Lifesizing a miniature model

Community General Discussions
1

Hi Elvensynth, welcome to the RobotShop Forum.

To understand correctly, you are looking to scale an existing “enclosed” robot toy (female android or other) including reproducing the actuation and degrees of freedom?

If the robot is stationary and does not need to lift any weight (and you keep the support structure to a minimum) the actuators will not require too much torque. As soon as you want the robot to walk and lift any mass, the complexity and cost skyrockets.

Some design solutions include using cable/pulley systems instead of locating the motors at the respective joint (so reduce torque significantly), locating the center of mass as low as possible (even within the feet or lower legs). Although not exactly “walking” you may consider adding wheels or tracks and having the robot go through the motions of walking.

Sensors and electronics will take up <1% of the volume. Your first task might be to build an endo-skeleton structure and perfect the motions before adding a plastic cover (which can be made using vacuum-forming and Styrofoam). If you are looking to make an identical copy, you will need to have a company scan the parts with a 3D scanner and use CAD to scale them. The parts can then be made out of foam or other easily machined material (the cost for this may be rather high if this is a hobbyist rather than professional project). Again, the key to the success of the project will be to keep the weight to a bare minimum and centralize all heavy actuators.

Some companies will be flattered that you use their designs and help you with the design, though others may cite copyright infringement.

We hope this helps.

2

Note that RobotShop does offer a wide range of humanoid walking robots, though all are under 2’ tall. Note that Honda has spent millions of dollars in order to develop their line of walking robots (you can see when each of these robots was developed in the RobotShop Learning Center History section. The walking algorithms are very similar for humanoid robots, as most have the same degrees of freedom in their legs, arms and torso. There are quit a few humanoid robots now in existence, but you would be hard pressed to find a full scale walking humaoid made by a hobbyist; you certainly are a pioneer.

Several issues you will contend with are:

]Overall weight and center of gravity/:m]
]Torque required at each joint /:m]
]Inertia (an object in motion wants to remain in motion)/:m]

Consider using the RobotShop Robotic Arm Torque Calculator for a quick estimate of the torque your robot’s arms will require.