In the paper, a novel trajectory shaping scheme to improve the manipulation skill of the articulated manipulator
for the liquid container transportation is proposed. The paper investigated the transient free surface behavior of
liquid inside a cup during the horizontal transportation. Based on the observation of the free surface vibration of
the liquid, the adaptive command shaping filter is proposed for the generation of the transportation trajectory
to reduce the fluctuation magnitude without increasing the time required to travel the given transportation
distance. Simulation results verify the effectiveness of the proposed scheme. An experimental testbed of an
articulated manipulator with a simplified model of a liquid container is established. The proposed manipulation
approach is implemented in the experimental setup and the experimental results also verify the effectiveness of
the proposed scheme.
The tracking control of an automatic pipe cutting robot, called APCROM, with a magnetic binder was studied. Using magnetic force APCROM, a wheeled robot, binds itself to the pipe and executes unmanned cutting process. The gravity effect on the movement of APCROM varies as it rotates around the pipe laid in the gravitational field. In addition to the varying gravity effect other types of nonlinear disturbances including backlash in the driving system and the slip between the wheels of APCROM and the pipe also cause degradation in the cutting process. To maintain a constant velocity and consistent cutting performance, the authors adopted a repetitive learning controller (MRLC), which learns the required effort to cancel the tracking errors. An angular-position estimation method based on the MEMS-type accelerometer was also used in conjunction with MRLC to compensate the tracking error caused by slip at the wheels. Experimental results verify the effectiveness of the proposed control scheme.