Motion control of a cable robotic LED light fixture with IoT connectivity

This thesis focuses on the development of an Internet of Things (IoT) based control scheme for a 2-degree-of-freedom Cable-Suspended Parallel Robot (CDPRS) with a Light-Emitting diodes (LED) light panel as its end effector. It is recognized that smart and intuitive monitoring and control of a greenhouses is essential for a successful yield. To this end, we developed a monitoring and control system for light fixtures that can provide a solution to non-uniformity of light distribution for plant growth aimed while enhancing light energy efficiency and lowering energy cost. Ideally, the height and angle of the light panel should adjust when a physical parameter such as plant height changes. This has not been considered in conventional non-robotic lighting systems. Furthermore, conventional non-robotic light fixture setups cannot be used to optimize light uniformity during different stages of plant growth. The aim of this thesis is to address the above problems while developing an interface for data acquisition and data visualization. The proposed setup contains of two main parts: (i) Internet of Things (IoT); and (ii) Motion control unit, which is designed to control the translational and rotational motion of the robotic light fixture. The motion control unit consists of a Trajectory Planner, which receives the controller parameters and desired reference values via proposed IoT platform and trajectory controller, which is DC motor current control or DC voltage control. The trajectory is planned based on a 5th order polynomial motion profile, which can impose kinematics constraints such as position, velocity and acceleration. The numerical simulations of the proposed trajectory generator and controllers (PID and state feedback) demonstrated accurate performance in generating the trajectories that ensure kinematic constraints are met and can be accurately tracked using a dc motor controller. A 2-degree-of-freedom Cable-Suspended Parallel Robot (CDPRS) prototype was built and used to validate the performance of the motion control unit. A digital controller was implemented using Texas Instruments CC3220S-LAUNCHXL and was programmed using Energia Integrated Development Environment (IDE) and used to control two DC motors using current control and voltage control methods for trajectory tracking. Based on experimental results, the motioned control unit successfully tracked the trajectory each time a new set point was available. The controller can perform data acquisition and data transmission to a web server with the desired frequency.