With the advancement of industrial automation and smart manufacturing, robotic arms and robot systems are increasingly applied on production lines. From traditional tasks such as material handling, assembly, and welding to modern flexible automated production units, robots play a central role. Both industrial robots and collaborative robots rely on program control for operation. The choice of robot programming method affects not only development efficiency but also production flexibility, deployment speed, and human‑robot collaboration safety. Teach pendants and lead‑through programming are two common online programming methods. This article explains their concepts, principles, advantages, disadvantages, and core differences, helping readers understand the design philosophy and suitable application scenarios of each method.
Significance and Classification of Robot Programming
Robot programming essentially provides information on trajectory, motion, and logic so that a robot can automatically perform tasks according to a predefined process. Programming methods can be classified in several ways:
Online programming: Programming directly on the robot system;
Offline programming: Designing and simulating on a computer, then uploading to the robot;
Teach‑based programming: Operators “teach” the robot actions via interaction;
Automatically generated programs: Path planning generated by software or algorithms.
Within teach‑based methods, the most representative and widely applied are teach pendant programming and lead‑through programming.
Teach Pendant: Concept and Principle
What is a teach pendant?
A teach pendant is a handheld device used for robot control and programming. It usually connects to the robot controller and allows operators to move robot joints, input position data, and issue commands via buttons, switches, an LCD, or a touchscreen. Operators move the robot to a target position and save this data to the program, creating a sequence of tasks.
Also called a programmer pendant or control pendant, it is one of the most common industrial robot programming tools. It serves as both a control device and a programming interface, especially important during the robot teaching phase.
Working Principle
The teach pendant works via interactive human‑robot operation. The programmer uses buttons, joysticks, or touchscreen interfaces to move the robot along specified paths to desired positions, setting parameters such as motion speed, delay, and tool state. Each position and its associated commands are stored in the controller for later task execution.
In short, the teach pendant functions as a human‑machine interface, enabling:
Position setting: Recording robot joint positions in space;
State control: Defining end‑effector actions (grasping, spraying, welding, etc.);
Logic flow: Setting conditional jumps, loops, and control logic;
Motion parameters: Specifying speed, acceleration, and pauses.
Example
Traditional teach pendants include physical buttons, switches, and emergency stops. Modern pendants may integrate touchscreens and simplified graphical interfaces for more intuitive operation.
Lead‑Through Programming: Concept and Principle
What is lead‑through programming?
Lead‑through programming is a teach method in which the operator manually guides the robot’s end effector along the desired path and positions. The control system records these points and paths for task execution. It is also called hand guidance or walk‑through programming.
In this method, the robot arm is essentially “led” through its motions. The operator moves the end effector along the trajectory to key points, and the controller stores the data as program instructions. This approach is suitable for continuous motions, simple paths, or repetitive tasks and does not require in‑depth programming knowledge.
Working Principle
The robot enters a “teach mode,” allowing the operator to push joints directly (common with lightweight collaborative robots) or use sensors at the end effector to detect applied force. The system records actions including position, speed, and acceleration.
Lead‑through programming is based on demonstrative input—essentially showing the robot what to do rather than typing commands—so it resembles a learning or motion-copying method.
Core Differences
Input Method
Teach pendant: Input actions and parameters via the pendant interface, manually setting each point, speed, and logic.
Lead‑through: Demonstrate the task by moving the end effector; the system automatically records data without manual entry of numbers.
Operator Skill Requirement
Teach pendant: Requires familiarity with the interface, button operation, command system, and basic programming logic.
Lead‑through: More intuitive; operator only moves the robot, while the controller handles recording, suitable for non‑experts.
Applicable Robot Types
Teach pendant: Common for traditional six-axis industrial robots, especially for high-precision or complex tasks.
Lead‑through: Popular for collaborative robots, which are lightweight, easy to guide manually, and designed for direct interaction. Traditional industrial robots may not be suitable due to size, inertia, and safety concerns.
Speed and Efficiency
Lead‑through: Often faster, as entire paths are recorded in a single demonstration.
Teach pendant: Slower, requires step‑by‑step input for each action, particularly for complex motions.
Precision and Controllability
Teach pendant: Allows precise adjustment of position and speed, suitable for tasks like assembly or welding.
Lead‑through: Precision depends on manual guidance; may be less accurate for complex paths.
Flexibility and Complexity
Teach pendant: Handles complex logic, conditional branching, and IO control more effectively.
Lead‑through: Primarily linear path demonstration, less suitable for tasks requiring complex logic.
Application Scenarios
Teach pendant is better for:
Fine motion and point-based tasks (precision assembly, accurate welding);
Complex logic and condition-based tasks (branching, IO control);
Large-scale industrial robot applications in traditional production lines.
Lead‑through programming is better for:
Collaborative robots (lightweight and safe to guide);
Simple, repetitive paths (spraying, polishing);
Fast deployment with low programming skill requirements.
Trends and Integration
Robot programming methods are evolving to combine multiple approaches, such as touchscreen teaching, lead‑through posture guidance, voice commands, and graphical offline programming. While teach pendants remain mature, they are evolving toward more intuitive and intelligent interfaces, especially in collaborative robot applications.
Lead‑through programming increasingly integrates sensors and collision‑avoidance systems, making manual guidance safer and more reliable. Future methods will likely be more interactive, automated, and closely integrated with human‑robot collaboration.
Teach pendants and lead‑through programming are both important online programming methods. Teach pendants emphasize point-by-point programming via the controller interface, suitable for precise, complex, and logic-intensive tasks. Lead‑through programming emphasizes intuitive demonstration of robot trajectories, lowering the programming threshold and speeding up deployment. Each method has advantages and is suitable for different scenarios. Understanding their differences aids in selecting the optimal programming approach and improves automation project efficiency and execution stability.
