|
Students from the University of the Witwatersrand proposed a Self-Propelled Seedling Planter as their "pick and place" application. The proposed design of the seedling planter incorporates both pneumatic and electric drive products offered by Festo and SEW Eurodrive.
|
Competing Students - John Dickens; Steven Dinger; Matthew Song; David Buchalter
Email us for more information about these students or their Self-Propelled Seedling Planter.
|
1. Introduction
The automation of tree planting removes the limits of manual labour and could possibly increase the speed of planting. The seedling planter is designed to be a self-powered track driven vehicle with a battery pack providing power for electrical components and a compressed air tank to drive the pneumatics. The vehicle uses two electric motors to independently drive the tracks, a third motor attached to an electric cylinder, drills the holes for the seedlings. A pneumatic semi-rotary drive is used to actuate the seedling dispenser mechanism.
2. Elements of the Design
The automatic skid-steered track drive system of the seedling planter would need to plant 600 trees per hour (a seedling every six seconds) in order to compete economically with hand planting. The entry proposes the following main design elements:
2.1. Soil Auger The hole for each seedling will be drilled by a soil auger designed to plant seedlings in 2.5 l bags. The auger unit is designed to be driven into the ground by a SEW Eurodrive electric cylinder.
2.2 Drive Motors Allowing for two seconds for the auger to drill the hole for a seedling, the planter is left with four seconds drop the seedling into the hole and then move to the next position. In order to meet these operational requirements, the track-driven system would need a gear-motor with a maximum speed of at least 70 rpm. The 4 kW SEW Eurodrive helical gear-motor with 500 Nm was chosen since it fulfills both the speed and torque requirements. The drive motors are designed to be fitted with a SEW Eurodrive Encoder Card in order to allow the planter to be positioned accurately.
2.3. Planting Pneumatics The seedling planting machine is designed to carry 50 seedling bags with a mass of each seedling being no more than 4 kg. The inclined platform allows for the seedlings to be move under their own weight towards the dispensing mechanism at the back of the machine. The dispenser consists of a trap door, latch and cup that is rotated by a semi-rotary pneumatic drive. A 10 l compressed air cylinder is used to power the pneumatic drive.
The cost of building the seedling planter has been estimated at almost R 140,000.
|
|