Development of a Rotary Tiller Blade using Three-dimensional Computer Graphics

Coordinate transformations were used to simulate the kinematics of a rotary tillage, C type blade. Using three-dimensional computer graphics, a Bezier surface of the rear surface of the blade was generated. The error in generating the surface remained below 1·2, 5 and 8 per cent for the x, y and z coordinates, respectively, joining multiple Bezier surface patches. The analysis was carried out at rotor speeds of 180, 200 and 220 min−1 and at tractor forward speeds of 3, 3·25 and 3·5 km h−1 and for two blade orientations: namely, 0° and 20°. The interaction of the blade with soil during its operation was analysed using a scan of trochoidal paths of the leading and trailing edges of the blade (LT scan) computer programmed in language C/C++. Interference of the trailing edges of the blade with uncut soil was eliminated by design changes and checked with LT scans for the range of selected rotor speeds and forward speeds. The rectified surface was manufactured using high carbon steel.