Redundant Robot Admittance Control for Precise Hand Guiding
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Solution Overview
Problem
Existing methods for carrying out tasks with redundant robots, such as those with seven or more joints, often result in unsatisfactory precision during hand guiding.
Innovation Solution
The robot performs an admittance motion dependent on externally exerted force, utilizing virtual mass, stiffness, and damping in the zero space, allowing it to be hand-guided with increased precision through its redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hand guiding is used to operate redundant robots, then ease of operation is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent changes the dynamic parameters of the robot system by introducing virtual mass, virtual stiffness, and virtual damping parameters. These parameters are adjusted to create an admittance control model that allows the robot to respond naturally to manual forces while maintaining task precision. The virtual parameters enable the robot to exhibit desired dynamic behavior during hand guiding without sacrificing accuracy.
Solution Approach 2:
The patent introduces an admittance control model as an intermediary between the human operator and the robot execution system. This model acts as a mediator that translates manual forces into meaningful robot motions while filtering out unwanted disturbances. The admittance model with virtual mass, stiffness, and damping serves as a buffer that improves both operability and precision simultaneously.
2Adaptability or versatility
If redundant robots are used to carry out tasks, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent extracts and separates the task execution component from the redundant degrees of freedom by utilizing the zero space concept. The task-relevant motions are extracted and controlled precisely, while the redundant motions are handled separately through admittance control. This separation allows the robot to maintain high adaptability for various tasks while managing the complexity of redundant structures through systematic decomposition.
Solution Approach 2:
The patent segments the robot's motion space into task space and zero space, allowing independent control strategies for each. The task space handles precision positioning requirements, while the zero space accommodates redundant motions through admittance control. This segmentation reduces the overall control complexity by dividing the problem into manageable, independent sub-problems.
3Manufacturing precision
If virtual mass and stiffness are predetermined for admittance motion, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces virtual dynamic parameters (mass, stiffness, damping) that can be adjusted to optimize positioning accuracy. These parameters are incorporated into the admittance control model, allowing precise control of robot behavior during hand guiding. The virtual parameters provide a straightforward method to enhance precision without modifying the physical robot structure.
Solution Approach 2:
The patent incorporates virtual damping parameters into the admittance control model to improve stability and reduce oscillations during hand guiding. By adjusting the virtual damping coefficient, the system can achieve smoother motion and better positioning accuracy. This parameter-based approach simplifies the control design compared to more complex physical damping mechanisms.
Data Source
AI summary
A method for carrying out a predetermined task using a robot, which is redundant with regard to the task. When the task is carried out, an admittance motion that is dependent on a force exerted externally on the robot and on a predetermined virtual mass, stiffness and/or damping is carried out in the zero space.