Humanoid Robotics
Humanoid robots are machines designed with a body structure similar to a human form. The purpose of this design is to allow the robot to interact with environments that were originally built for people, such as workspaces, tools, and machinery. Humanoid robots operate through a combination of mechanical systems, electrical power, sensors, and computer-based control systems.
Servo Motor Systems
Movement in most humanoid robots is produced by servo motors. A servo motor is a type of electric motor designed for precise motion control. Unlike a basic motor that simply spins when power is applied, a servo motor uses feedback from an internal position sensor to maintain a specific angle or movement. Servo motors also contain a computer CPU.
Each robotic joint, such as the shoulder, elbow, wrist, hip, or knee, can contain one or more servomotors. A controller sends a position command to the servo, and the motor adjusts until it reaches the desired position. The internal feedback device continuously reports the motor’s position, allowing the system to correct errors and maintain accuracy.
Because of this feedback loop, servo motors are commonly used in robotics when precise movement, repeatability, and controlled torque are required.
Basic Servo Motor Diagram.
Artificial Muscle Concepts
Some robotics research explores alternatives to conventional motors using artificial muscle systems. Artificial muscles are materials or fiber structures that contract or expand when electrical energy is applied.
One possible approach uses conductive fibers embedded within flexible materials such as dielectric gels or polymer structures. When electrical energy interacts with the material, physical forces within the structure can cause the fibers to shorten or change shape. This movement can produce a pulling force similar to the contraction of biological muscle.
Artificial muscles are studied because they may allow robotic systems to produce smoother movement while reducing mechanical complexity. However, many artificial muscle technologies are still being investigated and are not yet as widely used as electric motors in most robotic systems.
The Electrical Society is actively conducting research into artificial muscle technologies for improved accuracy and human-like dexterity of robotics. The human body is extremely energy efficient and has self-healing abilities to repair damaged tissues. However, current robotic technologies are unable to do this.
Artificial Intelligence and Control
Humanoid robots depend on computer control systems to coordinate movement and process information from sensors. These systems can range from simple programmed instructions to more complex software that uses artificial intelligence.
Control software manages several important functions, including joint coordination, movement timing, and system stability. Artificial intelligence methods may be used to interpret sensor data, recognize objects, or assist with navigation. In more advanced systems, machine learning algorithms allow robots to improve their performance by analyzing previous actions and outcomes.
Sensor Systems
Sensors are essential components that allow a robot to detect conditions inside the machine and in the surrounding environment. Different types of sensors provide different forms of information.
Examples of sensors commonly used in robotics include:
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Position encoders that measure the rotation of motors and joints
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Inertial measurement units (IMUs) that detect acceleration, orientation, and balance
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Force sensors that measure loads placed on joints or grippers
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Proximity or distance sensors that detect nearby objects
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Temperature sensors that monitor the operating conditions of electronic components
These sensors provide feedback that allows the robot’s control system to adjust movement and maintain stable operation.
Vision Systems
Many humanoid robots use vision systems to collect visual information from their surroundings. These systems usually consist of cameras combined with image-processing software.
The software analyzes the captured images and can identify objects, detect motion, or estimate distance. Some systems use multiple cameras to create depth perception, allowing the robot to estimate the position of objects in three-dimensional space.
Vision systems play an important role in tasks such as navigation, object manipulation, and environmental awareness.
Materials and Structural Design
The physical structure of a humanoid robot must be strong enough to support moving parts while remaining light enough to reduce power consumption (3D printing technologies are becoming very popular in robotics). Engineers typically use materials that provide a balance between strength, weight, and durability.
Common materials used in robotic structures include:
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Aluminum alloys for frames and joint housings
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Engineering plastics for lightweight components
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Carbon fiber composites for high strength with low weight
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Flexible polymers or elastomers for parts that require limited deformation
In systems that experiment with artificial muscle technology, flexible materials such as dielectric gels or polymer matrices may also be used to surround conductive fibers and allow controlled movement.
How do Industrial Robots Operate?
Robotic systems typically operate using their own dedicated controllers and unique programming languages. A robot’s movements are programmed using the teaching pendant. This is a handheld device used to move robots, as well as see faults. When integrating these systems with PLCs (Programmable Logic Controllers), communication becomes more complex. Each robot’s movement instructions are handled by its PLC located in its controller, which in turn communicates with the main PLC. The robot's PLC sends commands and receives feedback, such as position data from encoders and motion status from servo motors. This back-and-forth communication allows the PLC to monitor and coordinate robotic actions in real time.
To learn more about robotics, check out the TES Electrical Guidebook!