Planning of Time-Efficient Trajectories for Mobile Robots with Differential-Drives

To effectively utilize the capacities of the production facilities, flexible and fast transport, and manipulation technology is essential. Current path planning methods use simple paths without exploiting the physical limitations of mobile robots. This paper deals with the time-efficient kinematic planning of path and velocity trajectories for autonomous mobile robots equipped with a differential-drive, used to load and unload machine tools. For a close parking position next to the machine tools, the mobile robot must approach practically straight without the necessity of turning at the end. After a brief definition of the kinematics of a mobile robot with nonholonomic constraints, a Bezier-curve is combined with multiple jerk-limited velocity trajectories considering the initial and final state as well as the physical limitations. For a time-efficient acceleration and deceleration the maximum acceleration of the mobile robot is used and differentiated into the radial and tangential acceleration. This allows a quickly reached close parking pose next to a machine tool. The algorithm is tested with simulations in RVIZ in combination with Gazebo and ROS2 as well as with the real mobile robot Tend-o-Bot.