Motion Control of a Cable Robotic LED Light Fixture with IoT Connectivity**

This paper presents development of a 2-degrees-of-freedom cable-suspended motion mechanism for a light-emitting diode (LED) horticultural light fixture with Internet-of-Things (IoT) connectivity. The proposed light motion mech-anism is intended to provide uniform light distribution on the plant canopy to optimize growth through proper position and orientation control with set-points determined, for instance, by natural light conditions and based on the plant's growth stage. The setup was built to have two main features: (i) Motion control of fixture's height and roll angle; and (ii) IoT connectivity. The motion control unit consists of a trajectory planner, which receives the control set-points via an IoT module, and embedded firmware. The reference values are obtained, for instance, through a light recipe database that provide the required data from a remote digital twin computer. The desired motion trajectory is obtained based on the dynamics of the system such that the tension of cables remain positive during the motion. To this end, conditions are obtained for the desired motion trajectory to guarantee positive tension in the cables which is utilized in the trajectory tracking controller. A hardware prototype was built to evaluate performance of the system which is presented along with experimental results.