The Body – Systems & Parts

Its important to have at least a basic understanding of how the body works and its various main parts if you plan to build a realistic human like robot.

It could be that you simply want the face and eyes to move and look like a real person or you may want the arms to move in a smooth or realistic way.

Perhaps you want the robot to bend at the hips in a realistic way or to lift up objects without dropping them.

These areas are mostly mechanical and elecronic matters which have to do with the type of material used for the head or arms and the quality of the servo motors used to move the eyes or limbs.

Then of course we would talk about the type of sensors to use to replicate the robot seeing things in front of it or being able to get up after it falls.

After this we would decide if we wanted to make an autonomous robot which could learn and make some of its own decisions on movement and this is where we would be dealing with software issues like machine learning and the various parts of artificial intelligence.

So lets start by naming the systems of the body and then we will get into the specifics of the structure and bones and tendons found in the major parts of the body and how we could reproduce these in a robot form.

We will then address some of the body parts of animals like dogs and cats and flying creatures as well as swimming and crawling creatures.

Yes we are in for quite a fascinating ride and huge amount of information…only some of which will be covered in this website.

Now the text books will ususally say that there are 11 or 12 systems in the human body and of course we will really only have to concern ourselves with a handful of them when dealing with our robots…for the most part.

The systems are the muscular, skeletal, circulatory, respiratory, digestive, urinary, endocrine, nervous, integumentary, reproductive, and immune.

So of course we don’t have to worry about the reproductve the immune, the urinary and the digestive and a few others….or do we?

Well….if we are to create an ultra realistic robot like the kind you can see on the Engineered Arts website that is sitting in a cafe until the people around it realize that it is a robot and not a human…then you may need to worry about a few other details and simulating actual bodily systems or functions.

For example eating and drinking as a robot.

You very well can’t be sitting with a robot at a restaurant and wonder why the robot never takes a drink of its coffee.

As funny as this sounds….we must recognize that we have had baby dolls for children for probably 30 years that the child was able to put food (of sorts) in its mouth and the doll toy had a hole near its bottom where the liquid could come out.

So its not that hard to create a human sitting robot doll that could pour liquid into a removable stomach like chamber which could be removed later.

One could give the robot a chewing simulation and have the food go into this same stomach chamber if you are really going for the ultra realistic robot.

For the most part we could be robot building like Hollywood would do it where we simply have to create the illusion of a humanoid robot for a half hour and not for a week or permananently.

So for a mere thousands of dollars we could pull off this Hollywood version of an ultra realistic robot but for $200,000 + we could achieve more.\

So lets deal with the major systems and how we need to worry about it in terms of building our realistic humanoid robot.

The musculatory and skeletal system understanding hel;s us to build our arms/legs/torso/shoulder/feet/hands-fingers so we can kenow what our ultimate goal could be.

We know that a human hand has 5 fingers and that we could create a usable hand gripper with 2 or 3 finger like appendages or use a 4 finger cartoon Mickey Mouse hand…but we are going for a realistic look of 4 fingers and a movable thumb.

So lets proceed now with the skeletal and musculatory systems of the body.


So the entire body has 206 bones with joints (arm/shoulder/elbow/wrist/hand/fingers) and legs (pelvis/knee/ankle/foot/toes) and head-neck-shoulder and torso (stomach/backbone/) etc

The robot body can be made to move and walk or you could create just the top and have it wheeled around to impress the crowds like how Sophia is moved around with a platform by Hanson Robotics.

This cuts down your cost and sophistocation by probably 70%.

Creating a heavy humanoid that can walk reasonably and get up after a fall requires a great deal of understanding of motion and balance and robot gears and springs and servos and gyros and sensors like acceleromers, gyros, tilt.

Simple walking requires arms that swing and understaning of the center of balance and much more.

We of course will be trying to rely on previoulsy written open source library code to accomplish much of what we will need to achieve fair results…and of course custom code would be needed to go to the next level.

Something as simple as designing the foot with a pivoting etoe and ankle can make all the difference with how a robot moves.

WowWee Toys had their Robosapien designed with special hip gears and springs which allowed it tyo walk reasonably and let up after it fell without using countless sensors. Mark Tilden did things old school back then.

Now in terms of the skeleton there are two parts.

The axial which is the skull, torso and backbone basically and the appendicular which is the rest including all that gets attached to the axial skeleton.

People often ignore the shoulder blade or scapula when making a simple robot. They mereley put arms onto the main torso and throw on a rotating neck with a head and call it done.

A shoulder allows for much more realistic arm movement which is seen when throwing a baseball or picking up a hammer on the ground.

A adult human male skeleton differs from a female skeleton in several ways.

The easiest way to tell a male or female skeleton in a forensics/crime situation is to look at the shape of the pelvis due to the need for the female to handle child birth.

From there you can see differences in the shape of the head and the thicker bones found on the male overall and in the femur/leg bone which is at a sharper angle on the female.

One would generally create a male robot to be taller than a female robot and of course lighter and more stream lined haa.

Later of course when adding skin and muscle mass, the male could have an adams apple added and facial hair. Personality differences of course would have to be handled by the AI software.

This is a simplification but generally those 3 areas can distinguish the male from the female.

In terms of making a robot, you can concentrate on making the female robot overall shorter and thinner and you could ensure that the skull is less angular and that the femur has more angle.

Now lets talk about the various parts head/arms-legs/torso