Inverse Kinematics Solution for ABB IRB120 Robot

In industrial robotics applications, inverse kinematics represents a fundamental challenge that determines how to convert end-effector positions and orientations into corresponding joint angles. The ABB IRB120, as a compact 6-axis robot, requires handling complex geometric relationships and multiple solution scenarios in its inverse kinematics computation.

Solution Methodology The IRB120 utilizes a classic 6-axis serial structure, with its inverse kinematics solution typically following these computational steps: First, the wrist center point position is extracted from the end-effector pose matrix using geometric methods to solve the first three joint angles (θ1-θ3). Then, based on the known first three axes and end-effector orientation, the remaining three joint angles (θ4-θ6) are calculated through coordinate system transformations. Due to trigonometric function multi-valued properties, multiple theoretical solutions may exist for each joint.

Orientation Selection Mechanism The program automatically filters feasible solutions through predefined joint limits and mechanical constraints: - Prioritizes solutions closest to current joint positions to minimize abrupt movements - Eliminates invalid solutions exceeding physical joint limitations - Selects appropriate solutions based on wrist flip flags (Flip/Non-Flip) according to process requirements

This solution approach ensures real-time performance while adapting to various installation configurations (floor-mounted/upside-down/tilted mounting). Practical implementations must also consider singularity avoidance and trajectory smoothing treatments. The algorithm typically involves matrix decomposition techniques and trigonometric solving functions, with implementation often utilizing coordinate transformation libraries and constraint validation modules.