Build a Robot, Lab Report Example

Summary and Introduction

This Lab report is based on the building and designing of a robot that can move through check points from one starting point to the other. In order for the robot to do that, the sensors need to identify the locations and find out the spots which will trigger a signal visually. This will help the robot to avoid the obstacle it faces along the way. Once all of these requirements of the design are complete, then we will use the tools to map the environment. In order to build the sensors, the NXT Lego set will be used in Arduino board to build the robot instead of the controller NXT.

Design of Robot

In order to design the robot, an H-bridge circuit is used. It will help the motor inside the robot to drive it in reverse and forward position. It is a circuit that is very simple and needs only handful parts to be built. In the design, we will use the basic operations of an H-bridge to transform it into versions that are more complex and help support bigger and stronger motors.

Explanation of requirements

The design of the robot involves the use of 2 DC motors, bred board, H-bridge and an Arduino Uno.  The sensors will comprise of the red and green LEDs with ultrasonic sensor and a phot electric cell. In order to control the direction and rotation of a small motor there is no need to use any mechanical relays. The use of Instruments of Texas dual H-bridge L293D IC will help to separate the two control circuits. This helps to control the 2 ways DC conventional motors or the motor which is one step higher. In this Lab report, the H-bridge IC will be used to control the two way DC. The parts required are A bred board, a 9-Volts snap battery and a battery, 4 NPN transistors, 4 ohm resistors of 22k, spare wire, jumpers, two push button switcher, Green and red light Led and a small motor capable DC circuit operating at volts 7.

Description of the reasoning and the mechanical design

The sketch of the Arduino as seen in the picture, control the motor by adjusting the voltage on 2 of the pins of output. This help to connect to the L293D H-bridge inputs which helps to control the motor. This is indicated by the GREEN signal LED which means to stay off. The other signal used is the RED signal LED which means the check point will turn from OFF to ON. There are four possible values involved in these two output signals of GREEN and RED.

• One is 00 and 11 both mean stop- which means there is no output voltage
• 01 means the current supply in one direction to the motor
• 10 means the current supply in the opposite direction to the motor.
• The diagram Frit zing shows the connections.

Explanation of each task

In order to avoid the reverse and forwards temptation in the sensors of the robot, the motor must clearly be aligned in an appropriate direction. This can be achieved if the motor is connected properly and how it defines the reverse and forward in the applications of the design. Some of the controlled circuits will use a +5V pins enabled to connect together. However, in our design it is not recommended due to the results which have to enable always. There are other circumstances such as the IC can short out the 0V and +5 V when the output polarity is switched. So, it is better to have a Enabled pin which separate the sequence. It means that there must be a polarity, disable output and an enable output switch. Another reason is that the Enable pin helps to separate the logic of voltages of +5 V typically while maintaining the voltage supply to the motor which can go up to 36V. The ultrasonic sensors inserted in the robots design help it to analyze the distance of the wall. The following figure shows the calculated distance of the wall. The measured distance for the wall is around 220 cm with the margins of error of 4 cm.

Discussions and Conclusion

The things I learned in this report is that the Arduino Robot design requires two processors one is to be fitted on each of its board. The motor is controlled by the Motor board and the Board of control reads the sensors. Once the sensor are read, the robot performs the required operations i.e. go reverse or move forward. The board is fully programmed using the Arduino board and the IDE Arduino technology. Another thing I learnt is that both the Control board and the motor are based on the microcontroller boards. There are many pins on the Robot which are mapped on the actuators and to on-board sensors. The robot programming is synonymous to the process used with the Leonardo Arduino. Both of the processors have USB communication on built in them, which removes the reliance on a secondary processor. This helps the Robot to remain connected with the virtual (CDC) COM serial port and to the computer.

Analysis and Demo of Robot performance

In order to analyze the functionality of the Robot design and to demonstrate it we need to look at the Motor board of the Robot. As this is the main component that helps the robot to function. It is intended to be the ‘state machine’ of the robot to work. It means that the robot takes command from the Board of control and executes the command accordingly. The data is also returned when requested. It means that the motor board is the default board and it consists of a firmware which doesn’t match with the intelligence and there is no need to adjust this from majority of the applications. In order to analyze and extend the functionality of the robot, the motor boards needs to be modified by creating our own commands. It can be done by going through the library files of the board. The robot designed with the help of Arduino board and H-bridge has a number of modes that are pre-defined. One’s the motor board instruction as how to operate. We can see in the figure the different modes that are integrated in the robots functionality. The integrated sensors are mounted and arrayed on the bottom of the motor board which helps the robot to calculate the direction desired and manipulate directly the motor.

The robot designed have a lot of actuators and in built sensor which help to access its functionality. These two boards are the control and the motor board. Every board has a different processor of programming. These various peripherals and sensors helps to control the board.