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WO1999039952A1 - Commande electronique de freins de remorque - Google Patents

Commande electronique de freins de remorque Download PDF

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Publication number
WO1999039952A1
WO1999039952A1 PCT/US1999/002338 US9902338W WO9939952A1 WO 1999039952 A1 WO1999039952 A1 WO 1999039952A1 US 9902338 W US9902338 W US 9902338W WO 9939952 A1 WO9939952 A1 WO 9939952A1
Authority
WO
WIPO (PCT)
Prior art keywords
force
control circuit
signal
brake control
hitch
Prior art date
Application number
PCT/US1999/002338
Other languages
English (en)
Inventor
Lawrence W. Hill
Henry J. Szmyt
Frederick Williams Sarles
Original Assignee
Dbi Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dbi Corporation filed Critical Dbi Corporation
Publication of WO1999039952A1 publication Critical patent/WO1999039952A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • B60R16/023—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for transmission of signals between vehicle parts or subsystems
    • B60R16/0231—Circuits relating to the driving or the functioning of the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/04—Brake-action initiating means for personal initiation foot actuated
    • B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B60T7/20—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger specially for trailers, e.g. in case of uncoupling of or overrunning by trailer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/1701—Braking or traction control means specially adapted for particular types of vehicles
    • B60T8/1708—Braking or traction control means specially adapted for particular types of vehicles for lorries or tractor-trailer combinations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/24—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to vehicle inclination or change of direction, e.g. negotiating bends

Definitions

  • Trailers for automotive vehicles often employ trailer brakes to provide adequate braking resources for both the trailer and the towing vehicle.
  • trailer brakes are typically connected to the brake light circuit of the towing vehicle. As the brake light circuit is activated by a switch which is closed when the brake pedal is depressed, the trailer brakes are activated upon application of the towing vehicle brakes.
  • McGrath senses force on the brakes themselves, not the force on the hitch, and further does not use closed loop control.
  • Milner U.S. patent No. 5,286,094 suggests a compression sensing transducer attached to opposed sides of a drawbeam. The Milner system, however, is directed to compression sensing, not shear force sensing, and further controls a fluid based braking system, not an electrically powered braking system.
  • Brearley, et al . U.S. patent No. 5,080,445 suggests a pneumatic sensor on the trailer hitch, however, such pneumatic sensors are prone to mechanical fatigue and impact.
  • a control circuit for trailer brakes which includes a force sensor on the trailer hitch to monitor and control braking force, and which results in improved control of the towing vehicle and reduced wear on the trailer brakes.
  • Closed loop feedback control logic in the control circuit monitors the force exerted by the trailer on the hitch.
  • the feedback control logic governs the application of the trailer brakes to maintain a braking force such that a consistent, predictable force is exerted by the trailer on the towing vehicle through the hitch during braking.
  • Towing vehicle control is then improved because the trailer is not exerting excessive force upon the towing vehicle, and trailer brake wear is minimized because the trailer is not exerting excessive backward drag force on the towing vehicle.
  • Feedback control logic controls the braking force exerted by the trailer brakes such that the shear force is maintained at a constant level while braking. In one embodiment, this level is such that a slight backward drag force is exerted on the towing vehicle by the trailer. In this manner, trailer brake force is maintained at a level which is proportional to the brake force of the towing vehicle.
  • Data for the braking force requirement is derived from the strain gauge installed on the hitch by which the trailer is towed.
  • a microprocessor in the brake control circuit processes this data via a software PID (proportional - integral -differential) loop and generates a PWM (pulse-width modulated) output to a brake solenoid amplifier circuit which in turn controls current in the brake solenoids.
  • This braking control circuit is capable of modulating braking effort so that the towing vehicle/trailer combination feels like a single vehicle to the driver and is consequently much easier to drive than conventional systems.
  • the present invention yields true proportionality with the trailer brakes being constantly modulated during stopping to maintain force equilibrium between the trailer and the towing vehicle.
  • parameter coefficients within the PID loop shown in detail in appendix A, can be modified to compensate for different vehicle and trailer characteristics.
  • the variation of forces upon the hitch during braking are complex due to different weights of the vehicle and the trailer, different suspension actions on the vehicle and the trailer, and different wheelbases of the vehicle and the trailer.
  • Utilization of the PID loop in the feedback control logic together with the speed of the microprocessor in reacting to force changes results in smooth braking action in a variety of braking contexts .
  • a manual override to bypass the control circuit to allow independent operator control of the braking force to be exerted by the trailer brakes.
  • Such an override can be mounted on or in the steering wheel , and activated when the driver squeezes the steering wheel, or override control, as in a panic stop situation.
  • the control circuit also performs system diagnostics, such as brake solenoid continuity, and produces status signals indicative of system failures.
  • status signals also include the current level of braking force, and are sent to a cab display unit adapted to be mounted in view of the driver.
  • Fig. 1 is a block diagram of the brake control circuit as defined herein;
  • Fig. 2 shows a perspective view of a prior art trailer hitch and hitch box
  • Fig. 3 shows placement of a hitch on a trailer and towing vehicle
  • - 6 -
  • Fig. 4 shows a side view of a hitch and hitch box as defined by the present invention
  • Fig. 5 shows a perspective view of the trailer hitch according to the present invention
  • Fig. 6a shows a side view of the hitch connecting a trailer to a towing vehicle
  • Fig. 6c shows a side view of the hitch of Fig. 6a during acceleration of the towing vehicle
  • Fig. 7 shows an alternative location for strain gauge placement
  • Fig. 8a shows the strain gauge placement on the hitch
  • Fig. 8b shows one embodiment of strain gauge orientation as defined in the present invention
  • Fig. 9 shows a seven pin connecter as defined in the present invention.
  • Fig. 10c shows an alternative embodiment of the pressure sensors of Fig. 10a
  • Fig. 11 shows a front elevation of the cab display unit
  • Fig. 12 shows a block diagram of the schematic of the braking control circuit as defined herein;
  • Fig. 13 shows a schematic of the strain gauge amplifier circuit of Fig. 1;
  • Fig. 15 shows a schematic of the brake solenoid amplifier circuit of Fig. 1;
  • Fig. 16 shows a schematic of the manual override circuit of Fig. 1
  • Fig. 17 shows a schematic of the cab display unit circuit of Fig. 1.
  • a braking control circuit in accordance with the present invention is shown in Fig. 1 and includes a braking control module 10 connected to strain gauge amplifier circuit 12 to control the trailer brakes 14 which also receives input from cab display unit 16.
  • Strain gauge amplifier circuit 12 receives an analog shear force signal 18 indicative of forward or backward shear force on the hitch 20; the amplified strain gauge signal 22 is sent to the braking control module for A/D conversion.
  • Braking control module 10 sends a braking control signal 24 to the brake solenoid amplifier circuit 25 to apply the trailer brakes 14.
  • cab display unit 16 transmits and receives diagnostic and control information over cab data link 26.
  • Manual override 28 transmits signals from steering wheel grip sensors 30 mounted on the steering wheel 32 to increase braking force.
  • Keypad 34 is used for operator input of sensitivity and gain control, described further below, to adjust braking force.
  • a visual display 36 informs the operator of system activation and diagnostics.
  • typical prior art hitch arrangements attach a trailer 40 to a towing vehicle 42 through a hitch 38 inserted into a receptacle 58 in the fifth wheel 46, which is designed to pivotally mate with hitch 38.
  • the fifth wheel 46 is secured to the towing vehicle 42, as shown in Fig. 2, and the hitch 38 is welded to a hitch box 44 which is on the forward underside of the trailer 40.
  • any difference in braking force between the towing vehicle and the trailer causes a corresponding shear force on the hitch.
  • This shear force bearing on the hitch causes subtle mechanical deformations of the hitch through strain, resulting in surface variations which can be detected through micromechanical sensors such as strain gauges. Strain gauges can convert such small mechanical deformations into an - 8 - electrical signal by measuring resistance in a wire or semiconductor attached to the surface so deformed.
  • the braking control circuit as defined by the present invention monitors this shear force bearing on the hitch 38 to control the braking force exerted by the trailer brakes.
  • a modified hitch 20, shown in Figs. 4 and 5 is elongated to include a shear zone 52.
  • a hitch bore cavity 68 from the top of the hitch extending below the shear zone 52 provides a protected exit for the strain gauge wire 64; additionally adjustment of the shear zone wall thickness by altering the bore cavity diameter during hitch manufacture permits scaling of a ratio indicative of strain-stress in the shear zone 52.
  • the hitch is attached to the trailer hitch box 44 through a lock nut 48 and threads 50 on the hitch. In alternative embodiments, other methods of attachment, such as welding, could be employed.
  • a recessed attachment point on the hitch box to provide protection for the shear zone 52.
  • a pair of strain gauges 54 is affixed on the outer surface 56 of the shear zone.
  • the strain gauge 54 is affixed in a position so as to detect forward and backward shear force only.
  • a strain gauge such as the MM 187UV is affixed to opposed sides of the hitch at points tangent to a line parallel to the direction of travel, however various other types and placement of strain gauges could be used.
  • the shear zone 52 of the present invention allows the strain gauge 54 to sense the shear force in the hitch while avoiding contact with the receptacle 58 of the fifth wheel as it secures the hitch, as shown in Figs 6a-6c.
  • Fig. 6a shows a hitch 20 secured in a fifth wheel receptacle 58 while the trailer and towing vehicles are at rest.
  • Hitch 20 is secured in place by square bar 60, which allows sideways pivotal movement of the hitch while ensuring secure coupling.
  • a tolerance gap 62 around the hitch allows for limited vertical pivoting of the towing vehicle and trailer, to compensate for uneven travel surfaces .
  • Fig. 6b shows braking action by towing vehicle 44 causing the hitch to strain, as shown by dotted line 70, as it is forced within the limit of the range of movement afforded by the fifth wheel receptacle 58 and tolerance gap 62.
  • dotted line 70 enhances the actual degree of deformity for purposes of clarity.
  • Strain gauge 54 located in shear zone 52, senses the resulting strain while avoiding potentially damaging contact with other surfaces.
  • Fig. 6c shows the hitch 20 during acceleration. Hitch 20 is forced against square bar 60, causing the hitch to strain in the opposed direction, as illustrated by dotted line 70, showing enhanced movement for clarity.
  • strain gauge 54 is placed inside hitch bore cavity 68, at a point below the recess plate 67 which provides for the shear zone 52. Such installation, however, must be carefully verified to ensure proper strain gauge adhesion to the interior surface.
  • Braking force is then controlled by closed loop feedback control logic based on the strain gauge signal 22. Braking force is maintained such that a slight backward drag force is exerted by the trailer on the towing vehicle, as shown in Fig. 6c. In this manner, the trailer does not push against - 10 - or significantly pull back on the towing vehicle, allowing the towing vehicle to handle as if no trailer were present.
  • This closed loop feedback control logic is embodied in the C++ code listing in appendix A, illustrating the use of proportional integral differential (PID) computations and closed loop feedback to evaluate the force on the hitch and control the braking force accordingly to maintain the slight backward drag force on the hitch.
  • Control logic is activated by the strain gauge signal 22, and does not require activation from the brake light signal of the towing vehicle.
  • Brake light signal is used in the braking control module 10 for diagnostic reasons, and alternative embodiments incorporate the brake light signal into the closed loop feedback control logic to anticipate deceleration of the towing vehicle.
  • Control logic releases braking force when the strain gauge signal is unchanged for a predetermined period, as a static signal is indicative of the towing vehicle and trailer at rest . In alternative embodiments, however, such a static signal is measured to detect, for example, parking of the trailer and towing vehicle on a hill so that appropriate brake force may be applied.
  • Strain gauge sensor 54 is shown in more detail in Figs. 8a and 8b. As indicated above, strain gauge sensors are mounted on the shear zone 52 at point substantially tangent to the direction of motion such that only forward and backward shear force are sensed. Two opposed sensors are used so that torsional and binding force readings are minimized. The gauge is so oriented that it responds only to the shear modes arising from forward or backward forces on the pin; in particular, the strain gauge does not respond to the bending modes induced by trailer bucking, bouncing, or porpoising or to the shear modes arising from side thrust forces on the pin.
  • each opposed strain gauge comprises two sensor wire elements 72, oriented as indicated at about 45 degrees such that only forward and - 11 - backward shear force are sensed, as torsional forces tend to cancel due to the opposed diagonal orientation of each pair of strain gauges.
  • other strain gauges having alternative sensor wire sub-element placement could be used, provided that only forward and backward shear force, and not lateral or vertical forces, are sensed.
  • a full bridge strain gauge is used, however a half bridge strain gauge can be used in alternative embodiments. Such a half bridge embodiment would place a single sensor wire element 72 on each opposed side, thereby providing about half the sensitivity of the full bridge embodiment .
  • Braking control module 10 is connected to the cab display unit 16 via cab data link 26 (Fig. 1) .
  • the cab data link 26 is provided through an industry standard seven conductor plug 74 and cable commonly used to electrically connect a trailer and towing vehicle. This seven conductor plug contains an auxiliary conductor 76 which is frequently unused.
  • Cab data link 26 is carried on the auxiliary conductor, preferably using a noise- immune protocol as will be described below. Such a noise-immune protocol permits cab display unit 16 to send and receive signals from braking control module 10, mounted on the trailer, despite the inherently noisy operating environment.
  • auxiliary conductor 76 powers backup lights on the trailer.
  • the backup light signal from the towing vehicle is provided to the cab display unit 16, backup lights on the trailer connected to braking control module 10, and the backup light signal carried over the cab data link 26.
  • this link 26 is a current loop on one conductor of the standard electrical cable customarily used with such trailers, this conductor being the one which is normally used for auxiliary functions in - 12 - conventional installations, with the return path being via the cable ground wire.
  • the current loop is preferred because of robustness and noise immunity; however other standard implementations can be employed.
  • a half duplex block-ahead acknowledge protocol is used on this link.
  • the link and protocol deliver adequate data reliability through utilization of certain techniques according to U.S. patent Nos. 4,597,082 and 5,448,593, assigned to the assignee of the present application. Since the system data transfer rates required across this link are of a low bandwidth, this link can also be used for non system data or voice transmission between tow vehicle and trailer.
  • the present invention provides for the manual application of the trailer brakes and emergency override. It is very desirable in many instances, such as long downhill runs, or to prevent jackknifing, to apply brakes to the trailer only.
  • many prior art devices have either a lever or a pushbutton which is often mounted in an awkward location, such as under the dashboard, and which is difficult to access during emergencies.
  • the present invention utilizes a manual override pressure sensor mounted on the steering wheel. To activate the trailer brakes manually, the driver grips the steering wheel in the area where the sensor is mounted and applies finger or thumb pressure. The amount of force required for different drivers to activate the manual override can be predetermined and stored in memory by the microprocessor system.
  • the manual override circuitry also has a second threshold, activated by a higher force, reserved for emergencies.
  • the override signal will use an alternate link, bypassing the microprocessors, and activate the trailer brakes directly and forcefully.
  • steering wheel grip sensors 30 are mounted around steering wheel 32 and connected to the manual override 28.
  • a first embodiment shown in Fig. - 13 -
  • such sensors are a thin film 80 having a conductive pressure-sensitive material applied at a sensor portion 82.
  • Conductive traces 84 of the same pressure sensitive material allows connection to terminals 86.
  • These sensors can then be adhered by any suitable means, such as taping, to the steering wheel 32.
  • the electric resistance of this pressure- sensitive material varies with pressure so applied, providing an indication of the driver's grip pressure which is carried through coiled wire 78.
  • Coiled wire 78 is of a length such that the steering wheel is allowed to rotate lock to lock without sagging or stretching.
  • Figure 10c shows a steering wheel cross sectional view of a manual override embodiment designed to be manufactured in the steering wheel itself; this approach is aimed at specialized steering wheels which would most likely be factory installed.
  • Steering wheel rim 127 has been modified to contain the manual override mechanism. Pressure is applied to a pad 125 which is held in position by a retainer 126 and return springs 128. Movement of the pad compresses the sensor pressure spring 129, increasing the pressure on the pressure sensor 130.
  • Suitable pressure sensors are commercially available, such as the Motorola MPX 20xx series of pressure transducer sensors. In a factory installation environment, the steering wheel would be designed such the sensor wiring would be internal to the steering column.
  • pressure sensitive elements such as a resistive semiconductor
  • measurable voltage and/or current differences are provided in response to the gripping force applied by the driver to the steering wheel mounted sensor.
  • cab display unit 16 is shown.
  • Cab display unit contains truck circuitry and manual override circuitry, and is used to interact with the operator through visual display 36 and keypad 34.
  • a menu style interface allows the user to monitor and control system functions such as braking force, manual override sensitivity, and trailer lights.
  • cab display unit 16 is connected to braking control module 10 through cab data link 26, and can control all trailer electronics through trailer circuitry, described further below.
  • FIG. 12-17 Further description of the schematic diagrams shown in Figs 12-17 will illustrate the internal electronic circuit elements of the system. Referring to Fig. 12, a block diagram of the electronic schematics is shown. Five major subcircuits are shown, corresponding substantially to the elements indicated in the block diagram of Fig. 1.
  • Fig. 13 shows the analog strain gauge amplifier circuit 12.
  • Strain gauge 54 is connected to a strain gauge integrated circuit U6 which not only senses and amplifies the bridge output but also supplies a regulated bridge drive.
  • U6 is a Burr-Brown IMA 125, however alternative ICs or circuit designs which provide low offset voltages and adequate bandwidth of several hundred hertz will suffice.
  • the succeeding microprocessor A/D converter U5, Fig. 14
  • the output for zero- shear must be offset to 2.5 volts to accommodate both positive and negative shear.
  • the voltage follower U7A uses an available on-chip 2.5V reference to set the I.MA125 zero- strain output to the required 2.5 V, and the difference amplifier U7B scales the I.MA 125 output range appropriately so that the ensuing input stage is not overdriven. - 15 -
  • Fig . 14 shows the braking control module which implements the PID control logic as listed in appendix A.
  • a PIC16C73 is employed as microprocessor U5 , although any processor with at least the equivalent capabilities and necessary I/O ports could be employed.
  • the output STRAIN from the strain gauge amplifier circuit 12 is received by microprocessor A/D input U5/pin 2, which implements PID logic as listed in appendix A.
  • This PID control logic first scales the input and adds an offset so that a zero value corresponds to the desired drag force on the hitch.
  • This logic implements dead-bands in order to achieve smooth operation of the brake solenoids, and two different proportional gains are used, one near zero and a larger gain for rapid response when the error is large.
  • Braking control signal 24 is then output on the microprocessor U5 PWM outputs from U5/pin 12.
  • the remaining A/D inputs U5/pins 3-5 are utilized to monitor the performance of the brakes and the status of the trailer electrical system. Failures can be reported via the cab data link 26 for operator display.
  • Microprocessor U5 and associated software allows the operator to tailor operational and/or test parameters, and can be stored in nonvolatile flash memory U4.
  • the cab data link 26 is implemented via a current loop interface with a noise immune protocol as indicated above.
  • An RS232 driver/receiver U8 is included to provide an external interface for testing, diagnostics, debugging, and future expansion.
  • the brake solenoid amplifier circuit 25 is shown.
  • the PWM signal output from the microprocessor U5 is applied to the input of comparator U2A, the output of which drives the bases of the complementary emitter follower pair Q2 , Q3.
  • This pair in turn drives the gate of the P-channel power MOSFET Ql which applies modulated 12V DC directly to the brake solenoids 14.
  • a P-channel power MOSFET is employed because electric brake solenoids are manufactured with one end of the solenoid winding connected - 16 - to the solenoid frame and therefore to the chassis ground. Since the brake solenoids are inductive, current will ramp up during an ON portion of the Ql switching cycle and continue to flow during the OFF portion of the switching cycle. During this OFF portion, power diode D2 clamps the solenoid winding to chassis ground and conducts the freewheeling current.
  • the other comparator U2B provides for emergency override operation.
  • the manual override signal provides a signal indicative of a point on a continuum, varying thresholds of operation can be provided.
  • the manual override circuitry 28 is designed so that pressure significantly exceeding that which is typical for normal operation must be applied to the manual override to cause the GRIP signal to exceed a 4.8V threshold level at U2B/pin 5.
  • the comparator outputs are open collector wire-ORed, so that when the GRIP signal exceeds the 4.8V threshold, the output of U2B takes precedence, driving Ql to the ON state regardless of the output of U2A.
  • Manual override circuitry receives input from the pressure sensitive element 30 (Fig.
  • the ensuing difference amplifier U14B subtracts Vref from Vout and multiplies this by the ratio Rb/Ra, so the final output at the GRIP point is:
  • GRIP Vref Gs (Rfl + Rf2) Rb/Ra which is therefore a quasi linear function of pressure. - 17 -
  • the GRIP signal provided by the manual override circuit can take two control pathways.
  • Emergency path 29 goes directly to the brake solenoid amplifier circuit for emergency activation above a predetermined threshold.
  • the other path goes to the A/D input of microprocessor U10 in cab display unit circuit 16, described below. If the GRIP signal is below the emergency threshold, it is processed by microprocessor U10 and sent to U5 in the braking control module 10 for manual brake activation.
  • Cab display unit circuit 16 is shown in more detail in Fig. 17.
  • Cab display unit has flash memory U9 , RS232 interface for future expansion, visual display 36 connected to LCD, current loop interface for data link 26, and also drives the user interface which allows manual operator input to override system defaults, gains, and thresholds.
  • braking control module 10 can be configured without cab display unit and manual override, to eliminate the need for cab data link 26. Such operation would result in braking control module 10 operating with default values.
  • #def-ne SINE 1 #define SQUi RE 2 int PASCAL WinMain(HANDLE, HANDLE, LPSTR, int); long PASCAL MainWndProc(HWND, UINT, WPARAM, LPARAM);
  • SenclMessage (Ge ⁇ igItem(hWn-UIX _COMB01) , CB_SETCURSEL, 0, OL); break; case WM_COMMAND: witch(LOWORD(wP--ram))
  • HDChDC HDChDC
  • PAINTSTRUCT ps PAINTSTRUCT ps; int i, .k, px, py; char n[6];
  • WS_VSCROLL output_pos[4].x+90, io_pos[0].y+70, 50, 60, hWnd, IDC_GAIN, hlnst, NULL); SendMessage(hAddrComboBox, CB DDSTRING, NULL, (LONG)(L.PSTR)"r); SendMessage(hAddrComboB ⁇ 3-, CB_ADDSTRING, NULL, (LONG)(LPSTR)"2");
  • WS_CHILD I WS_VISIBLE
  • BS_LEFTTEXT output_pos[4].x+50, io_pos[0].y-5,25,15, hWnd,UX;_DA, lilnst, NULL);
  • WS_CHILD I WS_VISIBLE
  • BS_LEFTTEXT output_pos[4].x+50, io_pos[0].y+31 ⁇ 5J5, hWnd,H>C_DA+2, hlnst, NULL);
  • W_812_DI(DI_LO_BYTE,&input_lo); W_812_DI(DI_HIJBYTE,&input_hi); input (((unsigned int)input_hi) «8>+input_lo; - 28 -

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • Automation & Control Theory (AREA)
  • Regulating Braking Force (AREA)

Abstract

L'invention concerne un circuit de commande (12) pour freins de remorque (14) comprenant un détecteur de force (54) situé sur l'attelage (38) de la remorque, destiné à contrôler et à commander la force de freinage et permettant d'obtenir une meilleure commande du véhicule remorqueur (42) et de réduire l'usure des freins de remorque (14). Une logique de commande à rétroaction en boucle fermée dans le circuit de commande contrôle la force exercée par la remorque (40) sur l'attelage. La logique de commande à rétroaction régule l'application des freins de remorque (14) pour maintenir une force de freinage telle qu'une force constante, prévisible est exercée par la remorque sur le véhicule remorqueur par l'attelage pendant le freinage.
PCT/US1999/002338 1998-02-04 1999-02-03 Commande electronique de freins de remorque WO1999039952A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US7362798P 1998-02-04 1998-02-04
US60/073,627 1998-02-04

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Publication Number Publication Date
WO1999039952A1 true WO1999039952A1 (fr) 1999-08-12

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PCT/US1999/002338 WO1999039952A1 (fr) 1998-02-04 1999-02-03 Commande electronique de freins de remorque

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2353340A (en) * 1999-08-20 2001-02-21 Vincent Roy Garvey Trailer brake control system
WO2009043321A1 (fr) * 2007-10-04 2009-04-09 Conti Temic Microelectronic Gmbh Dispositif de commande d'un système de sécurité de véhicules automobiles, auquel sont reliées des sondes qui saisissent des grandeurs d'état de conduite et des actionneurs qui actionnent les systèmes de sécurité
EP1904351B1 (fr) 2005-07-11 2016-03-30 Volvo Lastvagnar Ab Système et procédé de stabilisation d un attelage
US10703345B2 (en) 2018-01-23 2020-07-07 Ford Global Technologies, Llc Methods and apparatus to automatically calibrate electronic trailer brake gain
US10836366B2 (en) 2018-05-31 2020-11-17 Ford Global Technologies, Llc Methods and apparatus for automatic calibration of electronic trailer brake gain
US11385651B2 (en) 2018-06-26 2022-07-12 Ford Global Technologies, Llc System and methods for detection and response to interference between trailer coupler and hitch ball
US12005877B2 (en) 2020-05-06 2024-06-11 TRP International, LLC Electric over hydraulic brake system with magnetic sensor

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US2856036A (en) * 1956-12-03 1958-10-14 Robert D Mullen Automatic electric trailer brake control system
US3955652A (en) * 1969-05-23 1976-05-11 Ab Linde International Operating systems for trailer brakes
US4231442A (en) * 1974-06-15 1980-11-04 Mogens Birkeholm Apparatus for braking a train of vehicles
US5335743A (en) * 1990-10-19 1994-08-09 Saab Automobile Aktiebolag Operation of servo devices for driving a motor vehicle - control, arrangement and method
US5423569A (en) * 1991-07-08 1995-06-13 United Technologies Automotive, Inc. Electric signalling in a supplemental passenger restraint system

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Publication number Priority date Publication date Assignee Title
US2856036A (en) * 1956-12-03 1958-10-14 Robert D Mullen Automatic electric trailer brake control system
US3955652A (en) * 1969-05-23 1976-05-11 Ab Linde International Operating systems for trailer brakes
US4231442A (en) * 1974-06-15 1980-11-04 Mogens Birkeholm Apparatus for braking a train of vehicles
US5335743A (en) * 1990-10-19 1994-08-09 Saab Automobile Aktiebolag Operation of servo devices for driving a motor vehicle - control, arrangement and method
US5423569A (en) * 1991-07-08 1995-06-13 United Technologies Automotive, Inc. Electric signalling in a supplemental passenger restraint system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2353340A (en) * 1999-08-20 2001-02-21 Vincent Roy Garvey Trailer brake control system
WO2001014188A1 (fr) 1999-08-20 2001-03-01 Vincent Roy Garvey Systeme de commande de frein de remorque a fonction de securite
GB2353340B (en) * 1999-08-20 2003-11-05 Vincent Roy Garvey Trailer safety
AU774283B2 (en) * 1999-08-20 2004-06-24 Vincent Roy Garvey Trailer brake control system with safety function
EP1904351B1 (fr) 2005-07-11 2016-03-30 Volvo Lastvagnar Ab Système et procédé de stabilisation d un attelage
WO2009043321A1 (fr) * 2007-10-04 2009-04-09 Conti Temic Microelectronic Gmbh Dispositif de commande d'un système de sécurité de véhicules automobiles, auquel sont reliées des sondes qui saisissent des grandeurs d'état de conduite et des actionneurs qui actionnent les systèmes de sécurité
US10703345B2 (en) 2018-01-23 2020-07-07 Ford Global Technologies, Llc Methods and apparatus to automatically calibrate electronic trailer brake gain
US10836366B2 (en) 2018-05-31 2020-11-17 Ford Global Technologies, Llc Methods and apparatus for automatic calibration of electronic trailer brake gain
US11385651B2 (en) 2018-06-26 2022-07-12 Ford Global Technologies, Llc System and methods for detection and response to interference between trailer coupler and hitch ball
US12005877B2 (en) 2020-05-06 2024-06-11 TRP International, LLC Electric over hydraulic brake system with magnetic sensor

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