endofstroke

End of stroke, often abbreviated EOS, is a term used in mechanical engineering and automation to denote the final position of a linear actuator's travel. It occurs when the actuator reaches the limit of its extension or retraction, typically at a physical stop or when a sensing system confirms the position. EOS is important for controlling motion, preventing over-travel, and enabling home or reference positioning.

End-of-stroke mechanisms can be physical or electronic. Physical end stops are machined stops or cushions built into the actuator assembly to absorb impact and limit travel. Electronic end-of-stroke detection uses limit switches, magnetic switches, inductive or capacitive proximity sensors, or optical encoders to provide a discrete or continuous position signal. In many systems, a combination is used: a mechanical stop provides a hard limit while sensors generate a feedback signal for control.

In hydraulic and pneumatic cylinders, end of stroke is often managed with end-of-stroke cushions or snubbers to reduce shock and wear when the piston reaches the limit. In robotics, CNC machines, and automated equipment, EOS signals are used to perform homing, coordinate multi-axis motion, and ensure safe stop points or fault responses.

Design considerations for EOS include selecting appropriate travel length, ensuring sufficient clearance, avoiding premature triggering due to vibration or backlash, and locating sensors to maintain reliable detection over temperature and wear. Proper EOS integration improves safety, repeatability, and the efficiency of automated processes.