Robot manipulator control

As the number of robot joints increases in parallel with the robot dexterity. But, control of the robot manipulator also gets difficult and complex. In this study, axis-specific and cartesian-specific robot manipulator control methods are implemented which are common well-known methods in industry. In the axis-specific part of the research, the control of a six-axes robot manipulator with a joystick is achieved with simplicity and efficiency. The designed digital circuit for controlling the robot manipulator is implemented on a general purpose FPGA board with Verilog hardware description language. The developed system comments the input signals which are taken from the joystick then generate the necessary PWM signal to drive the related axis motor. In the cartesian-specific part of the research, cartesian-specific control of a three axes robot manilpulator is implemented on a FPGA board which is developed for DSP applications. The developed system evaluates signals which are taken from the joystick, and finds the direction of motion of the manipulator, and finds the new coordinate x, y values, then sends them to the kinematic block. In the kinematic block, joint angles, which are necessary for the desired coordinates (x and y) values, are obtained by solving inverse kinematic equations of the robot. These obtained joint angles are put into direct kinematics equations of the robot to check if the final gripper position is in the work space of the manipulator. If it is in the work space of the robot manipulator then the required joint angles for achieving the desired motion are kept correctly and rapidly. Thus, obtained joint angles are sent to the angle-pulse widht block. The angle-pulse width block reads the input values of the angles, calculates the necessary pulse widths for allocating the servo motors at the desired angles, and then sends the obtained pulse widths to the axis controllers. The axis controllers reads the input values of the pulse widths, and generates necessary PWM signals to drive the corresponding axis motor. Key Words : Robot manipulator, FPGA, joystick, control