SELF-PROPELLED MOVABLE BODY, HUMIDITY SENSOR, LIQUID DETECTION DEVICE
FIG4 is a graph showing an example of a change in humidity with respect to a distance between a floor and a humidity sensor in a case where liquid is present on the floor  FIG3 is a graph showing an example of a change in humidity over time in a case where liquid is present on a floor
Next, with reference to FIG4, the following will discuss an example of a change in humidity with respect to a distance between a floor and the humidity sensor 16 in a case where liquid is present on a surface to be cleaned. In a graph of FIG4, a horizontal axis represents the distance between the surface to be cleaned and the humidity sensor 16 (unit: mm), and a vertical axis represents a humidity (unit: %). As shown in FIG4, the change in humidity is larger when the distance between the surface to be cleaned and the humidity sensor 16 is not more than 20 mm. In such a case, it is easy to determine whether or not liquid or an obstacle containing liquid is present. Therefore, the humidity sensor 16 is provided so that the distance between the humidity sensor 16 and the surface to be cleaned will be not more than 20 mm.  The following will discuss an example of a change in humidity over time in a case where liquid is present on a floor, with reference to FIG3. The humidity is detected by use of the humidity sensor 16 which is provided in the self-propelled cleaner 1 in accordance with the present embodiment. In a graph of FIG3, a horizontal axis represents time (unit: seconds) and a vertical axis represents a humidity (unit: %). As shown in FIG3, the humidity changes by approximately 5% within approximately one second, in a case where liquid is present on the floor. In other words, in a case where an abrupt change in humidity occurs during constant monitoring of the humidity, it can be determined that liquid or an obstacle containing liquid is present on the floor. Accordingly, the control section 20 can determine whether or not liquid or an obstacle containing liquid is present on the floor, by determining whether or not a change in humidity is not less than a predetermined threshold. In a case where the change in humidity is determined at time intervals of one second, the predetermined threshold can be set to 5%. For example, in a case where only whether the humidity is larger or smaller than a set value is determined, a result of determination is dependent on an environment of a space where a target to be cleaned is present. In contrast, in a case where a local change in humidity is caught as in the present embodiment, it is possible to reliably determine the presence of liquid or an obstacle containing liquid.
graph
30
moving mechanism
10
sensor section
20
control section
25
September
['2. The self-propelled moving body as set forth in claim 1, further comprising: a moving mechanism configured to cause the self-propelled moving body to move, the control section controlling the moving mechanism with reference to the result of detection by the humidity sensor.']