Reference Coordinate Systems

The base coordinate system is the fundamental coordinate system of industrial robots, representing the robot’s absolute position in space. If the industrial robot is installed on the ground, this coordinate system is mostly located on the base, with the origin at the center of the robot base. The XY plane coincides with the base plane, typically with the X-axis direction pointing toward the robot’s "back" direction, and the Z-axis direction pointing vertically upward. If the robot is mounted inverted, the Z-axis points downward.

Coordinate Definition:

The base coordinate system serves as the absolute reference frame for the robot workspace, with all positions and orientations defined relative to the base coordinate system. In simple applications, users can directly program robot actions in the base coordinate system.

Generally, the world coordinate system and base coordinate system coincide. If the robot is installed on the ground, programming based on the base coordinate system is very simple. However, in certain special cases, using a world coordinate system can bring greater convenience.

Application Scenarios:

User coordinate systems are defined based on the world coordinate system. Industrial robot applications typically involve workbenches or fixtures. User coordinate systems are designed to handle different fixtures or workbenches with different positions and orientations, typically defining an independent user coordinate system for each fixture or workbench.

By establishing user coordinate systems, when workpiece or workbench positions change, robot programs can quickly adapt by adjusting user coordinate system parameters without rewriting entire programs, greatly improving programming flexibility and efficiency.

The flange coordinate system is a coordinate system fixed at robot factory delivery and cannot be changed. The origin is located at the center of the six-axis robot flange, the XY plane coincides with the flange plane, and the Z-axis direction extends perpendicularly outward from the flange.

The flange coordinate system serves as the reference frame for robot end effectors, with all tool coordinate systems defined based on the flange coordinate system. This coordinate system provides a unified reference standard for various tools mounted on the flange.

Coordinate Definition:

The tool coordinate system is a coordinate system established with the Tool Center Point (TCP) as origin, describing the positional relationship of robot end tools relative to the flange coordinate system. The Tool Center Point is the origin of the tool coordinate system and is one of the key technologies in industrial robotics.

Tool coordinate system parameters can be obtained through robot teaching or by precisely measuring tool dimensions. TCP setup facilitates programming and program adjustment: when the robot moves, the position, path, precision, and speed commonly referred to for the robot actually refer to the TCP’s position, path, precision, and speed.

The tool coordinate system enables robots to precisely control tool endpoint positions rather than flange center, which is crucial for precision operations such as welding, assembly, and grasping.

The camera coordinate system is fundamental to robot vision systems, established with the camera optical center as origin. Its function is to convert image information captured by cameras into three-dimensional spatial coordinate information, providing basic data for robot vision positioning and recognition.

Coordinate Definition:

The calibration board coordinate system is the standard reference coordinate system during hand-eye calibration processes. The calibration board coordinate system provides standard geometric references for establishing transformation relationships between camera coordinate systems and robot coordinate systems, serving as an important foundation for achieving precise hand-eye calibration.

Coordinate Definition:

The model coordinate system is the coordinate system for three-dimensional model data, typically related to point cloud data. Initially consistent with camera coordinate system, after alignment the origin moves to point cloud center, with coordinate axes defined referencing model bounding box directions.

In three-dimensional vision recognition and positioning, the model coordinate system provides coordinate correspondence between models and actual workpieces, enabling robots to accurately position and operate workpieces based on vision recognition results.

The container coordinate system is a coordinate system established with containers or workbenches as reference, facilitating batch processing of workpieces. The origin is typically selected at a corner of the container, with coordinate axes established along container edge directions, aimed at simplifying position calculations for batch workpieces.

In automated production, container coordinate systems facilitate orderly operations on multiple workpieces in containers. Through regular coordinate offsets, each workpiece position in containers can be accessed sequentially without individually teaching each workpiece position.

The workpiece coordinate system describes the positional relationship of workpieces relative to the base coordinate system, using the base coordinate system as reference point to describe workpiece (or workbench) positional relationships relative to robot base. When workpiece positions change, quick adaptation is achieved by adjusting workpiece coordinate system parameters.

The main function of workpiece coordinate systems is to achieve robot program flexibility. When workpiece positions change, only workpiece coordinate system parameters need adjustment without modifying entire program point data, greatly improving production efficiency and program reusability.