Heuristic Approaches for the Coordinated Motion of a Redundant Heavy-Duty Hydraulic Excavator

Presently the control of the arm systems of hydraulic excavators is based on individual manipulation of each linear hydraulic actuator by a set of joysticks. The precision of the displacements of the end-effector at the desired directions depends on the experience of the human operator to produce coordinated motion. Adding redundant degrees of freedom to an excavator arm leads to the greater dexterity in maneuvering, capacities for obstacles avoidance, but increases the complexity of the human manipulations. The approach of coordinated motion control appears as a solution to discharge the operator from a fastidious and monotonous work so that he can focus more on the critical situations and takes the appropriate decisions in dynamical and unstructured environments. The advantages and disadvantages of the inverse kinematics methods are well known. To deal with a real 12 MXT MECALAC redundant excavator two heuristic approaches are developed. The effectiveness and real time capacities of these approaches, before the real excavator implementation, are validated using a graphical simulator