What is the practical implication of inaccurate DH parameter values in robot forward kinematics calculations?

The practical implication of inaccurate Denavit-Hartenberg (DH) parameter values in robot forward kinematics calculations is that the calculated end-effector position and orientation will deviate from the actual physical position and orientation. DH parameters are a standardized way to represent the geometric relationships between the links of a robot arm. Forward kinematics is the process of calculating the end-effector pose (position and orientation) given the joint angles and the DH parameters. Inaccurate DH parameters, which describe link lengths, link twists, joint offsets, and joint angles, lead to errors in the transformation matrices that are used to map joint space to Cartesian space (the 3D space where the robot operates). This means that when the robot is commanded to move to a specific Cartesian coordinate based on its internal model, it will not reach that exact location in the real world. For example, if the link length parameter is slightly off, the robot might consistently undershoot or overshoot its target position. Similarly, inaccuracies in the joint offset or link twist parameters will cause errors in the orientation of the end-effector. These errors can accumulate through the robot's kinematic chain, resulting in significant deviations, especially for robots with many joints. In practical terms, inaccurate DH parameters lead to problems with precision tasks like assembly, welding, or machining, where accurate positioning is essential. The robot might fail to grasp an object correctly, miss a weld point, or create parts that are out of tolerance. The robot's perceived location and actual location differ due to an imprecise model.