An FPGA-based controller design for a 5 d.o.f. robot for repairing hydraulic turbine blades

Renato C. Sampaio¹; José Mauricio Motta¹; Carlos H. Llanos¹

¹ UnB

doi:10.20906/CPS/COB-2015-0935

Resumo

This paper presents the design of a FPGA-based embedded system for control and monitoring a robot which has a spherical topology with 5 d.o.f., electric stepper and DC servo motors. The embedded robot controller has been developed using a hardware/software codesign approach, in which a soft- DE2-115 development kit, together with several hardware modules such as timer, JTAG, I/O, memory and RS-232, USB, and connected via the Avalon bus. Additionally, several specific hardware modules have been designed in order to provide signals to the motor drivers and measure encoder signals. Otherwise, a power-board has been designed to provide an opto-coupled connection to the first three motor drivers and their respective encoders. Finally, the control system also provides a RS-232 interface to the pan-tilt, which provides the last two degrees of freedom to the manipulator. The robot inverse kinematics was described in C language, running in the NIOS II soft-processor, which receives spatial coordinate points from two processes running on a PC via an USB interface. These process are responsible for processing the surface using specific image processing techniques based on a LASER sensor. The another process generates the trajectories that the robot will follow during the welding task. The embedded software guarantees a suitable synchronization among all motors of the manipulator by using a Finite State Machine (FSM)

Palavras-chave: Welding robots; FPGA; Reparing processes