1. Field of the Invention
The present invention relates to mobile robots and the tracking of their movement. More particularly, the present invention relates to an apparatus and method for detecting movement errors due to wheel slippage or transient current generated while a mobile robot is traveling.
2. Description of the Related Art
Mobile robots, such as cleaning robots, require precise recognition of locations while they are moving. To this end, mobile robots adopt an absolute navigation and a dead-reckoning navigation.
Absolute navigation is performed conventionally using a global positioning system (GPS). When GPS is applied to navigation in mobile robots, it allows the mobile robots to obtain an absolute position. On the other hand, GPS increases the manufacturing costs of mobile robots, and GPS use does not reduce or restrict certain errors in the position accuracy of mobile robots. In particular, since GPS cannot be used in a restricted area, such as inside building, it is difficult to apply GPS to mobile robots used indoors.
Dead-reckoning navigation, which estimates a current position based upon a previously determined position or fix, is performed using an encoder, an acceleration sensor or a gyro sensor. When dead-reckoning navigation using sensors is applied to mobile robots, it reduces the manufacturing costs of mobile robots and allows the mobile robots to calculate a precise position. On the other hand, since the position is obtained by an integral method, as the mobile robots travel further and increase their rotation movement errors increase.
In particular, when wheel slippage occurs while the mobile robot is traveling, a large positional error is generated. in addition, when the wheels cannot roll due to an obstacle, the drive motors of the wheels are overloaded (i.e., transient current flows to the driver motors), which reduces the life span of the drive motors and can even cause the driver motors to malfunction.