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
  • B62D5/046—Controlling the motor
  • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
  • B62D6/001—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits the torque NOT being among the input parameters

Definitions

• the invention is in the field of controlled steering of motor vehicles, such as the power assisted steering or the electric steering ("steer by wire”).
• the electric power steering is a very common equipment in current motor vehicles. It consumes little energy, and in addition to its own role of assisting the driver in steering the steering wheel, it communicates and interacts with various vehicle systems, such as the brakes or the stability control system (ESC, Electronic Stability Control).
• ESC Electronic Stability Control
• the document FR2906519 describes a method of preventing overbraking providing for the application of a braking torque, for example of the viscous type, applied in addition to the assist torque of the electric motor of the electric assistance.
• the invention provides a device for controlling the direction of a motor vehicle driven steering, the device comprising a means for obtaining an angular speed of a steering wheel of the vehicle, characterized in that the control device further comprises means for obtaining a value representative of a vehicle speed in relation to the ground, and further comprises means for controlling the power of the electric power steering assistance motor. vehicle to a defined value according to said angular velocity and said value representative of a vehicle speed relative to the ground.
• the means for adjusting the power of the electric motor can adjust said power on the basis of values extracted from a power limitation table with two inputs, the two inputs being the speed of rotation of the steering wheel and the speed of the vehicle. compared to the ground. Given the two entries to obtain a value, we use a 3D map.
• the control device may be configured to control said power progressively as a function of said angular velocity and of said value representative of a vehicle speed relative to the ground and respects predetermined adjustment values.
• a magnitude of the power reduction of the electric motor can be defined according to a static stability index of the vehicle.
• the invention also relates to the motor vehicle comprising a steering control device as evoked.
• FIG. 1 is a diagram showing a system incorporating the invention.
• FIG. 4 represents the dimensioning of the device as a function of a stability parameter of the vehicle
• FIG. 1 shows the activation of the device according to the invention according to the speed of the vehicle relative to the ground.
• FIG 1 there is shown the architecture of a system in which the invention is inscribed. This is implemented in an automobile, and the diagram represents the direction of it.
• the pilot actuates a steering wheel 100.
• the latter transmits the pilot's control to an electric power steering computer 1 10 and the latter actuates an electric power steering motor 120.
• the engine 120 is an electric motor which acts to provide a assisting the steering effort (changing the orientation of the wheels), the driver turning the wheels by a steering wheel action via the steering column, with assistance of the engine, thus turning the vehicle to the left or to the right .
• FIG 2 there is shown the implementation of the invention in this context.
• the embodiment shown uses a means for obtaining the angular speed of the flywheel 130.
• This means 130 may incorporate, for example, an angular position sensor of the steering wheel and a means of derivation of the value measured by the sensor.
• the embodiment shown also uses a means for obtaining or estimating the speed of the vehicle relative to the ground, for example a means for obtaining the speed of wheels 140.
• This means 140 is based on functions already available in the CAN bus ("Controller Area Network", for CAN network or field bus).
• the means 130 and 140 transmit the corresponding information to a control computer of the dynamics of the steering wheel 150, which can be separated from the assistance steering computer 1 10 or be part of it.
• the control computer of the dynamic steering wheel 150 based on the information transmitted by the means 130 and 140, decides whether or not to limit the control generated by the electric power steering computer 1 10 for the power steering motor 120
• the activation of the control of the dynamics of the steering wheel is represented as a function of the angular speed of the steering wheel as obtained using the means 130.
• the speed of rotation of the steering wheel was given in degrees per second, from 0 to 1260 degrees per second.
• an activation percentage of the control function of the dynamics of the steering wheel that is to say the amplitude with which the control computer of the dynamics of the steering wheel 150 acts on the command issued by the electric assist steering computer 1 10 for the electric assist motor 120.
• the activation rate of control of the dynamics of the steering wheel is zero when the steering wheel speed is 0 degrees per second, then gradually increases to the value of 50% which is reached for a value close to 360 degrees per second. But for low speed values of the steering wheel, the function can also remain under surveillance without intervention, the activation rate remaining at 0% and becoming positive only from a threshold in angular speed.
• a second zone referenced 1010, between 360 degrees per second and 850 degrees per second, the activation rate of control of the dynamics of the steering wheel continues to increase continuously, then approaches and stabilizes at the value 100%.
• This domain is qualified here as a "customer domain with strong dynamic flying", corresponding for example to a sporty driving or to a situation likely to create accidents.
• 850 degrees per second the speed of rotation of the steering wheel is particularly abrupt and it is considered that we have here simply a domain usable only during tests of the vehicle, referenced 1020.
• the control of the dynamic steering wheel is activated at 100%.
• Figure 4 there is shown a dimensioning element of the control of the dynamics of the steering wheel according to the target vehicle, and in particular of its geometry.
• the static stability index of the vehicle SSF (Static Stability Factor"). This index applies to minivans and sedans and is concerned with risk management for high reversion vehicles. It is calculated as the ratio between the width of the track (which is related to the width of the vehicle) and the height of the center of gravity of the vehicle. By convention, this last report is divided by two to get the SSF.
• the SSF index varying from 1 to 2.
• the width of the vehicle is equal to twice the height of its center of gravity.
• the width of the vehicle is four times this height.
• the ordinate shows the activation percentage of the control of the dynamics of the steering wheel according to the SSF of the vehicle. From a value of SSF 1 to an SSF value of 1, 2 (zone referenced 2000), it is agreed, provided that such a vehicle is implemented, to strongly activate the control of the dynamics of the steering wheel, and the activation value is conventionally set to 100%. The activation is then greatly reduced for the SSF values between 1, 2 and 1, 4 (zone referenced 2010 and beyond), the value gradually decreasing from 100% to 20%. We then choose to lower the value gradually, but more slowly from 20% to 0% when the value of SSF increases between 1, 4 and 2 (zone referenced 2020). In the diagram, the border between the 2010 and 2020 zones is chosen to correspond to an activation value of 50%.
• the control of the dynamics of the steering wheel is totally disabled, leaving the power applied to the engine 120, expressed in speed equivalent steering wheel rotation, unchanged. Then, when the speed of the wheels increases, the control is activated gradually for speeds between the first horizontal speed determined by the manufacturer v- ⁇ and a second horizontal speed determined by the manufacturer. v 2 (zone referenced 3010).
• the progressive activation is done in a linear manner, with a slope that is adjusted according to the manufacturer's knowledge of the uses made by the customers for the vehicle model considered.
• the electric power supplied to the engine 120 is lower than that which would be provided solely on the basis of the speed of rotation of the steering wheel. It is equivalent to only a fraction of the rotational speed of the steering wheel, which decreases.
• the control of the dynamics of the steering wheel is maintained activated with a constant amplitude, leaving the electrical power supplied to the motor 120 constant.
• the control of the dynamics of the steering wheel can be deactivated again, in a progressive manner, for example linearly with a slope. determined according to the known uses of the customers for the considered model.
• the activation rate of the control of the dynamics of the steering wheel can be again, by choice of the manufacturer, as an example, fully disabled (referenced area 3040).
• the power supplied to the engine 120 is equal to that corresponding to the speed of rotation of the steering wheel. It can also be weaker, equal to or different from that obtained in zone 3000.
• the curve represented in FIG. 3 can take different forms depending on the ground speed of the vehicle.
• the curve shown in Figure 5 can take different forms depending on the speed of rotation of the steering wheel.
• One embodiment uses a two-input table, the two inputs being the rotational speed of the steering wheel and the speed relative to the road.
• the values given in the table are the electrical power values supplied to the motor.
• the intervention of the function is automatic and is managed by the slopes and levels of adjustment of the function, which makes it transparent to the driver.
• This system is remarkable in that it only requires an evolution of the power steering software and therefore does not require hardware changes, such as the implementation of a new sensor.
• This system is also remarkable in that it is not intrusive in the driver's steering mode as could be by example an evolution of a stability control system (ESC).
• ESC stability control system
• the proposed solution presents an excellent compromise between the service provided and the security provided.
• the solution presented is transparent to the driver and allows, for the manufacturer, a wide possibility of controlling the control function of the dynamics of the steering wheel through the parameters of the curves of Figures 3 and 5.
• control computer of the dynamics of the steering wheel 150 can enable the function only on a range of rotational speed of the steering wheel, regardless of the speed relative to the ground, and a speed range by relative to the ground regardless of the speed of rotation of the steering wheel.
• the invention is not limited to the embodiment shown but extends to all variants within the scope of the claims.
• it can be implemented with a power steering ("steer by wire").

Landscapes

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

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=52345300

Family Applications (1)

Country Status (4)

Citations (2)

Family Cites Families (11)

• 2014
  • 2014-10-14 FR FR1459827A patent/FR3027010B1/fr active Active
• 2015
  • 2015-09-11 EP EP15771206.8A patent/EP3206935A1/fr not_active Withdrawn
  • 2015-09-11 CN CN201580055497.XA patent/CN106794859A/zh active Pending
  • 2015-09-11 WO PCT/FR2015/052430 patent/WO2016059310A1/fr active Application Filing

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events