The subject of my diploma thesis is the design and build of an Automated Guided Vehicle. The robot is able to autonomously follow a predetermined route. The route is designated by an active wire loop attached onto the floor, which is sensed by inductive sensors. The operation of the robot can be monitored and remote controlled with a LabVIEW program.
Literature study has been done before the design, where information has been collected about the structure and operation of AGVs. The design part consisted of several parts. When designing the chassis, the goal was a strong but light structure. To achieve this, it can be assembled from laser-cut PMMA sheets. During the electronics design, several area of my electronics knowledge was covered. The wire sensor is an analog circuit, the motor controller and the power supply covers power electronics, and the controller board is digital. After the design the electronics and the chassis were assembled, followed by the design and implementation of the control loops into the microcontroller. The control and other tasks of the robot are done by an STM32F401 microcontroller. Several control loops were implemented to follow the wire. Motors have a cascaded PI controller for current and speed control, the steering is done by a PD controller. The transfer functions for the current and speed controllers were made by identification, and then the controller parameters were designed according to them. The steering controller was manually tuned. Then the LabVIEW program was created to monitor important variables during operation and start the robot in automatic or manual mode. The UART communication between the robot and the computer is done through Wi-Fi. Also a simple station following task has been implemented into the robot, which stops the robot at specified distances for a set amount of time while autonomously following the wire.
The task has been fulfilled, the robot is able to autonomously follow the given track. While fulfilling the task I have gained experience in designing a complex system, and in designing and implementing control loops into a microcontroller.