Robotic Manipulators in Horticulture: A Review

Abstract This paper covers the use of jointed manipulators in handling biological materials within the horticultural industry. Potential applications are reviewed by looking at previous research work and the scope for future development based on economic as well as technical considerations. It is concluded that applications with long seasons are the most viable, with flexibility of use between tasks an important consideration for applications with short seasons. A general specification highlighting the differences between horticultural and manufacturing industry requirements has been derived and some engineering proposals put forward to meet it. The use of computer vision is thought to be the best choice of primary sensor system. A geometrical layout which allows the manipulator to approach the target along a "line of sight" is favoured, as it simplifies collision avoidance in an unstructured environment and might allow recalibration of manipulator position during extension. Pneumatic actuators are thought to offer many advantages over electric or hydraulic drives provided that adequate dynamic control can be achieved. It is concluded that the generic differences in specification between industrial and horticultural manipulators provide an opportunity to take a new approach in manipulator design. In order to provide the analytical tools necessary for this new approach further research is needed in the interrelated areas of actuator choice, geometrical configuration and control strategy.