What is a robot teach pendant?

The programming and control technology for industrial robots has seen significant development and new applications in recent years. One key component is the "robot teach pendant."

What is a teach pendant? It is a handheld device used for manual robot manipulation, programming, parameter configuration, and monitoring.

Learning Methods

"Robot teaching" is a crucial process for robots to learn to perform specific tasks, typically through two main learning methods:

1. Offline Programming: This method uses computer software to pre-program the robot's motion trajectories and actions. Without direct interaction with the robot, the programmer builds a detailed model of the robot and its working environment, and plans its movements using a robot-specific programming language.

2. Online Teaching: The operator interacts directly with the robot, using tools such as teach pendants and joysticks to guide it directly in completing specific tasks. This method allows the operator to teach the robot how to perform complex tasks more intuitively while ensuring operational safety.

Both methods require close monitoring of the robot's safe operation and performance. Teach pendants play a crucial role in this process—they are not only used for manually operating and programming the robot, but also responsible for setting operating parameters and monitoring the robot's performance, ensuring the accuracy and efficiency of the operation.

The numerous advantages of teach pendants

Teach pendants offer many advantages that make them indispensable for engineers.

The first significant advantage lies in enhanced safety. For non-cooperative industrial robot programming, disability switches are an essential configuration. These switches have an automatic response function, triggering automatically when the operator becomes incapacitated, loses consciousness, or leaves the control device. As an important form of fail-safe technology, disability switches can promptly stop machine operation, effectively preventing potential hazards. Teach pendants provide users with a convenient operating method; using a key, users can easily switch the robot's operating mode between teach mode and unrestricted operation mode, thus achieving precise control of the disability switch.

For collaborative robots, there are also emergency situations requiring the robot to autonomously stop working. In these cases, the teach pendant plays a crucial role in protective shutdown, ensuring safety. Since all systems are susceptible to failure, operators must possess the ability to control the robot and switch its behavior mode to a safe mode to enter the work cell or move the robot to a designated location when necessary. The teach pendant is the most effective tool for performing these operations.

The second advantage lies in its powerful monitoring capabilities. The teach pendant can monitor the robot and all devices in the work cell in real time, issuing an immediate alarm upon detecting behavioral errors. Even more impressively, it can even predict potential robot errors. During program execution, the teach pendant acts as an intuitive window, allowing operators to clearly understand the robot's operation and the control position of the entire program.

The third advantage is its efficient testing capability. The teach pendant is an ideal tool for testing new robot programs, offering convenience and speed. Of course, in addition to using the teach pendant for testing, third-party tools, such as OLRP applications, can also be used. Compared to OLRP, the teach pendant is superior in completing simple programming tasks, offering faster speed and easier operation. OLRP software tools are better suited for handling complex applications with hundreds or thousands of points, such as the fine path planning required for welding. However, many tasks do not involve such complex movements. Programming operations such as robot stretching, pick-and-place, straight-line welding, and dispensing are relatively simple and need to be completed quickly, especially in high-complexity, low-batch production environments where minimizing changeover time is crucial. Of course, regardless of the testing tools used, all testing must be conducted slowly under strict operator supervision to prevent hardware damage due to operational errors. During testing, the operator needs to carefully check the clearance between the robot and the hardware (such as the machine tool) in the work cell. Furthermore, a teach pendant can be used to perform other testing activities, such as teaching the basic framework and tooling framework. The operator can have the robot run slowly to confirm its movement within the work cell and verify the range of motion of the robot and its tooling within the work cell.

The fourth advantage is the ability to adjust the robot program in real time. In actual operation, the robot may err for various reasons, such as drifting a certain distance in a certain direction, leading to decreased accuracy; inaccurate alignment of the end effector (EOAT) or failure to reach the part position; and differences between the simulated state and the real world. For example, when the robot moves on the seventh-axis guide (manually moved via the teach pendant), the simulation expects perfect, jitter-free movement, but this is not the case in reality. The teach pendant can compensate for these situations. Although the compensation may be small, even a tiny adjustment of 1 millimeter can significantly optimize the welding results to a satisfactory level.

A fifth advantage is that the teach pendant can reliably and proactively prompt the operator for the necessary input. Especially when starting a new task, the operator may want to pause the program to inspect parts or other blocks of the application. While the application is running, the operator can also interact with the task using the teach pendant. This type of operation is not possible in OLRP software.

The sixth advantage of a teach pendant is that it can integrate many components within a work cell, such as laser scanners and stack lights. The operator loads the program onto the robot and then writes subroutines to coordinate the robot's movement with the activities of other components in the work cell. The code for these subroutines is also executed by the teach pendant. Many factories have specifically developed subroutines, such as those for part removal, which can be easily stored in the teach pendant. In OLRP, this is not possible.

The seventh advantage of a teach pendant is that it allows the user to add control logic. Once the operator has created and tested their program, they need to run dozens of parts. Using a teach pendant, they can add control logic, allowing the application to run unattended, often in conjunction with other robots or devices in the work cell. Conversely, most OLRP software neither has a built-in control logic structure nor allows it to be added.

Finally, the teach pendant provides a high degree of interactivity between configuring and executing the application. Because there is no need to transfer programs from other devices, the operator can perform tasks quickly and efficiently.

Having discussed the advantages, let's now look at the disadvantages. Currently, most teach pendants are independently developed by each brand, making them non-shared and difficult to use. For example, teach pendants from several well-known robot suppliers, such as Kuka, ABB, and Fanuc, are not interchangeable. Many teach pendants also lack some basic functions expected from everyday equipment; for instance, simple copy and paste is impossible on many current models.

Therefore, teach pendants urgently need innovation, and some companies have already made progress in this area. Innovative teach pendants can significantly reduce or even eliminate the training time required to use robot systems, while also reducing robot downtime. Furthermore, they can support the deployment of more robot systems and enable faster programming operations.

With the help of visual programming software, such as Task Canvas, which runs on READY Robotics' Forge/OS interface, its functionality is very powerful and can control almost all brands of industrial robots. It's worth noting that there are currently over 70 well-known robot brands worldwide, each with its own proprietary teach pendant and control software. Moreover, almost every robot is equipped with a unique programming or scripting language, requiring operators to undergo extensive training to use it correctly. The revamped teach pendant no longer relies on complex robot programming languages; it is equipped with an intuitive touchscreen interface, eliminating the need for operators to access cumbersome menus via keyboard.