Machinery TwinFive-bar linkage
A 2-DOF planar mechanism with two motor cranks, including workspace (IK) control.
The five-bar linkage has two independently driven cranks whose coupler links meet at a shared point, the layout behind planar parallel pick-and-place robots and XY plotter mechanisms. Two degrees of freedom means the coupler point can be steered anywhere in its workspace.
Parameters
| Parameter | Meaning |
|---|---|
| Input variable 1 / 2 | The two crank angles in degrees (joint-space mode) |
| Ground length | Distance between the two fixed crank pivots |
| Links | 5 links with lengths and model slots (the fifth is the ground link, no model) |
| Solution 1 / 2 | Assembly branch per kinematic chain |
| Control mode | Joint space or Workspace |
| Workspace variables | X and Y of the coupler point (workspace mode) |
Two control modes
Joint space, you (or the PLC) provide both crank angles; the solver finds the coupler point. Use when the twin mirrors real motor positions.
Workspace, you provide the coupler point's X/Y target; the built-in inverse kinematics computes both crank angles. Use when your logic thinks in Cartesian coordinates, e.g. a state machine or cams describing a pick path in X/Y.
Solution flags
Each of the two chains independently has an elbow-up/elbow-down branch, four assemblies total. Flip solution 1 / solution 2 until the linkage matches the real machine's assembly.
Workspace limits
In workspace mode, targets outside the reachable area have no IK solution. Keep targets within the physical workspace, clamp the target variables' min/max if a driver could overshoot.