Manipulator Risk Control Using Trajectory and Velocity Switching
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Solution Overview
Problem
Current cooperative work systems between humans and robots in factory automation face high computing loads due to frequent changes in robot trajectories to avoid interference, particularly when interacting with humans.
Innovation Solution
A control apparatus that calculates a risk value of interference and generates commands to adjust the robot's trajectory or velocity based on predefined operations, reducing computing load and interference by setting different operation groups depending on the robot's position relative to a reference point and the risk value range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trajectory of the robot is frequently changed to avoid interference with the human, then the safety and reliability of cooperative work is improved, but the computing load increases
Solution Approach 1:
The patent segments the operation space into multiple regions (first operation space and second operation space) based on the robot's position relative to a reference position. Different operation groups are assigned to different regions, allowing the system to apply computationally intensive trajectory changes only when necessary (in the first operation space) while using simpler velocity adjustments in the second operation space, thus reducing overall computing load while maintaining safety
Solution Approach 2:
The patent dynamically selects from multiple operation groups based on real-time conditions including the robot's position, velocity, and risk value. The control apparatus transitions between different operation modes (trajectory change vs. velocity reduction) depending on the operational context, optimizing the balance between safety and computing resource utilization
2Reliability
If the trajectory is changed to lower the risk value, then the interference between the manipulator and object is suppressed, but the computing load increases
Solution Approach 1:
The patent applies different control strategies to different spatial regions. In the first operation space (when closer to start position), trajectory changes are applied to reduce risk. In the second operation space (when closer to goal position), velocity reduction is preferred over trajectory changes. This localized application of control measures reduces overall computing load while maintaining interference suppression where most needed
3Productivity
If the robot operates at high velocity, then the productivity is improved, but the risk of interference with the object increases
Solution Approach 1:
The patent implements dynamic velocity adjustment based on real-time risk assessment. The control apparatus continuously evaluates the risk value and adjusts the robot's velocity accordingly - maintaining high velocity when risk is low to preserve productivity, and reducing velocity when risk increases to prevent interference, thus dynamically optimizing the trade-off between productivity and safety
Data Source
AI summary
A control apparatus generates a command for causing a manipulator to operate, based on a target operation selected in accordance with a risk value from a group. The control apparatus sets a first group when the manipulator is closer to a start position than a reference position, and sets a second group when the manipulator is closer to a goal position than the reference position. The first group includes a first operation that changes a trajectory, as an operation when the risk value is within a first range. The second group includes the first operation as an operation when the risk value is within a first subrange of the first range; and a second operation that reduces a velocity without changing the trajectory, as an operation when the risk value is within a second subrange of the first range.