A Continuation from the previous Idea and Research, Part 1 where I wanted to do an Animatronic Turtle.
The Difference between a Turtle and a Tortoise is that all Tortoises are turtle and not all turtles are tortoise. Generally, Tortoise live on land and turtle lives in water most of the time, with exceptions which I’ll not go into. However in my Project, I’ve decided to use “Turtle” as I simply prefer the sound of Turtle more than Tortoise.
How do Turtle/Tortoise walk?
Tortoise are cute! and the way they walk naturally are quite robotic =D
the “Hand” are much longer and the “feet” are much shorter in comparison. This is how a Tortoise retract its head, by bending its “neck” inwards. maybe I could emulate this.
I could use a lever system to move the front and back legs so that I could use smaller motor and all 3 motor placed in the shell so the overall weight of the feet will be greatly reduced to allow me to use smaller/weaker motors.
From my research I’ve done and found this EEZYbotARM on Thingiverse which I could use it to study the mechanics I could potentially use in the feet of the Turtle.
The two motor is at the base of the mechanical arm(Typebot), in comparison to our typebot, This Typebot system is less efficient unless the torque of the motor far exceed the weight of the system and only a when there is a short (A) to (B) distance(longer fulcrum, more torque needed to turn it)
So to understand how fully it works and if there are any restrictions to this lever system, the best way is to having a study model to study how I could incorporate it into my Turtle. I also purchased a few servo few weeks ago and they also arrived so I used them in the study model.
The movement is really smooth and the movement coverage is definitely good enough for my turtle, However this system could barely carry its own weight as the base is relatively heavy, this Lever system could work great as a Type bot kind of project because doesn’t need to carry the base of the robotic arm, in my opinion, this probably wont work in my Turtle since each leg will still carry its motor weight because they are all in the shell, so having Motor(A) not carrying Motor(B) is of less importance since Motor(A) and Motor(B) will ultimately carry the weight of (A)+(B)+the mount+components+the shell in the end.
I’ll need to find a more efficient system or use a bigger motor to do the work of lifting everything in the shell along with the motors and still able to cover the movements. Now my main concern will be
Weight of motor VS its Torque
Size of Motor (slightly bigger motor will result in MUCH BIGGER TURTLE which I’ll try to avoid as I wanted a COMPACT turtle, not a monster.)
Movements of motor especially within the shell.