Report On Circuit Designing Of Robotic Fish

Introduction

In this career episode I developed the fish robot. I have done this project in a group of three students at University of Central Punjab, Lahore, Pakistan. It was necessary to complete this project in order to meet my credit hours requirement and to get my degree.

Background

We have found that the one robot which is called "Robotic FISH" is requested in business sector as an exceptional robot which can swim with genuine fishes and appears as to be exactly like them. That is why we decided to develop such robot which has unique qualities and capacities to which all individuals are going to love. This robot took a shot at control system of servo engines with the assistance of three dimensional esteemed movement handling unit. All its development was depended on the idea of move, pitch and yaw by gyro and accelerometer. This robot was designed to move inside water. It was capable to attain some specific height under the depth of water with the help of ultrasonic sensor and IMU (Inertial Measuring Unit) and balance itself.

Designing of Robotic Fish

The circuit consists of three servo motors which are connected to the Mega 2560 via PWM pins. To keep the voltage of the servos stable we basically used three 7805 power transistors in parallel. The circuit also contains one ultrasonic sensor for the hurdle avoidance and this device is shipped with an internal RC oscillator at 8. 0 MHz and with the fuse CKDIV8 programmed. The MPU 6050 was used as it works on the basis of magnetic field but in water the magnetic field was considerably reduced which caused several problems.

Sensors being used in the project:

1 Ultrasonic sensor: Ultrasonic sensors has to do a lot with sound waves. It actually sends sound waves and then if it receives it back it means it has detected something in front of it. The signal it sends is actually echo signal. In our project, ultrasonic sensor was being used for depth measurement and hurdle avoidance. As it was going to sense the hurdle, if any, and would pass the signal to microcontroller and with the help of motors robotic fish would slightly change its path and safe the robot.

IMU Sensor: MPU 6050 provides three built in package sensors

• Gyro
• Accelerometer
• Temperature sensor.

All the Sensors work in three dimensional space. It gives a X, Y and Z bearing extent values by interfacing with Arduino. It is moved remotely in air/water and change values in 3 headings. It is a serial gadget and interface with SDA pin 20, SCL pin 21 of Mega 2560. We had set 9600 Baud rate for testing reason. In our project, we needed to balance our robotic fish under the water in such a way that it’ll not fall down towards right or left side. Either it should be straight (vertical direction) and then swim. For this purpose, we are using MPU6050 to measure x, y, z directions and make them according to our desire with the help of servo motors.

Testing of the structure: We tried almost seven different prototypes, some with different materials and some with different location of the internals like the battery, Arduino and sensor. Some were not completely waterproof and some were not stable. After a lot of testing and experimentation we chose the current structure. Before testing the robot into water we checked every mechanical and electrical connection. Turned the fish on and controlled the movements and ensured that ultrasonic sensor provide signal to the Arduino. We used a multimeter to measure the voltage on their output: in the absence of obstacles the signal should be high. Checking voltage supply was not a bad idea. We made sure that it is at least 5. 5 V. At this point we were ready to waterproof the robot. We used the plastic food wrap for this purpose because it was stretchable and it did not provide any hindrance in the movement of the three different parts and used rubber bands to keep the plastic lying close to the body joints of the robotic fish and made sure the servos are free to move. The swim will take place in surface of water: you’ll probably have to weigh down the robot with sufficient weight to keep it at the correct height. As mentioned above, in our prototype, we added like 3. 56kg. Once the robot floats in the right way you can turn it on by the switch and let it swim.

Problem statement

This project had the overall problem of keeping the structure stable. It was very challenging for us to keep it underwater and keep it stable as well. We used jumbolon in the first place and observed that the structure was not even sinking in the water at all. After giving a thought to it, we decided to use Thermopore instead because it was easy for us to carve the structure in to our desired shape and size, as we all know that Thermopore is a porous material and it can be carved to any form with the help of a simple sandpaper or a file. Surprisingly, Thermopore appeared to be more stable in water.

The tests we did went smoothly and had no problems, except for the fact that the structure tumbled a lot during some experiments. Therefore, we had to take the measurements of the degree of rotation of all servos quickly and we basically tried three different models of the MPU until the tumbling problem was fixed. We faced some major issues with the waterproofing of the motors and the structure itself. But luckily, with a lot of experimentation we managed to sort everything out and got the fish swimming at its full pace without any water damage to the fish internals.

Summary

This robot takes a shot at control system of servo engines with the assistance of three dimensional esteemed movement handling unit. Development depends on the idea of move, pitch and yaw by gyro and accelerometer.

Results

The fish body can work under actuated framework, where a solitary control information can energize numerous methods of movement. Utilizing only the front actuator pair rather than each of the four accessible actuators for forwarding swimming permits the fish to moderate the restricted liquid vitality put away locally available.

The forward-swimming results demonstrate that the independent incitation framework is equipped for supported operation, exemplified by forward fishlike velocity. Be that as it may, the swimming stride we display here is surely problematic. An exhaustive scope over driving weights, tail frequencies, and body firmness would permit enhancement of forward velocity.