Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D5/00—Power-assisted or power-driven steering
  • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
  • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
  • B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures

Definitions

• the invention relates to a method for operating a power steering system and such a power steering system.
• Power steering systems are known and provide that an applied by a driver manual torque by means of a motor, an engine torque is superimposed. Since the power steering is usually used outdoors, it is exposed to external influences, in particular environmental and temperature influences. As a result, the functionality of the steering can be impaired. In particular, a freezing of the power steering system by penetrated water is a particular problem.
• a water drain valve in a steering housing, in particular in an axis-parallel arrangement that opens when water enters and ensures that in the steering gear penetrated water drain again and thus can not freeze the steering at cryogenic temperatures.
• the electromechanical system includes an electric motor, at least one mechanical element that is moved by the electric motor, and a controller.
• the control unit is supplied with at least one input variable, wherein the control unit determines from the input variable a desired value for the electric motor. It is envisaged that a manipulated variable ße the mechanical element is detected and transmitted to the control unit, wherein from the comparison of target size for the electric motor and manipulated variable of the mechanical system, a stick-slip effect is detected.
• a stick-slip recognizer can be, for example, a means for recording noises or structure-borne noise.
• the described method for operating a power steering system provides that an engine torque given by a motor is superimposed on a manual torque given by a driver in an overlay unit.
• an impairment of the power steering system is detected by evaluation of engine speed patterns.
• the proposed method is particularly suitable for detecting a freezing of the power steering system, in the steering or the steering linkage.
• boundary conditions such as a rotor speed, a manual torque, a nominal engine torque, a steering angle, a vehicle speed, an end stage temperature (ECU), an external temperature and / or a gear indicator can be used.
• the direction of action of the manual torque and the effective direction of the Motornnonnents be considered. Care is taken to see whether the manual torque and the engine torque, which give the effective torque, act in the same direction. This promotes the robustness of the method, since it can be checked whether the detected speed pattern is due to an operation of the driver and is not caused by external disturbances.
• a warning signal (optical and / or acoustic) can be output.
• the power steering system described has a steering handle for specifying a manual torque, a motor, usually an electric motor, and an overlay unit, with which the motor torque of the motor is superimposed on the hand torque predetermined by a driver.
• the power steering system is characterized by the fact that an impairment of the power steering system can be detected by evaluating engine speed patterns.
• a control unit which detects and evaluates the speed pattern of the engine.
• a method which recognizes a freezing of the steering in design based on speed patterns and detected friction.
• an oscillating engine torque can be applied, which means that the freezing steering is better manageable and does not freeze completely.
• the described method can be implemented in a microprocessor or a computing unit of a control device.
• the method is realized in a software or a computer-implemented algorithm, which is executed automatically and detects and processes technical quantities.
• the input variables of the algorithm may be rotor speed, absolute rotor speed, manual torque, nominal engine torque, absolute steering angle, typically filtered vehicle speed, ECU final stage temperature, transmission index, and detected coefficient of friction.
• the steering starts to freeze, the engine speed is very small ( ⁇ 5 rpm) for about 100 ms, then the steering is "released" by the driver, resulting in a brief jump in speed Steering again slightly fixed, which again results in a very small speed for a short time If this speed pattern occurs several times in succession, for example 10 times, and other boundary conditions are met, such as temperature ⁇ + 5 ° C, system friction> 0.2 Nm, etc., a freezing of the steering is detected.
• an oscillating engine torque After detecting an oscillating engine torque can be applied, which prevents further freezing, thereby significantly improving the controllability of the vehicle, since the stick-slip effects no longer occur during freezing.
• the oscillating moment also serves as haptic feedback to and for the driver to warn him. In this way, it is possible that the freezing steering is better manageable by the driver and not completely freezes.
• a fault lamp and / or an acoustic signal can be activated.
• the input variables of the computer-implemented method are a rotor speed and / or a manual torque and / or a nominal engine torque and / or a steering angle and / or a vehicle speed and / or an end stage temperature (ECU) and / or an outside temperature and / or a printed circuit board temperature and / or a gear indicator indicator and / or a determined coefficient of friction are provided.
• ECU end stage temperature
• the presented computer program comprises program code means to perform all the steps of a method as described above, when the computer program is executed on a computer or a corresponding computing unit.
• the computer program product includes these program code means stored on a computer readable medium.
• This computer program can be stored on a computer-readable data carrier, such as a floppy disk, CD, DVD, hard disk, a USB memory stick or the like, or an Internet server as a computer program product. From there, the computer program can be transferred to a memory element of the control unit.
• a computer-readable data carrier such as a floppy disk, CD, DVD, hard disk, a USB memory stick or the like
• an Internet server as a computer program product. From there, the computer program can be transferred to a memory element of the control unit.
• Figure 1 shows a schematic representation of an embodiment of the proposed power steering system.
• FIG. 2 shows a speed curve with jumps.
• FIG. 3 shows a jump into a speed curve.
• FIG. 1 shows a power-assisted steering system, which is denoted overall by the reference numeral 10.
• the illustration showed a steering handle 12, which is designed as a steering wheel, an overlay unit 14, which is assigned to a motor 16 for torque superposition, a rack 18, two articulated wheels 20, a motor 16 associated with the control unit 22nd
• the control unit 22 is formed in addition to the control of the motor 16 to speed pattern, ie a specific course of the speed, this Mo- to detect sector 16. These speed patterns are evaluated and detected in this way, whether an impairment, for example. Freezing, the power steering system 1 0 is present. If an impairment is detected, then countermeasures, for example an oscillatory action on the power steering system 10 by the motor 16, are initiated. In addition, the driver is warned.
• a counter can be used which is reset after a certain period of time, for example by a timer or timer.
• FIG. 2 shows a speed curve with jumps over time. The time in ms is shown on an abscissa 50, the value of a counter on a first ordinate 52 and the speed in revolutions per minute on a second ordinate 54.
• the illustration shows a curve 56 which represents a speed curve, which in turn is composed of a number of speed patterns 58, 60 and 62.
• certain characteristic jumps in the curve 56 are recognized as speed patterns 58, 60 and 62 typical of a stick-slip effect.
• a counter is incremented, as illustrated by another curve 64.
• the number of specific speed pattern or the number of characteristic jumps in the curve 56 and thus in the Track the speed recorded. If the meter reaches a certain, specifiable level, freezing is detected and suitable measures are taken. After a certain period of time, however, the counter is reset to ensure robust operation.
• FIG. 3 shows a jump in a speed curve.
• the time in ms is plotted on an abscissa 80.
• An ordinate 82 shows the course of the rotational speed in revolutions per minute.
• a curve 84 shows a jump in the course of the speed.
• One threshold 86 indicates an upper speed threshold and another threshold 88 indicates a lower speed threshold.
• a first time range 90 indicates the minimum time for the lower speed, another time range 92 a maximum time until reaching the upper speed, another time range 94 a maximum time until re-reaching the lower speed and yet another time range 96 a minimum time for the lower speed. This analyzes the curve 84 and analyzes the jumps in it. In this way, characteristic speed patterns are determined.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Steering Control In Accordance With Driving Conditions (AREA)
• Power Steering Mechanism (AREA)

Priority Applications (6)

Applications Claiming Priority (4)

Related Child Applications (1)

Publications (1)

Family

ID=43877767

Family Applications (1)

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Cited By (4)

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Citations (2)

Family Cites Families (8)

• 2010
  • 2010-03-12 DE DE102010002803A patent/DE102010002803A1/de not_active Withdrawn
  • 2010-10-25 JP JP2012537341A patent/JP6061294B2/ja active Active
  • 2010-10-25 RU RU2012122544/11A patent/RU2509673C2/ru active
  • 2010-10-25 CN CN201080049933.XA patent/CN102753421B/zh active Active
  • 2010-10-25 BR BR112012010506A patent/BR112012010506A2/pt not_active Application Discontinuation
  • 2010-10-25 WO PCT/EP2010/066053 patent/WO2011054692A1/de not_active Ceased
  • 2010-10-25 EP EP10771426.3A patent/EP2496461B1/de active Active
• 2012
  • 2012-05-02 US US13/462,337 patent/US20120239254A1/en not_active Abandoned
• 2015
  • 2015-08-31 JP JP2015171044A patent/JP2016026126A/ja active Pending

Patent Citations (2)

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