Estimation of slope for mobile manipulator

In most of industrial applications such as factory automation, a mobile manipulator has been used in a flat plane without slope. From a practical point of view, however, it is important to deal with various conditions of the floor surface to increase the reliability and the flexibility of the locomotion. Then the mobile robot is applicable to the workspace with unknown environment. With recent advances of sensor technologies, it is possible to know the position and configuration of mobile manipulator by acceleration sensors such as gyroscope. They are so powerful, but their cost is still high. This paper proposes a sensorless approach to detect the position and configuration of mobile manipulator without external sensor. In the proposed approach, a slope angle of the floor is estimated by using wheel torque and is utilized for a stable motion planning of the mobile manipulator. Several experimental results are also shown.