Robot Surface Contact Sensing for Command and Safety Control

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Solution Overview

Problem

Current robotic systems, particularly collaborative robots, face limitations in extending the field of interactivity and registering possible commands from contact with control objects without using additional sensors, while ensuring safety and optimal operation.

Innovation Solution

A method that detects contact and the extent of contact between control objects and a robot's surface, using existing capacitive sensors to generate varied commands, incorporating torque measurements for validation and force calculation, allowing for increased interactivity and command registration without additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors are used to detect contact extent and force, then measurement precision and interactivity are improved, but device complexity and cost increase

Engineering Contradiction:
Improvecontact extent detectionVSAvoidsensor system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes existing capacitive sensors perform multiple functions: detecting contact presence, measuring contact extent (area), and estimating contact force. By analyzing capacitance variations and their temporal derivatives, the system extracts multiple parameters from a single sensor type, eliminating the need for additional force sensors or pressure sensors.

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

Solution Approach 2:

The system uses the robot's existing capacitive sensor infrastructure to serve the additional function of contact extent and force measurement. The capacitive sensors, originally designed for simple contact detection, are repurposed to provide comprehensive contact characterization through signal processing of capacitance values and their rates of change.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If contact extent information is processed to generate varied commands, then adaptability and interactivity are improved, but control system complexity increases

Engineering Contradiction:
Improvecommand registrationVSAvoidcontrol system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system dynamically adapts robot behavior based on contact extent measurements. Different contact areas trigger different command responses: small contacts may initiate gentle interaction modes, while large contacts trigger emergency stops or significant motion adjustments. The system continuously monitors capacitance changes and adjusts control parameters in real-time based on the evolving contact state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes control parameters based on contact extent measurements. By analyzing the magnitude of capacitance variations, the system adjusts operational parameters such as robot speed, acceleration, and interaction force thresholds. This allows a single control system to handle multiple interaction scenarios without requiring separate control logic for each case.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If capacitive sensors are used for contact detection, then ease of manufacture is improved, but measurement precision for force and extent is limited

Engineering Contradiction:
Improvesensor implementationVSAvoidcontact force
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical force sensors with capacitive sensing. Instead of using complex force measurement devices, the system uses electrical capacitance measurements to infer mechanical contact properties. The capacitance changes caused by contact are processed to estimate force magnitude, providing a simpler, more manufacturable solution while maintaining adequate measurement precision for collaborative robot applications.

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

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 field of interactivity and command registration by utilizing existing sensors to determine contact extent and force, improving safety and operational efficiency in robotic systems.

Implementation Method 1

at least one position sensor comprises at least one capacitive measuring electrode arranged to provide a measurement signal relative to a coupling capacitance between the measuring electrode and the object

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3846982B1Method and device for controlling a robot, and robot provided with such a device
Publication Date: 2023.11.08 FOGALE SENSORS
  • EP3846982B1 patent drawingFigure 1~2
  • EP3846982B1 patent drawingFigure 3~4b
  • EP3846982B1 patent drawingFigure 5~7

AI summary

The invention relates to a method (100) for controlling a robot, comprising the following steps: - detecting (102) at least one contact between an object and the robot by means of at least one sensor, referred to as the position sensor, fitted to said robot; - determining (104), for said at least one contact, a contact range according to a measurement of the at least one position sensor; and - executing (106) a robot control command taking into account information relating to said contact range. The invention also relates to a device and a robot implementing the method.