Automation application in crop harvesting has increased in the past decades. Various types of harvesting robots are emerging in both commercial and research areas. One of the main challenges is the precision alignment of the gripper and the target crop. An undesired dislocation can harm both the gripper and the crop, which is mainly caused by uncertainties from the sensors and the manipulator. To solve the problem, the dual-camera setup is designed and implemented on a self-built robot. The perception of the tomato is done by a fixed depth camera and a camera without depth on the gripper. The proposed dual-camera image-based visual servoing (IBVS) controller is designed to deal with the image feedback from both cameras and the proof of asymptotically convergence is provided. Furthermore, the cumulative error compensation reduces the time for the harvesting process. The experiments were conducted in the greenhouse and tested under various conditions. The time cost is formulated as a function and the success picking rate of tomatoes is 68.4%.

Traditional vertical take-off and landing (VTOL) aircraft can not achieve optimal efficiency for various payload weights and has limited mobility due to its under-actuation. With the thrust-vectoring mechanism, the proposed modular team UAV is fully actuated at certain attitudes. However, the attainable force space (AFS) differs according to the team configuration, which makes the controller design difficult. We propose an approximation to the AFS and a full-pose tracking controller with an attitude planner and a force projection, which guarantees the control force is feasible. The proposed approach can be applied to UAVs having multiple thrust-vectoring effectors with homogeneous agents. The simulation and experiment demonstrate a tilting motion during hovering for a 4-agent team.

Delayed channel state information (CSI) feedback was shown to be very helpful in enlarging the capacity region of the two-user broadcast packet erasure channel (PEC), even with single-user feedback. However, feedback link itself requires additional resources and may also cause additional delay to data transmission. In this work, we aim to study how to optimally tradeoff the number of feedback bits and the reliable forward communication rate. In our model, one receiver does not provide its CSI while the other one can alternate between delayed CSI feedback and no feedback. This model includes the intermittent single-user feedback as a special case. Our achievability is an extension of previous opportunistic network coding such that the network coding gain can still be enjoyed even when the single-user feedback is not always available. Interestingly, when two users have the same link erasure probabilities, boundaries of the capacity regions are identified since they can be achieved by the proposed schemes. Our results also reveal that even when the single-user feedback is alternating, strictly positive capacity benefits can be attained over the no-feedback capacity.