Dynamics of robotic manipulators with electropneumatic proportion/servo balancing system

A single-axis robotic manipulator with an electropneumatic proportion/servo balancing system was designed and built. The pneumatic cylinder controlled by two pressure proportion valves was used as the balancing mechanism, the pressures of the cylinder at the rod-end and the blank-end could be adjusted to balance gravity loading terms. The authors have analysed pneumatic dynamic balance (PDB) of the robotic manipulator, and proposed the PDB control model based on two pressure proportion valves. Through the experiment in balancing the gravity loading terms, the function of the balancing mechanism was shown, simultaneously, the deferral of the balancing force caused the interference between the joint motor and the balancing cylinder. This is because of the compressibility of air