No Wheel, No Rover

Curiosity Wheel Damage article from space.com.

This article from space.com discusses the damage to Curiosity’s wheels.  Curiosity is a robotic rover on the planet Mars.  The rover team here on Earth has had to learn to drive carefully on Mars to protect the wheels the same way trail riders choose their path to protect their horse’s hooves.

You can see some of the holes in this picture:

You  can see the tracks left by Curiosity in this picture.  Notice how the rover is driving on soft dirt rather than through the rocks.

A Non-Horsey Post: Be part of launching a space telescope!

ARKYD is a space telescope built by Planetary Resources that will be partially funded through Kickstarter. This allows the public to be a part of building a robot spaceship!  They have some great options for the public to be part of the science of outer space on Kickstarter as well as plans for schools to be involved in researching space.

You can check out Planetary Resources and read about their plans for the ARKYD telescope and for mining asteroids at their website: http://www.planetaryresources.com/

And you can join their Kickstarter project at: 

http://www.kickstarter.com/projects/1458134548/arkyd-a-space-telescope-for-everyone-0

The scientific pony has supported ARKYD and will be getting a “Space Selfie”.  We will be taking some pictures of our own Doktor Pepper and Einsteed.  Later we will need your input on which picture to send to space.

Here is some info on ARKYD provided by Planetary Resources:

The Robot Horse: If-Then Statements

If-Then statements are a fundamental logic used in computer programming.  They are how a program makes decisions.  They are usually phrased as:

IF "question" THEN "action"

The "IF" part of the statement is followed by a question or equation that the program evaluates such as "Do you own a pony?".  The condition statement can be true (if you own a pony), in which case the program takes the action following the "THEN" or it can be false (if you do not own a pony) in which case the program does not take the action.  The action can be whatever you need the program to do, for example it could then calculate the amount of hay a pony needs every day. It could even have a series, or list, of actions to take. It could ask you for information like how much your pony weighs and how much work he does every day and then calculate exactly how much you should feed him. This is an example of basic programming, but I want to explain the idea in the more physical world, so lets look at riding.

Horses have very simple brains so their thinking often seems similar to If-Then.  When you are riding a horse he is constantly listening for a new command from you.  IF he hears or feels that command THEN he takes the action you have requested.

For example your horse should be trained to know that IF you squeeze with your legs THEN he should go faster.  He should also know that IF you pull back on the reins THEN he should slow down.

When programming a computer, the commands are usually written in a programming language. However, when designing a program, programmers often write out their commands in a shorthand called "pseudo code" before translating them into the language they want.

Writing the above horsey examples in pseudo code would look something like this:

IF legs = squeeze THEN go faster

IF reins = pull THEN slow down

A couple of additions to the IF condition statement are AND and OR.  Both are used to combine conditions for evaluation.  If 2 conditions are joined by an AND then they both must be true for the action to occur.  If two requirements are joined by an OR then either can be true for the action to occur.

For example:

IF outside leg = kick OR rider says "canter" THEN canter

In this case your horse would pick up a canter if you are silent and kick with your outside leg, OR if you don't move your legs but you say "canter" to him, OR if you kick and say "canter" at the same time.  As long as one or both of these statements is true he will canter.

Here is an example of AND:

IF rider in 'jump position' AND fence in front of me THEN jump

In this example your horse will only jump if you are in jump position on his back AND there is a fence to jump.  I have attempted to illustrate the possibilities below.

First, if you are not in jump position and there is no fence then your horse will walk along normally:

Next, if you are in jump position while walking along with nothing to jump in sight, then your horse will just continue to walk along:

Next, if you are sitting in your saddle and you come to a fence, your horse will stop and look confused (At least mine looks confused, he eyes the fence like “who put a fence in the middle of my ring?”  Of course Pepper is western trained and not jump trained.):

Finally, if you are in jump position and there is a jump in front of your horse he will jump over it:

As you can see, the only time a horse jumps over a fence is when both conditions are met.

Of course the problem with thinking of your horse as a robot is that you have to be ready for the unexpected. While you are thinking about what to tell him, his brain is running more algorithms like:

IF plastic bag flaps THEN jump straight up in the air and run away

IF other horse = too close AND gait = canter THEN kick

You have to be ready to react and respond if he does anything unexpected.

IF-THEN statements are a very fundamental part of computer programming, but they are a very small part.  When you think, your brain uses many different types of logic and thought processes which programmers are trying to replicate in computers and robots.  We will be looking into many of these logic concepts in future "Robot Horse" installments.

Why do we Fall Off of Horses? (Newton's 1st Law of Motion)

Why do we fall off of horses?

The answer is in Newton’s 1st law of motion

Lets start off with a definition of Newton’s 1st law of motion from from The Physics Classroom:

Newton's first law of motion is often stated as

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

You can read their explanation at this link: http://www.physicsclassroom.com/Class/newtlaws/u2l1a.cfm

When you are riding a horse you have 2 objects or bodies in motion together, you and your horse.  Your horse is providing the force that gives you (and him) velocity (speed) moving you both forward.  The key to understanding falling off is the last line of the law “unless acted upon by an unbalanced force.”  When another force acts on your horse that is when you fall.

The force that your horse uses to stop is friction.  We will go into details on friction later, for now we can leave friction as the force created when your horse plants his feet on the ground rather than picking them up and pushing forward.  Friction is the “unbalanced force” from Newton’s law above.  It changes the horse’s motion from forward to stopped.  However, the rider is another “object in motion” which now stays in motion moving forward over the horse’s shoulders and neck and eventually on to the ground.

According to Newton’s law, when you fall off you should continue to move forward through the air at the same speed (or velocity) you were going.  But as you don’t see riders floating along through the arenas or down the trail you have probably guessed that there is another force we haven’t mentioned yet.  Well you are right!  That force is GRAVITY!

Gravity is the force pulling you down to the ground even as your velocity from your horse is still moving you forward.  

The part of Newton's law about keeping the same direction can also be a reason we fall.  I once fell off when the horse I was cantering shied away from the rail, suddenly jumping about 3 feet to the side. He didn't break his canter but I found myself still traveling along our original path with no horse under me.  It was a very "Wile E Coyote" moment as I looked down and realized I was not going to be able to stay up in the air, then I hit the ground.

So we have discussed why we fall, but not every sudden stop or spook results in a fall.  What keeps riders on?  Well let's go back to the idea of "unbalanced forces". When your horse changes his motion unexpectedly either by stopping or by moving to a new place he is exerting a force on his own body to make that change. As a rider you need to exert a force on your body to also make that change.

There are a couple of "staying on" forces that are commonly seen. One is using your legs as springs and the other is using your saddle or part of your horse to crash into.

Our legs are very effective springs, we use them when we run or skip ourselves and when we are in two-point or jump position on a horse.  Our knees are the best springs, but our ankles and hips can also help out.  When your horse stops suddenly, if you can keep your heels down and legs in position you may be able to let your joints stretch out like a spring and then pull you back into your seat, or at least back onto the horse.

Alternately you need to find something on your horse or saddle that can exert a force on you when you crash into it.  Western and Australian Saddles are best for this as they have higher pommels than English saddles.  This makes it easier for you to crash into it to stop your motion.  Of course sometimes this method can be almost as painful as falling (especially for boys).

The Beginning

I was inspired to start The Scientific Pony after a conversation with a coworker.  I had met her young daughter at a work lunch the previous weekend and had been playing with her for a while so her mother (my co worker) could get a chance to eat.  The little girl had brought some of the My Little Pony toys and she was impressed that I knew their names and even more impressed when I told her I had a real pony of my own who I rode.  Well, that Monday my co worker came over to thank me for talking to her daughter.  The child had been talking all weekend about how a girl could like both ponies and Mars, like me.  

I realized that even the pushes to get girls into science tend to group girls.  There are the science girls, the fashion girls, the sports girls, and of course the horse girls who I see running around the barn every day.  There is a tendency by these girls to settle into their category and to lose interest in other categories.  My hope is that The Scientific Pony can help break down some of the barriers between girly things and science and technology.

I’ll be starting off with a discussion of Newton’s 1st law and then varying the topics to cover a number of different concepts.  I hope you enjoy The Scientific Pony.