Introduction to Robotics Experience

I feel that i have not learn't as much as i though i would in robotics.

During this time i have worked with robotics the construction have probably not been necessary for me. I know enough about constructing robots from the old Lego robotics to be able to build many things. I have for example built a robot that can climb on bars. I felt that this part was unnecessary for me to do.

The programing that we where supposed to use was to easy so i kept trying to take it up another step and develop more sophisticated programing then we where supposed to have. I haven't learn't a lot from the basics that we where supposed to work with. I have done other things like a avoidance program avoiding cans that are in the way.

The thing that i learnt most from was about the sensors. I learn't how to work with threshold and how to Detect, sense and most importantly interact with the enviornment. I have learnt most also from taking the tasks one step further then before.

Most of the time we have used Fysics (math in use) to predict behaviours and draw conclusions by observing what is correct. I feel that i haven't deepend my understanding in science or math here but i did have a slight improvement in my knowladge about technology but not as large as i would like.

In my view this course was to easy for me i needed to take a harder level of robotics

Tractor challange

This is our last challenge of the year. It is called the tractor challenge. WE are supposed to pull a sled with weights. For the tractor challenge we need to change the gears on our robot and program the robot so it is very slow to be able to move the weights.

Drag race

Last class we had a drag race. In the Dragrace the robot was supposed to go 3 meter and win the race. So we had to make it as fast as possible. We tried a very high gear ratio. We did not have enough torque so the robot went slower. we had to pull down the gear ratio. As we did not have time to build a new robot we had to use the taskbot.

The picture is of the robot i would build and use if i had the time. It is generated in LDD. The wheels would be changed but LDD only has these wheels

Gears and Speed invistigation

In the gears of speed investigation we had two Hypotheses

First we find a value that we could compare the other values to. That means we tried to find Speed 1 and we used a number with the wheel ratio of 1 and running for 3 sec for gear ratio 1. We then measured the length of how long it traveled and the calculated the speed of the robot.

After predicted what the speed of speed 2 would be if gear ratio 2 is larger then 1 or smaller then 1. in both Hypotheses


When we tested how fast it went if the gear ration is larger or smaller then 1 we found that the values where closer to the prediction of hypothesis B. Then we reached the conclusion that hypothesis B is true and Hypothesis A is false

Get in Gear investigation and my presenation

Today i presented a presentation about values, numbers and the obstacle detection program it was about how to use values and numbers

Today we tried to increase the size of the driving gear and the driven gear. When we increased the driving gear and the driven gear the robot went faster.

When we did the opposite the robot went slower.

This is due to the trade between torque and speed.

Summary chapter 2 Gears

In chapter 2 it talks about gears. It talks about how to county teeth to get a gear ratio that you can use to convert speed to power (toque). The teeth in a gear is used to mesh with the other gear pushing making it spin. The tuque and velocity are different things one is the power the other is the velocity of the robot. to get speed you need a gear with many teeth that drives a gear with less teeth to get tuque you need the opposite with one gear with less teeth and the other gear with many teeth.

A gear that is useful is the worm gear because it can only move in one direction so if you are trying to lift a arm then the arm wont fall down.

Another wheel is the bevel gear that is used to change direction with between perpendicular axis.

The last wheel is the know wheel. That wheel is actually not a wheel it is a four pieces gear that one part that pushes the other parts

Classic Projects (Chapter 14)

The most classic project to do is the detection of obstacles in a room. When doing this you need a couple of sensors. The ones that are used to do this is the Ultrasonic Sensor, Touch sensor and the light sensor. When doing this it is important to decrease the speed of the robot so it has a chance to register the object. Indirect obstacle detection is when for example a touch sensor is pushed until it is released so it rater detects the release then the push an "In Direct (not Direct)" It also talks about a steering follower. It is a steering assembly with a light sensor that keeps trying to follow a line and by doing that steering the robot after that line. It mentions some methods how to increase the speed. They are changing gears, Changing wheels and Decreasing weight. It is important o decrease gear slack because it can make the robot malfunction by the gears hacking and being damaged.

Program for the obstecle course

We have writted most of the program but we still have to write the part were we avoid the cans.

We haven't done any test because of a need to focus on building our robot.

Here is a list on what we need to do on monday

Building

Put on the last tread on the robot

Programming

Finish the avoid cans program part

Calculations

Threshold values for Sound sensor, Ultrasonic (at bottles and wall) (there might be a problem with the pillar) and light sensor (full room light)

Turn value on both wheels for a 90 degree turn

Testing

Test a couple of times and then correct any difficulties we might have

sorry there are no pictures there is need to focus and hurry with the robot to the deadline so i have had to put in extra time and rush.

Our robot

Now me and my parter are finished with the basic design of our robot. It was a complicated robot that used many parallel beam connecters especialy on the top where we put our Programeble brick. It is hard to explain exactly how the robot looks but to say it is bulky and has a large height. it has a wide area between the back wheels. We have a caster in front that makes the robot go on three wheels. 

I will take some pictures for the next post about the robot

The Chalange

1 st we need the robot to register a clap before it starts sound sensor i needed for this

2 we need to robot to move a given distance and stop at a given point the light sensor is needed for this

3 we need to have it wait there for 5 seconds

4 we need it to go forward and bump into a wall straight forward so we need the touch sensor

5 we need it to turn to the right

6 Go forward until it detects a wall for this we need the ultrasonic sensor

7 turn right again and find the bottles and navigate around then we need the ultrasonic sensor.

My robot

Currently i am running a side prodject in robotics. My plan is to be able to have a robot running throgh a labyrinth but the plan is to use the new robot for the challange if i am allowed to do that

Currently i have the motors in place and the rotating base

There will be more updates on this in the near future

Summary of Chapter 1:Understanding LEGO Geometry

In chapter 1 of Building Robots with LEGO MINDSTORMS NXT it talks about sizes and units, Vertical Bracing, Diagonal bracing and Technical lift arms.

It starts to mention the 3 types of main LEGO part: The brick, The technical beam and the Stud less beam.one unit (Stud or LEGO unit) of a LEGO brick correspond with 5 horizontal cm and 6 vertical cm. It also mentions that three plates makes  one brick in height. 

When it talks about vertical bracing it is important to remember the 6:5 ratio that happens when you put one beam or block with a 90 degree angle to each other. the versatile construction of the Stud less beams have helped the robot to become more light and flowing in its motions

A option when building is to place a Diagonal bracing. to use it you need the Pythagorean theorem to find the measure that you need for the beam

The last one is the Lego lift arms. They help to get angles without using extra beams but can also be used to reinforce the structure

Ultrasonic Experiment

When we did the experiment to determine how far the ultrasonic sensor could detect we first put down a tape and measured and noted down on the tape where every 10 cm, 20, 30, 40 and so on distance was. Then we started looking how far out on each side of the tape the sensor could register with 10 cm intervals when we got a point that it was not possible to register we put a black piece of tape there and registered it on a sheet of paper where that we have as one of the pictures