced the control signal is positioned. Further, the method involves: producing, in each of the brake actuators, a respective brake-force signal based on the control signal; receiving each of the respective brake-force signals in one of the brake units in the same railroad car as the brake actuator which produced the brake-force signal is positioned, and causing, in each brake unit, a pressing member to apply a braking force to the rotatable member so as to reduce a rotation speed of at least one wheel of at least one railroad car in response to the brake-force signal. Specifically, the method involves, generating in each of the control units, the respective control signal on the further basis of at least one motion parameter expressing a respective movement of each of the railroad cars. The advantages of this method, as well as the preferred embodiments thereof are apparent from the discussion above with reference to the proposed control unit.
According to a further aspect of the invention, the object is achieved by a computer program loadable into a non-volatile data carrier communicatively connected to a processing unit. The computer program includes software for executing the above method when the program is run on the processing unit.
According to another aspect of the invention, the object is achieved by a non-volatile data carrier containing the above computer program.
Further advantages, beneficial features and applications of the present invention will be apparent from the following description and the dependent claims.
The invention is now to be explained more closely by means of preferred embodiments, which are disclosed as examples, and with reference to the attached drawings.
In
The rail vehicle contains at least two railroad cars, here exemplified by 111, 112 and up to 11n, where n may designate any number from say 3 to 200. The rail vehicle is equipped with a braking system, which, in turn, includes: a number of control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2; a number of brake actuators 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b; and a number of brake units 141-1, 141-2, 141-3, 141-4, 142-1, 142-2, 142-3, 142-4, 14n-1, 14n-214n-3 and 14n-4.
The control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2 arranged in the railroad cars 111, 112 and 11n so that there is at least one control unit in each railroad car, for example one per railroad car or one per bogie of each railroad car.
In any case, each control unit is configured to receive a brake input signal B designating a braking action to be effected. For instance the brake input signal B may have been generated in response to a service brake command, an emergency brake command or a parking brake command. Each of these commands may, in turn, be produced manually (i.e. by a human operator), or automatically by safety and/or comfort mechanisms in the rail vehicle.
The brake input signal B may be fed in parallel to all the railroad cars 111, 112 and 11n as illustrated in
It is generally preferable if the rail vehicle has a first communication bus 151 configured to feed the brake input signal B to each of the at least two railroad cars 111, 112 and 11n, for example from a locomotive in the rail vehicle (not shown). Preferably, according to the invention, the locomotive is regarded to be a frontmost railroad car in the rail vehicle, which may or may not be configured to also carry passengers and/or goods. The first communication bus 151 may be of electronic or optic format.
Alternatively, instead of using a bus format, data and control signals may be exchanged between the railroad cars 111, 112 and 11n on an analog format, for example employing pulse width modulation.
In response to the brake input signal B, each of the control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2 is configured to generate at least one control signal c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4 respectively, which control signal designates a desired brake force to be applied. For example, an operator may produce a service brake command designating 40% of a full braking capacity. In case of emergency braking, the brake input signal B is equivalent to 100% of the full braking capacity.
Each brake actuator 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b respectively is configured to receive a control signal generated by one of the control units located in the same railroad car as the brake actuator itself. For example, a control unit 121-1 may feed control signals c11 and c12 to the brake actuators 1311a and 1311b, which, in turn, feed resulting brake-force signals f11 and f12 to the brake units 141-1 and 141-2 respectively, each of which brake unit 141-1 and 141-2 is responsible for braking a separate wheel pair in a particular bogie, say the front bogie of the first railroad car 111. Analogously, each remaining control unit 122-1, 122-2, 12n-1 and 12n-2 may be configured to control the braking of a respective bogie in the railroad cars 111, 112 and 11n of the rail vehicle.
Based on the respective control signals c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4, each brake actuator 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b is configured to produce a brake-force signal f11, f12, f13, f14, f21, f22, f23, f24, fn1, fn2, fn3 and fn4 respectively, which is fed to a particular brake unit 141-1, 141-2, 141-3, 141-4, 142-1, 142-2, 142-3, 142-4, 14n-1, 14n-2, 14n-3 and 14n-4. Each of the brake units has a pressing member and a rotatable member that is mechanically linked to at least one wheel of a railroad car 111, 112, or 11n.
The brake units are configured to receive the brake-force signals f11, f12, f13, f14, f21, f22, f23, f24, fn1, fn2, fn3 and fn4 produced by the brake actuators 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b respectively. Specifically, a given brake unit receives a brake-force signal produced by a brake actuator located in the same railroad car as the brake unit itself, for example as described above and illustrated in
According to the invention, not only the brake input signal B serves a basis for the control signal c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4. Namely, each of the control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2 is configured to generate the respective control signal c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4 on the further basis of at least one motion parameter expressing a respective movement m1, m2 and mn of the railroad cars 111, 112 and 11n.
As is well known in the art, there exists various forms of a articulated railroad cars, for example in commuter trains and tramway vehicles. In rail vehicles with this type of railroad cars, so-called Jacobs bogies are commonly used. Jacobs bogies are arranged between two carriages, or segments of an articulated railroad car. Thereby, the weight of the adjoining carriages/segments is spread across the Jacobs bogie. This design provides a smooth ride of bogie carriages without requiring any additional weight and drag. In the present invention, the segments of an articulated railroad car being connected over a Jacobs bogie are considered to form part of one and the same railroad car. Consequently, these segments will be assigned an identical movement m1, m2 or mn according to the above.
According to one embodiment of the invention, it is presumed that the brake actuators are electrically controlled. Therefore, each of the railroad cars 111, 112 and 11n contains at least one battery unit 161, 162 and 16n respectively. The battery units 161, 162 and 16n are configured to provide electric energy to the control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2 and the brake actuators 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b located in the same railroad car as the at least one battery unit 161, 162 and 16n itself is located. The battery unit 161, 162 or 16n may be comprised in, or be co-located with each, a particular one of the control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2.
In any case, two or more control units, e.g. 121-1 and 121-2, in a particular railroad car 111 may share a common battery unit 161. Similarly, two or more brake actuators, e.g. 1311a, 1311b, 1312a, and 1312b, in a particular railroad car 111 may share a common battery unit 161. If the battery unit 161 constitutes such a shared resource, it is preferably not integrated into one of the control units. However, from a technical point-of view, this is not excluded either. In any case, the battery units provide an important back-up source of energy for effecting the braking functionality in case a main electric supply to the braking system is broken.
According to one embodiment of the invention, at least one battery charger (not shown) is included in each of the railroad cars 111, 112 and 11n, which at least one battery charger is configured to charge the at least one battery unit 161, 162 and 16n during operation of the rail vehicle. Hence, reliable backup energy can always be provided to the braking system.
It is worth noticing that, in a braking system wherein the brakes are controlled pneumatically/hydraulically, accumulator tanks holding pressurized gas/fluid may serve as battery equivalents to provide backup sources of energy enabling brake functionality in case of a malfunctioning brake control system.
An accelerometer as exemplified by 211 is comprised in each of the railroad cars 111, 112 and 11n, and each accelerometer is configured to produce at least one vector signal representing an acceleration in at least one dimension of the railroad car in which the at least one accelerometer 211 is comprised. For example, the at least one accelerometer 211 may produce vector signals expressing respective accelerations in the three spatial directions aX, aY and aZ and/or rotational accelerations yaw aR, pitch aP and roll aw of the railroad car. In any case, the at least one vector signal expresses the respective movement m1, m2 and mn of the railroad cars 111, 112 and 11n respectively.
Further, each of the control units 121-1, 121-2, 122-1, 122-2, 12n-1 and 12n-2 is configured to receive each of the at least one vector signal from each accelerometer in each railroad car 111, 112 and 11n in the rail vehicle, and based thereon generate the control signals c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4 respectively.
Here, each of the railroad cars 111, 112 and 11n contains at least one rotational speed sensor exemplified by 212, which at least one rotational speed sensor 212 is configured to produce at least one speed signal sω representing a respective speed ω of a wheel 221 of the railroad car in which the at least one rotational speed sensor 212 is comprised. Thus, the rotational speed sensor 212 may have sensor elements arranged on one or more wheels and/or on one or more axles of a railroad car. In any case, the at least one speed signal sω expresses the movement m1, m2 and mn respectively of the railroad car.
Analogous to the above, each of the control units 121-1, 121-2, 122-1, 122-2, 12n-1, 12n-2 is configured to receive the at least one speed signal sω from each railroad car 111, 112 and 11n in the rail vehicle, and based thereon generate the control signal c11, c12, c13, c14, c21, c22, c23, c24, cn1, cn2, cn3 and cn4 respectively.
According to one embodiment of the invention, each control unit, for example 121-1 in the railroad car 111, is configured to receive at least one of the at least one motion parameter expressing the respective movement of each other railroad car 112 and 11n in the rail vehicle, i.e. m2 and mn respectively.
The control unit 121-1 is further configured to determine an average motion parameter mavg based on the at least one received motion parameter m2 and mn, and an own motion parameter expressing the movement m1 the railroad car in which the control unit 121-1 is comprised. Here, the motion parameters expressing the movements m1, m2 and mn may for example be represented by respective speed signals sω and/or respective accelerations ay lengthwise the railroad cars 111, 112 and 11n.
Moreover, the control unit 121-1 is configured to generate the respective control signal c11 and c12 such that it causes the brake actuators 1311a and 1311b respectively controlled by the control unit 121-1 to produce brake-force signals f11 and f12 respectively causing the pressing members of the brake units 141-1 and 141-2 to apply braking forces being modified relative to what would be given by the brake input signal B alone. Specifically, the control unit 121-1 is configured to generate the respective control signal c11 and c12 such that it causes the brake actuators 1311a and 1311b to produce a respective brake-force signal f11 and f12 to the brake units 141-1 and 141-2 resulting in an increased braking force, if the own motion parameter expresses that the movement m1 of the railroad car 111 has a magnitude larger than what is expressed by the average motion parameter mavg. In other words, if the own railroad car 111 runs somewhat faster than a current average magnitude of motion of the railroad cars in the rail vehicle, the brakes in the own railroad car 111 will brake a bit harder.
Similarly, according to one embodiment of the invention, each control unit 121-1 is configured to generate the control signal c11 and c12 such that it causes the brake actuators 1311a and 1311b respectively controlled by the control unit 121-1 to produce the respective brake-force signals f11 and f12 to the brake units 141-1 and 141-2 causing the at least one pressing member to apply a decreased braking force, if the own motion parameter expresses that the movement m1 of the railroad car 111 has a magnitude smaller than what is expressed by the average motion parameter mavg. In other words, if the own railroad car 111 runs somewhat slower than a current average magnitude of motion of the railroad cars in the rail vehicle, the brakes in the own railroad car 111 will brake a bit less hard. This results in a relatively jerk free braking process.
Exactly how much harder or less hard the brake shall be controlled if the own railroad car 111 is found to run faster or slower respectively than the current average magnitude of motion of the railroad cars in the rail vehicle is a design parameter, which inter alia depends on how often the motion parameters expressing the movements m1, m2 and mn are updated.
According to one embodiment of the invention, each control unit 121-1 is configured to generate the control signal c11 and c12 such that it causes the brake actuators 1311a and 1311b respectively controlled by the control unit 121-1 to produce the respective brake-force signals f11 and f12 to the brake units 141-1 and 141-2 causing the at least one pressing member to apply a maintained braking force, if the own motion parameter expresses that the movement m1 of the railroad car 111 has a magnitude equal to what is expressed by the average motion parameter mavg. In other words, if the own railroad car 111 has a magnitude of motion coinciding with a current average magnitude of motion of the railroad cars in the rail vehicle, the brakes in the own railroad car 111 will continue to brake as they do in order to attain an overall smooth braking process.
According to one embodiment of the invention, the rail vehicle includes a second communication bus 152, which is configured to exchange the motion parameters expressing the respective movements m1, m2 and mn of the railroad cars 111, 112 and 11n respectively. The second communication bus 152 may be of electronic or optic format, and the second communication bus 152 may either be physically and/or logically separate from the first communication bus 151, or the second communication bus 152 may form a physically integrated part of the first communication bus 151, and/or the second communication bus 152 may form a logically integrated part of first communication bus 151. In any case, a communication bus is generally preferred for exchanging the motion parameters because the bus format provides an efficient means of exchanging data between the different railroad cars 111, 112 and 11n.
Referring again to
Exactly how much the braking force shall be lowered is a design parameter, which inter alia depends on the threshold value for the degree of slip and how often the slip signal s11 is updated.
It is further advantageous if two or more of the brake actuators 1311a, 1311b, 1312a, 1312b, 1311a, 1311b, 1312a, 1312b, 13n1a, 13n1b, 13n2a and 13n2b exchange slip-related information between one another. Namely, this enables a second brake unit, e.g. 141-2, to take over a part of the braking responsibility from a first brake unit, e.g. 141-1, if the degree of slip exceeds the threshold value in the first brake unit, however not the second brake unit.
It is generally advantageous if the above-described braking procedure is effected in an automatic manner by executing one or more computer programs. Therefore, each control unit and brake actuator respectively preferably includes processing circuitry and programmed memory units, the designs of which will be briefly described below with reference to
As explained above, the control unit 121-1 is configured to receive the brake input signal B and the motion parameters expressing the respective movements m2 and mn of the other railroad cars 112 and 11n in the rail vehicle; and output at least one control signal, here exemplified by c11.
As explained above, the brake actuator 1311a is configured to receive the control signal c11, and preferably the slip signal s11; and output the brake-force signal f11.
Naturally, although the control unit 121-1 and the brake actuator 1311a have been described as separate entities above, these entities may equally well be partially or fully co-located with/integrated into one another. In particular, according to the invention, at least one control unit and at least one brake actuator, two or more control units and/or two or more brake actuators may share common processing resources.
In order to sum up, and with reference to the flow diagram in
A first step 510, checks if a brake input signal has been received. If so, a step 520 follows; and otherwise, the procedure loops back and stays in step 510.
In step 520, a respective movement of each railroad car is determined, for example via acceleration measurements and/or wheel speed measurements. Thereafter, a step 530 follows that generates, in each of the control units, a respective control signal. Here, each control signal is generated in response to the brake input signal. The control signal is based on the movement of the railroad car itself and the movement of the other railroad cars. As discussed above, a relationship between the movement of the railroad car itself and the average movement of all the railroad cars in the rail vehicle may influence an applied brake force up or down relative to what is stipulated by the received brake input signal.
The control signals generated in step 530 are fed to respective brake actuators. Specifically, each control unit feeds its control signal to one or more brake actuators located in the same railroad car as the control unit itself.
In a step 540 subsequent to step 530, each brake actuator produces a respective brake-force signal based on the control signal received from the control unit. Each brake-force signal is fed to one or more brake units located in the same railroad car as the brake actuator itself.
Then, in a step 550, each brake unit causes a pressing member to apply a braking force to a rotatable member mechanically linked to at least one wheel of a railroad car so as to reduce a rotation speed of the at least one wheel in response to the brake-force signal.
Thereafter the procedure ends. Of course, in practice, step 510 may be reactivated, for example to check if a renewed brake input signal has been received.
All of the process steps, as well as any sub-sequence of steps, described with reference to
Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.
The term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components. The term does not preclude the presence or addition of one or more additional elements, features, integers, steps or components or groups thereof. The indefinite article “a” or “an” does not exclude a plurality. In the claims, the word “or” is not to be interpreted as an exclusive or (sometimes referred to as “XOR”). On the contrary, expressions such as “A or B” covers all the cases “A and not B”, “B and not A” and “A and B”, unless otherwise indicated. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.
It is also to be noted that features from the various embodiments described herein may freely be combined, unless it is explicitly stated that such a combination would be unsuitable.
The invention is not restricted to the described embodiments in the figures, but may be varied freely within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21162663.5 | Mar 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/081228 | 11/10/2021 | WO |
