Study on passive compliance control in robotic belt grinding of nickel-based superalloy blade

To overcome the effect of fluctuation of normal grinding force on belt precision grinding of nickel-based superalloy blade with the robot, a novel passive compliance control method is proposed in this work. A passive compliance grinding device was designed to reduce the fluctuation of robotic normal grinding force, and the mechanical modeling and analysis of this device were performed. In consideration of the effect of elastic deformation of contact wheel, inherent accuracy error of robot, non-uniform allowance distribution and weak rigidity of blade, the control model of the robotic normal grinding force was established to maintain its stability. The experimental results revealed that the presented control method was beneficial to stabilize the normal grinding force in robotic grinding of nickel-based superalloy blade, and control accuracy of normal grinding force with this proposed method increased by 64.81% than that without the control method. This control method significantly improved the surface profile accuracy of nickel-based superalloy turbine blade to 0.10309 mm. Furthermore, the mathematical model of residual height based on the proposed control method was obtained to explain the relationship between residual height and machined surface roughness of concave surface and convex surface.