Adaptive Haptic Feedback Control for User Interface Actuators

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Solution Overview

Problem

Existing haptic user interfaces do not adapt to individual user input characteristics, leading to inconsistent and potentially unnoticed haptic feedback, which can be problematic in environments where user attention is divided, such as in vehicle operation.

Innovation Solution

A method and system that adjust the intensity of haptic feedback signals based on user-specific reaction times and sensor signal amplitudes, reducing intensity if reaction times are quick or amplitudes are low, and increasing intensity if reaction times are slow or amplitudes are high, to ensure perceivable feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If haptic feedback signals are output with constant intensity, then the system structure remains simple, but the feedback may not be reliably perceived by all users in divided attention environments

Engineering Contradiction:
Improvefeedback perception reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The haptic feedback intensity is dynamically adjusted based on detected user input characteristics. The system transitions from static constant-intensity feedback to dynamic adaptive feedback, where the actuator modifies signal parameters in real-time according to measured user reaction patterns and sensor signal amplitudes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a closed-loop feedback mechanism where sensor signals detect user input characteristics, the control unit analyzes these characteristics, and adjusts subsequent haptic feedback intensity accordingly. This feedback loop enables continuous optimization of feedback perception reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If haptic feedback intensity is increased to ensure perception, then feedback reliability improves, but users with quick reaction times or low input amplitudes may be overwhelmed by excessive intensity

Engineering Contradiction:
Improvefeedback perception reliabilityVSAvoidoverwhelming feedback intensity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The haptic feedback intensity is customized for each user based on their individual input characteristics. Instead of applying uniform intensity to all users, the system adapts the feedback quality locally to match each user's reaction time and input amplitude profile, ensuring optimal perception without overwhelming any individual user.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the parameters of haptic feedback signals based on detected user characteristics. By measuring reaction times and input amplitudes, the control unit adjusts signal intensity parameters to achieve reliable perception while avoiding excessive intensity for sensitive users.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the system adapts to individual user characteristics, then feedback usability improves, but the device complexity increases due to additional sensing and control requirements

Engineering Contradiction:
Improvefeedback usabilityVSAvoidsensing and control complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control unit performs multiple functions: it generates haptic feedback signals, detects sensor signals, analyzes user input characteristics, and adjusts feedback intensity. By consolidating these functions in a single control unit, the system achieves user adaptation without proportionally increasing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system automatically detects and adapts to each user's characteristics without requiring manual configuration or calibration. The control unit self-adjusts feedback parameters based on real-time sensor data, eliminating the need for complex setup procedures or user intervention.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system ensures that haptic feedback is optimally perceived by each user, enhancing user interaction by automatically adapting feedback intensity to their input characteristics, thereby improving feedback reliability and usability, especially in multi-user scenarios and divided attention environments.

Implementation Method 1

an actuator connected to a control element (201) of a manual user interface (200) and is used to output a haptic feedback signal SA(t) via the control element (201) to a user

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

a sensor present in the control element (201), which detects a sensor signal Ss(t) generated by a manual input by the user into the operating element (201) as a reaction to the output feedback signal SA(t)

Methodology Applied
Scientific EffectSensor detection:

Data Source

PatentEP3387514B1Haptic feedback in a user interface
Publication Date: 2019.06.26 MERCEDES BENZ GROUP AG
  • EP3387514B1 patent drawingFigure 1
  • EP3387514B1 patent drawingFigure 2

AI summary

The invention relates to a user interface (200) and a method for controlling an actuator (202) that is connected to an operating element (201) of a manual user interface (200), and for outputting a haptic feedback signal SA(t) to a user via the operating element (201). A sensor (203) is provided in the operating element (201), which detects a sensor signal SS(t) that is generated via a manual input of the user in reaction to the output feedback signal SA(t). The method according to the invention is characterised in that, after the output of a feedback signal SA(t) at time t0 via the actuator, a reaction time (RZ) of the user is determined based on the sensor signal SS(t) for t > t0 , wherein if the determined reaction time (RZ) is less than a predetermined limit value GRZ, haptic feedback signals SA(t) to be output in the future are changed in such a way that their haptically perceptible intensity is reduced, and if the determined reaction time (RZ) is greater than a predetermined limit value GRZ, haptic feedback signals SA(t) to be output in the future are changed in such a way that their haptically perceptible intensity is increased, and/or in that, after the output of a feedback signal SA(t) at time t0 via the actuator, a maximum value |SS(t)|max of the sensor signal SS(t) is determined based on the sensor signal SS(t) for t > t0, wherein if the determined maximum value |SS(t)|max is less than a predetermined limit value GSsmax, haptic feedback signals SA(t) to be output in the future are changed in such a way that their haptically perceptible intensity is reduced, and if the determined maximum value |SS(t)|max is greater than a predetermined limit value GSsmax, haptic feedback signals SA(t) to be output in the future are changed in such a way that their haptically perceptible intensity is increased.