Fig. 1.
Schematic of Cartesian gantry (a) and H-Bot gantry (b) CNC machines (M – motor, P-passive pulley, q1,q2 – H-bot motors, X1,X2,Y – cartesian gantry motors, X,Y-Cartesian axes)
Fig. 2.
NURBS toolpath (blue) with control points (red circles) and control polygon (red dashed)
Fig. 3.
NURBS toolpath interpolation process
Fig. 4.
Block schematic of the feedrate optimization algorithm
Fig. 5.
S-curve jerk limited feedrate profile (T1-T7 – durations of each profile segment)
Fig. 6.
Picture of the experimental setup with the H-Bot CNC machine
Fig. 7.
Block schematic of the H-Bot control system
Fig. 8.
Initial S-curve Feedrate profile with chord error feedrate limit (dashed line) and axial velocity, acceleration and jerk profiles for both axes - “flower” NURBS toolpath
Fig. 9.
“Flower” NURBS toolpath. The curve color indicates the feedrate in mm/s
Fig. 10.
Feedrate profile and axial velocity, acceleration and jerk profiles for both axes - “flower” NURBS toolpath
Fig. 11.
Drive current and following error in X and Y axes.