DFlip Flops You have been tasked with designing a digital co

D-Flip Flops

You have been tasked with designing a digital controller for an Unmanned Ground Vehicle (UGV) which is essentially a robot that can navigate terrain autonomously. The application requires you to develop a robotic UGV that is capable of sensing radiation levels inside a nuclear power plant, where safety precautions do not allow personnel to enter with handhold sensors.

To get out of simple mazes, the ‘Right Hand Rule” algorithm is commonly used. Although this is certainly not an efficient path planning technique, it will always help your UGV find its way back to its home position, assuming that there is only one entry/exit point for the nuclear core facility. In the three-wheeled UGV shown in Figure 4.1, an antenna provides an input signal to the digital controller, R=1 when a wall is within 10-cm of the right-hand side of the vehicle, and R=0 otherwise. A bumper on the front of the vehicle also activates a switch, with B=1 when the UGV bumps into a wall and B=0 otherwise. The turn-right actuator causes the vehicle to turn right 10 degrees when TR=1, while the turn-left actuator causes the UGV to turn left 10 degrees when TL=1. Both TR and TL would most likely not be asserted at the same time. Figure 4.2 shows a simple state diagram of the state machine that can control the robot.

Figure 4.1: Three-Weeled UGV. Figure 4.2: State diagram of the UGV.

How many D flip flops are needed? Give a binary code to each state.

Solution

INPUT-B and R;

OUTPUT-TL and TR

States-Home,Go_straight,Go_left,Go_right

State Table:

No of D-flioflop=Log₂(No of States)

Log₂(4)=2;

the required no of D flip flop is 2 named Da and Db and

Assign Homme=00;

  Go_straight=01,

Go_left=10,

Go_right=11

Transient Table: