Study on acceleration/deceleration feedrate planning for multi-block line segments using estimated contour error formulation

Acceleration/deceleration (Acc/Dec) federate planning is used to generate smooth command in motion control. Typically, acceleration/deceleration before interpolation (ADBI) scheme is to plan the tangent direction velocity profile for the trajectory using a look-ahead function. However, the ADBI scheme could cause the axis velocity command´s discontinuity at the line segments junction. Although the Acc/Dec after interpolation (ADAI) can solve the discontinuity problem, it might cause the command contour error. In this paper, the scheme which combines the ADBI and ADAI modules is applied to generate the position commands. The estimated maximum contour error equation is derived and could be used to determine the maximum allowable corner velocity. Simulation results verify the accuracy of the equation. It is also found that the time constant of the ADAI has significant influences on contour errors. Based on the tolerance constraint set on the maximum contour error, the proposed interpolation method based on the estimated error equation can be applied to determine the interpolation parameters such as corner velocity and time constant of ADAI.