A method including operating a vehicle in a medium. The vehicle is subject to advection due to movement of the medium. The method also includes measuring, using a navigation system, positions of a vehicle over time. The method also includes measuring, using a directional sensor, a course-through-medium over the time. The method also includes calculating, using the positions and the course-through-medium, a variation of a speed-over-ground of the vehicle over the time as a function of the course-through-medium over the time. The method also includes concurrently estimating, using the variation, 1) an average speed-through-medium for the vehicle over the time, and 2) an advection rate of the medium, and 3) an advection direction of the medium.

A robotic vehicle (10) may include a chassis supporting a storage tank in which an aqueous solution is contained, a mobility assembly operably coupled to the chassis to provide mobility for the robotic vehicle about a service area (20), a positioning module (60) configured to provide guidance for the robotic vehicle (10) during transit of the robotic vehicle (10) over the service area (20), a spray assembly (90) and control circuitry (12).

Methods and apparatuses for indicating the presence of a directional differential pressure between separated adjacent spaces are provided. A differential pressure set point indicator may be configured to correlate multiple potential angles of inclination of an elongated conduit to respective threshold differential pressures between two spaces which generate net flow of fluid sufficient to cause a lightweight ball to move from one region of the conduit to an opposing region. The elongated conduit may be adjustable in length so as to accommodate installation of the device into walls of varying thickness. The device may include a sound attenuator that reduces noise upon impact of the ball with either end of the conduit. The device may also include a sealing material that is flexible yet firm enough to provide both a seal with the exterior surface of the conduit and support for the conduit when oriented in a tilted configuration.

An airflow detection device for detecting whether an air output path is obstructed can be mounted in the air output path and includes a carrying portion, a metallic sensing portion and a metallic air plate portion that are respectively positioned on the carrying portion and have different electrode polarities, so as to detect obstruction of the air output path. The airflow detection device can be applied to products located in remote areas, mountain areas, or other places where maintenance workers cannot inspect the products frequently for the state of their dust screens or ventilation holes, and can help warn of conditions such as ventilation hole obstruction to avoid product overheating due to dust or dirt accumulation on dust screens or ventilation hole obstruction, adverse impacts on product performance, service live or stability, or system crash.

Methods and apparatuses for indicating the presence of a directional differential pressure between separated adjacent spaces are provided. A differential pressure set point indicator may be configured to correlate multiple potential angles of inclination of an elongated conduit to respective threshold differential pressures between two spaces which generate net flow of fluid sufficient to cause a lightweight ball to move from one region of the conduit to an opposing region. The elongated conduit may be adjustable in length so as to accommodate installation of the device into walls of varying thickness. The device may include a sound attenuator that reduces noise upon impact of the ball with either end of the conduit. The device may also include a sealing material that is flexible yet firm enough to provide both a seal with the exterior surface of the conduit and support for the conduit when oriented in a tilted configuration.

A method including operating a vehicle in a medium. The vehicle is subject to advection due to movement of the medium. The method also includes measuring, using a navigation system, positions of a vehicle over time. The method also includes measuring, using a directional sensor, a course-through-medium over the time. The method also includes calculating, using the positions and the course-through-medium, a variation of a speed-over-ground of the vehicle over the time as a function of the course-through-medium over the time. The method also includes concurrently estimating, using the variation, 1) an average speed-through-medium for the vehicle over the time, and 2) an advection rate of the medium, and 3) an advection direction of the medium.

Methods and apparatuses for indicating the presence of a threshold directional differential pressure between separated adjacent spaces. An inclined conduit contains at least one movable element that indicates whether the pressure difference between the two spaces is at least as high as a threshold pressure difference. The apparatus may include an on-board pitch indicator and a roll indicator which are used together to calibrate the apparatus and its installation. The apparatus may provide only one or more discrete number of pressure difference set points and be non-adjustable once installed. The inclined conduit may be non-rotatable relative to the baseplate, and the baseplate may be rotatable to change threshold pressure difference set points. The apparatus may provide a tamper-resistant indication of whether a threshold pressure differential is present.

Methods and apparatuses for indicating the presence of a threshold directional differential pressure between separated adjacent spaces. An inclined conduit contains at least one movable element that indicates whether the pressure difference between the two spaces is at least as high as a threshold pressure difference. The apparatus may include an on-board pitch indicator and a roll indicator which are used together to calibrate the apparatus and its installation. The apparatus may provide only one or more discrete number of pressure difference set points and be non-adjustable once installed. The inclined conduit may be non-rotatable relative to the baseplate, and the baseplate may be rotatable to change threshold pressure difference set points. The apparatus may provide a tamper-resistant indication of whether a threshold pressure differential is present.

An airflow detection device for detecting whether an air output path is obstructed can be mounted in the air output path and includes a carrying portion, a metallic sensing portion and a metallic air plate portion that are respectively positioned on the carrying portion and have different electrode polarities, so as to detect obstruction of the air output path. The airflow detection device can be applied to products located in remote areas, mountain areas, or other places where maintenance workers cannot inspect the products frequently for the state of their dust screens or ventilation holes, and can help warn of conditions such as ventilation hole obstruction to avoid product overheating due to dust or dirt accumulation on dust screens or ventilation hole obstruction, adverse impacts on product performance, service live or stability, or system crash.

Methods and apparatuses for indicating the presence of a directional differential pressure between separated adjacent spaces are provided. A differential pressure set point indicator may be configured to correlate multiple potential angles of inclination of an elongated conduit to respective threshold differential pressures between two spaces which generate net flow of fluid sufficient to cause a lightweight ball to move from one region of the conduit to an opposing region. The elongated conduit may be adjustable in length so as to accommodate installation of the device into walls of varying thickness. The device may include a sound attenuator that reduces noise upon impact of the ball with either end of the conduit. The device may also include a sealing material that is flexible yet firm enough to provide both a seal with the exterior surface of the conduit and support for the conduit when oriented in a tilted configuration.