Flexible Capacitor Array for High-Pressure Robot Foot Sensing

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Solution Overview

Problem

Existing mechanical sensors in robots, particularly multi-axis force sensors, are rigid and bulky, limiting their application in small spaces, while flexible sensors lack sufficient sensitivity and stability for ultra-high pressure applications, making it difficult to measure forces on a robot's foot and maintain stability during movements like walking, running, and jumping.

Innovation Solution

A flexible capacitor array with a rapid response speed, high precision, and strong impact resistance is developed, comprising a first and second flexible electrode layer, a dielectric layer, and spacer layers to form ionic double electric layer capacitors, enhancing sensitivity and stability, and allowing accurate detection of impact forces for balance control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multi-axis force sensors are used in robots, then force measurement capability is provided, but the sensors are rigid and bulky, limiting their application in small spaces

Engineering Contradiction:
Improveforce measurement capabilityVSAvoidsensor volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces traditional mechanical force sensors with a capacitive sensing system. The capacitive sensor uses electrical fields rather than mechanical contact to detect force, enabling miniaturization while maintaining measurement capability. The flexible substrate with capacitor structures allows force detection in compact forms suitable for robot feet.

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

Solution Approach 2:

The patent employs a flexible substrate with thin-film capacitor structures to create a compact, adaptable sensor that can conform to small surfaces. This flexible design replaces rigid mechanical sensors, reducing volume while preserving force measurement functionality through capacitive changes detected during compression.

Inventive Principle:
Principle #30Flexible shells and thin films

2Volume of moving object

If flexible sensors are used to miniaturize the sensor, then volume is reduced, but the pressure measurement capability and stability are insufficient for ultra-high pressure applications

Engineering Contradiction:
Improvesensor volumeVSAvoidpressure measurement capability
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent uses composite capacitor structures with multiple layers including flexible substrates, dielectric materials, and electrode patterns. This composite design enhances the sensor's ability to detect ultra-high pressure while maintaining flexibility and miniaturization. The layered structure provides both mechanical compliance and electrical sensitivity for accurate pressure measurement.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes capacitor parameters such as electrode area, spacing, and dielectric properties to enhance sensitivity for ultra-high pressure detection. By adjusting these parameters, the sensor achieves sufficient measurement precision for robot foot forces while maintaining a miniaturized flexible form factor.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If flexible sensors are used to reduce sensor size, then volume is reduced, but stability is insufficient to accurately measure pressure during robot movement

Engineering Contradiction:
Improvesensor volumeVSAvoidmeasurement stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent divides the sensing area into multiple capacitor elements arranged in arrays on the flexible substrate. This segmentation allows for spatial resolution of pressure distribution while the collective measurement provides stable overall force detection. The segmented structure compensates for local deformations, maintaining measurement stability during dynamic robot movement.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If traditional sensors are used for force detection, then force measurement is possible, but it is difficult to calculate zero torque points and construct dynamic balance controllers for stable movement

Engineering Contradiction:
Improveforce detection capabilityVSAvoidbalance control system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent's capacitive sensor array provides multi-functional capability by simultaneously measuring force magnitude, direction, and distribution across the foot surface. This rich data set enables comprehensive balance control algorithms to calculate zero torque points and construct dynamic balance controllers, reducing the need for separate specialized sensors and simplifying the overall control system.

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

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 flexible capacitor array enables precise detection of impact forces, facilitating balance control and stability in robot movements by calculating zero torque points and constructing dynamic balance controllers, improving movement stability and adaptability to complex environments.

Implementation Method 1

A flexible capacitor array with a rapid response speed, high precision, and strong impact resistance is developed, comprising a first and second flexible electrode layer, a dielectric layer, and spacer layers to form ionic double electric layer capacitors

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

spacer layers to form ionic double electric layer capacitors, enhancing sensitivity and stability

Methodology Applied
Scientific EffectIonic double electric layer:

Data Source

PatentEP4019920B1Flexible capacitor array and preparation method therefor, capacitor array detection system, and robot
Publication Date: 2025.11.12 TENCENT TECHNOLOGY (SHENZHEN) CO LTD
  • EP4019920B1 patent drawingFigure 1~2A
  • EP4019920B1 patent drawingFigure 2B~2C
  • EP4019920B1 patent drawingFigure 2D~3A

AI summary

A flexible capacitor array (20), comprising: a first flexible electrode layer (201), a first electrode array (2012) being provided thereon; a second flexible electrode layer (202), a second electrode array (2022) provided opposite the first electrode array being provided thereon; and a spacer layer (204) and a dielectric layer (203), the spacer layer and the dielectric layer being provided between each electrode pair provided opposite each other in the first electrode array and the second electrode array, and each unit capacitor of the flexible capacitor array comprising an electrode pair, the spacer layer and the dielectric layer. Also disclosed are a preparation method for the flexible capacitor array, a capacitor array detection system, and a robot. The flexible capacitor array realizes the flexibility, high sensing density and high sensitivity of a mechanical sensing system by combining the flexible electrode layers and the dielectric layer, and improves the stability of the flexible capacitor array while achieving high sensitivity by means of the spacer layer, so that the flexible capacitor array as a whole exhibits flexibility and greatly improves the sensitivity, stability, and ability to withstand high pressure of a pressure sensing system. The motion balance control of the robot can be performed on the basis of the result of the capacitor array detection system.