3D Robot Workspace Sensing for Self-Object Removal
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Solution Overview
Problem
Existing proximity sensors using electrostatic capacitance methods in collaborative robots mistakenly detect robot peripherals as interfering objects, leading to restricted movement and reduced production efficiency.
Innovation Solution
A robot system equipped with a three-dimensional sensor that photographs a work space, generates a virtual robot model, and distinguishes between the robot and interfering objects by removing self-representing data points, allowing for accurate detection of approaching objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrostatic capacitance proximity sensor is used to detect interfering objects, then the robot can detect approaching objects before contact occurs, but the robot mistakenly detects its own peripherals as interfering objects
Solution Approach 1:
The detection space is segmented into robot-owned space and external space by creating a virtual robot model that represents the robot's own perimeter. The system segments the point cloud data into points belonging to the robot model and points representing external objects, allowing differentiated handling of each segment.
Solution Approach 2:
A virtual robot model (copy of the robot's geometric representation) is created using link parameters and joint angles. This virtual model serves as a reference to identify and exclude points corresponding to the robot's own peripherals from the sensor data, preventing false detection.
2Reliability
If the robot detects its peripherals as interfering objects, then safety detection is enhanced, but the robot's movement range is restricted and production efficiency drops
Solution Approach 1:
Points representing the robot's own peripherals are extracted and removed from the set of detected interfering objects. The system identifies points that belong to the virtual robot model and excludes them from safety detection considerations, allowing the robot to move freely within its designated workspace without false restrictions.
3Measurement precision
If the robot uses a three-dimensional sensor to photographically scan the workspace, then the robot can accurately detect interfering objects, but the system complexity increases
Solution Approach 1:
Instead of using complex hardware modifications, the system creates a software-based virtual robot model that replicates the robot's geometric structure. This virtual copy enables precise differentiation between robot and external objects using standard three-dimensional sensor data and point cloud processing techniques.
Data Source
AI summary
A processor of a controller executes processes of storing values of link parameters of a robot in a memory, collecting data points, which include a set of coordinates that set forth positions of surface points in a surface of an object found in a space, collecting a contemporaneous state of joint angles of respective joints of a robot arm, generating a virtual robot model that simulate a contemporaneous posture of the robot, based on the link parameters and the joint angles, removing at least data points representing the robot from the collected data points by using the virtual robot model and presenting the remaining data points as a representation of the interfering object, which is defined by a set of coordinates that set forth positions of surface points of an interfering object, and calculating a distance between the potentially interfering object and the robot by using the representation of the potentially interfering object and the virtual robot model and determining whether the potentially interfering object is approaching the robot or not, based on the calculated distance between the potentially interfering object and the robot.