Driving simulator braking system with controlled pedal feedback

Abstract

A braking system for a driving simulator, the braking system comprising a master cylinder chamber and a slave cylinder chamber arranged to be in fluid communication via a hydraulic system. The master cylinder chamber comprises a master cylinder piston, which is mechanically connected to a brake pedal such that movement of the brake pedal causes the master cylinder piston to translate along an axis of the master cylinder chamber. The hydraulic system comprises a pressure module arranged to divide the hydraulic system into a master side in fluid communication with the master cylinder chamber and a slave side in fluid communication with the slave cylinder chamber. The pressure system is adapted to intermittently increase and decrease the pressure in the hydraulic system so as to provide tactile feedback to the brake pedal.

Description

Technical Field

[0001] The invention relates to a brake system for a driving simulator, in particular to a hydraulic brake system with tactile feedback. Background Art

[0002] Simulation systems for simulating driving a car are used both for gaming and for training people involved in driving a vehicle, such as racing car drivers.

[0003] A driving simulator can be defined as a system that simulates the operating conditions of a vehicle in an environment. When the simulated vehicle is a car, the vehicle will typically include typical car controls such as a steering wheel, gear lever, accelerator pedal, and brake pedal. Generally speaking, the vehicle will be simulated in an environment that typically includes a road.

[0004] Driving simulators provide a method for effectively training vehicle operators. Vehicle operators can safely learn from the simulator how the vehicle will operate under a given set of conditions without actually subjecting the operator to any of the risks inherent in the real-world operation of the vehicle. The experience gained by making mistakes on the simulator is invaluable compared to the inherent risk of vehicle damage and operator injury associated with making driving mistakes in real-life situations. For example, in a police training application, a student can learn the limitations of a police car or pursuit guidelines and perform tests in those areas without any of the risks associated with real-life training.

[0005] In addition to concerns about operator safety and vehicle damage, training through actual vehicle operation has other drawbacks. In particular, the cost of the instructor's time may be prohibitive. Furthermore, specific vehicles such as race cars or trucks may simply not be available for training purposes.

[0006] In order to improve the effectiveness of the training provided by the driving simulator, it is necessary to ensure that the simulator realistically simulates the feeling of operating the vehicle, as well as realistically simulates the effects of operating the various vehicle controls in specific situations. Realistically simulating the feeling of operating the vehicle includes simulating the feeling of the vehicle as it is driven in the simulated environment and simulating the feeling of the various vehicle controls during actual use.

[0007] In a driving simulator, if the operator's feel of the brake pedal when depressing it is very close to the feel of the actual brake pedal in a real car, the effectiveness of the training given by the simulator will be further enhanced. In addition, the effect perceived by the operator (or user) of depressing the brake pedal by a given amount in a car simulator should also be very close to the effect of depressing the brake pedal by the same amount in a real life car.

[0008] Today's cars are equipped with anti-lock braking (ABS) systems. ABS systems are a safety feature added to cars to enhance the controllability of the car during braking maneuvers. When non-ABS brakes are applied suddenly or with great force, these brakes can lock, causing the car to often begin to skid uncontrollably. Car tires slip on the ground when the forward momentum of the car exceeds the speed of the tires, thereby dragging the tires forward on the ground in a slipping motion with less grip than the wheels have when they are spinning. ABS braking systems prevent this uncontrollable skidding by sensing when the tires are dragging on the ground and then reducing the amount of stopping pressure applied by the brakes to the wheels just enough to allow the tires to continue rolling on the ground while still slowing the tires' rotation. The ABS system then typically oscillates between increasing and decreasing the amount of braking force applied to the brakes and the amount of braking force applied to the tires as the ABS system attempts to slow the tires' rotation while also preventing the brakes from locking. This oscillation causes the brake pedal to produce a distinctive vibrating pulsation during braking.

[0009] US5607308 discloses a vehicle simulator with realistic operational feedback. However, the vibration pulsation that occurs in the brake pedal when the ABS system is activated is generated by a single solenoid that causes the brake pedal to vibrate via an arm. Although a simple mechanical system causes the brake pedal to vibrate, the feeling is not exactly the same as in real life driving.

[0010] DE 10 2018 202 311 A1 discloses a braking system for a motor vehicle, which provides a braking system that is highly complex and unrealistic when used in a simulator. Summary of the invention

[0011] According to a first aspect of the present invention, there is provided a brake system for a driving simulator. The brake system comprises a master cylinder chamber and a slave cylinder chamber in fluid communication via a hydraulic system.

[0012] Fluid communication is understood to mean that an exchange of fluid, in particular hydraulic fluid, can take place between the master cylinder chamber and the slave cylinder chamber.

[0013] The master cylinder chamber also includes a master cylinder piston. The master cylinder piston is mechanically connected to the brake pedal so that movement of the brake pedal causes the master cylinder piston to translate along the axis of the master cylinder chamber.

[0014] The movement of the master cylinder piston is arranged to act on the hydraulic fluid in the master cylinder chamber. Since the master cylinder chamber and the slave cylinder chamber are in fluid communication, this allows the movement of the brake pedal to affect the slave cylinder chamber via the hydraulic fluid.

[0015] The hydraulic system further includes a pressure module arranged such that the pressure module divides the hydraulic system into a master side in fluid communication with the master cylinder chamber and a slave side in fluid communication with the slave cylinder chamber.

[0016] In other words, the pressure module is fluidly arranged between the master cylinder chamber and the slave cylinder chamber. In one variant, this can be done by integrating the pressure module with a fluid conduit of the brake system. In another variant, this can be done by providing the pressure module with a fluid inlet and a fluid outlet, wherein fluid conduits connected to the master cylinder chamber and the slave cylinder chamber, respectively, can be connected to the fluid inlet and the fluid outlet. This arrangement of the pressure module enables the pressure module to temporarily break the contact between the master side and the slave side of the hydraulic system and interact differently with these two sides.

[0017] A pressure system is adapted to intermittently increase and decrease pressure in the hydraulic system such that tactile feedback is provided to the brake pedal.

[0018] By intermittently increasing and decreasing the pressure in the hydraulic system, the resistance felt by the user to the force applied to the brake pedal will also change intermittently. When the pressure in the hydraulic system decreases, the brake pedal can be depressed by the force applied by the user. When the pressure in the hydraulic system increases, the pressure in the hydraulic system may act on the master piston and force the brake pedal toward the user despite the pressure applied by the user to the brake pedal. The alternation between these two conditions will provide the user with vibratory tactile feedback when the brake pedal intermittently moves in opposite directions.

[0019] This haptic feedback provides the user with a tactical response during the driving simulation that closely corresponds to the tactile feel of the brake pedal in a vehicle when the ABS function is enabled. This realistic tactile response is beneficial because it allows for a more realistic simulation.

[0020] According to a further embodiment of the first aspect of the invention, the brake system comprises a pressure sensor for detecting the pressure in the hydraulic system and transmitting the measurement result to the driving simulator. The pressure sensor is arranged in fluid communication with the hydraulic system.

[0021] By placing a pressure sensor in fluid communication with the hydraulic system, the pressure within the hydraulic system can be detected. Since this pressure is related to the movement of the brake pedal through the movement of the master cylinder piston, the measurement result of the pressure sensor corresponds to the force applied to the brake pedal. Therefore, the pressure sensor can provide a signal to the simulation software that can be used to determine the amount of braking of the simulated vehicle.

[0022] The pressure measurement result can also be used to determine when an ABS braking session should be initiated. For example, an ABS braking session can be initiated when the magnitude of the detected pressure exceeds a predetermined threshold for a predetermined duration.

[0023] In a preferred variant, the pressure sensor is arranged in direct fluid communication with the slave side of the hydraulic system. Direct fluid communication is understood as fluid communication between the pressure sensor and the slave side of the hydraulic system not via the master side of the hydraulic system.

[0024] In an alternative preferred variant, the pressure sensor is arranged in direct fluid communication with the primary side of the hydraulic system. Direct fluid communication is understood as a fluid communication between the pressure sensor and the primary side of the hydraulic system not via the slave side of the hydraulic system.

[0025] According to a further embodiment of the first aspect of the invention, the pressure module comprises a pump adapted to increase the pressure of the hydraulic system when the pump is activated.

[0026] According to a further embodiment of the first aspect of the invention, the pressure module comprises an accumulator and a first valve. The first valve is adapted to open and close a fluid connection between the hydraulic system and the accumulator.

[0027] In a preferred variant, the accumulator and the first valve are arranged such that when the first valve is open, the accumulator is in fluid communication with the primary side of the hydraulic system.

[0028] The accumulator includes a chamber that increases the total volume of the hydraulic system when in fluid communication with the hydraulic system. When the volume of the hydraulic system increases, the pressure in the hydraulic system will decrease.

[0029] According to a further embodiment of the first aspect of the present invention, the first valve is a solenoid valve.

[0030] A solenoid valve is particularly suitable because it can be activated electronically by remote control, making it readily suitable for activation by a computer system controlling the simulation software.

[0031] According to a further embodiment of the first aspect of the invention, the pressure module comprises a second valve adapted to temporarily close and open a fluid communication between the master side and the slave side of the hydraulic system.

[0032] A benefit of enabling the pressure module to temporarily disconnect the connection between the master side of the hydraulic system and the slave side of the hydraulic system is that the pressure on the master side, which affects the brake pedal and therefore the tactile response, can be controlled without affecting the slave cylinder.

[0033] According to a further embodiment of the first aspect of the present invention, the second valve is a solenoid valve.

[0034] According to a second aspect of the invention, there is provided a pressure module for use with a hydraulic brake system of a driving simulator. The pressure module comprises means for establishing a fluid connection between the pressure module and the hydraulic system.

[0035] Establishing a fluid connection is understood to mean that the pressure module can be directly integrated in a fluid conduit of the brake system or it can comprise a fluid inlet and a fluid outlet for connection to the fluid conduit at a first end, which are connected to the brake cylinder at a second end, thereby forming a hydraulic system.

[0036] The hydraulic system includes a master side and a slave side.

[0037] The pressure module also includes an accumulator for increasing the volume and thereby reducing the pressure of the hydraulic system.

[0038] The pressure module also includes a pump for increasing the pressure of the hydraulic system.

[0039] The pressure module also includes a first valve arranged to control fluid communication between the accumulator and a primary side of the hydraulic system.

[0040] The pressure module further comprises a second valve arranged to control fluid communication between the master side and the slave side 303 of the hydraulic system.

[0041] The pump, the first valve, and the second valve of the pressure module are configured to be controlled by the driving simulation software to provide tactile feedback.

[0042] The driving simulator software may send signals to the components of the pressure module to sequentially activate the valves and / or pumps, thereby providing tactile feedback through the brake pedal corresponding to the tactile response in the brake pedal of the vehicle during ABS braking. Thus, the simulation software may send signals to activate (i.e., open and close) the first valve and the second valve. Similarly, the simulation software may send signals to turn on and off the pump of the pressure module.

[0043] According to a further embodiment of the second aspect of the present invention, the first valve is a solenoid valve.

[0044] According to a further embodiment of the second aspect of the present invention, the second valve is a solenoid valve.

[0045] According to a further embodiment of the second aspect of the invention, the pump is driven by a DC motor.

[0046] According to a third aspect of the present invention, there is provided a method of generating haptic feedback in a brake pedal of a braking system for a driving simulator.

[0047] The method comprises the steps of providing a braking system having a pressure module. In response to a signal from simulation software of the driving simulator, an ABS braking phase is initiated. During the ABS braking phase, the pressure module alternates between two or more modes such that the pressure within the hydraulic system of the braking system varies during the ABS braking phase regardless of the pressure applied to the brake pedal.

[0048] According to a further embodiment of the third aspect of the invention, one of the two modes is a pump mode during which the pump is activated to increase the pressure in the hydraulic system.

[0049] According to further embodiments of the third aspect of the invention, one of the two modes is an accumulator mode in which the first valve is activated open and provides fluid communication between the accumulator and the hydraulic system such that the volume increases and the pressure decreases.

[0050] According to further embodiments of the third aspect of the invention, alternation between two or more modes occurs at a frequency in the range of 1-15 Hz, more preferably in the range of 5-10 Hz.

[0051] These frequency ranges that alternate between these two or more modes cause the haptic response of the brake system to occur at a frequency that corresponds to the frequency of the vehicle's ABS braking system providing a realistic response. That is, the movement of the brake pedal in response to the action of the pressure module will occur at a frequency such that the movement of the pedal in response to the simulation will occur at a frequency that corresponds to the movement of the vehicle's brake pedal in response to ABS braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will now be described in further detail with reference to the accompanying drawings, in which:

[0053] Figure 1 A brake system according to the invention for use with a brake cylinder is shown.

[0054] Figure 2 is a schematic diagram of a system according to the present invention.

[0055] FIG. 3A to FIG. 3D Schematic depiction of the principle of the pressure module when the valve is in different configurations.

[0056] The accompanying drawings are intended only to illustrate the principles of the invention and may not be accurate in every detail. In addition, components that do not form part of the present invention may be omitted. The same reference numerals are used for the same components. DETAILED DESCRIPTION

[0057] Figure 1A braking system for use with a driving simulator is shown. The braking system comprises a brake pedal 101 connected to a brake cylinder 201. The brake cylinder 201 may be Figure 1 The compact structure shown, or the chamber of the brake cylinder can be divided into different independent chambers. Figure 1 As shown schematically, the brake cylinder 201 can be connected to a pressure module 301. "Connected" is understood to mean that they at least share a fluid connection. The pressure module can be connected to the brake cylinder 201 and positioned away from the brake cylinder 201 itself. In other embodiments based on the same working principle, the pressure module 301 can be integrated with the brake cylinder 201 or mounted directly on the brake cylinder 201.

[0058] In a preferred embodiment, the brake pedal 101 and the brake cylinder 201 are mounted on a support surface 103. In a preferred embodiment, the brake pedal 101 may be mounted on the support surface 103 via a pivot 105, the support surface 103 being adapted to ensure that the brake system is supported in a stable manner, because the area of ​​the support surface 103 is larger than the area of ​​the mounted pedal 101 and the brake cylinder 201 protruding into the plane of the support surface, so that it increases the contact area between the brake system and the surface on which the brake system is located, thereby reducing the risk of the brake system tilting during use. The support surface 103 also contributes weight, so that the center of mass of the brake system is lowered, thereby further increasing the stability of the brake system in its position when in use.

[0059] The braking system is adapted to communicate with a computer running the vehicle simulation software, the communication between the braking system and the computer system being carried out via a wired means such as USB or a wireless means such as Bluetooth. The communication should preferably be in real time (or at least close to real time due to the computational limitations of processing input and data in modern computers) to ensure that any action on the brake pedal is immediately transmitted to the software for an instant reaction and a realistic feel in the simulation software. The communication may include information exchange, for example the sensors of the braking system may provide sensor data to the computer system relating to the amount of force applied to the brake pedal 101. The simulation software of the computer system may also control parts of the braking system, for example controlling when the ABS braking phase is activated, i.e. when it starts and when it ends, as it may at least partially control the activation of the active components of the braking system.

[0060] During operation, when the brake pedal 101 is depressed, i.e., when the user begins to apply force to the brake pedal, the force is transmitted to the master cylinder piston 107, which causes the piston in the brake cylinder 201 to move and thus change the pressure in the brake cylinder 201. The sensor 109 detects the pressure in the brake cylinder 201 and transmits the pressure back to the computer system. The sensor is able to detect the time, degree and speed of the pressure change on the brake pedal. The simulation software then relates the pressure measurement results to the braking force.

[0061] The brake cylinder is connected to the brake pedal 101 via a rod connector 111 at the end of the piston rod of the master cylinder piston 107. The rod connector 111 is connected to a mounting plate 113 on the arm of the brake pedal 101. In a preferred embodiment, the rod connector 111 is a rod U-shaped clamp that is connected to the mounting plate 113 by clamping around the mounting plate 113 and releasably fixed by fixing means such as screws or bolts.

[0062] When the user applies force to the brake pedal 101, i.e., when it is depressed, the movement of the brake pedal 101 is considered to be the forward movement of the brake pedal 101. The opposite direction of the movement of the brake pedal 101 (i.e., the direction in which the pedal moves as the force applied to the brake pedal 101 decreases) is considered to be the backward movement of the brake pedal 101.

[0063] Figure 2 Components of the brake system are shown schematically and are not drawn to scale.

[0064] The brake cylinder 201 includes a master cylinder chamber 207 and a slave cylinder chamber 217. In some preferred embodiments, the master cylinder chamber 207 and the slave cylinder chamber 217 can be integrated in the same housing of the brake cylinder, such as Figure 2 In an alternative preferred embodiment, the master cylinder chamber 207 and the slave cylinder chamber 217 may be two separate units.

[0065] When the brake pedal 101 is depressed, the master cylinder piston 107 is adapted to translate within the master cylinder chamber 207 along the axis of the master cylinder chamber 207. The movement of the master cylinder piston 107 acts on the hydraulic fluid in the master cylinder chamber 207.

[0066] The slave cylinder chamber 217 of the brake cylinder 201 includes a slave cylinder piston 218. The slave cylinder piston 218 is connected to a damping system 221 via a slave cylinder rod 219. The damping system 221 is configured to control the stiffness and length of the brake pedal 101. In some preferred embodiments, the damping system 221 is configured to enable a user to adjust the stiffness and length of the brake pedal 101. The slave cylinder piston 218 is adapted to translate along the axis of the slave cylinder chamber 217. This translation occurs in response to the hydraulic pressure in the brake cylinder 201.

[0067] The master cylinder chamber 207 and the slave cylinder chamber 217 are in fluid communication, so that an exchange of hydraulic fluid between the chambers 207, 217 is possible. Fluid conduits facilitate the hydraulic communication of the chambers. The pressure module 301 is connected to these fluid conduits, so that the hydraulic communication between the master cylinder chamber 207 and the slave cylinder chamber 217 occurs via the pressure module 301.

[0068] In other words, the hydraulic system 300 of the present invention includes the master cylinder chamber 207 and extends from the master cylinder chamber 207 to the slave cylinder chamber 217 via the pressure module 301. Therefore, the hydraulic system 300 forms a fluid connection between the master cylinder chamber 207 and the slave cylinder chamber 217.

[0069] The pressure module 301 divides the hydraulic system 300 into a master side 302 and a slave side 303 , such that the master side 302 is a side including the master cylinder chamber 207 , and the slave side is a side including the slave cylinder chamber 217 .

[0070] The pressure module 301 includes a first valve 311 and a second valve 312. In a preferred embodiment of the present invention, the first valve 311 and / or the second valve 312 is a solenoid valve.

[0071] The second valve 312 is configured so that it can open and close the fluid connection between the master side 302 and the slave side 303 of the hydraulic system 300. When the second valve 312 is opened, the master side 302 and the slave side 303 are in fluid communication. When the second valve 312 is closed, the fluid connection between the master side 302 and the slave side 303 is disconnected. Thus, the pressure module 301 controls the connection between the master side 302 and the slave side 303 in the hydraulic system 300.

[0072] The pressure module 301 also includes an accumulator 310. The accumulator 310 forms a chamber having a certain volume. A first valve 311 is configured to open and close the connection of the accumulator to the main side 302 of the hydraulic system 300. When the first valve 311 is opened, the accumulator is in fluid communication with the main side 302 of the hydraulic system 300, thereby increasing the effective volume of the hydraulic system 300. When the first valve 311 is closed, the accumulator 310 is disconnected from the rest of the hydraulic system 300, thereby limiting the volume of the hydraulic system 300.

[0073] In a preferred embodiment of the present invention, valves 311 and 312 are controlled by simulation software. In such an embodiment, the simulation software can then enable the ABS braking mode in response to a simulated situation where the ABS is suitable, such as due to road conditions, or in response to a braking signal that exceeds a threshold value in magnitude and / or duration.

[0074] The pressure module further comprises a pump 307. In a preferred embodiment, the pump 307 is driven by a DC motor 305. The pump is arranged such that it can increase the pressure in the hydraulic system 300 when the pump is activated.

[0075] Thus, translation of the master cylinder piston 107 within the master cylinder chamber 207 may be due to any of the following reasons: depression of the brake pedal 101, release of the brake pedal 101 and the reaction of system action on the master cylinder piston 107, or an increase in pressure in the hydraulic system 300 caused by activation of the pump 307 of the pressure module 301, which pressure increase will force the brake pedal 101 to return to its default, non-depressed position.

[0076] Although the pressure module 301 is shown in Figure 1 301 as a region of a combined brake system including multiple features, but it should be understood that in practice the pressure module 301 may be one or more separate components having a fluid inlet and a fluid outlet for releasably connecting the pressure module 301 to the brake cylinder 201 via a fluid conduit. Such an assembly of the brake system has the advantage of easier maintenance and replacement of worn parts.

[0077] Although not in Figure 2 , but the brake system also includes a pressure sensor. The pressure sensor can be installed anywhere in fluid communication with the hydraulic system 300. For example, it can be as Figure 1 It is shown connected to either of the cylinder chambers 207, 217, or as another example, it may be connected to the hydraulic system as part of the pressure module 301. In other exemplary variations, the sensor may be separately connected to a fluid conduit of the brake system.

[0078] FIG. 3A to FIG. 3D The pressure module is schematically shown in different operating modes. FIG. 3A to FIG. 3D In the figure, if the valve has oblique hatching, it is schematically depicted as closed, and if it has no hatching, it is depicted as open. If the fluid conduit has circular hatching, the fluid conduit is depicted as being in fluid communication with the master cylinder chamber; note that the hatching is only a schematic illustration and does not indicate the actual distribution of fluid flow through the valve, only whether the valve is open or closed.

[0079] Figure 3A A first mode of the pressure module 301 is schematically shown, in which the brake system is in a normal braking mode, i.e., a default situation where ABS is not applied. This normal braking mode is adopted during normal driving (i.e., the opposite of ABS braking conditions) and occurs when the braking force does not exceed threshold conditions of magnitude and / or duration. In such a normal driving and normal braking mode, the simulation software will not enable the ABS simulator system in the brake system.

[0080] In this default state of normal braking conditions, the first valve 311 is closed, disconnecting the accumulator 310 from the rest of the hydraulic system, and the second valve 312 is open, allowing fluid communication between the master cylinder chamber and the slave cylinder chamber.

[0081] In this default state of normal braking, when the brake pedal 101 is depressed due to a force being applied to the brake pedal 101, the force will be transferred from the pedal to the master cylinder piston 107, which in turn will cause the master cylinder piston 107 to act on the hydraulic fluid in the master cylinder chamber 207. The force applied to the hydraulic fluid in the master cylinder chamber 207 will force the hydraulic fluid from the master cylinder chamber 207 through the fluid conduit of the hydraulic system 300. When the second valve 312 is open, the hydraulic fluid will be forced into the slave cylinder chamber 217, where the pressure of the fluid drives the slave cylinder piston 218. The slave cylinder piston 218 interacts with the damping system 221, for example by compressing a damper in the damping system 221 and / or by contacting a mechanical mass. When a force is applied to the brake pedal 101 and the damping system 221 provides resistance, the hydraulic fluid is squeezed between the master cylinder piston 107 and the slave cylinder piston 218, causing the pressure in the hydraulic system 300 to increase. The increase in pressure is detected by a pressure sensor in fluid communication with the hydraulic system 300 .

[0082] During normal braking operation, i.e., when the simulation software does not indicate the need to simulate ABS braking conditions, the pressure module 301 remains at Figure 3A The default state shown is that the first valve 311 is closed and the second valve 312 is open. When force is applied, the user will feel the depression of the brake pedal 101, followed by a period of time where the user may feel little to no movement as the pressure in the hydraulic fluid increases.

[0083] When the user releases the brake pedal 101, i.e. by applying a reduced force or no force to the brake pedal 101, the brake pedal 101 will return to its default position. The pressure in the hydraulic system 300 will decrease again, and both the slave cylinder piston 218 and the master cylinder piston 107 will move back to their default positions. In a preferred embodiment, the brake cylinder comprises an elastic structure, such as an elastic material and / or a spring, which is arranged to apply a force to the slave cylinder piston 218 and / or the master cylinder piston 107 so that they are pushed back to their default positions when no pressure is applied to the brake pedal 101.

[0084] The simulator software controls the activation of the ABS simulator system, for example due to conditions in the simulated world, such as braking when the simulated vehicle is located on a specific type of simulated surface or in response to sensor data from a pressure sensor exceeding a threshold condition, or it can be enabled by software, such as due to detection that the left front wheel is not moving or moving slower than the other wheels, or simply based on readings from a pressure sensor that detects brake pressure above a specific threshold. When the ABS simulator system is enabled, the braking system will alternate between different modes of the system. As the different modes change the pressure in the hydraulic system 300, they will affect the resistance felt during the application of pressure to the brake pedal 101, thereby causing a tactile response of the user stepping on the brake pedal 101. Preferably, the change of the operating mode of the pressure module 301 during the ABS braking phase occurs quickly in short intervals, giving a pedal vibration or bump feeling that corresponds to the feeling when the ABS system is activated in real life driving. For example, the change of the mode in the pressure module 301 during the ABS braking phase can occur at a frequency that can be adjusted by the user to achieve the best and most realistic feeling for a given vehicle. In a preferred embodiment, the frequency of the mode change during the ABS braking phase is 1-15Hz, more preferably 5-10Hz. The ABS braking phase is understood as Figure 3A The default configuration shown depicts the period from the start of ABS braking mode until the end of ABS braking mode and return to normal braking mode.

[0085] Figure 3B The second mode of the pressure module 301 is shown, also referred to as the closed mode. In this closed mode, the first valve 311 will remain closed and the second valve 312 will also be closed. When the second valve 312 is closed, the master side 302 and the slave side 303 of the hydraulic system 300 are disconnected from each other. It should be noted that the hydraulic fluid is not exhausted from the slave side 303 of the hydraulic system 300, and the hatching indicates fluid communication with the master side 302, only for the purpose of illustrating the valve effect.

[0086] When the second valve 312 is closed and the slave side 303 is disconnected from the master side 302, applying pressure to the brake pedal 101 will still cause the pressure on the master side 302 of the brake system to increase, but the slave cylinder piston 218 will no longer move. Therefore, the resistance experienced by the user applying force to the brake pedal 101 is the resistance of compressing the brake fluid. For liquids that are low compressibility or incompressibility fluids, the resistance experienced will be high and the brake pedal 101 will feel motionless to the user. In an embodiment of the present invention, a pressure sensor is connected to the slave side 303 of the hydraulic system 300, and when the second valve 312 is activated, the detected pressure will remain constant regardless of the force applied to the brake pedal 101. In an embodiment of the brake system where the pressure sensor is connected to the master side 302 of the hydraulic system 300, any increase in pressure due to the force applied to the brake pedal 101 will be recorded in this mode of the ABS braking phase.

[0087] Figure 3C The third mode of the pressure module 301 is shown, also known as the accumulator mode. In this accumulator mode, the first valve 311 is opened, whereby the accumulator 310 is in fluid communication with the master side 302, thereby increasing the volume of the master side 302. The second valve 312 is closed, so that the master side 302 is disconnected from the slave side 303 of the hydraulic system 300. In the accumulator mode, the pressure on the master side is reduced because the first valve 311 is opened and the volume of the master side 302 is increased. The reduction in pressure will reduce the resistance felt by the user when stepping on the pedal. As the volume increases, the pedal can move a greater distance under the same force applied than the distance the pedal was able to move before the volume increase (i.e., when the first valve 311 is closed). This is called pedal lengthening because the pedal can move a greater distance under the same pressure. Since the volume changes immediately when the first valve 311 is opened, the change in the resistance of the brake pedal 101 will be a sudden change, causing the user's foot to rush forward because the ABS braking phase will begin at the moment the user applies force to the brake pedal 101.

[0088] Figure 3D The fourth mode of the pressure module 301 is schematically shown, also called the open mode, in which both the first valve 311 and the second valve 312 are open. In this case, the accumulator 310 is in fluid communication with the rest of the hydraulic system 300, thereby facilitating the volume increase. At the same time, the master side 302 and the slave side 303 of the hydraulic system 300 are in communication. This mode may be Figure 3A The illustrated mode is an alternative default mode in which normal mode braking operation is achieved because the master cylinder chamber and the slave cylinder chamber are in fluid communication.

[0089] Increasing the volume in fluid communication with the primary side 302 of the hydraulic system 300 by opening the first valve 311 and allowing fluid to enter the accumulator 310 has the same effect of reducing the resistance felt by a user applying pressure to the brake pedal 101, whether the second valve 312 is open or closed. Figure 3C and Figure 3D In either configuration, the user will feel the brake pedal 101 lengthen and jolt forward under the pressure applied by the user.

[0090] Although not shown in the figure, there is a fifth mode of the pressure module 301, which is also referred to as the pump mode. In this pump mode, the pump 307 is enabled. The pump 307 is configured to increase the pressure in the hydraulic system 300. As the pressure in the hydraulic system 300 increases, it will increase the force applied to the master cylinder piston 107 in the direction opposite to the force applied by the user pressing the brake pedal 101. This will cause the resistance force (also referred to as the reaction force) on the brake pedal 101 to increase. Therefore, the pressure increase caused by the activation of the pump 307 causes the brake pedal 101 to move backwards towards the user applying force to the brake pedal 101, thereby giving tactile feedback of pushing the user's foot.

[0091] It should be understood that the pump mode may be engaged simultaneously with any other mode described for the pressure module 301. That is, the pump 307 may be enabled regardless of the state of the first valve 311 and the second valve 312, ie, whether they are open or closed.

[0092] By alternating or cycling the various modes described in rapid succession throughout the ABS braking phase, a different ABS experience can be achieved.

[0093] In one example of a preferred embodiment, once the simulation software signals the start of the ABS braking phase, the second valve 312 will close, thereby isolating the primary side 302 and the secondary side 303 of the hydraulic system 300. While the second valve 312 remains closed, the pressure module 301 will alternate between opening the first valve 311 and activating the pump 307. When the first valve 311 is opened, the volume of the primary side 302 of the hydraulic system 300 increases, causing the pressure to decrease, and if the user maintains the same pressure applied to the brake pedal 101 as before the first valve 311 was opened, the brake pedal 101 will bump forward. Then when the pump 307 is activated, the pressure on the primary side 302 of the hydraulic system 300 will increase, forcing the master cylinder piston 107 and the brake pedal 101 backward, pushing against the user's foot that applied pressure to the brake pedal 101. When the pressure module 301 alternates between these modes at lower and higher pressures respectively throughout the ABS braking phase, when the user applies pressure to the brake pedal 101, the brake pedal 101 will move forward and backward quickly, giving the user tactile feedback corresponding to the feedback felt when the ABS of a real vehicle is turned on. In a preferred embodiment, the alternation between modes during the ABS braking phase occurs at a frequency between 4-12 Hz, more preferably between 5-10 Hz. Such a frequency causes the movement of the brake pedal 101 to give the user tactile feedback in the form of vibrations.

[0094] Once the simulation software signals that the ABS braking phase has ended, the pressure module 301 will revert to a normal state in which the primary side 302 and the secondary side 303 of the braking system are in fluid communication.

[0095] In other equally preferred embodiments, the mode change during the ABS braking phase may be different from the previously described examples. For example, in some embodiments, the first valve 311 may remain open throughout the ABS braking phase while the pump 307 is switched on and off to induce a vibration response. In other variations, the pump 307 may be configured to be enabled when the first valve 311 is closed and to be switched off when the first valve 311 is open. In some embodiments, the second valve 312 may be closed at the beginning of the ABS braking phase and opened at the end of the ABS braking phase. In other embodiments, the opening and closing of the second valve 312 may also be alternated throughout the braking phase.

[0096] When the braking phase by the ABS simulator system is completed, the second valve 312 opens so that the connection between the master side 302 and the slave side 303 is open, and the valve 311 closes so that the volume of the hydraulic fluid is adjusted to the volume present in the hydraulic system before the braking phase.

[0097] The components of the pressure module 301 are controlled by simulation software. The pressure module 301 may be integrated with the hydraulic brake system. The pressure module 301 may be one or more separate components coupled to the fluid conduit of the hydraulic brake system.

Claims

1. A pressure module for use with a hydraulic brake system of a driving simulator, the pressure module (301) comprising: means for establishing a fluid connection between the pressure module and a hydraulic system (300), the hydraulic system comprising a master side (302) and a slave side (303); an accumulator (310) for increasing the volume of the hydraulic system (300) and thereby reducing the pressure of the hydraulic system (300); a pump (307) for increasing the pressure of the hydraulic system (300), a first valve (311) configured to control fluid communication between the accumulator (310) and the primary side (302); a second valve (312) configured to control fluid communication between the master side (302) and the slave side (303) of the hydraulic system (300), The pump (307), the first valve (311) and the second valve (312) are configured to achieve different operating modes of the pressure module by alternately opening and closing the first valve or the second valve, and to provide tactile feedback to the main side by alternating different operating modes at a set frequency. 2 . The pressure module of claim 1 , wherein the first valve is a solenoid valve.

3. The pressure module according to claim 1 or 2, wherein the second valve (312) is a solenoid valve.

4. The pressure module according to claim 1 or 2, wherein the pump (307) is driven by a DC motor (305).

5. A driving simulator braking system, comprising: a master cylinder chamber (207) and a slave cylinder chamber (217), the master cylinder chamber and the slave cylinder chamber being in fluid communication via a hydraulic system (300); The master cylinder chamber (207) includes a master cylinder piston (107) which is mechanically connected to a brake pedal (101) such that movement of the brake pedal (101) causes the master cylinder piston (107) to translate along an axis of the master cylinder chamber; The driving simulator braking system comprises a pressure module (301) according to any one of claims 1 to 4, the pressure module being arranged such that the pressure module divides the hydraulic system into a master side (302) in fluid communication with the master cylinder chamber and a slave side (303) in fluid communication with the slave cylinder chamber; The pressure module (301) is adapted to intermittently increase and decrease the pressure in the hydraulic system so as to provide tactile feedback to the brake pedal (101).

6. The driving simulator braking system according to claim 5, comprising a pressure sensor for detecting the pressure in the hydraulic system and transmitting the measurement result to the driving simulator, the pressure sensor being arranged in fluid communication with the hydraulic system.

7. A method for generating tactile feedback in a brake pedal of a braking system for a driving simulator, the method comprising the following steps: Providing a braking system having a pressure module (301) according to any one of claims 1 to 4, in response to a signal from the simulation software of the driving simulator, starting an ABS braking phase, During the ABS braking phase, alternating between two or more modes of the pressure module causes pressure within the hydraulic system of the braking system to vary during the ABS braking phase regardless of the pressure applied to the brake pedal.

8. The method of claim 7, wherein one of the two modes is a pump mode during which a pump is activated to increase pressure within the hydraulic system.

9. A method according to claim 7 or 8, wherein one of the two modes is an accumulator mode, in which the first valve (311) is enabled to open and provide fluid communication between the accumulator (310) and the hydraulic system (300), so that the volume increases and the pressure decreases.

10. The method of claim 7 or 8, wherein alternation between the two or more modes occurs at a frequency in the range of 1-15 Hz.

11. The method of claim 10, wherein alternation between the two or more modes occurs at a frequency in the range of 5-10 Hz.

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