On Achieving Bounded Harvest Times in Robotic Fruit Harvesting: A Finite-Time Visual Servo Control Approach

Abstract

To improve commercial feasibility of robotic harvesters, it is utmost important to reduce and be able to guarantee harvesting times. A significant portion of this responsibility is on the control system. Current visual servo control methods can at best achieve exponential regulation of a robot (i.e., theoretically infinite convergence time), making it impossible to predict harvest time. The aim of this paper is to introduce a new finite-time visual servo control approach that guarantees finite (i.e., bounded) and computable harvest times. To this end, a continuous terminal sliding mode visual servo controller is developed, and Lyapunov-based stability analysis is presented to guarantee finite-time regulation of the robot to a target fruit. Further, we derive expressions for the bound on the harvesting time, which can aid post-harvest operations management. The developed controller is validated through numerical simulations.