Patent Description:
The prior art will be described below with particular reference to the field of railway vehicles. Nevertheless, that which is described in the following may also apply, where possible, to vehicles in other fields.

In the railway transport system, the instantaneous grip value between the wheel and the track represents the maximum braking force limit that may be applied to the axles without the wheels of said axles starting to progressively skid.

When an axle enters a skidding phase, if the applied braking force is not promptly and suitably reduced, the axle progressively loses angular velocity until it has completely jammed, resulting in immediate overheating and damage caused by the overtemperature of the surface of the wheels of said axle at the point of contact between the wheels and the track. It is known that this situation not only significantly increases the stopping distances as a result of a further reduction in the coefficient of friction, but may also cause the railway vehicle to derail at high operating speeds.

In order to overcome the drawback described above, known pneumatic railway braking systems are provided with a protection system known as an anti-skid system.

A known anti-skid system is shown by way of example in <FIG>. In one example, this anti-skid system is used for a railway vehicle having four axles <NUM>, <NUM>, <NUM>, <NUM>. On the basis of a request for braking pressure or braking force (not shown in <FIG>), a braking system <NUM> produces a pneumatic braking pressure, thus supplying respective brake cylinders <NUM>, <NUM>, <NUM>, <NUM>. These brake cylinders are each responsible for braking the respective axles <NUM>, <NUM>, <NUM>, <NUM> by means of pneumatic supply ducts <NUM>, <NUM>. Four anti-skid valve modules <NUM>, <NUM>, <NUM>, <NUM> are controlled by an anti-skid device <NUM> and are placed between the pneumatic supply ducts <NUM>, <NUM> and the respective brake cylinders <NUM>, <NUM> and <NUM>, <NUM>. Angular velocity sensors <NUM>, <NUM>, <NUM>, <NUM> detect the angular velocity of each of the axles <NUM>, <NUM>, <NUM>, <NUM>, respectively. Said angular velocity sensors <NUM>, <NUM>, <NUM>, <NUM> are electrically connected to the anti-skid device <NUM>, continuously providing an electrical signal that represents the instantaneous angular velocity information of each axle <NUM>, <NUM>, <NUM>, <NUM>. The anti-skid device <NUM> continuously estimates the instantaneous linear velocity of the vehicle by means of operations carried out on the instantaneous angular velocity information of the axles <NUM>, <NUM>, <NUM>, <NUM>.

By continuously evaluating differences ΔV between the instantaneous linear velocity of the single axle, which instantaneous linear velocity is obtained from said instantaneous angular velocity of the axle, and the estimated instantaneous linear velocity of the vehicle, the anti-skid device <NUM> detects if one or more axles have started to skid. If one or more axles have started a skidding phase, the anti-skid device controls the skidding of said axles by reducing and suitably modulating the pressure at the brake cylinders relative to the skidding axles, acting on the valve groups relating to said skidding axles by means of known algorithms, for example as described in <CIT> and <CIT>, preventing said axles from becoming jammed, and attempting to obtain the best braking force while remaining in a sliding phase.

Said anti-skid valve modules <NUM>, <NUM>, <NUM>, <NUM> each assume the detailed form represented by the pair of pneumatic solenoid valves <NUM>, <NUM> shown in <FIG>.

The pneumatic solenoid valves <NUM>, <NUM> are energized by the anti-skid device <NUM> by means of respective switching elements <NUM>, <NUM>. These switching elements <NUM>, <NUM> are typically solid-state electronic components.

For simplicity of illustration, <FIG> does not show the connection of solenoids, i.e. electrical coils, <NUM>, <NUM> to earth.

The anti-skid valve modules <NUM>, <NUM>, <NUM>, <NUM> may assume a total of four states.

The first state is defined as a "filling state" and corresponds to a state in which both of the electropneumatic valves are de-energized, as shown in <FIG>: the electropneumatic valve <NUM> allows the pressure present in a pneumatic duct <NUM>, corresponding to the pneumatic duct <NUM>, <NUM> in <FIG>, to access a brake cylinder <NUM>, corresponding to the brake cylinder <NUM>, <NUM>, <NUM>, <NUM> of <FIG>, while the electropneumatic valve <NUM> prevents the brake cylinder <NUM> and the pneumatic duct <NUM> from emptying into the atmosphere. This state represents the rest state, or state of non-intervention, of the anti-skid device, in that it constitutes a direct connection between the brake cylinder <NUM> and the pneumatic duct <NUM>, via which connection the braking system directly controls the pressure at the brake cylinder <NUM> from a zero value to a maximum value.

The second state is defined as a "hold state" and corresponds to a state in which the electropneumatic valve <NUM> is energized. In this case, the pressure in the brake cylinder <NUM> may not be modified by variations in pressure in the pneumatic duct <NUM>. The pneumatic solenoid valve <NUM> continues to keep the brake cylinder <NUM> isolated from the atmosphere. The pressure at the brake cylinder <NUM> generally holds its value indefinitely unless there are leaks in the brake cylinder.

The third state is defined as a "discharge state" and corresponds to a state in which both the pneumatic solenoid valves <NUM>, <NUM> are energized. In this case, the pressure in the brake cylinder <NUM> may not be modified by variations in pressure in the pneumatic duct <NUM>. The energized pneumatic solenoid valve <NUM> connects the brake cylinder <NUM> to the atmosphere, thus reducing the pressure at the brake cylinder, optionally to a value of zero.

The fourth state is defined as a "prohibited state" and corresponds to a state in which only the pneumatic solenoid valve <NUM> is energized. In this case, the pneumatic solenoid valve directly connects both the brake cylinder <NUM> and the pneumatic duct <NUM> to the atmosphere, causing the pressure produced by the braking system to unduly discharge to the atmosphere.

In order to systematically prevent the "prohibited" state, the switching element <NUM> is connected to a node <NUM> downstream of the switching element <NUM>. In this way, when the switching element <NUM> is closed by an improper command from the circuit upstream or as a result of a short circuit of said circuit, it is not possible to energize the pneumatic solenoid valve <NUM> unless the switching element <NUM> is also closed, in which case the pneumatic solenoid valve <NUM> would also be energized, effectively bringing the brake cylinder <NUM> into the "discharge" state but preventing the pneumatic duct <NUM> from discharging to the atmosphere.

The prior art discloses various circuits for controlling the pneumatic solenoid valves, either in relation to the supply or in relation to the ground, which allow the "prohibited" state to be systematically prevented.

In its functional action, the anti-skid system generally inevitably reduces the braking force. It is clear how, in certain hardware or software failure modes, the anti-skid device is able to keep the pneumatic solenoid valves <NUM>, <NUM> permanently energized, resulting in a total loss of braking force. In order to limit cases of permanently energized valves, the European railway standard EN15595:<NUM> "Railway applications - Braking - Wheel slide protection" §<NUM>. <NUM>, <NUM> December <NUM>, states:.

In other words, the standard dictates three important points:.

These one or more timer devices are introduced in order to temporally limit the continuous activation of the pneumatic solenoid valves <NUM>, <NUM>.

<FIG> shows a possible functional embodiment of the control system of an anti-skid system. A control means, e.g. a microprocessor <NUM>, executes functions/algorithms for recognizing and controlling skidding of the axles, for example but not exclusively as described in <CIT> and <CIT>, by generating respective command signals <NUM>, <NUM> for the switching elements <NUM>, <NUM>.

When the control means <NUM> brings the command signal <NUM> to a logic level "<NUM>", i.e. which is intended to activate the switching element <NUM>, the transition <NUM> → <NUM> of the command signal <NUM> activates the timer device <NUM>, which in turn brings an output <NUM> thereof to a logic level "<NUM>" for a time interval T1 that is equal, for example but not exclusively, to <NUM>. A logic gate <NUM> executes an AND function between the command signal <NUM> and the output signal <NUM>, thus causing a signal <NUM> to effectively command the closure of the switching element <NUM>, in order to subsequently energize the pneumatic solenoid valve <NUM>.

When the microprocessor <NUM> brings the command signal <NUM> to a logic level "<NUM>", before the time T1 has expired, in order to de-energize the pneumatic solenoid valve <NUM>, it then puts the timer device <NUM> into a reset condition via an active low input R thereof, preparing it for a subsequent transition <NUM> → <NUM>.

If the command signal <NUM> were to remain permanently blocked at logic level "<NUM>" as a result of a hardware failure of the microprocessor <NUM> or as a result of a software error of the anti-skid control algorithm, the time T1 counted by the timer device <NUM> would then expire, causing the signals <NUM>, <NUM> to return to a logic level "<NUM>", resulting in the permanent de-energizing of the pneumatic solenoid valve <NUM>.

The same applies to the timer device <NUM> in relation to the electropneumatic valve <NUM>.

In some cases, there is a pressure transducer <NUM> present that indicates to the control means <NUM>, via a connection <NUM>, the pressure upstream of the pneumatic solenoid valve <NUM>, and there is a pressure transducer <NUM> present that indicates to the control means <NUM>, via a connection <NUM>, the pressure at the brake cylinder <NUM>.

The prior art discloses circuit variants for implementing the function of timing and inhibiting the commands for energizing the electropneumatic valves <NUM>, <NUM>.

The timing circuits shown in <FIG> are replicated for each anti-skid valve group <NUM>, <NUM>, <NUM>, <NUM>.

In each case, according to the prior art, the timer devices <NUM>, <NUM> are hardware circuits independent from the control means <NUM>, in accordance with the cited standard.

The solution described above represents the prior art identified by all railway operators and railway safety agencies as a method for reducing the risk that hardware failures or software problems may cause a permanent undue reduction in pneumatic pressure during a braking phase.

Disadvantageously, it is not possible to apply the solutions described above to electromechanical braking systems on account of the significant structural differences by comparison with pneumatic braking systems.

<CIT> relates to a rail vehicle electromechanical brake antiskid control system, <CIT> relates to a microcomputer-controlled electromechanical braking system, <CIT> relates to an actuator for a braking system of a rail vehicle and <CIT> relates to a brake actuator for a braking system of a vehicle, however, the above-mentioned problems remain unresolved.

The object of this invention is therefore to provide a solution that allows an anti-skid function to be executed safely in an electromechanical braking system of at least one vehicle, for example at least one railway vehicle.

The aforesaid and other objects and advantages are achieved, according to an aspect of the invention, by an anti-skid system for an electromechanical braking system having the features defined in claim <NUM>. Preferred embodiments of the invention are defined in the dependent claims, the content of which is to be understood as an integral part of the present description.

The functional and structural features of some preferred embodiments of an anti-skid system for an electromechanical braking system according to the invention will now be described. Reference is made to the accompanying drawings, in which:.

Before describing a plurality of embodiments of the invention in detail, it should be clarified that the invention is not limited in its application to the construction details and configuration of the components presented in the following description or illustrated in the drawings. The invention is able to assume other embodiments and to be implemented or constructed in practice in different ways. It should also be understood that the phraseology and terminology have a descriptive purpose and should not be construed as limiting. The use of "include" and "comprise" and the variations thereof are intended to cover the elements set out below and their equivalents, as well as additional elements and the equivalents thereof.

New technologies, including mechatronic technologies, are being introduced to the field of braking systems, for example railway braking systems.

For the sake of completeness of information, the following will provide a description of various modules/blocks that may be part of an electromechanical braking system. For example, <FIG> show possible non-exclusive block diagrams of electromechanical braking systems.

A braking control module <NUM> may be provided in order to be interfaced with control systems of the vehicle or convoy, for example railway vehicle or convoy, by means of signals <NUM> via which it may receive the service braking requests and/or receive an emergency braking request <NUM>.

This braking control module <NUM> may convert the service braking or emergency braking requests that come from the vehicle or convoy (for example railway vehicle or convoy) into a braking force application request <NUM>. It is not the aim of this invention to illustrate how the braking control module <NUM> is implemented, whether this is with one or more independent control means, and what safety level SIL has to be assigned to the individual elements that form said braking control module <NUM>.

According to the prior art, an electromechanical module <NUM> may comprise at least one electric motor and mechanical components adapted to transform the rotary motion and the torque produced by said at least one electric motor into a linear movement and a linear force, respectively, which are transferred to an arm <NUM> or brake shoe <NUM>, in order to generate a braking force on the wheel <NUM>.

It is known from the prior art that the arm <NUM> and the brake shoe <NUM> may have, as an alternative means of braking, a system of brake levers and pads that act on a brake disc.

An electronic module <NUM> for controlling the braking force may be arranged to receive an electrical supply <NUM> and the braking force application request <NUM> generated by the braking control module <NUM>, and is arranged to generate at least one supply signal <NUM> for the at least one electric motor inside the electromechanical module <NUM> and to receive at least one applied braking force signal <NUM> generated by said electromechanical module <NUM>, said applied braking force signal <NUM> assuming an instantaneous value corresponding to the instantaneous value of the braking force applied by said electromechanical module <NUM> to the wheel <NUM>.

The electronic force control module <NUM> may execute control algorithms by suitably modulating the at least one supply signal <NUM> such that said electromechanical module <NUM> continuously produces an applied braking force signal <NUM> corresponding to the braking force application request value <NUM>.

If the electronic force control module <NUM> and the braking control module <NUM> are separate physical units, the braking force application request <NUM> may physically consist of a point-to-point network connection as shown in <FIG>, or, as shown in <FIG>, of a communication network <NUM> to which more electronic force control modules <NUM>I, <NUM>II,. , <NUM>n are connected, with which modules the respective electromechanical modules <NUM> for braking the respective wheels <NUM> are associated. The electromechanical modules <NUM> and the wheels <NUM> are not shown in <FIG>.

Unlike pneumatic braking systems where the anti-skid device acts directly on the flow of the means that transfers the braking force, i.e. on the flow of pressurized air toward the brake cylinder, the systems described in <FIG> are not suitable for the incorporation of an anti-skid system that acts directly on the means for transmitting the braking force. Conversely, this invention proposes solutions that act on the logic flow of the braking force application request.

Returning now to this invention, it relates to an anti-skid system for an electromechanical braking system of at least one vehicle.

For example, said at least one vehicle may be at least one railway vehicle.

This vehicle includes at least one wheel.

In one embodiment, the anti-skid system comprises an anti-skid module <NUM> arranged to execute a predetermined anti-skid function and to provide an output, the value of which is determined by said predetermined anti-skid function.

For the purposes of this invention, the anti-skid function <NUM> may be any anti-skid function currently known in the field.

The anti-skid system also comprises a supervisor module <NUM>, <NUM> which is arranged to monitor said anti-skid module <NUM>. The supervisor module <NUM>, <NUM> is also arranged to receive the output of the anti-skid module <NUM> and a braking force application request signal <NUM>, the value of which is indicative of a braking force application request value.

The supervisor module <NUM>, <NUM> includes a braking force application request adjustment module <NUM>, <NUM> which is arranged to adjust the value of said braking force application request signal <NUM> according to said output of the anti-skid module <NUM>.

The supervisor module <NUM>, <NUM> and the anti-skid module <NUM> are modules that are distinct from each other.

The supervisor module <NUM>, <NUM> may clearly be a hardware module or a software module, and the module <NUM> for executing the anti-skid function may be a hardware module or a software module. Distinct may be understood to mean, inter alia, at least all of the following cases:.

The braking force application request adjustment module <NUM>, <NUM> is therefore arranged to adjust the braking force application request signal <NUM> independently of the execution of the anti-skid function <NUM> by the anti-skid module <NUM>.

With reference to <FIG>, in one embodiment, the anti-skid module <NUM> may be arranged to generate, at said output thereof, a braking force reduction signal <NUM>. The value of this braking force reduction signal is indicative of a braking force reduction value. The anti-skid module <NUM> may be arranged to adjust the value of the braking force reduction signal <NUM> such that the braking force reduction value is non-zero, in the presence of at least one skidding condition of at least one wheel <NUM> of the at least one vehicle, in accordance with said predetermined anti-skid function.

For example, an anti-skid module <NUM> may be arranged to receive an instantaneous velocity signal <NUM> of the vehicle, at least one instantaneous velocity signal <NUM> of the wheel <NUM>, which signal is generated by the velocity sensor <NUM> associated with said wheel <NUM>, and optionally further velocity signals <NUM>I. <NUM>n from other velocity sensors associated with further wheels. The anti-skid module may be arranged to execute anti-skid algorithms, not exclusively as described in <CIT> and <CIT>, and to calculate a braking force reduction value <NUM> if the wheel <NUM> is skidding.

The supervisor module <NUM> may be arranged to receive the braking force application request signal <NUM> and the braking force reduction signal <NUM> generated by the anti-skid module <NUM>. The supervisor module <NUM> may also be arranged to generate an adjusted braking force signal <NUM> indicative of an adjusted braking force value.

The supervisor module <NUM> may also include a time-out module <NUM> which is arranged to receive the braking force application request signal <NUM> and the braking force reduction signal <NUM> generated by the anti-skid module <NUM>. The supervisor module <NUM> may also be arranged to generate a timed braking force reduction signal <NUM>. The value of this timed braking force reduction signal <NUM> is indicative of a timed braking force reduction value.

The time-out module <NUM> may be arranged to adjust the value of the timed braking force reduction signal <NUM> such that the timed braking force reduction value:.

The supervisor module <NUM> may include a braking force application request adjustment module <NUM> which is arranged to adjust the value of said adjusted braking force signal <NUM> such that the adjusted braking force value coincides with the value of the difference between the braking force application request value indicated by the braking force application request signal <NUM> and the timed braking force reduction value indicated by the timed braking force reduction signal <NUM>.

For example, the supervisor module <NUM> may include a summing node <NUM> which is arranged to subtract the value of the electrical timed braking force reduction signal <NUM> from the value of the electrical braking force application request signal <NUM>. The summing node <NUM> may propagate the result of the subtraction in the form of an adjusted braking force value <NUM> to a possible electronic force control module <NUM> of an electromechanical braking system.

Preferably, the first time interval may be monitored by a first timer means <NUM> and the second time interval may be monitored by a second timer means <NUM>.

For example, the time-out module <NUM> may:.

In other words, the time-out module <NUM> may therefore set the timed braking force reduction value to be equal to the braking force reduction valve <NUM> until the first timer means <NUM>, i.e. the partial braking force reduction timer <NUM>, has reached a predefined maximum partial braking force reduction time, i.e. the first time interval.

When the first timer means <NUM>, i.e. the partial braking force reduction timer, has reached the predefined maximum partial braking force reduction time, i.e. the first time interval, the time-out module <NUM> may set and maintain the braking force reduction value equal to zero. The value may be held at zero for example until the velocity value <NUM> of the vehicle assumes a non-zero value.

In order to respect the values cited in the standard EN15595:<NUM> §<NUM>. <NUM>, the first time interval may assume the value of <NUM> seconds and the second time interval may assume the value of <NUM> seconds <NUM>.

With reference to <FIG>, an alternative embodiment is shown in which the anti-skid module <NUM> is arranged to generate, at said output thereof, a braking force hold signal <NUM> and a braking force reduction signal <NUM>, in the presence of at least one skidding condition of at least one wheel <NUM> of said at least one vehicle, in accordance with said predetermined anti-skid function.

For example, the anti-skid module <NUM> may be arranged to receive the instantaneous velocity signal <NUM> of the vehicle, at least one instantaneous velocity signal <NUM> of the wheel <NUM>, which signal is generated by the velocity sensor <NUM> associated with said wheel <NUM>, and optionally further velocity signals <NUM>I. <NUM>n from other velocity sensors associated with other wheels.

The anti-skid module may be arranged to execute, for example, anti-skid algorithms which are not exclusively as described in <CIT> and <CIT>. Similarly to pneumatic anti-skid systems as shown in <FIG>, the supervisor module <NUM> may generate the braking force hold signal <NUM>, which is analogous to the signal <NUM> in <FIG>, and the braking force reduction signal <NUM>, which is analogous to the signal <NUM> in <FIG>.

The supervisor module <NUM> may be arranged to receive the braking force application request signal <NUM>, the braking force hold signal <NUM> and the braking force reduction signal <NUM>, and to generate the adjusted braking force signal <NUM> indicative of the adjusted braking force value. Similarly to pneumatic anti-skid systems as shown in <FIG>, the supervisor module <NUM> may generate a braking force hold signal <NUM>, which is analogous to the signal <NUM> in <FIG>, and a braking force reduction signal <NUM>, which is analogous to the signal <NUM> in <FIG>.

The supervisor module <NUM> may also include a time-out module <NUM> which is arranged to receive the braking force hold signal <NUM> and the braking force reduction signal <NUM> and to generate a timed braking force hold signal <NUM> and a timed braking force reduction signal <NUM>.

The time-out module <NUM> may be arranged to:.

For example, the first predetermined value and the second predetermined value may both be a logic condition <NUM>, and the first predetermined default value and the second predetermined default value may both be a logic condition <NUM>. In different embodiments, the first predetermined value and the second predetermined value may be different, and the first predetermined default value and the second predetermined default value may be different.

The supervisor module <NUM> also includes a braking force application request adjustment module <NUM> which is arranged to receive the braking force application request signal <NUM>, said timed braking force hold signal <NUM> and said timed braking force reduction signal <NUM>, and to output an adjusted braking force signal <NUM>.

The braking force application request adjustment module <NUM> is arranged to:.

Preferably, for this embodiment as well, the first time interval may be monitored by a first timer means <NUM> and the second time interval may be monitored by a second timer means <NUM>.

For example, the first timer means <NUM>, which may also be called the "force hold timer", associated with the hold signal <NUM> may be arranged to count the period of time in which the value of said hold signal <NUM> continuously assumes the logic value <NUM>, i.e. the first predetermined value, and the second timer means <NUM>, which may also be called the "force reduction timer <NUM>", associated with the braking force reduction signal <NUM> may be arranged to count the period of time in which the braking force reduction signal <NUM> continuously assumes the logic value <NUM>, i.e. the first predetermined value.

In this embodiment as well, in order to respect the values cited in the standard EN15595:<NUM> §<NUM>. <NUM>, the first time interval may assume the value of <NUM> seconds and the second time interval may assume the value of <NUM> seconds <NUM>.

According to the prior art, the time-out devices <NUM>, <NUM> of a pneumatic braking system are developed according to a safety level SIL3, and are typically implemented using hardware devices so as to guarantee the functional independence of the microprocessor <NUM>.

Furthermore, the electropneumatic architecture formed by the switching devices <NUM>, <NUM> and the electropneumatic valves <NUM>, <NUM> is considered to have a safety level of SIL≥<NUM>, as a result of its design and defined "service proven", i.e. a "level of safety proven by long and reliable service".

Preferably, in order to reach the same safety level for an electromechanical braking system, it is possible to develop the braking force application request adjustment module <NUM>, <NUM>, which may be functionally similar to the switching devices <NUM>, <NUM> and the electropneumatic valves <NUM>, <NUM>, and the time-out module <NUM>, <NUM>, which may be similar to the time-out devices <NUM>, <NUM>, by means of software functions according to a safety level SIL≥<NUM>, which software functions are executed, for example, by microprocessor architecture which is itself developed according to a safety level SIL≥<NUM>.

For any of the embodiments described above, the time-out module <NUM>, <NUM> and the braking force application request adjustment module <NUM>, <NUM> may preferably be integrated into one module.

For any of the embodiments described above, the braking control module <NUM> and the anti-skid module <NUM> may preferably be integrated into one module.

With reference to <FIG>, an embodiment is shown of an electromechanical braking system for a vehicle, for example at least one railway vehicle, which system includes an anti-skid system, analogous to the pneumatic braking system shown in <FIG>, using the solutions shown in <FIG> and <FIG> as described above.

Four force control modules <NUM>I <NUM>II,. may each control a particular electromechanical module <NUM>I, <NUM>II,. in order to brake a particular wheel <NUM>I, <NUM>II,. It is clear to a person skilled in the art of braking control systems, for example railway braking systems, that in reality, for each wheel <NUM>I, <NUM>II,. shown in <FIG>, there are two wheels associated with the same axle, and that for each axle, there is a pair of electromechanical modules <NUM>I, <NUM>II,.

The braking control module <NUM> may generate a braking force application request <NUM> which is sent to the supervisor modules <NUM>I, <NUM>II,. that each correspond to the supervisor module <NUM> in <FIG> or to the supervisor module <NUM> in <FIG>. The supervisor modules <NUM>I, <NUM>II,. may each be associated with the particular braking force control module <NUM>I, <NUM>II,.

An anti-skid module <NUM> may be arranged to receive the instantaneous velocity signal <NUM> of the vehicle and the instantaneous velocity signals <NUM>I, <NUM>II,. of the respective wheels <NUM>I, <NUM>II,. that are each generated by the velocity sensors <NUM>I, <NUM>II,. which are each associated with the respective wheels <NUM>I, <NUM>II,.

The anti-skid module may be arranged to execute anti-skid algorithms and generate groups of force adjustment signals <NUM>I, <NUM>II,. , said adjustment signals <NUM>I, <NUM>II,. being dependent on the slippage of the corresponding wheel <NUM>I, <NUM>II,. , and said adjustment signals <NUM>I, <NUM>II,. being sent to the respective supervisor modules <NUM>I, <NUM>II,.

Each group of adjustment signals <NUM> functionally corresponds to the timed braking force reduction value <NUM> in <FIG> or to the braking force hold signals <NUM> and braking force reduction signals <NUM> in <FIG>.

The physical implementation of <FIG> may have some degree of freedom but it is necessary to respect the requirement for physical independence between the supervisor modules <NUM>I, <NUM>II,. and the anti-skid module <NUM>.

The anti-skid system may therefore preferably comprise a plurality of supervisor modules <NUM>I, <NUM>II, <NUM>III, <NUM>IV. Each of the supervisor modules <NUM>I, <NUM>II, <NUM>III, <NUM>IV may be arranged to generate a relevant adjusted braking force signal <NUM>I, <NUM>II, <NUM>III, <NUM>IV. In this case, the plurality of supervisor modules <NUM>I, <NUM>II, <NUM>III, <NUM>IV may be integrated into a single module <NUM>.

In other words, one possible embodiment integrates the supervisor modules <NUM>I, <NUM>II,. into one module <NUM> that is independent from the anti-skid module <NUM>. The single module <NUM> may preferably be implemented at a safety level SIL ≥<NUM>. The single module <NUM> may be implemented by means of a system that has one or more control means, e.g. microprocessors, or has one or more programmable logic units, or using a mixed microprocessor and programmable logic units system.

In turn, the single module <NUM> may be integrated with the braking control module <NUM>, the new integration being kept independent from the anti-skid module <NUM>, and at least the portion responsible for the single module <NUM> preferably being implemented at a safety level SIL ≥<NUM>.

In both of the integration cases described, where the force adjustment signals <NUM>I, <NUM>II,. comprise each of the pair comprising the hold signal <NUM> corresponding the signal <NUM> in <FIG> and the braking force reduction signal <NUM> corresponding to the signal <NUM> in <FIG>, the anti-skid module <NUM> may advantageously include an anti-skid device for pneumatic braking systems according to the prior art that corresponds to the anti-skid device <NUM>.

Herein, the value of a signal may clearly be understood to mean, for example, the amplitude thereof or the frequency thereof or any other value of a signal that may be adjusted and measured.

As described above, this invention is particularly applicable to the field of railway vehicles/convoys that travel on railway tracks. For example, a vehicle as referred to herein may be a locomotive or a carriage, and a course/route may include tracks on which the wheels of the locomotive roll. The embodiments described herein are not intended to be limited to vehicles on tracks. For example, the vehicle may be a car, a truck (for example a highway semi-trailer truck, a mining truck, a truck for transporting timber or the like) or the like, and the route may be a road or a trail. For example, a convoy may include a plurality of these vehicles connected or associated with each other.

Claim 1:
An anti-skid system for an electromechanical braking system of at least one vehicle, in particular at least one railway vehicle, including at least one wheel, wherein said anti-skid system comprises:
- an anti-skid module (<NUM>) arranged to execute a predetermined anti-skid function and to provide an output, the value of which is determined by said predetermined anti-skid function;
- a supervisor module (<NUM>, <NUM>) arranged for monitoring said anti-skid module (<NUM>) and to receive the output of said anti-skid module (<NUM>) and a braking force application request signal (<NUM>), the value of which is indicative of a braking force application request value;
wherein said supervisor module (<NUM>, <NUM>) includes a braking force application request adjustment module (<NUM>, <NUM>) arranged to adjust the value of said braking force application request signal (<NUM>) according to said output of the anti-skid module (<NUM>);
wherein the supervisor module (<NUM>, <NUM>) and the anti-skid module (<NUM>) are modules that are distinct from each other, and the braking force application request adjustment module (<NUM>, <NUM>) is arranged to adjust said braking force application request signal (<NUM>) independently of the execution of the anti-skid function (<NUM>) by the anti-skid module (<NUM>).