Robot Manipulator Insertion With Force-Regulated Tilt Correction

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Solution Overview

Problem

Existing methods for inserting objects into object holders using robotic manipulators are complex and lack robustness, leading to low success rates and inefficiencies.

Innovation Solution

A method involving force-controlled and impedance-controlled rotational/tilting movements of the object relative to the target orientation, combined with predefined trajectories and sensor feedback for error correction, ensures precise and reliable insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If force-controlled and impedance-controlled rotational/tilting movements are implemented, then insertion success rate improves, but control complexity increases

Engineering Contradiction:
Improveinsertion success rateVSAvoidcontrol complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic control by switching between different control modes (force control and impedance control) during the insertion process. The controller adapts the control strategy based on the insertion stage, using impedance control for initial approach and force control for final engagement, thereby improving success rate while managing complexity through structured control transitions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes control parameters dynamically during insertion. Impedance parameters (stiffness, damping) are adjusted during approach, while force thresholds and limits are modified during engagement. This parameter adaptation allows the system to handle varying insertion conditions, improving reliability without requiring permanently complex control architecture

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple sensor feedback mechanisms are integrated for error correction, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveerror detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple sensor types (force sensors, position sensors, and potentially vision systems) into a unified feedback loop. The controller integrates data from these sensors to comprehensively monitor insertion status and detect errors, achieving high measurement precision through sensor fusion rather than separate independent systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements real-time feedback mechanisms where sensor data continuously informs controller decisions. Force feedback detects contact and resistance, position feedback monitors trajectory deviations, and this feedback loop enables dynamic error correction during insertion, improving precision while using feedback efficiently to avoid unnecessary system complexity

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If force-controlled and impedance-controlled movements are used, then manufacturing precision improves, but energy consumption increases

Engineering Contradiction:
Improveinsertion precisionVSAvoidrobot manipulator energy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic control adjustments during the insertion process. Impedance parameters are updated at specific intervals during approach, and force control parameters are adjusted based on detected contact events. This periodic parameter updating achieves high precision without continuous high-energy control activation, reducing overall energy consumption

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adapts control stiffness and damping parameters during insertion. Higher impedance (stiffer control) is used only when precision is critical (near final engagement), while lower impedance (more compliant control) is used during approach phases where absolute precision is less critical, thereby reducing energy consumption while maintaining manufacturing precision

Inventive Principle:
Principle #15Dynamics

4Reliability

If predefined joining trajectories are used with error correction, then reliability improves, but cycle time increases

Engineering Contradiction:
Improveinsertion reliabilityVSAvoidcycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements selective feedback-based error correction rather than continuous correction. The system monitors for specific error conditions (trajectory deviations, force anomalies) and only intervenes when errors are detected, allowing normal predefined trajectory execution to proceed at high speed without unnecessary corrections that would increase cycle time

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent allows the robot to rush through well-characterized, error-free portions of the insertion trajectory at high speed using predefined paths. Error correction and slower, more careful control are applied only when and where errors are detected, skipping unnecessary caution in safe zones and thereby maintaining reliability while minimizing cycle time

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentEP3448634B1Method for joining an object into an object receiving area using a robot manipulator
Publication Date: 2026.03.11 FRANKA EMIKA GMBH
  • EP3448634B1 patent drawingFigure 1

AI summary

The invention relates to a method for joining an object into an object receiving area using an actuator-driven robot manipulator of a robot. The robot manipulator has an effector at the distal end of the robot manipulator, said effector being designed to receive and/or grip the object. A joining trajectory T is defined for the object receiving area and the object to be joined, and a target orientation (II) of the object to be joined is defined along the joining trajectory T for locations (I) of the joining trajectory T. The method has the following steps: receiving/gripping (101) the object using the effector; moving (202) the object using the robot manipulator along the joining trajectory (III) into the object receiving area while rotating/tilting the object relative to the target orientation (II) in a force-regulated and/or impedance-regulated manner until a specified threshold condition G1 for a torque acting on the effector and/or a force acting on the effector is reached or exceeded and/or a provided force/torque signature and/or a position/speed signature on the effector is reached or exceeded which indicate(s) that the object has been completely successfully joined into the object receiving area within specified tolerances; releasing (103) the object by means of the effector; and moving (104) the effector away from the object receiving area along the exit trajectory A using the robot manipulator.