9.1.1. Definition

Humanoid robots are designed to replicate the human body's structure, including the head, torso, arms, and legs, typically with a degree of freedom that mimics human joints.

Humanoid robots are machines created to imitate the physical features and movements of humans. They are designed with different parts like the head, trunk, arms, and legs, just like humans. A key aspect of these robots is that they possess joints that allow for a range of motion similar to human joints, which means they can move in ways that are natural for humans.

Think of a humanoid robot like a puppet that can move its arms and legs just like a person does. If you were to manipulate the puppet's joints, it would mimic human movements. Similarly, humanoid robots use motorized joints to move flexibly, allowing them to walk, wave, or perform tasks that require a human-like mannerism.

● Degrees of Freedom (DoF): Replicating joint mobility with actuators (e.g., shoulder has 3 DoF). ● Anthropometry: Designing robots with proportions similar to the average human. ● Actuation Mechanisms: ○ Electric motors for lightweight joints ○ Hydraulic actuators for high-force applications ○ Series Elastic Actuators (SEA) for compliant control

Several crucial factors are considered when designing humanoid robots. First, 'Degrees of Freedom' (DoF) refers to the number of movements a joint can make; for instance, the human shoulder can move in 3 different ways (up/down, forward/backward, and rotation). Second, 'Anthropometry' involves adjusting the robot's dimensions so that it resembles the average human's size and shape. Lastly, the methods used to create movement, known as 'Actuation Mechanisms', include electric motors for lighter joints, hydraulic systems for stronger movements, and Series Elastic Actuators that provide flexibility and control during actions.

Consider how a marionette works. Each joint of a marionette is attached to a string (like joints to actuators) that can pull it in various directions. The designer considers how many strings to use (DoF) and how they are positioned (Anthropometry) to ensure the puppet can move gracefully. The type of material used for the strings (Actuation Mechanisms) can affect performance—some are stiff, while others have more elasticity, allowing for smoother movements.

● Honda ASIMO ● Boston Dynamics’ Atlas ● SoftBank’s Pepper (for upper body humanoid interaction)

There are several notable examples of humanoid robots. ASIMO, created by Honda, is known for walking, climbing stairs, and even running. Boston Dynamics' Atlas is designed for more rugged environments and can perform complex tasks like backflips and navigating obstacles. On the other hand, SoftBank's Pepper is focused on interaction rather than complex movements, being designed to communicate and engage with humans effectively.

You can think of these robots as the different types of athletes. ASIMO is like a sprinting athlete, built for speed and agility. Atlas is like a gymnast, capable of incredible feats of balance and strength. Meanwhile, Pepper is akin to a performer, engaging the audience with its charm and interaction skills, just like a movie star.

● Gazebo with ROS plugins ● OpenSim for musculoskeletal simulation

To design and test humanoid robots before building them, engineers use computer-aided design (CAD) and simulation tools. Gazebo, often used with ROS (Robot Operating System) plugins, allows developers to create realistic environments to test robot behaviors. OpenSim is another tool that focuses specifically on biological and musculoskeletal simulations, helping to analyze how robot limbs would move similarly to human muscles.

Imagine you're a movie director planning a big action scene. Before filming, you can use storyboard software (like CAD) to visualize every angle and movement, as well as computer graphics (like simulations) to understand how physics will work in your scene. These tools allow for planning and adjustments to make everything run smoothly during the actual shoot.

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