Robot Arm Parameter Estimation for Precise Joint Calibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Robots lack the sophistication to accurately and precisely execute complex tasks due to inadequate calibration, which is essential for mimicking human-like interactions and movements, especially in environments like warehouses where precise object handling is required.

Innovation Solution

A computing system that communicates with a robot arm to perform calibration by selecting specific joints or segments, generating movement commands, and using sensor data to estimate physical properties such as friction and center of mass, allowing for more accurate control and trajectory planning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If robot calibration is performed using traditional methods, then the robot can execute basic tasks, but the accuracy and precision of complex tasks remain insufficient

Engineering Contradiction:
Improvemovement accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration process is segmented into distinct phases: selecting specific joints or arm segments for calibration, generating targeted movement commands for selected components, collecting sensor data from specific components, and estimating physical properties for individual segments. This segmentation allows the system to focus computational resources on critical calibration tasks rather than calibrating the entire robot system simultaneously, thereby improving measurement precision without proportionally increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by pre-selecting joints or arm segments that require calibration before executing the full calibration sequence. Movement commands are generated in advance based on predefined calibration trajectories, and sensor data collection is prepared beforehand. This preliminary preparation ensures that when calibration is executed, the robot is already positioned and configured optimally, improving measurement accuracy while reducing the complexity of real-time calibration coordination.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the robot arm moves faster to improve productivity, then task completion time decreases, but measurement noise increases reducing control precision

Engineering Contradiction:
Improvetask execution speedVSAvoidmovement measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically changes operational parameters based on the calibration stage and task requirements. During calibration phases, the robot arm operates at controlled speeds that optimize measurement accuracy for estimating physical properties. During actual task execution, the system adjusts speed parameters to achieve desired productivity levels while applying the calibrated parameters to maintain control precision. This parameter adaptation allows the system to optimize for either speed or precision depending on the operational context.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If comprehensive sensor data collection is performed to improve calibration accuracy, then measurement precision increases, but data processing time and computational load increase

Engineering Contradiction:
Improveparameter estimation accuracyVSAvoidcalibration processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts and focuses on collecting sensor data from specifically selected joints or arm segments that are most critical for the calibration task at hand, rather than collecting comprehensive data from all robot components simultaneously. By extracting only the necessary data subsets, the system achieves sufficient calibration accuracy for the selected components while significantly reducing the overall data processing time and computational load. This selective data extraction approach maintains measurement precision for critical parameters without the overhead of processing entire robot system data.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11691285B2Method and computing system for estimating parameter for robot operation
Publication Date: 2023.07.04 MUJIN INC
  • US11691285B2 patent drawing
  • US11691285B2 patent drawing
  • US11691285B2 patent drawing

AI summary

A computing system and method for estimating friction and/or center of mass (CoM) are presented. The system may perform the method by selecting at least one of: (i) a first joint from among a plurality of joints, or (ii) a first arm segment from among a plurality of arm segments. The computing system further outputs a set of one or more movement commands for causing robot arm movement that includes relative movement between the first arm segment and a second arm segment via the first joint, and receiving a set of actuation data and a set of movement data associated with the first joint or the first arm segment. The computing system further determines, based on the set of actuation data and the set of movement data, at least one of: (i) a friction parameter estimate or (ii) a CoM estimate.