lineardeltakins − Kinematics for a linear delta robot
The kinematics model is appropriate for a rostock/kossel-style design with three joints arranged in an equilateral triangle. (0,0) is always the center of the working volume. Joint 0 is at (0,R) and subsequent joints are 120 degrees clockwise (note that joint 0 is not at zero radians). The length of the arm is L.
Joints 0-2 are the linear carriages. Axes ABC and UVW are passed through unchanged in joints 3-8, so that e.g., A can still be used to control an extruder.
lineardeltakins.R float in
Effective diameter of the platform.
R is different than the distance from the center of the table to the center of the belt/smooth rod/extrusion that the joints ride on. In RepRap delta parlance, R is DELTA_RADIUS which is computed as
DELTA_SMOOTH_ROD_OFFSET - DELTA_EFFECTOR_OFFSET - DELTA_CARRIAGE_OFFSET.
lineardeltakins.L float in
Length of the rod connecting the carriage to the effector. In RepRap delta parlance, L is DELTA_DIAGONAL_ROD
The R and L values can be adjusted while LinuxCNC is running. However, doing so while in coordinated mode will lead to a step change in joint position, which generally will trigger a following error if in joint mode with machine on.