Design of a Novel Rotary Balance Cylinder for Heavy-Duty Robotic Arms*

Balancing cylinders are widely used in heavy-payload robots, aiming at improving the operation efficiency and stability of robotic arms by compensating gravity. However, the motion range of the robot arm is usually limited and a considerable space will be occupied due to the installation of hydraulic balancing cylinders. To solve these problems, a novel rotary balance cylinder with segmented oil chamber and multiple blades is developed. This design allows segmented output and adjustable torque characteristics while keeping a compact structure and large rotation range. In this paper, the gravity moment and its balanced torque of a heavy-duty robotic arm is modeled. The working principle of the proposed rotary balance cylinder is described. Simulations were conducted and the results show that the proposed balancing cylinder can provide appropriate gravity balancing moment, which highlight the potential for this design to be used in industrial robotic systems to facilitate efficient and stable robotic operations.