Top Applications of Articulated Robots in Industry

An articulated robot (also called a jointed-arm robot) is a type of industrial robot with a series of interconnected segments (links) and rotary joints that mimic the structure and movement of a human arm. Each joint provides a degree of freedom (DoF), enabling the robot to perform complex, multi-directional movements in 3D space—making it ideal for tasks requiring high flexibility, precision, and reach in manufacturing, assembly, and automation.

Core Structure & Components

Articulated robots are built around a modular, jointed structure, with key components that enable movement and control:

1. Robot Arm (Manipulator)

The primary mechanical structure, composed of rigid links connected by rotary joints (revolute joints):

Base: Fixed or mobile foundation that supports the entire arm (anchored to the floor, ceiling, or a mobile platform like an AGV).
Shoulder Joint: Rotates the arm horizontally (about the base’s vertical axis) and vertically (pitches up/down).
Elbow Joint: Extends or retracts the arm (pitches to adjust the distance between the shoulder and wrist).
Wrist Joints: Typically 2–3 joints (roll, pitch, yaw) that rotate the end effector to orient it precisely (e.g., twisting a tool, aligning a part).
End Effector: The “hand” of the robot (e.g., gripper, welding torch, spray nozzle, suction cup) that interacts with workpieces.

2. Degrees of Freedom (DoF)

Each joint adds a degree of freedom, defining the robot’s movement range:

4-DoF: Basic articulated robots (base, shoulder, elbow, wrist roll) for simple tasks (e.g., pick-and-place).
6-DoF: Most common industrial variant (base, shoulder, elbow, wrist roll/pitch/yaw) for full 3D movement (e.g., assembly, welding).
7-DoF (Redundant): Extra joint for increased flexibility (e.g., navigating tight spaces, avoiding obstacles in automotive assembly).

3. Actuation System

Servo Motors: Most common actuation method—provide precise control of joint rotation (position, speed, torque) via feedback from encoders.
Hydraulic/Pneumatic Actuators: Used in heavy-duty robots (e.g., material handling of large parts) for high force output.
Direct Drive Motors: Eliminate gearboxes for higher precision and lower maintenance (used in collaborative robots).

4. Control System

Controller: A computer that executes pre-programmed motion commands (G-code, robot-specific languages like KRL for KUKA or RAPID for ABB).
Sensors: Encoders (joint position), force/torque sensors (collision detection), vision systems (part alignment), and proximity sensors (safety).
Software: Interfaces for programming (teach pendants, offline simulation tools like RobotStudio) and integration with factory systems (PLCs, IoT platforms).

Key Types of Articulated Robots

Articulated robots are classified by size, payload, and application:

1. Small Collaborative Robots (Cobots)

Payload: 0.5–16 kg
Reach: Up to 1.5 m
Features: Built-in force/torque sensors for safe human-robot interaction (no safety cages required), easy programming (drag-and-drop).
Use Cases: Pick-and-place, assembly, packaging, quality inspection (e.g., Universal Robots UR5, Fanuc CRX).

2. Medium Industrial Articulated Robots

Payload: 10–50 kg
Reach: 1–3 m
Features: High precision (±0.01 mm), fast cycle times, designed for repetitive tasks.
Use Cases: Welding (MIG/TIG), painting, material handling, machine tending (e.g., ABB IRB 1600, KUKA KR 60).

3. Large Heavy-Duty Robots

Payload: 50–1,000 kg+
Reach: 2–6 m
Features: Hydraulic or high-torque servo actuation, rugged construction for heavy loads.
Use Cases: Automotive body assembly (lifting car frames), foundry work (pouring molten metal), large part machining (e.g., Fanuc M-2000, Yaskawa Motoman MH500).

4. SCARA-Articulated Hybrids

Combines SCARA (Selective Compliance Assembly Robot Arm) and articulated design: 4 DoF with rigid vertical axis and compliant horizontal axes.
Use Cases: High-speed assembly (electronics), pick-and-place (packaging) (e.g., Epson GX series).

Key Performance Metrics

Metric	Definition	Relevance
Payload Capacity	Maximum weight the end effector can handle (kg).	Determines suitability for light (electronics) vs. heavy (automotive) tasks.
Reach	Maximum distance from the base to the end effector (m).	Critical for accessing large workpieces or reaching multiple workstations.
Repeatability	Ability to return to a programmed position (±mm/µm).	Essential for precision tasks (e.g., micro-assembly, welding).
Cycle Time	Time to complete a single task (e.g., pick-and-place cycle in seconds).	Impacts production throughput in high-volume manufacturing.
Accuracy	Deviation from the intended position (vs. repeatability: deviation from a taught position).	Important for tasks requiring absolute precision (e.g., machining, inspection).

Applications of Articulated Robots

1. Automotive Manufacturing

Welding (body-in-white spot welding), painting (car bodies), assembly (engine components, door handles), and material handling (lifting chassis).
Example: 6-DoF robots in Tesla’s Gigafactories for battery pack assembly.

2. Electronics & Semiconductor

Micro-assembly (circuit board component placement), soldering, and inspection (PCB quality checks).
Collaborative robots for handling delicate semiconductor wafers.

3. Food & Beverage

Packaging (placing products into boxes), palletizing (stacking cases), and sorting (grading fruits/vegetables).
Sanitary designs (stainless steel arms) for food-safe environments.

4. Aerospace

Drilling and fastening (aircraft fuselage panels), composite material layup, and inspection (non-destructive testing with ultrasonic tools).
Heavy-duty robots for handling large aircraft wings.

5. Medical & Pharmaceutical

Surgical robots (e.g., da Vinci Surgical System—7-DoF articulated arms for minimally invasive surgery).
Pharmaceutical packaging (filling vials, labeling) and lab automation (sample handling).

6. Metal Fabrication

Welding (MIG/TIG for structural steel), cutting (plasma/laser cutting), and grinding (deburring metal parts).

Advantages & Limitations

Advantages

Flexibility: Multi-DoF movement enables complex tasks (e.g., reaching around obstacles, orienting parts at any angle).
Precision: High repeatability and accuracy for consistent quality in manufacturing.
Productivity: 24/7 operation with no fatigue, reducing cycle times and labor costs.
Versatility: Interchangeable end effectors allow the same robot to perform welding, assembly, or packaging.
Safety: Cobots with force sensing enable safe human-robot collaboration; industrial robots with safety cages prevent accidents.

Limitations

Cost: High initial investment (industrial robots: $50,000–$500,000) plus installation and programming.
Programming Complexity: Advanced tasks require skilled programmers (mitigated by user-friendly cobot software).
Space Requirements: Large industrial robots need dedicated floor space and safety barriers.
Payload/Reach Tradeoff: Higher payload often reduces reach and speed (and vice versa).
Sensitivity to Environment: Dust, moisture, or extreme temperatures may require specialized enclosures (e.g., for foundry robots).