positiesensing

Positiesensing is the measurement of the position of a moving or stationary object relative to a defined reference frame. It provides real-time feedback used by closed‑loop motion control systems, robotics, and surveying equipment to enable accurate positioning, velocity estimation, and control.

Common sensing technologies include optical encoders (slotted disks or printed tracks paired with light detectors), magnetic encoders (magnetoresistive or Hall-effect sensors with permanent magnets), capacitive sensors, inductive sensors, and interferometric or laser-based methods for high‑precision metrology. Potentiometers and resolver-based systems are older or specialized alternatives. Encoders can be implemented in linear or rotary form and may differ in noncontact versus contact operation, resolution, and robustness.

Encoders are typically categorized as absolute or incremental. Absolute encoders output a unique position value for every angle or stroke, often via serial interfaces such as SSI, BiSS, or SPI. Incremental encoders produce quadrature A/B signals (and sometimes an index Z) representing relative motion and require a homing sequence to establish a reference position.

Performance is described by resolution, accuracy, repeatability, linearity, and environmental robustness. Position sensing is used in CNC machines, robotics, automotive systems, elevators, aerospace instruments, and consumer devices such as touchscreens. Trends in the field emphasize higher resolution and non‑contact sensing, multi‑turn capability, and rugged, temperature‑stable sensors suitable for harsh environments.