Robot Controller Deformation Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Industrial robots face inaccuracies due to deformations caused by gravity and manufacturing tolerances, which result in deviations between the actual and target positions of the tool center point, especially when connected to elastic fastening devices.
Innovation Solution
An improved robot controller that incorporates an absolutely accurate model accounting for the deformations of both the industrial robot and its fastening device, using parameters such as stiffness, mass, and gravity to compensate for these deviations, allowing for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the robot uses a simple kinematic model for control, then the device complexity is reduced, but the positioning accuracy deteriorates due to deformations from gravity and manufacturing tolerances
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing compensation values for deformations in a lookup table before operation. The absolutely accurate model computes compensation values for various axis positions and gravity conditions in advance, allowing the controller to quickly retrieve and apply appropriate corrections during runtime without performing complex real-time calculations, thus maintaining low device complexity while achieving high positioning accuracy
Solution Approach 2:
The patent changes the control parameters by introducing an absolutely accurate model that incorporates deformation parameters (stiffness, mass, gravity) alongside the standard kinematic parameters. This model transforms the control approach from using only ideal geometric parameters to using corrected parameters that account for elastic deformations, thereby improving positioning accuracy without significantly increasing device complexity through the use of lookup tables
2Measurement precision
If the robot controller incorporates an absolutely accurate model accounting for deformations, then the positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The absolutely accurate model computes and stores compensation values in advance for various operating conditions (axis positions, gravity effects) in lookup tables. During actual operation, the controller only needs to retrieve pre-computed compensation values based on current axis positions, avoiding the need for complex real-time deformation calculations and keeping the runtime controller complexity low while maintaining high positioning accuracy
Solution Approach 2:
The patent segments the control system into two parts: an offline model generation stage where the absolutely accurate model is computed and stored, and an online control stage where pre-computed compensation values are retrieved and applied. This segmentation moves the computationally intensive model generation to an offline phase, allowing the online controller to remain relatively simple while still benefiting from high-precision compensation
3Measurement precision
If the fastening device is made more rigid to reduce deformation, then the positioning accuracy is improved, but the ease of manufacture deteriorates due to stricter tolerance requirements
Solution Approach 1:
The patent replaces the mechanical solution of increasing fastening device rigidity with a computational approach. Instead of making the fastening device mechanically stiffer (which would require tighter manufacturing tolerances and increase manufacturing difficulty), the system uses an absolutely accurate model to calculate and compensate for deformations software-based, maintaining positioning accuracy while allowing more relaxed manufacturing tolerances and easier assembly
Solution Approach 2:
The patent changes the approach from modifying physical parameters (increasing rigidity) to modifying control parameters (adding deformation compensation). By incorporating stiffness, mass, and gravity parameters into the absolutely accurate model, the system compensates for deformations through parameter-based calculations rather than requiring physically rigid components, thereby improving positioning accuracy without compromising ease of manufacture
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 solution enhances the accuracy of industrial robots by accounting for the deformations of both the robot and its fastening device, reducing the difference between actual and target positions, thereby improving the overall control and regulation of the robot's movements.
Implementation Method 1
elasticities in the joints and/or structural components of the robot can be the cause of errors in the absolute accuracy of the robot
Implementation Method 2
Due to gravity and manufacturing tolerances, the actual position of the so-called tool center point (TCP) approached due to programming can deviate from its target position
Implementation Method 3
gravity causes a moment that deforms the elasticity c, causing the axis angle that actually occurs q A not equal to the target axis angle q should
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The robot control device has a precision model for an industrial robot (R) connected to at least one component (40). The robot has at least one axis. The precision model reproduces the deformation of the industrial robot and the deformation of the component on the basis of the setting of the axis or axes and of gravity.