Robots sent for space exploration missions are usuallyfully/semi-autonomous. Therefore, more sensory data is required to assess the environment around the robot like contact angle of wheels with the ground, slip detection, rover exact position and orientation.
Wheel/terrain interaction can play an important role on the motion planning and it is difficult to model and compute. Installation of special sensors for measuring contact angle could be very expensive and mechanically no possible due to design issues. So, it is required to develop some simple but useful methods that can estimate the contact angle of the wheel with the terrain by using the information available.
Due to complex dynamic terrain characteristics, wheels of the rover might slip in the rolling, side or rotational directions. It is always very useful to detect wheel slip in order to make the controller more optimal, reduce errors in odometry and navigation.
In this thesis a generic method is presented to formulate the forward and inverse kinematics of complex locomotion subsystems. The method is generic and can be applied on any type of wheel mobile robots. Kinematics equations are used to estimate the contact angle of wheels with the ground. Three types of slips are identified during the motion of robot on uneven terrain. A traction control scheme is presented which uses the contact angle information and the slip detection to increase the traction of the wheel with the ground.
Reduction of slip is achieved to improve the energy efficiency of the robot and to have better rolling and steering commands which also enhances the stability of motion. Simulations have been performed in ROCK (Robot Construction Kit) to prove the concept and to potentially make some tests with the real system, the DFKI SpaceBot rover.