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Magnetic guide sensor

Suitable for line following robots

Published 2018-01-05

Roboteq (USA) has introduced a sensor capable of detecting and reporting the position of a magnetic field along its horizontal axis. The CAN-interface is avialble at the M12 connector.

The sensor measures 165 mm x 25 mm x 35 mm enclosed in a rugged, watertight, all-metal housing. (Photo: Roboteq)

The MGSW1600 sensor uses advanced signal processing to accurately measure its lateral distance from the center of the track, with millimeter resolution, resulting in nearly 160 points end-to-end. Tape position information can be output in numerical format on the sensor's CAN interface, alternatively on the USB or EIA-232 ports. The position is also reported as a 0-V to 3-V analog voltage output and as a variable PWM output. Additionally, the sensor supports a dedicated Multi-PWM mode allowing seamless communication with all Roboteq motor controllers using only one wire.

The product is primarily used to steer Automatic Guided Vehicles (AGVs), moving material on factory floors. However, its unique sensitivity and accuracy opens a world of other application opportunities, such as automatic shelf replenishing in supermarkets, patient transport in hospitals, stage theater props, or rail-less tramways. Compared to other guiding techniques, magnetic guides are totally passive and therefore easy to lay and to modify. The tape creates an invisible field that is immune to dirt and unaffected by lighting conditions. The magnetic track can be totally hidden under any non-ferrous flooring material, such as linoleum, tiles, or carpet.

The sensor detects and manages up to 2-way forks and can be instructed to follow the left or right track using commands issued via CAN. All of the sensor's operating parameters and commands are also accessible via the CAN interface. In addition to detecting a track to follow, the sensor detects and reports the presence of magnetic markers. Markers are pieces of tape of opposite magnetic polarity that may be positioned on the left or right side of the track. The sensor is equipped with four LEDs for easy monitoring and diagnostics.

The sensor incorporates a high-speed, Basic-like scripting language that allows users to add customized functionality to the sensor. A PC utility is provided for configuring the sensor, capture and plot the sensor data on a strip chart recorder, and visualize in real time the magnetic field as it is “seen” by the sensor. The sensor firmware can be updated in the field to take advantage of new features as they become available.

Roboteq provides drawings, how-to videos, and software free-of-charge for building Magnetic Track Guided mobile robots. The supplier’s RoboAGVSim software package lets the user develop and simulate such robots. The company also sells adhesive magnetic tape of 25-mm and 50-mm width, in 50-m rolls. The sensor products by Roboteq are used by Artisteril (Spain), ASI Technologies (USA), Divel (Canada), DTA (Spain), Ideasparq (Malaysia), and Tekno (USA), for example. The company founded in 2002 has equipped more than 7000 original robot designs.

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