Derived from Solid.

Charger {   MFFloat   battery        []   SFColor   emissiveColor  0 1 0   # [0,1]   SFBool    gradual        TRUE   SFFloat   radius         0.04   # (0,inf) }

3.7.1 Description

The Charger node is used to model a special kind of battery charger for the robots. A robot has to get close to a charger in order to recharge itself. A charger is not like a standard battery charger connected to a constant power supply. Instead, it is a battery itself: it accumulates energy with time. It could be compared to a solar power panel charging a battery. When the robot comes to get energy, it can't get more than the charger has presently accumulated.

The appearance of the Charger node can be altered by its current energy. When the Charger node is full, the resulted color corresponds to its emissiveColor field, while when the Charger node is empty, its resulted color corresponds to its original one. Intermediate colors depend on the gradual field. Only the first child of the Charger node is affected by this alteration. The resulted color is applied only on the first child of the Charger node. If the first child is a Shape node, the emissiveColor field of its Material node is altered. If the first child is a Light node, its color field is altered. Otherwise, if the first child is a Group node, a recursive search is applied on this node in order to find and every Light, Shape and Group nodes are altered according to the two previous rules.

3.7.2 Field Summary

The fields specific to the Charger node are:

• battery: this field should contain three values: the present energy of the charger (J), its maximum energy (J) and its charging speed (W=J/s).

• emissiveColor: color of the first child node (see above) when the charger is full.

• gradual: defines the behavior of the indicator. If set to TRUE, the indicator displays a progressive transition between its original color and the emissiveColor specified in the Charger node, corresponding to the present level of charge. If set to FALSE, the indicator remains its original color until the charger is fully charged (i.e., the present energy level equals the maximum energy level). Then, it switches to the specified emissiveColor.

• radius: radius of the charging area in meters. The charging area is a disk centered on the origin of the charger coordinate system. The robot can recharge itself if its origin is in the charging area (see figure 3.2).

  

  Figure 3.2: The sensitive area of a charger

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