As robots take on increasingly complex and autonomous roles in manufacturing, assembly, and logistics, the question of how they sense and respond to unexpected forces and obstacles has become one of the most critical engineering challenges in automation system design. Two sensor technologies are central to addressing this challenge: the anti collision sensor and the broader category of force sensors. The anti collision sensor protects the robot and its tooling from damage when an unexpected collision occurs, while force sensors provide the robot with a sense of touch, enabling it to detect, measure, and respond to the forces acting on its end-of-arm tooling during task execution. Together, these technologies make robots safer, smarter, and more capable of working alongside humans in collaborative environments.
What Is an Anti Collision Sensor?
An anti collision sensor, sometimes called an anti-collision unit or collision protection device, is a mechanical and electronic safety device that mounts between the robot flange and the end-of-arm tooling. When the robot or its tooling makes unexpected contact with a fixture, workpiece, or person, the anti collision sensor deflects, absorbing the impact force and simultaneously generating an electrical signal that causes the robot controller to halt motion immediately. This response happens within milliseconds, before the collision force can damage the robot’s wrist joints, the tooling, or the workpiece.
SCHUNK offers a range of Anti-Collision Units as part of its Automation Technology product category. The SCHUNK anti-collision unit is designed to protect robot tools and enable safe automation processes, listed directly in the company’s official product navigation under Automation Technology. The anti-collision unit from SCHUNK incorporates a spring-based deflection mechanism that allows controlled compliance in all directions during a collision event, combined with a sensor that provides an immediate stop signal to the robot controller. After a collision, the anti collision sensor unit resets automatically, allowing the robot to resume operation quickly once the cause of the collision has been identified and corrected.
Applications of Anti Collision Sensors in Industrial Robots
The anti collision sensor is particularly important in applications where the robot operates in close proximity to fixtures, workpieces, or human operators. In robotic assembly, where tight clearances between the gripper and assembly fixtures are common, an anti collision sensor provides essential protection against the consequences of a robot following an incorrect path or a workpiece being incorrectly positioned. In collaborative robot (cobot) applications, the anti collision sensor provides an additional layer of safety beyond the inherent force limiting capability of the cobot arm, protecting both the cobot and its operator from the consequences of unexpected contact.
Force Sensors: Giving Robots a Sense of Touch
While the anti collision sensor responds reactively to collision events, force sensors provide a proactive, continuous measurement of the forces and torques acting on the robot’s end-of-arm tooling during task execution. This real-time force and torque data allows the robot controller to adjust the robot’s motion and force in response to what is actually happening at the workpiece interface, rather than simply following a pre-programmed path regardless of the forces being generated.
SCHUNK offers Force/Torque Sensors as a dedicated product category within its Automation Technology portfolio. These force sensors from SCHUNK measure all six components of force and torque (Fx, Fy, Fz, Mx, My, Mz) simultaneously, providing a complete picture of the interaction forces at the robot’s end-of-arm tool. This six-axis measurement capability is essential for applications such as force-controlled assembly, where the robot must feel the mating of parts and adjust its motion to complete an assembly without over-forcing a joint or missing a pocket. It is also critical for robotic grinding, polishing, and deburring applications, where the contact force between the tool and the workpiece must be maintained within a defined range to achieve consistent material removal and surface quality.
Force-Controlled Assembly and Insertion
Force-controlled assembly using force sensors allows robots to perform precise insertion tasks that would otherwise require exceptional positional accuracy or jig fixturing. When a robot attempts to insert a pin into a bore or seat a bearing into a housing, force sensors detect the forces generated as the parts come into contact and guide the robot’s motion to align the components correctly and complete the insertion without jamming or over-forcing. This capability dramatically expands the range of assembly operations that can be automated, including tasks that have traditionally required skilled human operators with a natural sense of touch.
Robotic Deburring and Grinding
In robotic deburring and surface finishing, force sensors allow the robot to maintain a consistent contact force between the deburring tool and the workpiece surface, compensating for variations in part geometry, tool wear, and workpiece positioning. Without force sensors, a robot performing deburring must follow a rigid path, which means that dimensional variation in the workpiece will translate directly into variation in the material removed, producing inconsistent results. With force sensors integrated into the process, the robot adapts its path in real time to maintain the required contact force, delivering consistent deburring quality regardless of part-to-part variation.
Read also: Automatic Tool Changer and Tool Holders: The Essential Guide to Flexible Manufacturing System Design
Combining Anti Collision Sensor and Force Sensors in Advanced Robot Applications
The most sophisticated robotic automation systems combine both the anti collision sensor and force sensors in a single end-of-arm architecture. The force sensors provide continuous active sensing of contact forces during normal operation, allowing the robot to perform force-controlled tasks with precision. The anti collision sensor provides a backstop protection layer for situations where unexpected high-force events occur that exceed the response capability of the force control loop, protecting the robot and tooling from damage. This two-layer sensing architecture, combining proactive force control through force sensors with reactive collision protection through the anti collision sensor, is becoming the standard approach for high-performance collaborative and industrial robot applications.
Conclusion
The anti collision sensor and force sensors are essential enabling technologies for safe, intelligent, and flexible robotic automation. They give robots the ability to sense and respond to their physical environment in ways that rigid path-following control cannot achieve. For manufacturers building or upgrading robotic automation systems, selecting high-quality anti collision sensor and force sensors solutions from a supplier with proven technology and broad application experience is critical to achieving reliable, safe, and high-performance results. SCHUNK, as the internationally recognised competence leader in gripping technology and automation technology with around 3,700 employees in more than 75 countries, offers both anti collision sensor and force sensors as part of its comprehensive Automation Technology portfolio, backed by deep engineering expertise and global application support.
