Mobile Manipulator Motion Planning Towards Multiple Goal Configurations

A number of methods have been developed for finding collision free paths for a manipulator moving from one configuration to another. In each of these cases the desired goal configuration must be chosen beforehand. However, in most applications there may be more than one configuration that satisfies the desired position and orientation requirements of the end effector. One of these configurations must be chosen for the path planner; generally we want to select the configuration that results in the lowest cost movement from the manipulator's current position. Until the motion plan is calculated, we cannot know which goal configuration to choose. This paper demonstrates a method for selecting the lowest cost path without needing to calculate a motion plan from the start position to all of the possible goal configurations. Generating motion plans is computationally expensive and it is desirable to limit these computations where ever possible. This is especially true in the case of mobile manipulators where the surrounding terrain for the motion planning calculation changes at each step, meaning that computational savings of reusing calculations from previous runs cannot be realised. The method demonstrated in this paper is shown to be much more suited to these types of applications than more traditional motion planning methods