FPGA based DC servo motor control for remote replication of movements of a surgical arm

This paper focuses on the implementation of the controller circuit for the DC servo motor with an UART module and PWM generator using ALTERA - FPGA board. The modules are developed using Verilog - HDL for programming it in FPGA. The work aims at making two arms, detecting the motion of the master arm, wireless transmission of the same and replicating the motion at the slave arm which is employed for surgery. The precise deviations of the master arm at each degree of freedom are sensed by potentiometers attached to it. These deviations are sensed as analog voltage variations that are fed into different ADC ports of ATmega16 microcontroller. Each of these inputs is sequentially polled for, and the analog values are converted to digital equivalent values. Using the UART feature of the microcontroller, these digital values are sent out in two packets of data containing an identification number for each degree of freedom followed by its data sensed. These packets are fed to the transmitter module which transmits them to a receiver module coupled to it with a channel identification number. These data packets received are given to the serial port of the FPGA. The FPGA analyses the data values received for every degree of freedom calculates the required pulse widths based on the pre-calibrated values and the PWM signals are fed to the respective control lines of the servo motors present at the slave arm (surgical arm). Hence the remote replication of the movements of a surgical arm can be achieved. The proposed system is analyzed for its working features with the help of the experimental setup.