Machinery TwinDelta manipulator
A 3-DOF parallel robot with analytic forward and inverse kinematics.
The Delta manipulator models the standard three-arm Clavel parallel robot used for fast pick-and-place machinery. Three rotary motors on a fixed base drive a moving platform with three translational degrees of freedom and fixed orientation.
Geometry
| Parameter | Meaning |
|---|---|
| Base radius | Base center to each motor pivot |
| Platform radius | Tool-center point (TCP) to each platform pivot |
| Upper-arm length | Motor pivot to elbow |
| Lower-arm length | Elbow to platform pivot |
The Delta's local base is the XY plane and its normal working volume extends along local -Z. New Delta objects are rotated X = -90 degrees in a Y-up project, so the platform hangs below the fixed base.
Two control modes
Joint space binds motor A, B, and C angles in degrees. The analytic forward kinematics computes all six arm segments and the platform position. Use this to mirror encoder feedback from a real controller.
Workspace binds the TCP X, Y, and Z position. The analytic inverse kinematics computes the three motor angles. Choose a global workspace frame for scene/world coordinates or local for coordinates relative to the Delta base.
Reachability
A Cartesian target must lie inside the physical workspace defined by the four geometry values. If a target has no real solution, the scene holds the last valid robot pose instead of displaying broken geometry.
Models and attachments
The object has seven moving model slots: upper and lower arms A, B, and C, plus the moving platform. Author arm models centered between their joints with their long axis along +X; author the platform at the TCP in local XY. Each slot is also an attachment frame, so tooling can ride directly on the platform.
State machines and derived signals
A Move Robot action can synchronize all three motor targets or an XYZ workspace target on one trapezoidal path. Variables can also read the solved motor angles and TCP coordinates through a Kinematics source, which is useful for tracing commands against the displayed mechanism pose.