This paper deals with methods to reduce the influence of gravitational force on machine tool vertical feed axes. It provides an overview of existing counterbalancing mechanisms that are used in industrial applications. The main focus is on an existing solution that uses a rotary piston hydromotor, which has a number of advantageous properties. However, its significant torque ripple limits the practical application in machine tools. This paper presents a method of connected servo-electric and servo-hydraulic drive control that overcomes the shortcomings of the original solutions and allows practical deployment on vertical feed axes.
Science Journal 