3D Sensing with SMA Actuators for Motion Compensation

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Solution Overview

Problem

Existing 3D sensing systems face challenges such as weak IR illumination in ambient light, distortion of depth maps due to device movement, and trade-offs between depth information quality and packaging constraints, particularly in mobile devices.

Innovation Solution

Utilizing shape memory alloy (SMA) actuator wires to control the position and orientation of components within 3D sensing apparatuses, compensating for movement and improving accuracy by creating interference patterns with light sources or beam splitters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If shape memory alloy actuator wires are used to control component position and orientation, then measurement precision and 3D representation accuracy are improved, but device complexity increases

Engineering Contradiction:
Improve3D representation accuracyVSAvoidactuator control system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical actuators (motors, gears, linkages) with shape memory alloy (SMA) actuator wires that use thermal expansion and contraction to produce mechanical movement. This substitution reduces the number of moving parts and control mechanisms while achieving precise position and orientation control of the emitter and receiver components, thereby improving measurement precision without proportionally increasing device complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent dimensional changes of shape memory alloy materials to control component positioning. By applying electrical current to heat the SMA wires and then allowing them to cool, the system achieves reversible expansion and contraction, enabling dynamic adjustment of component positions and orientations to maintain accurate 3D representations despite device movement

Inventive Principle:
Principle #35Parameter changes

2Reliability

If device movement is compensated for during 3D sensing, then depth map distortion is reduced, but additional control mechanisms increase device complexity

Engineering Contradiction:
Improvedepth map qualityVSAvoidmovement compensation system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where sensors detect the actual position and orientation of the device during 3D sensing operations. This feedback information is used to calculate compensation adjustments, which are then applied through the SMA actuator wires to the emitter and receiver components. This closed-loop feedback mechanism reduces depth map distortion caused by device movement while maintaining relatively simple system architecture

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary anti-action by pre-calculating and applying compensatory position adjustments to the emitter and receiver components before significant device movement occurs. The SMA actuator wires are positioned and tensioned to counteract anticipated gravitational and inertial forces, proactively preventing depth map distortion rather than reacting to it after the fact

Inventive Principle:
Principle #9Preliminary anti-action

3Measurement precision

If emitter and receiver positions are adjusted to maintain baseline, then 3D sensing accuracy is improved, but mechanical stability may be compromised

Engineering Contradiction:
Improve3D sensing accuracyVSAvoidemitter-receiver baseline stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent transitions from a static, fixed emitter-receiver baseline to a dynamic, adjustable baseline using SMA actuator wires. These wires can actively change the position and orientation of the emitter and receiver components in real-time to maintain optimal baseline geometry despite device movement or gravitational effects. This dynamic adjustment capability preserves measurement precision while adapting to changing operational conditions without compromising overall system stability

Inventive Principle:
Principle #15Dynamics

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

Enhances the accuracy and quality of 3D representations by compensating for device movement and improving resolution, despite potential interference with the emitter-receiver baseline.

Implementation Method 1

The actuation module comprises at least one shape memory alloy (SMA) actuator wire

Methodology Applied
Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 2

an emitter for emitting a plurality of waves, and a receiver for receiving reflected waves that are reflected by one or more objects in a scene being imaged

Methodology Applied
Scientific EffectElectromagnetic radiation reflection: Reflection

Data Source

PatentEP3775766B1Apparatus and methods for 3D sensing
Publication Date: 2025.08.06 CAMBRIDGE MECHATRONICS
  • EP3775766B1 patent drawingFigure 1
  • EP3775766B1 patent drawingFigure 2
  • EP3775766B1 patent drawingFigure 3

AI summary

Broadly speaking, embodiments of the present techniques provide apparatuses, systems and methods for generating a three-dimensional (3D) representation of a scene or for 3D sensing, by using shape memory alloy (SMA) actuator wires to control the position or orientation of one or more components of an apparatus used for generating the 3D representation/performing 3D sensing.