Piezoelectric Transducer Arrays for Haptic Feedback and Position Tracking

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Solution Overview

Problem

Individuals may struggle to perform specific body movements due to lack of motivation, experience, or training, particularly in activities requiring precise postures or positions, and existing haptic technologies do not effectively provide real-time guidance for such movements.

Innovation Solution

A wearable system using piezoelectric transducers operating in dual frequency mode, combining low frequency haptic feedback and ultrasonic localization, enables real-time tracking of body positions and posture, providing haptic guidance through transducer arrays on clothing or the environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single piezoelectric transducer operates at low frequency for haptic feedback, then haptic feedback is provided, but real-time position tracking capability is lost

Engineering Contradiction:
Improveposition tracking precisionVSAvoidhaptic feedback quality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The piezoelectric transducer is designed to perform multiple functions: generating haptic feedback at low frequencies (10-2000Hz) and emitting ultrasonic signals at high frequencies (15-50kHz) for position tracking. This multi-functional design allows a single device to provide both tactile feedback and spatial localization capabilities without requiring separate transducers for each function.

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

Solution Approach 2:

The transducer alternates between operating at low frequency for haptic feedback and high frequency for position tracking in periodic cycles. This time-division multiplexing approach ensures that haptic feedback is provided when needed while periodically updating position information, resolving the conflict between continuous haptic output and intermittent tracking requirements.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If ultrasonic frequency is used for position tracking, then position data is obtained, but haptic feedback quality is degraded

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidhaptic feedback reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system implements periodic switching between ultrasonic frequency operation for position tracking and low frequency operation for haptic feedback. By carefully timing these operations, the system ensures that ultrasonic bursts for measurement do not overlap with haptic feedback delivery, maintaining haptic reliability while achieving accurate position measurements during designated tracking intervals.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control module acts as an intermediary that coordinates between position tracking requirements and haptic feedback delivery. It manages the timing and sequencing of ultrasonic emissions versus haptic signal generation, ensuring that position measurement activities do not interfere with the reliability of haptic feedback to the user.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple piezoelectric transducers are used for position tracking, then position data is obtained, but system complexity increases

Engineering Contradiction:
Improveposition tracking precisionVSAvoidtransducer array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each piezoelectric transducer in the array is designed to be multi-functional, capable of both haptic feedback generation and ultrasonic signal emission for position tracking. This universality reduces overall system complexity compared to having separate specialized transducers for each function, as each element in the array contributes to both objectives simultaneously or alternately.

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

Solution Approach 2:

The position tracking function is segmented across multiple transducers in the array, with each transducer contributing partial position information. The control module integrates data from multiple transducers to calculate overall position, distributing the measurement burden across several simple elements rather than requiring a single complex transducer.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If low frequency signals are used for haptic feedback, then tactile sensation is provided, but position tracking capability is reduced

Engineering Contradiction:
Improvehaptic feedback qualityVSAvoidposition tracking precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system periodically switches between low frequency operation for haptic feedback and high frequency operation for position tracking. During haptic feedback phases, low frequency signals provide tactile sensation to the user. During tracking phases, the same transducers emit ultrasonic signals for position measurement. This periodic alternation ensures both functions receive adequate resource allocation without continuous interference.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

While the transducer alternates between haptic feedback and position tracking modes, the system maintains continuous useful action through rapid switching. The control module ensures that position tracking updates occur frequently enough to maintain accurate position knowledge, while haptic feedback is delivered continuously during its designated phases, creating the perception of continuous operation for both functions.

Inventive Principle:
Principle #20Continuity of useful action

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

Enables real-time haptic feedback to guide users in achieving desired postures and movements, enhancing learning and performance in activities like sports, gaming, and performing arts, while minimizing interference with haptic feedback.

Implementation Method 1

a piezoelectric transducer configured to generate a first signal at a first frequency, which is a haptic feedback signal

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

configured to generate a second signal at a second frequency, which is above the audible frequency range

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

The control module can use respective time stamps from the raw data representing the times of transmission of second signals from respective piezoelectric transducers of the second piezoelectric transducer array to determine a time of flight of the second signals

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3716017B1Haptic feedback
Publication Date: 2025.06.25 NOKIA TECHNOLOGIES OY
  • EP3716017B1 patent drawingFigure 1
  • EP3716017B1 patent drawingFigure 2
  • EP3716017B1 patent drawingFigure 3

AI summary

A system for providing haptic feedback to a user, the system comprising a first piezoelectric transducer array comprising multiple piezoelectric transducers worn by the user, respective ones of which being configured to generate a second signal at a second frequency (ultrasonic sound), and at least one of which being configured to generate a first signal at a first frequency (about 200 Hz haptic feedback signal), and a second piezoelectric transducer array comprising multiple piezoelectric transducers, respective ones of which configured to receive the second signal, which is a signal to track the user motion, and at least one of which configured to generate a third signal to initiate generation of the first signal, a haptic feedback signal, at the said at least one piezoelectric transducer of the first piezoelectric transducer array, the first frequency suitable for providing a haptic feedback signal for a user. placed on the user's body and at the same time exchanging ultrasonic sound information between the transducers allowing for tracking of user movements in order to provide or trigger associated haptic feedback to the user for exercising and learning purposes.