upgrade
upgrade

🤖Robotics

Fundamental Robot Components

Study smarter with Fiveable

Get study guides, practice questions, and cheatsheets for all your subjects. Join 500,000+ students with a 96% pass rate.

Get Started

Why This Matters

Every robot—whether it's a warehouse arm, a surgical assistant, or a Mars rover—is built from the same fundamental building blocks. Understanding these components isn't just about memorizing parts; it's about recognizing how sensing, processing, and acting form a continuous loop that enables autonomous behavior. You're being tested on your ability to trace how information flows through a robotic system and why specific components are chosen for specific applications.

The real exam questions won't ask you to simply list robot parts. They'll challenge you to explain why a particular sensor feeds a particular controller, or how power constraints limit actuator selection. Master the relationships between these components—the cause-and-effect chains that make robots work—and you'll be ready for any design scenario or troubleshooting problem they throw at you. Don't just memorize facts; know what engineering principle each component demonstrates.


The Sense-Think-Act Framework

Robots operate on a fundamental cycle: sense the environment, process that information, then act on it. These three functions map directly to core component categories that you'll see in every robotic system.

Sensors

  • Input devices that convert physical phenomena into electrical signals—the robot's eyes, ears, and skin for perceiving its environment
  • Types span multiple modalities: cameras for vision, ultrasonic sensors for distance, accelerometers for motion, and temperature sensors for thermal feedback
  • Enable closed-loop control by providing real-time feedback that allows the robot to adjust its behavior dynamically

Controllers

  • The computational brain that processes sensor data and generates actuator commands—where algorithms become actions
  • Range from simple microcontrollers to complex embedded systems: Arduino for hobbyist projects, PLCs for industrial automation, dedicated processors for real-time control
  • Execute the decision-making logic including path planning, object recognition, and safety protocols that define robot behavior

Actuators

  • Output devices that convert electrical signals into physical motion—the muscles that make robots move
  • Three main categories: electric motors (precise, efficient), hydraulic cylinders (high force), and pneumatic actuators (fast, compliant)
  • Selection depends on application requirements: torque, speed, precision, and power availability all influence actuator choice

Compare: Sensors vs. Actuators—both interface between the digital controller and physical world, but sensors convert physical-to-electrical while actuators convert electrical-to-physical. If asked to trace signal flow, remember: environment → sensor → controller → actuator → environment.


Physical Structure and Movement

The mechanical foundation of a robot determines what it can do and where it can go. Structural design directly constrains functional capability.

Frame/Chassis

  • The structural skeleton that supports and protects all other components—determines the robot's form factor and durability
  • Design considerations include weight distribution, rigidity, and material selection: aluminum for lightweight applications, steel for heavy-duty industrial use
  • Influences thermal management and component accessibility, affecting maintenance and operational reliability

Manipulators

  • Articulated arms that extend the robot's reach and dexterity—typically described by their degrees of freedom (DOF)
  • Kinematic chains define motion capability: a 6-DOF arm can position and orient an end effector anywhere in its workspace
  • Joint types include revolute (rotational) and prismatic (linear), each contributing different motion characteristics to the overall system

Locomotion Systems

  • Mobility mechanisms that allow robots to navigate their environment—wheels, tracks, legs, or hybrid designs
  • Terrain requirements drive design choices: wheels for flat surfaces (efficient), tracks for rough terrain (stable), legs for unstructured environments (adaptable)
  • Holonomic vs. non-holonomic constraints determine whether a robot can move in any direction instantly or must follow specific motion patterns

Compare: Manipulators vs. Locomotion Systems—both provide mechanical motion, but manipulators move objects relative to the robot while locomotion moves the robot relative to the environment. Design problems often require you to specify both for a complete system.


Task Execution and Interaction

The components that directly accomplish work determine a robot's practical utility. End effectors and software transform mechanical capability into useful function.

End Effectors

  • The tools attached to manipulators that physically interact with objects—grippers, welding torches, suction cups, or specialized instruments
  • Must be matched to task requirements: parallel-jaw grippers for rigid objects, soft grippers for delicate items, vacuum systems for flat surfaces
  • Often the most application-specific component, requiring custom design for unique manipulation challenges

Software and Programming Systems

  • The algorithms and code that orchestrate all hardware components—from low-level motor control to high-level task planning
  • Layered architecture typically includes: real-time operating systems, middleware like ROS (Robot Operating System), and application-specific programs
  • Enables simulation, debugging, and iterative development before deploying code to physical hardware

Compare: End Effectors vs. Software—end effectors determine what physical interactions are possible, while software determines how and when those interactions occur. A gripper without proper control code is just a paperweight.


Support Systems

Behind every active component are support systems that enable sustained operation. Power and communication infrastructure make autonomous function possible.

Power Supply

  • Provides electrical energy to all active components—the limiting factor for mobile robot endurance
  • Options include batteries (portable), tethered power (unlimited but constrained), and solar/alternative sources for extended deployment
  • Voltage and current requirements must match component specifications: motors draw high current, sensors typically need stable low-voltage supplies

Communication Interfaces

  • Enable data exchange between the robot and external systems—Wi-Fi, Bluetooth, serial protocols, or industrial buses like CAN
  • Critical for teleoperation, fleet coordination, and cloud computing integration in modern robotic systems
  • Bandwidth and latency requirements vary by application: video streaming needs high bandwidth, safety signals need low latency

Compare: Power Supply vs. Communication Interfaces—both are support systems, but power enables function while communication enables coordination. A robot can operate without communication (fully autonomous), but never without power.


Quick Reference Table

ConceptBest Examples
SensingCameras, ultrasonic sensors, accelerometers, encoders
ProcessingMicrocontrollers, PLCs, embedded computers, FPGAs
ActuationElectric motors, hydraulic cylinders, pneumatic actuators
StructureFrame/chassis, manipulator links, mounting hardware
MobilityWheels, tracks, legs, propellers
InteractionGrippers, welding torches, suction cups, tool changers
PowerBatteries, power adapters, solar panels, fuel cells
CommunicationWi-Fi, Bluetooth, CAN bus, Ethernet, serial protocols

Self-Check Questions

  1. Trace the signal flow for a robot arm picking up an object: which components are involved at each stage of the sense-think-act cycle?

  2. Compare and contrast hydraulic actuators and electric motors—what application requirements would lead you to choose one over the other?

  3. A mobile robot needs to operate for 8 hours in an outdoor environment with uneven terrain. Which components would you prioritize in your design, and why?

  4. How do degrees of freedom in a manipulator relate to the tasks an end effector can perform? Give an example where 4-DOF would be insufficient.

  5. If a robot's sensors detect an obstacle but the robot fails to stop, identify three different component categories where the fault could originate and explain what might have gone wrong in each case.