抄録
An electro-hydraulic manipulator using hydraulic actuators consists of many nonlinear elements with its parameter fluctuations being much greater than those of an electrically driven manipulator. So it is quite difficult to obtain stable control perfomance.
In this report, we have applied a disturbance estimation and compensation type robust control to all the axes in a 3-link electro-hydraulic manipulator. From the results, it was confirmed that the perfomance of trajectory tracking and attitude regulating was greatly improved by the disturbance observer, the model of which is the same for each axis.
On the other hand, for autonomous assembly tasks, it is said that compliance control is one of the most available methods. Therefore, we have proposed a compliance control based on the position control by a disturbance observer for our manipulator system. To realize more stable contact work, the states in the compliance loop are fedback, where not only displacement but also the velocity and acceleration are considered. We have also applied this compliance control to the Peg-in-Hole insertion task and analyzed the mechanical relation between the peg and hole. Moreover we have proposed a new method of shifting the position of the end-effector periodically for the purpose of a smoother insertion. As a result of using this method, it could be experimentally confirmed that the Peg-in-Hole insertion task with a clearance of 0.05 [mm] could be achieved.
