Working

The setpoint or desired position along with the controller parameters will be set by the  user in the GUI which has been developed in Processing software to be discussed in the next  chapter. These values are then sent to the Arduino UNO Microcontroller. The microcontroller  then sends corresponding PWM output signals to motor shield, which further controls the motor  responsible for the actuation of leadscrew and slider-nut mechanism. The displacement of nut  will thus be responsible for the actuation of tendon for the robotic finger. 

The actual position of the nut will be sensed by the IR sensor pair attached to the nut  screw mechanism. The signals from IR sensor circuit, prepared manually on PCB board, are  sent to the microcontroller as feedback signals. The PWM output signals from microcontroller  tend to minimize the difference in setpoint signals (desired position) from GUI and feedback  signals (actual position) from the IR sensor circuit, using PID control. Thus, the desired position  of the tendon tip can be obtained.