Collision avoidance of multi modal moving objects for mobile robot using hybrid velocity obstacles

Mobile robotic systems must have the ability to guarantee safety for operating in close proximity with other moving objects. This paper aims to develop collision avoidance method based on velocity control with respect to several modal of moving objects in the vicinity of wheeled mobile robot. We propose a method that is called Hybrid Velocity Obstacles to avoid multi modal moving objects. This is different from Hybrid Reciprocal Velocity Obstacles approaches in the assumption that objects in the robot's surrounding move with arbitrary speed and directions. The main advantage of the method is in the ability to avoid unknown nonlinear trajectories of moving objects. Collision avoidance is achieved by considering static objects, other mobile robots, and moving objects with nonlinear trajectories. These different characteristics of robot's surrounding objects are calculated to produce avoidance velocity. Our approach is implemented in simulations for a two-wheeled differential-steering mobile robot in the environment contains moving objects. The results show that our approach is capable to avoid collision with multi modal moving objects by maintaining safety with average value 0.17 of Proximity Index. It is envisaged that the proposed method can be very useful for developing transport robot that operate in human environment.