Orange slider performs planar motion without rotation.
Its upper surface is kept always horizontal thanks to a parallelogram mechanism driven by a motor. Distances between two revolute joints on the blue conrod and between two revolute joints of the base are equal.
Motion of the orange slider along sliding joint on the blue conrod is controlled by pink actuator.
Disadvantages:
The actuator is not base-mounted.
The calculation of trajectory of a point on the orange slider can not be based on polar coordinate system.