Robust real time control of robot manipulators in the presence of obstacles

The problem of real time robust control of robot manipulators in the presence of obstacles is considered. In order to achieve high speeds of operation in addition to obstacle avoidance, actuator dynamics and noise are modelled and added to the system description. The Obstacle Avoidance Strategy (OAS) translates each state constraint (obstacle) into state dependent control constraints (SDCC), which take the form of hyperplanes in the control space. The intersection of the sets defining the SDCC and the hard control bounds form a polygon in the control space. The Optimal Decision Stragety (ODS) is then used to calculate the control which lies in this polygon and minimizes the deviation between the acceleration vector of the CCR and a desired field of accelerations. Although the OAS algorithm is developed for a Cartesian Coordinate Robot (CCR), its approach can be utilized for articulated coordinate robots. Simulation results display the effectiveness of the algorithm for a workspace hosting multiple obstacles. The simplicity of the algorithm makes it desirable for real time control.