AU2016202499A1 - Method and system for automatic park brake activation and deactivation - Google Patents

Abstract

METHOD AND SYSTEM FOR AUTOMATIC PARK BRAKE ACTIVATION/DEACTIVATION An aspect of the invention provides a method performed by a microprocessor control unit (MCU) for automatic activation/deactivation of the park brake. The method comprises the steps of. determining that a manual brake control mechanism has been applied by an operator (steps 320, 330); subsequently determining that the manual brake control mechanism has been released by the operator (steps 340, 350); and subsequently deactivating an automatic brake control mechanism to release the brakes (step 360). 11211276 1 (IRN: P151030) C)) co C) E c'Jo C15 101695 (IN:P1770

Description

-1 - 2016202499 20 Apr 2016

METHOD AND SYSTEM FOR AUTOMATIC PARK BRAKE ACTIVATION & DEACTIVATION

[0001] This application claims priority from Australian Provisional Patent Application No. 2015902102, filed on 5 June 2015. Australian Provisional Patent Application No. 2015902102 is incorporated herein by reference in its entirety.

Technical Field [0002] The present invention relates generally to park braking systems and, more particularly, to methods and systems for the automatic activation and deactivation or release of vehicle parking or emergency brakes. The invention is broadly applicable to vehicles and/or machinery that are required to be controlled by a driver or operator. Examples of such vehicles and machinery include, but are not limited to: trucks, cranes, trains, cars, buses, road plant, etc.

Background [0003] Australian Patent No. 2003200668 B2, entitled “Automatic park brake actuation system and method for vehicles”, discloses a system which automatically actuates the brakes of a vehicle if a driver leaves the vehicle without manually actuating the park brakes. As can be appreciated, this capability is a valuable safety mechanism for preventing vehicle “runaway” and consequent damage, serious injury, and/or death. Such accidents are known as Parked Vehicle Rollaway (PVR). A number of sensors (e.g., a seat sensor, a door sensor, an ignition sensor, brake status sensors, accelerometer sensors and speed sensor) provide inputs that are used to determine when a driver or operator leaves the vehicle. If the driver leaves the vehicle, without applying the brakes, the brakes are automatically applied by an electronic control unit (ECU) that the various sensors are electrically coupled to. Upon returning to the vehicle the driver will need to apply the park brake then disengage the park brake to release the automatic park brake system. 11211276 1 (IRN: P151030) -2 - 2016202499 20 Apr 2016 [0004] There are disadvantages with the need for a driver to enter a code before the vehicle can be mobilised again. The operation of entering a code is inconvenient and drivers frequently forget their codes.

[0005] Accordingly, a need exists for improved systems and methods for deactivating brakes after automatic activation of those brakes.

Summary [0006] An aspect of the present invention provides a method performed by a microprocessor control unit (MCU) for automatic activation of the park brake. The method comprises the steps of determining that the driver is no longer seated in the driver’s position. Then based on the sensory inputs, door seat ignition and the vehicle speed and status of the speed sensor, the MCU will activate the automatic brake control mechanism in effect engaging the park brake.

[0007] Another aspect of the present invention provides a method performed by a microprocessor control unit (MCU) for automatic deactivation of brakes. The method comprises the steps of: determining that a manual brake control mechanism has been applied by an operator; subsequently determining that the manual brake control mechanism has been released by the operator; and subsequently deactivating an automatic brake control mechanism to release the brakes.

[0008] Another aspect of the present invention provides system for automatically deactivating brakes using pressure from a pressure reservoir. The system comprises: a manual brake control mechanism coupled to the pressure reservoir by a first portion of a brake line; an automatic brake control mechanism coupled to the manual brake control mechanism by a second portion of the brake line; a first pressure sensor disposed in the second portion of the brake line between the manual brake control mechanism and the automatic brake control mechanism; a second pressure sensor disposed in a third portion of the brake line between the automatic brake control mechanism and the brakes; and an microprocessor control unit (MCU) electrically coupled to the automatic brake control mechanism, the first pressure sensor, and the second pressure sensor. The MCU is adapted to: detect activation and subsequent deactivation of the manual brake control mechanism; 11211276 1 (IRN: P151030) -3 - 2016202499 20 Apr 2016 and deactivate the automatic brake control mechanism in response to the detection of activation and subsequent deactivation of the manual brake control mechanism, thereby releasing the brake.

[0009] An optional key pad is available to release the system and provide various systems diagnostics and system checks.

[0010] The described sensors and preferably all the sensors, are configured to be independent of other sensors within the vehicle to ensure redundancy and minimal use and impact on current vehicle systems.

Brief Description of the Drawings [0011] Fig. 1 is a schematic block diagram of a system for automated activating and deactivating vehicle parking brakes in accordance with an embodiment of the invention; [0012] Fig. 2 is a schematic block diagram of an microprocessor control unit with which embodiments of the invention may be practised; and [0013] Fig. 3 is a flow diagram of a method for automatically deactivating a vehicle’s parking or emergency brakes in accordance with an embodiment of the invention.

Detailed Description [0014] Embodiments of methods and systems for automatic brake activation and deactivation or release are described hereinafter. Although the embodiments are described with reference to vehicle parking and/or emergency brakes, embodiments of the invention may also be applied to various types of machinery. Examples of such vehicles and machinery include, but are not limited to: trucks, trains, cars, buses, cranes, hoists, road plant, etc.

[0015] The specific embodiments are described with reference to retro-fitting an existing vehicle having a range of existing components for traditional operation of the vehicle. However, specific implementations may be integrated in the construction of a new vehicle. 11211276 1 (IRN: P151030) -4 - 2016202499 20 Apr 2016 [0016] Fig. 1 is a schematic block diagram of a system 100 for automated activation and deactivation of vehicle parking and/or emergency brakes. The system 100 comprises a microprocessor control unit (MCU) 110 arranged to receive various input signals 123, 125, 127, 129, 131, and 133 and generate output signals to control the operation of a parking and/or emergency brake 180 of a vehicle. The input signals include signals respectively from an optional serial keypad 122, a door sensor 124, a seat sensor 126, an ignition sensor 128, a speed sensor 130, and an accelerometer sensor 132. The output signals include signals to activate and deactivate an automatic brake control mechanism 140, and an alarm output 116.

[0017] The automatic brake control mechanism 140 may comprise a bistable solenoid valve fitted in an existing pneumatic brake line 162 of the vehicle, thus forming pneumatic brake line sections 162a and 162b, for controlling activation and deactivation of pneumatic parking or emergency brakes. To activate the vehicle brakes 180, the MCU 110 activates the automatic brake control mechanism 140 to vent air from the brake line section 162b between the automatic brake control mechanism 140 and the vehicle brakes 180. In other embodiments with hydraulic or otherwise activated brakes, an alternate form of control valve may be used to practice the automatic brake control mechanism 140. The MCU 110 may comprise a combination of microprocessor, digital circuitry and/or analog circuitry.

[0018] A first air (post-brake) pressure sensor 154 is electrically coupled to provide a pressure signal 155 to the MCU 110 and is adapted to enable the MCU 110 to detect the presence or absence of air pressure in the brake line section 162b between the automatic brake control mechanism 140 and the brakes 180.

[0019] A second (pre-brake) air pressure sensor 152 is also electrically coupled to provide a pressure signal 153 to the MCU 110 and is adapted to enable the MCU 110 to detect the presence or absence of air pressure in the brake line section 162a between the manual parking or emergency brake mechanism 160 and the automatic brake control mechanism 140. 11211276 1 (IRN: P151030) -5 - 2016202499 20 Apr 2016 [0020] The pressure signals 153 and 155 are interpreted by the MCU 110 for operation of the system 100.

[0021] The MCU 110 receives input signals in the form of signals from the door sensor 124, the seat sensor 126, the ignition sensor 128, and the speed sensor 130. The door sensor input signal 125 is drawn from a new fitted door sensor 124. Existing door sensors, for example used to activate cabin lighting within the vehicle, are not used and the sensor 124 is independent of other sensors of the vehicle. The seat sensor input signal 127 is derived from a seat pressure sensor 126 independently installed in the seat as part of the installation of the automatic brake activation and deactivation system 100.

[0022] An input signal 129 from the ignition sensor 128 may be taken from a pre-existing control line which provides an indication of the ignition status of the vehicle.

[0023] The speed sensor input signal 131 is taken from a speed sensor 130 fitted as part of the system 100 and independent of any existing speed sensors of the vehicle.

[0024] The various sensor input signals are isolated, as will be described below, from the MCU 100 and used by the MCU 110 to determine when the brakes 180 need to be automatically actuated or applied using the automatic brake control mechanism 140. Typically, this occurs when the driver vacates the vehicle without applying the manual parking or emergency brake mechanism 160 and the vehicles is travelling below a certain speed.

[0025] The sensors are monitored by the MCU 110 to detect fault conditions in the sensors. The MCU 110 identifies abnormal signals that are output by the sensors to identify faulty sensors. The speed sensor 130 is one of the more important sensors, and the sensor 130 is monitored in three ways. Firstly, if pulses output by the speed sensor 130 suddenly drop to zero speed, the speed sensor 130 is determined to be faulty. Secondly, the current to the speed sensor 130 is also monitored and, if the current varies outside predetermined limits, the sensor 130 is deemed by the MCU 110 to be faulty. Thirdly, if during periods of acceleration as measured by the accelerometer 132, there are no detectable speed pulses, the speed sensor 130 will be deemed to be faulty by the MCU 110. Under these conditions 11211276 1 (IRN: P151030) -6- 2016202499 20 Apr 2016 the system 100 will output an alarm signal 115 to an alarm output device 116, but the Automatic Brake Control Mechanism 140 will not activate.

[0026] The MCU 110 is connected to the keypad 122, having buttons and indicators disposed thereon, and optionally provided so as to act as a user interface of the system 100 for the driver or operator. This enables the user interface for the system 100 to be located remotely from the MCU 110. As this interface is optional, a service port can be used to connect the keypad during service and maintenance periods. The keypad 122 preferably includes a numeric keypad (not shown).

[0027] The seat sensor input signal 127 from the sensor 126 is activated when the driver vacates the driver’s seat of the vehicle.

[0028] The door sensor input signal 125 from the sensor 124 is activated when the driver's door of the vehicle is opened.

[0029] The signals 153, 155 from the sensors 152,154 are used by the MCU 110 to determine the current state of the park brake and to avoid the MCU 110 transmitting a brake actuation signal 112 to the control mechanism 140 if the brakes 180 are already on, and to reset the system 100 via the MCU 110, once the brakes 180 are released.

[0030] Air pressure is supplied by an air supply 170 (e.g., a reservoir) via the manual parking or emergency brake mechanism 160, both of which are typically part of the existing components of the vehicle, together with the brakes 180. As such, both the manual parking/emergency brake mechanism 160 and the automatic brake control mechanism 140 are in-line between the air supply 170 and the vehicle brakes 180.

[0031] Pneumatically operated parking and emergency brakes on most vehicles such as trucks and buses work in a fail-safe manner. As such, pneumatic pressure is required to maintain the brakes released, such that release air or failure of the pressure circuit formed between the air supply 170 and the brakes 180 will cause application of the brakes 180. Referring to Fig. 1, deactivation of the manual parking or emergency brake mechanism 160 causes air to be applied to the pneumatic brake line 162 to the deactivate the brakes 180. A 11211276 1 (IRN: P151030) -7- 2016202499 20 Apr 2016 fault in the manual parking or emergency brake mechanism 160 or the brake lines will result in the brakes 180 being applied.

[0032] Under normal driving conditions, the automatic brake control mechanism 140 is controlled by the MCU 110 such that air pressure is applied to the brakes 180. This causes the brakes 180 to remain in the deactivated condition (released).

[0033] Normal operation of the manual parking / emergency brake 160 by a driver or operator results in interruption of the air supply to the brakes 180 and venting of the air pressure in the brake line 160 between the automatic brake control mechanism 140 and the brakes 180, thereby causing the brakes 180 to be activated or applied. When this occurs, the pressure sensor 154 detects a low pressure, which is returned via the signal 155 to the MCU 110.

[0034] In the event the MCU 110 determines that the brakes need to be applied automatically (for example, if the driver or operator vacates the vehicle without applying the manual parking or emergency brake 160, as determined by, for example the seat sensor 126 detecting vacancy and the pressure sensor 154 detecting a high pressure), the MCU 110 operates the brake control mechanism 140 such that the air supply is interrupted and the air pressure in the brake line 162 between the automatic brake control mechanism 140 and the brakes 180 (i.e. in the section 162b) is vented. This causes the brakes 180 to be activated or otherwise applied.

[0035] Upon returning to the vehicle, and realising that the manual parking or emergency brake 160 was not applied, the driver or operator is required, according to the present disclosure, to apply and manual parking or emergency brake 160, and to then release the manual parking or emergency brake 160, prior to driving the vehicle. Application of the manual parking or emergency brake 160 results in a venting of air from the brake line section 162a and the air pressure sensor 152 detecting a low air pressure in the brake line section 162a. In this circumstance, such has now effect on the brakes 180 which are already activated due to air being previously vented from the brake line section 162b. Subsequent release of the manual parking or emergency brake 160 by the driver or operator 11211276 1 (IRN: P151030) -8- 2016202499 20 Apr 2016 results air being conveyed from the air supply 170 into the pneumatic line section 162a and the air pressure sensor 152 detecting air pressure in the brake line.

[0036] Once the MCU 110 detects the change in air pressure caused by the application and release of the manual parking or emergency brake 160, the MCU 110 operates the automatic brake control mechanism 140 such that air pressure is applied from the brake line section 162a to the brake line section 162b and thus to the brakes 180. This causes the brakes 180 to be deactivated or released, such that the vehicle can be driven or operated.

[0037] Fig. 2 is a schematic block diagram of a preferred implementation of the microprocessor control unit (MCU) 110 which may be used to practice the microprocessor control unit (MCU) 110 of Fig. 1. The MCU 110 is desirably implemented using a microprocessor or a microcontroller 200. An input sensor interface 202 is provided to receive each of the ignition input signal 129, the door signal 125, the seat signal 127, the pre-brake pressure signal 153, the post-brake pressure signal 155 and a maintenance switch signal 250. The interface 202 accommodates different signal types, voltages and currents from the associated sensors, and converts the relevant signals into a form that may be understood by and communicated to the microprocessor 200 via a connection 204. An accelerometer interface 206 may include the accelerometer 132 and is coupled to the microprocessor 212 via a connection 208. An interface 201 is provided to couple the external speed signal 131 to the microprocessor 200 via a connection 212. A power input 216 is derived from a power source of the vehicles (e g. a 12 volt battery) and inputs to a powers supply 214 which provides various operating voltages for components of the system 100, the relevant connections not being illustrated for the sake of clarity). The microprocessor 200 has an output 220 which couples to solenoid output drivers 218 which are configured to drive solenoid vales formed in the brake control mechanism 140 and to provide the brake on 112 and brake off 114 signals required for operation thereof. An alarm output 115 is provided directly to the alarm device 116. An internal beeper 226 is provided coupled to the microprocessor 200 via a connection 228 for providing audible indication of operation status and error conditions. A serial interface 224 couples to a keypad interface 222 which in turn couples to the keypad 122 to afford the desired user interface for the system 100. 11211276 1 (IRN: P151030) -9- 2016202499 20 Apr 2016 [0038] Under normal circumstances the (MCU) 200 has no visual indicator to show that the Automatic Brake Control Mechanism 140 has activated. An internal audible alarm, provided by the beeper 226, and optionally an external alarm, provided by the alarm 116 will sound when the Automatic Brake Control Mechanism 140 has activated. Any attempt by the driver to move the vehicle, after Automatic Brake Control Mechanism 140 has activated, will result the vehicle not being able to move. Instinctively the driver will engage and disengage the park brake via the mechanism 160 and, in effect, release the Automatic Brake Control Mechanism. This method provides an easier to use system and in most cases does not require the driver to be aware of the safety systems having been fitted.

[0039] At least one method to put the (MCU) into maintenance mode is provided, such mode being activated by the maintenance signal 250. Either an electrical key switch (not illustrated) or the keypad 122 for example may be used to provide the signal 250. Once in maintenance mode, the system 100 will not activate or deactivate the Automatic Brake Control Mechanism 140. This allows maintenance personal to work on the vehicle safely.

In maintenance mode the internal alarm 226 and or external alarm 116 will sound if a driver sits in the driver’s seat, as detected by the sensor 126. This prevents the vehicle being driven whilst in maintenance mode.

[0040] The speed sensor input signal 131 is received by the speed detector and fault detector module 210. The operation of this module is described further below. The speed fault detector module 210, on detecting a fault, provides an input 212 to the microprocessor 200 indicating a faulty detector condition. Under these circumstances the MCU 110 will not engage the Automatic Control Mechanism 140, regardless of the sensory inputs. The MCU 110 will beep the internal alarm systems in a set sequence to indicate the fault condition to the operator.

[0041] The accelerometer module 206 provides signals to the microprocessor 200 to indicate that the vehicle is accelerating. Preferably the module 206 works in 3 dimensions. In the event that the speed sensor fails to sends pulses during times of acceleration, it will be deemed that the speed sensor has failed. At this time the MCU 110 will not activate the Automatic Brake Control Mechanism 140 under any circumstances. The MCU 140 will beep the internal alarm systems 226 in a set sequence to indicate the fault condition to the 11211276 1 (IRN: P151030) -10- 2016202499 20 Apr 2016 operator. The sequence is preferably unique for each type of failure so the failed module can be identified from the sequence of beeps.

[0042] Fig. 3 is a flow diagram of a method 300 for automatically releasing a vehicle’s parking or emergency brakes after the brakes have been automatically activated. The method of Fig. 3 may be practised in conjunction with the system 100 depicted in Fig. 1. Typically, the method 300 is programmed into the microprocessor/microcontroller 200 to execute operation of the system 100 in the manner described herein. Although the method of Fig. 3 is described hereinafter with reference to the system of Fig. 1 for ease and clarity of description, the method of Fig. 3 may alternatively be practised with other brake systems, including non-air pressure-driven brake systems such as hydraulic and other brake systems.

[0043] Referring to Figs. 1 and 3, at step 310 the status the vehicle’s brakes 180 is determined via the relevant sensors have been automatically applied by the automatic brake control mechanism 140 under control of the MCU 110, as opposed to the manual brake mechanism 160 having been activated by a driver or operator. As a result of automatic application of the brakes 180, there is air pressure in the brake line 162a between the manual brake mechanism 160 and the automatic brake control mechanism 140 (i.e., detected by air pressure sensor 152), and no air pressure in the brake line 162b between the automatic brake control mechanism 140 and the brakes 180 (i.e., detected by air pressure sensor 154).

[0044] At step 320, a determination is made by the air pressure sensor 152 and the MCU 110 whether there is air pressure in the brake line 162a between the manual brake mechanism 160 and the automatic brake control mechanism 140. If so (YES), processing reverts to step 320. If not (NO), the MCU 110 concludes at step 330 that the manual brake control mechanism 140 has been activated by a driver or an operator of the vehicle. Processing then continues at step 340.

[0045] At step 340, a determination is made by the air pressure sensor 152 and the MCU 110 whether there is air pressure in the brake line 162a between the manual brake mechanism 160 and the automatic brake control mechanism 140. If not (NO), processing 11211276 1 (IRN: P151030) -11 - 2016202499 20 Apr 2016 reverts to step 340. If so (YES), the MCU 110 concludes at step 350 that the manual brake control mechanism 140 has been released by the driver or operator of the vehicle. Processing then continues at step 360.

[0046] At step 360, the brakes 180 are automatically deactivated by the automatic brake control mechanism 140 under control of the MCU 110.

[0047] The status at step 370 is that the vehicle is now in a condition to move.

Industrial Applicability [0048] The embodiments described hereinbefore are applicable to the vehicle industry, for both original equipment manufacture (OEM) and aftermarket fitment scenarios.

[0049] The foregoing description provides exemplary embodiments only, and is not intended to limit the scope, applicability or configurations of the present invention. Rather, the description of the exemplary embodiments provides those skilled in the art with enabling descriptions for implementing embodiments of the invention. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the claims hereinafter.

[0050] Where specific features, elements and steps referred to herein have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. Furthermore, features, elements and steps referred to or described in relation to one particular embodiment of the invention may form part of any of the other embodiments unless stated to the contrary 11211276 1 (IRN: P151030)

Claims (11)

1. A method performed by a microprocessor control unit (MCU) for automatic activation/deactivation of brakes, said method comprising the steps of: determining that a manual brake control mechanism has been applied by an operator; subsequently determining that said manual brake control mechanism has been released by said operator; and subsequently deactivating an automatic brake control mechanism to release said brakes.

2. The method of claim 1, wherein the step of determining that a manual brake control mechanism has been applied by an operator comprises the step of determining that a brake line between said manual brake control mechanism and said automatic brake control mechanism is not pressurised.

3. The method of claim 1 or claim 2, wherein the step of subsequently determining that said manual brake control mechanism has been released by said operator comprises the step of determining that a brake line between said manual brake control mechanism and said automatic brake control mechanism is pressurised.

4. The method of any one of claims 1 to 3, wherein said step of subsequently deactivating an automatic brake control mechanism to release said brakes comprises the step of venting pressure from a brake line between said automatic brake control mechanism and said brakes.

5. A system for automatically activating/deactivating brakes using pressure from a pressure reservoir, said system comprising: a manual brake control mechanism coupled to said pressure reservoir by a first portion of a brake line; an automatic brake control mechanism coupled to said manual brake control mechanism by a second portion of said brake line; a first pressure sensor disposed in said second portion of said brake line between said manual brake control mechanism and said automatic brake control mechanism; a second pressure sensor disposed in a third portion of said brake line between said automatic brake control mechanism and said brakes; and a microprocessor control unit (MCU) electrically coupled to said automatic brake control mechanism, said first pressure sensor, and said second pressure sensor; wherein said MCU is adapted to: detect activation and subsequent deactivation of said manual brake control mechanism; and deactivate said automatic brake control mechanism in response to said detection, thereby releasing said brake.

6. The system of claim 5, wherein said first and second pressure sensors comprise air pressure sensors.

7. The system of claim 5, wherein said first and second pressure sensors comprise hydraulic pressure sensors.

8. The system of claim 5 or claim 6, wherein said automatic brake control mechanism comprises a pneumatic valve.

9. The system of claim 5 or claim 7, wherein said automatic brake control mechanism comprises a hydraulic valve.

10. An automated brake control system for a vehicle, said system comprising: a plurality of sensors including at least a speed sensor and a driver detection sensor; a control unit coupled to the sensors; a brake control mechanism coupled to and actuated by the control unit; the control unit being configured to detect that the vehicle is operating at a speed below a predetermined speed and an absence of a driver from the vehicle and to activate the brake control mechanism to apply brakes of the vehicle.

11. A system according to claim 10, wherein the speed sensor outputs pulses to the control unit, the pulses being associated with a sensed speed of the vehicle, said system further comprising: an accelerometer sensor coupled to the control unit; the control unit being further configured to determine correct operation of the speed sensor by comparing an output of the accelerometer with that of the speed sensor such that when no speed pulses are detected during periods of acceleration or deceleration, the speed sensor is determined to be faulty.