System for stabilizing a motor vehicle during acceleration in straight-line travel and in cornering

Abstract

The invention relates to a method and a system for stabilizing a motor vehicle during an acceleration maneuver. A slip condition of one or more wheels is detected on the basis of vehicle dynamics variables, including wheel speeds, yaw rate and lateral acceleration. Depending on the detected slip, alternating micro-steering impulses or micro-steering torque impulses are automatically applied to a steering system, the impulses having sub-degree steering angle variations and generating a lateral micro-movement of the tire contact patch. The micro-impulses serve to stabilize lateral forces and are executed in two operating modes: a symmetric mode for acceleration in substantially straight- line travel and an asymmetric mode with an impulse-time bias for acceleration in cornering. The impulse parameters are adapted to steering angle, yaw rate and lateral acceleration. The invention further comprises a system with sensors, a control unit and an actuator for generating the micro-steering impulses.

Description

00347484-0011 11.12.2025 PCT / DE0S£^ / |SQffi12711-12-2025-003 743 -0011TACTOS-7.0 - PCT Description Date: 09.12.2025DescriptionTACTOS-7.0 - System for Stabilizing a Motor Vehicle During Acceleration in Straight-Line and Cornering ManeuversTechnical Field

[0001] The invention relates to vehicle dynamics control of motor vehicles and concerns a system and a method for stabilizing a vehicle during acceleration maneuvers, both in straight-line travel and in cornering. The invention in particular relates to the generation of microsteering impulses or steering torque impulses for controlling slip and lateral force conditions.Re -la - -t -io -n t.o. t.he - Prio -rit.v An M-nlic >ation[0001a] This application claims the priority of German patent application DE 10 2024 004 430.2 of 17 December 2024, the entire disclosure of which is incorporated herein by reference.[0001b] The embodiments described herein are based on the same fundamental principle of contact-patch-modulating micro-steering impulses and constitute a single general inventive concept.Background of the Invention

[0002] DE 10 2024 001 244 A1 (DI) discloses a method for improving traction on loose ground, in which steering oscillations are used to avoid becoming stuck. Application during dynamic acceleration is not disclosed.

[0003] DE 10 2005 019 339 A1 (D2) describes steering oscillations at low speeds in off-road start-up situations. Reference to higher-dynamics driving states is missing.

[0004] DE 10 2015 224 760 A1 (D3) shows steering impulses for rocking free a stuck vehicle. The impulses are not intended for acceleration or cornering.

[0005] DE 11 2020 004 314 T5 (D4) relates to steering logic under slip conditions but without micro-steering impulses or friction- value regeneration.

[0006] DE 11 2019 002 782 T5 (D5) describes adaptive rear-wheel steering without reference to acceleration maneuvers or lateral contact-patch modulation.Page 1 to 500347484-0012 11.12.2025 PCT / DE0S£^ / |SQffi127TACTOS-7.0 -PCT Description Date: 09.12.2025

[0007] None of documents D1-D5 discloses micro-steering impulses in the sub-degree range (below 2°) at frequencies from 3 to 7 Hz for lateral migration of the tire contact patch during an acceleration maneuver, either in symmetric or asymmetric form.Object of the Invention

[0008] It is an object of the invention to stabilize a motor vehicle during an acceleration maneuver and to reduce undesired driving states, in particular when slip occurs on individual wheels or when increased lateral force demand exists during cornering.Extended Technical Problem

[0009] During rapid acceleration, changes in vehicle dynamics often occur earlier than perceived by the driver. An unstable slip distribution leads to delays in lateral force build-up and may cause understeer or oversteer before the driver can react.

[0010] As driver reactions typically occur with delays exceeding 200 ms, macroscopic counter-steering movements arise which may further amplify the unstable condition.

[0011] Micro-steering impulses with frequencies above the reaction dynamics controllable by the driver enable early correction of slip and lateral force distribution. Stabilization is thereby achieved at a stage in which macroscopic deviations of the vehicle trajectory are not yet visible.Summary of the Invention

[0012] The object is achieved by a method in which a slip condition of one or more wheels is detected during an acceleration maneuver and, depending thereon, alternating micro-steering impulses and / or micro-steering torque impulses are automatically applied to a steering system to generate stabilizing lateral forces. The impulses are generated depending on vehicle speed, yaw rate, lateral acceleration and / or road curvature.

[0013] A TACTOS sensor system detects friction-value variations on the basis of thermal, structural-mechanical, vibration-based and walk-dynamics features. Micro-steering impulses are understood as small, alternating steering-angle variations in the sub-degree range.

[0014] Two operating modes are distinguished:- symmetric mode for acceleration in substantially straight-line travel,- asymmetric mode for acceleration during cornering.Page 2 to 500347484-0013 11.12.2025 PCT / DE0S£ / |SQffi127TACTOS-7.0 - PCT Description Date: 09.12.2025lateral micro-migration of the tire contact patch.The TACTOS sensor system detects thermally overloaded contact regions, slip variations, or friction-value reductions. FIG. 3 shows a typical impulse profile.

[0020] FIG. 2 illustrates the detection of an incipient slip condition based on vehicle dynamics variables supplied by the sensors, including wheel speeds, yaw rate and lateral acceleration. The slip detection serves as a triggering criterion for the micro-steering impulses generated in the symmetric or asymmetric mode.Mode B - Cornering Acceleration

[0021] With increasing steering angle, the impulse mode is continuously adapted toward an asymmetric mode. FIG. 5 illustrates the transition.Dynamic Transition Mode

[0022] If the steering angle exceeds a vehicle-specific threshold (e.g. 1.5°), the system detects variations in slip, lateral acceleration and yaw-rate deviation.

[0023] The asymmetric mode generates micro-steering impulses having an amplitude of 0.5° to 2.0° and an impulse-time bias of > 60% in the direction of the outer side of the curve. The frequency typically lies in the range of 3 - 5 Hz.Example 1 - Straight-Line Acceleration

[0024] FIG.4 illustrates an example of full acceleration on a straight road section.

[0025] Micro-impulses (± 0.3° to ± 1.5°, 3 -7 Hz) are activated within the first 50 - 100 ms following the increase in drive torque.

[0026] The TACTOS system detects slip, thermal hotspots and friction- value drops.

[0027] An impulse phase of 300 - 800 ms leads to periodic engagement of adhesionproviding contact regions and stabilizes the frictional contact.Example 2 - Cornering Acceleration

[0028] FIG. 6 shows the stabilized vehicle trajectory in a long, constant-radius curve.Page 4 to 500347484-0014 11.12.2025 PCT / DE0S£ / |& Qffi127TACTOS-7.0 - PCT Description Date: 09.12.2025

[0029] At a speed of approximately 60 km / h and an acceleration of 4 - 5 m / s2, TACTOS detects slip variations, an increase in lateral acceleration and deviations between nominal and actual yaw rate.

[0030] The system activates the asymmetric mode and generates micro-impulses with amplitudes of 0.7° to 1.8° and an impulse-time bias of 60 - 75% toward the outer side of the curve.

[0031] The laterally load-bearing contact regions are enlarged so that the lateral guiding force is maintained even under high longitudinal drive forces.This effect is attributable to the fact that the asymmetric micro-impulses generate a controlled lateral migration of the effective contact zone and thereby activate the load-bearing outercurve tire flank, which provides the predominant portion of the lateral guiding force.

[0032] FIG.7 illustrates the resulting stabilized vehicle trajectory during acceleration in cornering, as achieved by the asymmetric micro-steering impulses described in paragraphs

[0028] to

[0031] ,Variants and Extensions

[0033] For acceleration from standstill or at very low vehicle speed,the micro-impulse amplitude may be larger than in deceleration from higher speeds.In.such start-up situations,, amplitudes in the range of ±0.5° to ±2.5°,and in particular cases up to ±3.0°, may be used without generating aperceptible or unstable steering response, since the lateral stiffness of the tireis significantly lower at low vehicle speed.

[0034] The impulse frequency may lie in an extended range between 1 Hz and 12 Hz.

[0035] The micro-impulses may exhibit non-linear impulse shapes, including step-shaped, exponential or adaptively modulated profiles.Conclusion

[0036] The invention operates not by brake interventions or drive-torque reduction, but by modulation of the contact-patch conditions, and constitutes an independent vehicle-dynamics control system.Page 5 to 500347484-0015 11.12.2025 PCT / DE0S^ / |»Qffi1271Reference Signs ListVehicle and contact10- Vehicle11 - Tire-road contact patchSteering and motion12 - Steering-angle change14 - Unstable vehicle trajectory30 - Vehicle acceleration / driving-force direction Sensor and trigger28 - Trigger point in the sensor signalAxes and signal quantities16 -Time axis18 - Steering-angle / signal axisMicro-steering impulses20 - Steering-signal / impulse sequence22 - Upper signal component / signal level24 - Positive micro-impulses26 - Negative micro-impulsesContact zones / lateral shift32 - Contact-zone segment34 - Lateral migration of the contact patch Trajectories40 - Unstabilized vehicle trajectory42 - Stabilized vehicle trajectory

Claims

00347484-0017 11.12.2025 PCT / DE0S£^ / |SQffi12711™ 12-2O25-0O347484- 17TACTOS-7.0 - PCT Claims Date: 09.12.2025Claims1 (independent method claim)A method for stabilizing a motor vehicle during an acceleration maneuver, wherein- a slip condition of one or more wheels is detected on the basis of vehicle¬ dynamics variables, and- in dependence thereon, alternating micro-steering impulses and / or micro¬ steering torque impulses are automatically applied to a steering system of the vehicle,whereinthe micro-steering impulses comprise sub-degree steering-angle variations and generate a lateral micro-movement of the tire contact patchin order to build up stabilizing lateral forces.Dependent claims - technical features (modes, parameters, triggers)2. The method according to claim 1,characterized in that the micro-steering impulses have an amplitude between ±0.1° and ±2.0°.

3. The method according to claim 1 or 2,characterized in that the micro-steering impulses are generated at a frequency between 1 Hz and 12 Hz.

4. The method according to any of the preceding claims,characterized in that the lateral micro-movement of the tire contact patch lies in a range from 0.1 mm to 5 mm.

5. The method according to any of the preceding claims,characterized in that slip detection is performed on the basis of wheel speeds, yaw rate and / or lateral acceleration.

6. The method according to any of the preceding claims,characterized in that thermal, structural-mechanical, vibration-based and / or walk-dynamics signals are used for friction-value detection.00347484-0018 11.12.2025 PCT / DE0S£^ / |SQffi12711 - 12^1925-0034 484- 18TACTOS-7.0 - PCT Claims Date: 09.12.2025Mode A - Straight-line travel7. The method according to any of the preceding claims,characterized in that a symmetric micro-impulse mode is used when acceleration occurs in substantially straight-line travel.Mode B - Cornering8. The method according to any of the preceding claims,characterized in that an asymmetric micro-impulse mode is used when acceleration in cornering is detected.

9. The method according to claim 8,characterized in that an impulse-time bias of at least 60% is generated toward the outer side of the curve.

10. The method according to any of the preceding claims,characterized in that the impulse direction, impulse frequency and / or impulse amplitude are adapted in dependence on steering angle, yaw rate or lateral acceleration.Dynamic transition11. The method according to any of the preceding claims,characterized in that a transition mode is executed in which continuous interpolation is performed between the symmetric and asymmetric micro-impulse modes.Physical mechanism - friction / contact zone12. The method according to any of the preceding claims,characterized in that the micro-steering impulses generate a controlled lateral migration of the effective contact zone,whereby adhesion-providing areas of the tire flank are incorporated into the frictional contact region.00347484-0019 11.12.2025 PCT / DE0S^|SS&12711”1>=2©25-00347484- 0019TACTOS-7.0 - PCT Claims Date: 09.12.202513. The method according to any of the preceding claims,characterized in that the micro-steering impulses are used to compensate a de ~cr ~e -a "s -in Cg? - late -r -a -l c g?uiding f -orc -e on the ~ o -u-t-e-r--c -urv.e - tire flankIntegration into vehicle logic14. The method according to any of the preceding claims,characterized in that the micro-steering impulses are generated by an electronic control unit which communicates with existing vehicle-dynamics systems. System claims15. A system for carrying out a method according to any of claims 1 to 14, comprising- at least one TACTOS sensor system for detecting vehicle-dynamics variables, - an electronic control unit, and- an actuator for generating the micro-steering impulses.

16. The system according to claim 15,characterized in that the actuator comprises an electrically assisted steering system or a steer-by-wire system.Control-unit claim (DPMA-safe, EPA-safe)17. An electronic control unit configured to carry out the method according to any of claims 1 to 14.Vehicle claim18. A motor vehicle comprising a system according to any of claims 15 or 16

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