  Blackberry harvesting is a labor-intensive and costly process, consuming up
to 50\% of the total annual crop hours. This paper presents a solution for
robotic harvesting through the design, manufacturing, integration, and control
of a pneumatically actuated, kinematically redundant soft arm with a
tendon-driven soft robotic gripper. The hardware design is optimized for
durability and modularity for practical use. The harvesting process is divided
into four stages: initial placement, fine positioning, grasp, and move back to
home position. For initial placement, we propose a real-time, continuous
gain-scheduled redundancy resolution algorithm for simultaneous position and
orientation control with joint-limit avoidance. The algorithm relies solely on
visual feedback from an eye-to-hand camera and achieved a position and
orientation tracking error of $0.64\pm{0.27}$ mm and $1.08\pm{1.5}^{\circ}$,
respectively, in benchtop settings. Following accurate initial placement of the
robotic arm, fine positioning is achieved using a combination of eye-in-hand
and eye-to-hand visual feedback, reaching an accuracy of $0.75\pm{0.36}$ mm.
The system's hardware, feedback framework, and control methods are thoroughly
validated through benchtop and field tests, confirming feasibility for
practical applications.

Robotics