Safely Interacting with Robots in Teach Mode: Best Practices for Human-Robot Collaboration
As industrial robots become increasingly common in manufacturing and warehouse environments, the need for safe human-robot interaction during programming and maintenance tasks grows more critical. One of the highest-risk situations occurs when robots are placed in teach mode, allowing technicians to guide or program the robot manually. This mode often requires proximity to the robot’s moving parts and can bypass normal safeguarding. Without proper controls and procedures, even a slow-moving robot can cause serious injury or death. Fortunately, standards, technology, and training can help mitigate these risks.
Understanding Teach Mode and its Risks
Teach mode (also referred to as manual or jog mode) allows operators to control a robot’s movement incrementally using a teach pendant. Unlike automatic mode, where robots follow a predefined path, teach mode is typically used for initial programming, calibration, and troubleshooting. Because the robot may move unpredictably or stop abruptly, it introduces unique hazards—especially if safeguards are disabled or overridden.
Operators in teach mode are often inside the robot’s working envelope, placing them at greater risk of contact. This is why OSHA, ANSI/RIA R15.06, and ISO 10218 require that specific safety protocols be followed when programming or teaching robots.
Use of DCS Zones and Restricted Space Safeguarding
Modern robots can be configured with DCS (Dual Check Safety) zones or similar virtual fences. These programmable safety zones use the robot’s own internal monitoring to restrict motion and prevent travel into defined hazardous areas. For example, you can set up a DCS zone that limits the robot's movement to a safe region while in teach mode, ensuring it cannot unexpectedly swing or extend into a technician’s space.
DCS zones are especially useful for complex work cells or applications with multiple robots. They provide a software-based safeguard, but like all controls, they must be properly validated and protected against unauthorized changes.
Enhancing Safety with Presence-Sensing Devices
Light curtains, area scanners, and pressure-sensitive mats are examples of presence-sensing devices that can detect human entry into hazardous zones and trigger a safety response. When integrated into the robot's safety control system, these devices can halt or restrict robot motion when someone enters a protected area.
However, during teach mode, certain safety devices may be temporarily muted or bypassed to allow necessary access. In these cases, muting should be controlled and limited in time, area, and function—with visual indicators and supervisory controls in place. Teach pendants should have enabling switches (also called “deadman” switches) that require continuous operator input to allow movement, ensuring that the robot stops immediately if the operator releases or drops the pendant.
Safe Work Practices and Training
No technology can replace well-established safe work procedures. Key practices include:
Use of approved teach mode procedures with documented risk assessments.
Limiting access to trained and authorized personnel only.
Wearing appropriate PPE based on risk (e.g., safety glasses, steel-toed boots).
Never turning your back on a robot in teach mode.
Maintaining clear communication with others in the area.
Conclusion
Safe interaction with robots in teach mode requires a combination of engineering controls, administrative procedures, and operator competence. Leveraging technologies like DCS zones and presence-sensing safeguards—while also adhering to strict programming and access protocols—ensures a safer work environment where humans and robots can collaborate effectively without compromising safety.
