Robot Motion Control for Human Pinch Risk Near Surrounding Objects
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Solution Overview
Problem
Conventional robot control methods fail to consider surrounding objects when preventing interference between humans and robots, leading to a risk of humans being pinched between the robot and surrounding objects.
Innovation Solution
A robot control device that includes an image recognition processing unit, a robot control processing unit, and a monitoring processing unit, which recognizes human and robot positions using vision sensors, determines potential pinching scenarios, and adjusts robot motion to prevent contact with surrounding objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the robot motion is restricted based only on distance between worker and robot from image information, then interference prevention is simplified, but the possibility of pinching between robot and surrounding object is not considered
Solution Approach 1:
The monitoring area is divided into multiple regions (first monitoring area closer to robot, second monitoring area farther from robot) with different safety levels. The control system applies different motion restrictions based on which region the worker is in, allowing simplified control when worker is in safer regions while maintaining high safety when worker is in critical regions.
Solution Approach 2:
The system performs preliminary presumption of interference modes before actual interference occurs. By analyzing the worker's position, motion direction, and velocity in advance, the system determines potential pinching risks with surrounding objects and proactively restricts robot motion to prevent the harmful event.
2Reliability
If the robot motion is slowed down to prevent interference, then safety is improved, but productivity decreases
Solution Approach 1:
The control system applies motion restrictions locally and selectively rather than globally. When a worker is detected in the first monitoring area with a pinching risk, motion restriction is applied only in the specific direction toward the worker, while other directions maintain normal operation speed, thus preserving productivity where safe.
Solution Approach 2:
The robot motion control is dynamic rather than static. The system continuously monitors worker position and adjusts robot velocity in real-time based on the current situation. Motion restriction is applied dynamically only when necessary (when worker enters critical zone with potential pinching risk), allowing the robot to operate at full speed during safe periods.
3Reliability
If comprehensive monitoring of surrounding objects and worker position is implemented, then pinching prevention is improved, but device complexity increases
Solution Approach 1:
The image recognition device performs multiple functions using a single system: it detects worker position, determines worker motion direction, calculates distance to robot, and identifies potential pinching risks with surrounding objects. This multi-functionality reduces the need for separate sensors and processing systems for each monitoring task.
Solution Approach 2:
The system uses two-dimensional image information from the image recognition device and transforms it into three-dimensional spatial understanding by calculating real distances using known camera parameters and perspective geometry. This allows accurate depth perception and pinching risk assessment without adding complex 3D sensing hardware.
Data Source
AI summary
A robot control device controls a robot. The robot control device includes an image recognition processing unit, a robot control processing unit, and a monitoring processing unit. The image recognition processing unit recognizes first information on the basis of measurement data in a monitoring area obtained from a vision sensor, the first information being information about a human present in the monitoring area. The robot control processing unit controls the motion of the robot in accordance with a motion program for moving the robot. On the basis of surrounding object data and the first information obtained from the image recognition processing unit, the monitoring processing unit determines a possibility of pinching of the human between the robot and a surrounding object. The surrounding object data is data indicating three-dimensional disposition states of the robot and a surrounding object that is an object other than the robot in the monitoring area.