Robots come in various types, each designed for specific tasks and environments. From mobile robots that navigate through spaces to stationary ones performing precise operations, the choice depends on the application. Understanding these distinctions is crucial for selecting the right robot for a given job.

Locomotion methods, such as wheels or legs, further define a robot's capabilities. Wheeled robots excel on flat surfaces, while legged ones adapt to uneven terrain. This diversity in design allows robots to tackle a wide range of challenges across different industries and research fields.

Mobile vs stationary robots

• Mobile robots have the ability to move and navigate through their environment, while stationary robots are fixed in place and perform tasks within a limited workspace
• Mobile robots are well-suited for tasks that require coverage of large areas or interaction with objects in different locations (exploration, delivery, surveillance), whereas stationary robots excel at precise, repetitive tasks in a fixed position (assembly, welding, dispensing)
• The choice between mobile and stationary robots depends on the specific application requirements, such as the need for mobility, workspace size, and the nature of the tasks to be performed

Wheeled vs legged locomotion

• Wheeled and legged locomotion are two primary means of mobility for robots, each with its own advantages and disadvantages
• Wheeled robots typically have simpler mechanical designs, are more energy-efficient, and can achieve higher speeds on flat, smooth surfaces (wheeled robots used in manufacturing, logistics, and transportation)
• Legged robots, inspired by biological systems, offer greater adaptability to uneven terrain and the ability to navigate obstacles, but are generally more complex and less energy-efficient (legged robots used in search and rescue, exploration, and research)

Stability of wheeled robots

• Wheeled robots generally have better stability compared to legged robots, especially on flat surfaces
• The stability of wheeled robots depends on factors such as the number and configuration of wheels (three-wheeled, four-wheeled, omnidirectional), the center of gravity, and the weight distribution
• Techniques such as differential steering and suspension systems can further enhance the stability of wheeled robots in dynamic environments (active suspension in planetary rovers)

Adaptability of legged robots

• Legged robots possess the ability to adapt to various terrains and navigate through unstructured environments
• The number and configuration of legs (bipedal, quadrupedal, hexapodal) influence the robot's stability, payload capacity, and maneuverability
• Legged robots can employ different gaits (walking, running, climbing) and control strategies (static stability, dynamic stability) to traverse challenging terrains (Boston Dynamics' Spot robot navigating rough terrain)
• Biomimetic designs inspired by animals (insects, mammals) can further enhance the adaptability of legged robots (gecko-inspired adhesive feet for wall-climbing robots)

Manipulator robots

• Manipulator robots, also known as robotic arms, are designed to perform tasks that involve interaction with objects in their workspace
• They consist of a series of linked segments (links) connected by joints, which enable the robot to position and orient its end effector (tool or gripper) in three-dimensional space
• Manipulator robots are widely used in industrial applications (assembly, welding, painting), as well as in fields such as surgery, space exploration, and research

Degrees of freedom

• Degrees of freedom (DOF) refer to the number of independent movements a robotic arm can perform
• Each joint in a manipulator robot contributes to the overall DOF, with most industrial robots having six or more DOF
• A higher number of DOF allows for greater flexibility and dexterity in performing complex tasks (KUKA's LBR iiwa robot with 7 DOF for human-robot collaboration)
• Redundant manipulators, with more DOF than necessary for a given task, offer increased maneuverability and the ability to avoid obstacles (NASA's Robonaut with 42 DOF for space operations)

End effectors

• End effectors are the devices attached to the end of a robotic arm, designed to interact with objects or perform specific tasks
• Common types of end effectors include grippers (mechanical, vacuum, magnetic), tools (welding torch, paint spray gun), and specialized attachments (camera, sensor)
• The choice of end effector depends on the application requirements, such as the object's shape, size, weight, and material properties
• Advances in end effector technology include adaptive grippers that can conform to various object shapes (Robotiq's adaptive gripper) and multi-functional end effectors that can perform multiple tasks (Schunk's EGP gripper with integrated camera and force/torque sensor)

Humanoid robots

• Humanoid robots are designed to resemble the human body in form and function, with a head, torso, arms, and legs
• The anthropomorphic design of humanoid robots allows them to operate in human-centered environments and interact with objects and tools designed for human use
• Humanoid robots have potential applications in fields such as personal assistance, healthcare, education, and entertainment (Softbank's Pepper robot for customer service and interaction)

Anthropomorphic design

• Anthropomorphic design in humanoid robots involves mimicking human anatomy, proportions, and movements
• This design approach enables humanoid robots to navigate environments designed for humans (doors, stairs, furniture) and manipulate objects using human-like grasping and manipulation techniques
• Challenges in anthropomorphic design include achieving human-like dexterity, balance, and locomotion, as well as managing the complexity and cost of the robotic system (Honda's ASIMO humanoid robot)

Social interaction capabilities

• Humanoid robots are often designed with social interaction capabilities to facilitate more natural and intuitive communication with humans
• These capabilities include facial expressions, gestures, speech recognition and synthesis, and the ability to interpret and respond to human emotions and social cues
• Social interaction capabilities can enhance the acceptance and effectiveness of humanoid robots in applications such as customer service, therapy, and education (Hanson Robotics' Sophia robot for social interaction and public engagement)
• Research in social robotics aims to develop algorithms and systems that enable humanoid robots to engage in more sophisticated and context-aware social interactions (MIT's Leonardo robot for studying social learning and collaboration)

Swarm robots

• Swarm robots are large groups of simple, autonomous robots that work together to perform tasks through local interactions and collective behavior
• Inspired by social insects (ants, bees), swarm robotics aims to achieve robust, scalable, and flexible systems that can adapt to changing environments and tasks
• Swarm robots have potential applications in areas such as search and rescue, environmental monitoring, exploration, and distributed manufacturing

Decentralized control

• Swarm robots operate under decentralized control, where each robot makes decisions based on local information and interactions with its neighbors
• Decentralized control allows swarm robots to be more resilient to failures and adaptable to changes in the environment or task requirements
• Local communication and sensing enable swarm robots to coordinate their actions without relying on a central controller or global information (Kilobot swarm robots using infrared communication for decentralized coordination)

Emergent behaviors

• Emergent behaviors in swarm robots arise from the collective interactions of individual robots following simple rules
• These behaviors can exhibit complex patterns and problem-solving capabilities that are not explicitly programmed into individual robots
• Examples of emergent behaviors in swarm robotics include self-organization, task allocation, collective decision making, and swarm intelligence (Harvard's Kilobots demonstrating self-assembly and collective transport)
• Research in swarm robotics focuses on understanding the principles and mechanisms underlying emergent behaviors and developing algorithms for controlling and optimizing swarm performance (SWARM-BOT project for developing self-assembling and self-organizing robot swarms)

Soft robots

• Soft robots are made from compliant, flexible materials that allow them to deform and adapt to their environment
• Unlike traditional rigid robots, soft robots can safely interact with delicate objects and conform to unstructured environments
• Soft robotics has applications in fields such as medical devices, wearable robotics, and human-robot interaction (Harvard's Octobot, a fully soft autonomous robot)

Flexible materials

• Soft robots are typically made from flexible materials such as silicone elastomers, thermoplastic polymers, and hydrogels
• These materials can undergo large deformations without damage, enabling soft robots to squeeze through tight spaces, absorb impacts, and conform to objects
• Advances in material science and fabrication techniques (3D printing, shape memory polymers) have expanded the range of materials available for soft robot construction (MIT's 3D-printed soft robots with embedded sensors)

Biomimetic inspiration

• Soft robot designs often draw inspiration from biological systems, such as octopuses, caterpillars, and elephant trunks
• Biomimetic soft robots aim to replicate the adaptability, compliance, and dexterity of these natural systems
• Examples of biomimetic soft robots include a soft robotic gripper inspired by octopus tentacles (Festo's OctopusGripper) and a soft crawler robot based on caterpillar locomotion (Tufts University's GoQBot)
• Research in soft biomimetics focuses on understanding the underlying principles of animal locomotion and manipulation and translating these principles into soft robot designs (Harvard's soft robotic fish inspired by manta rays)

Modular robots

• Modular robots consist of interconnected, reconfigurable units (modules) that can be rearranged to form different shapes and functionalities
• The modular design allows for flexibility, adaptability, and robustness, as modules can be added, removed, or replaced to suit different tasks or recover from damage
• Modular robots have applications in areas such as space exploration, search and rescue, and education (CKBot modular robot for research and education)

Reconfigurable components

• Modular robots are composed of standardized, interchangeable components that can be connected in various configurations
• These components typically include structural elements (frames, connectors), actuators (motors, pneumatics), sensors, and control modules
• The reconfigurability of modular robots enables them to adapt to different environments and tasks by changing their shape, size, and functionality (ATRON self-reconfigurable modular robot)
• Research in modular robotics focuses on developing efficient and reliable connection mechanisms, distributed control algorithms, and self-reconfiguration strategies (Roombots modular robot for adaptive furniture)

Adaptability to tasks

• The adaptability of modular robots allows them to perform a wide range of tasks by reconfiguring their structure and functionality
• Modular robots can adapt to different terrains and environments by changing their locomotion mode (snake-like, legged, wheeled) or morphology (Polybot modular robot with various locomotion configurations)
• Modular robots can also adapt to different task requirements by rearranging their components to form specialized tools or end effectors (SMORES-EP modular robot with reconfigurable manipulators)
• The adaptability of modular robots makes them well-suited for applications in unstructured and dynamic environments, where flexibility and versatility are essential (Sambot modular robot for search and rescue operations)

Autonomous vs teleoperated control

• Autonomous robots operate independently, making decisions and performing actions based on their own sensory inputs and programming
• Teleoperated robots, also known as remote-controlled robots, are controlled by a human operator from a distance using a communication link (radio, Wi-Fi, or wired connection)
• The choice between autonomous and teleoperated control depends on factors such as the complexity of the task, the level of human supervision required, and the communication bandwidth available

Fully autonomous operation

• Fully autonomous robots are capable of completing tasks without human intervention, relying on their own sensors, algorithms, and decision-making capabilities
• Autonomous operation requires advanced perception, planning, and control systems to enable robots to navigate, manipulate objects, and adapt to changing environments
• Examples of fully autonomous robots include self-driving cars (Waymo), autonomous drones (DJI Phantom), and robotic vacuum cleaners (iRobot Roomba)
• Research in autonomous robotics focuses on developing robust and reliable algorithms for perception (SLAM), decision making (planning, reinforcement learning), and control (adaptive control, robust control)

Human-in-the-loop control

• Human-in-the-loop control involves a human operator providing high-level commands, supervision, or intervention while the robot performs tasks semi-autonomously
• This control paradigm combines the strengths of human decision-making and robotic precision, speed, and repeatability
• Human-in-the-loop control is useful in applications where human expertise or judgment is required, such as surgery (da Vinci surgical robot), inspection, and maintenance (QinetiQ's Talon robot for bomb disposal)
• Challenges in human-in-the-loop control include designing intuitive human-robot interfaces, managing cognitive workload, and ensuring safe and seamless transfer of control between the human and the robot (NASA's Robonaut 2 for space operations with astronaut collaboration)

Single-purpose vs multi-purpose design

• Single-purpose robots are designed to perform a specific task or set of tasks, often with high efficiency and precision
• Multi-purpose robots, also known as general-purpose robots, are designed to perform a variety of tasks and can be adapted to different applications
• The choice between single-purpose and multi-purpose design depends on factors such as the application requirements, cost, and flexibility needed

Size considerations

• The size of a robot can vary greatly depending on its intended application, ranging from micro-scale robots (less than 1 mm) to large-scale robots (several meters)
• The size of a robot affects its mobility, payload capacity, power requirements, and interaction with the environment
• Miniaturization and scaling up robot size present unique challenges in terms of design, fabrication, and control

Miniaturization challenges

• Miniaturization of robots involves reducing the size of components such as actuators, sensors, and power sources while maintaining functionality
• Challenges in miniaturization include manufacturing precision, power density, and the scaling effects of physical forces (surface forces dominating over volume forces at small scales)
• Advances in micro-electromechanical systems (MEMS), nanotechnology, and 3D printing have enabled the development of miniature robots for applications such as medical diagnosis and treatment (pill-sized capsule endoscope robots), and environmental monitoring (Harvard's RoboBee)

Large-scale robot applications

• Large-scale robots are used in applications that require high payload capacity, long reach, or operation in expansive environments
• Examples of large-scale robots include industrial manipulators (ship-building cranes), construction robots (automated bricklaying systems), and mining robots (autonomous haul trucks)
• Challenges in large-scale robot design include structural integrity, power management, and safety considerations when interacting with humans or infrastructure
• Research in large-scale robotics focuses on developing efficient control algorithms, robust sensing and navigation systems, and human-robot collaboration methods (NASA's Robonaut 2 for assisting astronauts in space operations)