‘Pull to position’, a different approach to the control of robot arms for mobile robots

This paper investigates an alternative approach to the current techniques used in robotics for the control of articulated limbs. With an interest in equipping mobile robots with limbs, the starting point was to consider approaches used in other robot application domains, specifically industrial robotics as this is the domain where robotic arms have found most widespread application. The proposed control approach, however, differs radically from the inverse kinematic solution approach employed in current serially jointed robots. Creatures with limbs do not use inverse kinematics and transformation matrices when they move a limb from one position to another. Nature uses some other superior technique such that even insects are capable of controlling and coordinating the movement of six limbs each having up to five degrees of freedom. The approach used here is to develop a simple structured linked model of the articulated limb. This model is manipulated in simulation to ‘pull’ the end of the limb towards the desired destination position and orientation. Then the actual motion is realised by driving the joints and linkages through the trajectories followed in simulation. This control approach could be considered to be a primitive version of the perception driven control which living creatures can employ.