Ya Xiong

Dr. Ya Xiong

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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 August 2019 in Journal of Field Robotics
Verified
Journal Article
Open access
PDF file
YXYa Xiong
Ya Xiong
YGYuanyue Ge
Yuanyue Ge
LGLars Grimstad
Lars Grimstad
PFPål J. From
Pål J. From
This paper presents an autonomous robot capable of picking strawberries continuously in polytunnels. Robotic harvesting in cluttered and unstructured environment remains a challenge. A novel obstacle‐separation algorithm was proposed to enable the harvesting system to pick strawberries that are located in clusters. The algorithm uses the gripper to push aside surrounding leaves, strawberries, and other obstacles. We present the theoretical method to generate pushing paths based on the surrounding obstacles. In addition to manipulation, an improved vision system is more resilient to lighting variations, which was developed based on the modeling of color against light intensity. Further, a low‐cost dual‐arm system was developed with an optimized harvesting sequence that increases its efficiency and minimizes the risk of collision. Improvements were also made to the existing gripper to enable the robot to pick directly into a market punnet, thereby eliminating the need for repacking. During tests on a strawberry farm, the robots first‐attempt success rate for picking partially surrounded or isolated strawberries ranged from 50% to 97.1%, depending on the growth situations. Upon an additional attempt, the pick success rate increased to a range of 75–100%. In the field tests, the system was not able to pick a target that was entirely surrounded by obstacles. This failure was attributed to limitations in the vision system as well as insufficient dexterity in the grippers. However, the picking speed improved upon previous systems, taking just 6.1 s for manipulation operation in the one‐arm mode and 4.6 s in the two‐arm mode.

1 February 2019 in Computers and Electronics in Agriculture
Verified
Journal Article
Open access
YXYa Xiong
Ya Xiong
CPCheng Peng
Cheng Peng
LGLars Grimstad
Lars Grimstad
PFPål Johan From
Pål Johan From
VIVolkan Isler
Volkan Isler

9 October 2019 in IEEE Access
Verified
Journal Article
Open access
YGYuanyue Ge
Yuanyue Ge
YXYa Xiong
Ya Xiong
GTGabriel Lins Tenorio
Gabriel Lins Tenorio
PFPal Johan From
Pal Johan From

1 November 2017 in Computers and Electronics in Agriculture
Verified
Journal Article
Open access
YXYa Xiong
Ya Xiong
YGYuanyue Ge
Yuanyue Ge
YLYunlin Liang
Yunlin Liang
SBSimon Blackmore
Simon Blackmore

1 September 2020 in Biosystems Engineering
Verified
Journal Article
Open access
YGYuanyue Ge
Yuanyue Ge
YXYa Xiong
Ya Xiong
PFPål J. From
Pål J. From

1 May 2018
Verified
Conference Paper
Closed access
YXYa Xiong
Ya Xiong
PFPal Johan From
Pal Johan From
VIVolkan Isler
Volkan Isler
This paper presents a novel cable-driven gripper with perception capabilities for autonomous harvesting of strawberries. Experiments show that the gripper allows for more accurate and faster picking of strawberries compared to existing systems. The gripper consists of four functional parts for sensing, picking, transmission, and storing. It has six fingers that open to form a closed space to swallow a target strawberry and push other surrounding berries away from the target. Equipped with three IR sensors, the gripper controls a manipulator arm to correct for positional error, and can thus pick strawberries that are not exactly localized by the vision algorithm, improving the robustness. Experiments show that the gripper is gentle on the berries as it merely cuts the stem and there is no physical interaction with the berries during the cutting process. We show that the gripper has close-to-perfect successful picking rate when addressing isolated strawberries. By including internal perception, we get high positional error tolerance, and avoid using slow, high-level closed-loop control. Moreover, the gripper can store several berries, which reduces the overall travel distance for the manipulator, and decreases the time needed to pick a single strawberry substantially. The experiments show that the gripper design decreased picking execution time noticeably compared to results found in literature.