In the rapid development of robotics technology, mechanical structures play a crucial role, much like the "skeleton" of a robot's body. They are the fundamental architecture supporting robots in completing various tasks, providing stable physical support and flexible movement capabilities for all robot components. This ensures that hardware components such as sensors, processors, and actuators can work together precisely and efficiently to complete tasks. Whether it's the high-precision positioning of industrial robots in complex production processes, the efficient movement of service robots navigating different scenarios, or the reliable support of exploration robots facing complex terrain, the performance of the mechanical structure directly affects the robot's work efficiency, movement capabilities, and operational stability.
The robot structure is the foundation for a robot's normal operation and the completion of various tasks. The main structure of a robot includes the body, arm, wrist, end effector, motion mechanism, and drive system. The body is the supporting part of the robot, typically possessing a certain degree of rigidity and stability, providing the mounting base for other components. The arm is a key component for the robot's spatial movement, and its structural forms are diverse, commonly including Cartesian coordinate, cylindrical coordinate, spherical coordinate, and articulated types. The wrist connects the arm and the end effector, and is used to adjust the posture and position of the end effector. It generally has multiple degrees of freedom and can achieve flexible movement.
As the core component enabling flexible robot movement, the design of the motion mechanism directly determines the robot's mobility and adaptability under different terrain conditions. Among common types of motion mechanisms, wheeled mechanisms, with single-wheel drive, are suitable for flat indoor environments; dual-wheel differential drive achieves highly flexible steering through speed differences; multi-wheel drive (such as four-wheel/six-wheel) combined with an independent suspension system can handle complex outdoor terrain; tracked mechanisms, through the combination of tracks, drive wheels, guide wheels, and tensioning devices, are the first choice for rugged terrain (such as military reconnaissance and rescue scenarios) due to their strong grip; legged mechanisms mimic animal walking, with multi-joint and linkage structures forming independently controlled leg structures (such as the Boston Dynamics Spot robot), demonstrating high adaptability in extreme terrains such as mountains and forests; composite mechanisms combine the advantages of wheeled and tracked/legged mechanisms. For example, wheel-legged robots can switch movement modes according to terrain, achieving functional complementarity.
Arms
As a key component for achieving precise spatial manipulation, the robot arm's motion form and degrees of freedom directly determine its operating range and flexibility. The robot arm is mainly composed of joints and links: joints, as movable connecting units, typically integrate motors, reducers, and bearings; their number and type determine the degrees of freedom (e.g., a six-DOF robot arm has six independent motion joints); links, as rigid transmission components, directly affect the arm's motion trajectory and workspace through their length and shape. Based on coordinate system characteristics, robots can be divided into four main types: Cartesian coordinate robots cover regular spaces through linear motion along the X, Y, and Z axes; cylindrical coordinate robots combine horizontal rotation and two-axis linear motion to adapt to cylindrical operation scenarios; spherical coordinate robots achieve spherical space coverage through two-axis rotation and single-axis linear motion; and articulated arms, through combinations of multiple rotary joints (such as industrial six-axis robotic arms), can flexibly manipulate complex-shaped objects to meet high-precision operation requirements.
The wrist, as a key hub connecting the robot arm and the end effector, plays a crucial role in precisely adjusting the end effector's posture and position. Its flexibility and degrees of freedom directly determine the robot's ability to perform fine operations. Structurally, the core components of the wrist fall into two categories: first, rotational joints that enable multi-dimensional movement, such as a three-degree-of-freedom wrist which can cover three-dimensional space through combined movements of pitch, yaw, and roll; and second, rigid connection components that, through precise design, ensure smooth and reliable motion transmission between the wrist, arm, and end effector. Based on the degree-of-freedom configuration, wrists can be categorized into single-degree-of-freedom (supporting only a single rotational axis, suitable for basic tasks) and multi-degree-of-freedom (typically integrating 2-3 rotational axes, enabling complex gesture adjustments).
The end effector, as the direct execution unit for robot interaction with the outside world, has a functional form highly dependent on the application scenario. Common types can be divided into two main categories: first, gripping actuators, where parallel grippers use two parallel jaws to stably grasp regular objects (such as cylinders and cubes), while multi-finger grippers mimic the structure of human fingers, grasping irregular objects through multi-joint linkage; and second, tooling actuators, including welding torches used in welding scenarios, spray nozzles for painting operations, cutting and engraving tools, and vacuum suction cups designed for lightweight objects (glass, thin sheets, etc.). In addition, the integrated multi-joint bionic robotic hand can simulate human hand movements to complete complex grasping and manipulation tasks, further expanding the boundaries of the robot's operational capabilities.
Drive System
The drive system provides power for the robot's movement, converting electrical or other forms of energy into mechanical energy to drive the joints and end effectors.
Main Components
Motors: Common types include DC motors, AC motors, servo motors, and stepper motors. Servo motors and stepper motors are often used for robot joint drives due to their high precision and controllability.
DC Motors: Suitable for simple wheeled robots; low cost and easy control.
Servo Motors: Used for robots requiring high-precision control, such as leg joint drives.
Brushless Motors: High efficiency and long lifespan; suitable for high-performance mobile robots.
Reducers: Used to reduce motor speed and increase torque, ensuring the joints can output sufficient torque. Common reducers include harmonic reducers, planetary reducers, and RV reducers.
Planetary Reducers: Small size and high transmission efficiency; suitable for wheeled robots.
Harmonic Reducers: High precision; suitable for joint drives.
RV Reducers: High load capacity; suitable for large robots.
Transmission mechanism: Transmits power from the motor to the joints. Common transmission methods include gear drive, belt drive, and chain drive.
Gear drive: Used to transmit power and increase torque.
Belt drive: Suitable for lightweight robots, providing smooth transmission.
Chain drive: Suitable for heavy-duty robots, offering high transmission efficiency.
Steering System
The steering system, as the core module for flexible path planning in robots, ensures efficient navigation in complex environments through precise control of movement direction. Based on the driving method, mainstream steering types can be divided into three categories: differential steering, which achieves steering control by adjusting the speed difference between the two wheels, is common in two-wheel drive robots; steering wheel steering uses independently steerable drive wheels (or wheel sets), and is mostly used in multi-wheel drive platforms; omnidirectional wheel steering relies on the inclined roller design of Mecanum wheels, enabling robots to perform lateral translation and rotation in place, becoming a highly flexible solution for indoor logistics scenarios.
Suspension System
The suspension system improves the robot's motion stability by buffering ground impacts, and its structural form directly affects terrain adaptability. Independent suspension systems have independent shock absorption units for each wheel, which can specifically absorb vibrations from uneven road surfaces, significantly enhancing the ability to traverse complex terrains (similar to multi-link suspension in automobiles); non-independent suspension uses a multi-wheel shared frame design, which simplifies the structure and reduces costs, but the shock absorption effect is limited by the overall rigidity, making it more suitable for basic applications in flat environments.
Power System
The power system provides energy to the robot, ensuring its normal operation.
Common Types:
Batteries: Such as lithium-ion batteries and nickel-metal hydride batteries, used to provide electrical power.
Fuel Cells: Suitable for robots requiring long-term operation, with high energy density.
Solar Panels: Used for outdoor robots, charging via solar energy.
Connecting Components and Support Structures
These components connect the various major parts of the robot, ensuring the stability and reliability of the overall structure.
Common Components
Connecting Shafts: Used to connect motors and reducers, or components connecting joints.
Support Frames: Used to support the arms and wrists, ensuring their stability during movement.
Fixed Components: Such as bolts, nuts, screws, etc., used to secure various components, ensuring the structural robustness.
Sensor Mounting Components
Although the sensors themselves are part of the sensing component, their mounting components are part of the mechanical structure, used to fix and protect the sensors, ensuring their proper functioning.
Common Components
Sensor Brackets: Used to mount vision sensors (such as cameras), force sensors, tactile sensors, etc.
Sensor Protective Covers: Used to protect sensors from external environmental interference and damage.
Navigation and Positioning Components
These components help the robot navigate and locate itself in its environment, ensuring it can autonomously move to its target location.
Common Components
LiDAR: Used to measure distance and build environmental maps.
Camera: Used for visual navigation and target recognition.
Inertial Measurement Unit (INS): Used to measure the robot's acceleration and angular velocity, assisting navigation.
GPS Module: Used for outdoor robots, providing global positioning information.
Odometry: Calculates the robot's distance traveled and direction by measuring wheel rotation speed and angle.
Communication Components
Communication components are used for data transmission between the robot and external devices (such as a control center or other robots).
Common Components
Wireless Communication Modules: Such as Wi-Fi, Bluetooth, and 4G/5G modules, used for wireless communication.
Wired Communication Interfaces: Such as Ethernet interfaces, used for wired communication.
Cables and Conduits
Cables and conduits are used to transmit power and signals, ensuring the proper functioning of the robot's various components.
Common Components
Power Cables: Used to transmit electrical energy, powering motors and other electrical components.
Signal Cables: Used to transmit control signals and sensor feedback signals.
Air or Hydraulic Lines: For pneumatic or hydraulically driven end effectors, gas or liquid needs to be transported through pipes.
Protective Components: Protective components protect the robot from external environmental influences such as dust, liquids, and collisions, while also protecting the safety of operators.
Common Components:
Protective Covers: Used to cover critical robot components such as motors, reducers, and joints.
Safety Barriers: Used to isolate the robot's working area, preventing personnel from entering hazardous areas.
Dust Covers: Used to protect joints and sensors, preventing dust from entering.
Emergency Stop and Safety Devices: These devices are used to stop the robot's movement in emergencies, ensuring the safety of personnel and equipment.
Common Components:
Emergency Stop Button: Usually installed on the robot's body or control panel; pressing it immediately stops all movement.
Collision Sensor: Triggers an emergency stop when the robot collides with an object or person.
Safety Light Curtain: Used to detect personnel within the robot's working area; once personnel are detected, the robot's movement immediately stops.
These mechanical components together constitute the physical basis of the robot, enabling it to perform a variety of complex tasks.
