ORCID Profile
0000-0002-7570-1261
Current Organisation
University of Waikato
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Publisher: SPIE
Date: 09-08-2013
DOI: 10.1117/12.2028607
Publisher: IEEE
Date: 12-2019
Publisher: SPIE
Date: 09-08-2013
DOI: 10.1117/12.2028606
Publisher: Research Publishing Services
Date: 2014
Publisher: Elsevier BV
Date: 2017
Publisher: Trans Tech Publications, Ltd.
Date: 08-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.884.77
Abstract: Advances in agricultural automation, coupled with a general decline of available labour hasgenerated interest in automated harvesting of various crops. Paramount to the success of such systemsis the development of accurate, robust detection technologies and localization strategies. This paperpresents an overview of sensor technologies used in the detection and localization of green aspara-gus spears for robotic harvesting. Tactile, photoelectric, machine vision and time-of-flight sensors areinvestigated and their applicability for use in robotic asparagus harvesting is evaluated. Investigationof previous asparagus harvesting devices has revealed that no such device has yet achieved commer-cial viability. It was identified that this is likely due to weaknesses in currently employed detectiontechnologies, namely slow response times, high sensitivity to changes in ambient lighting conditionsand requirement for frequent manual calibration. Of the sensor technologies investigated it was foundthat time-of-flight cameras, such as the Microsoft Kinect V2 are the most feasible for the detectionof asparagus spears for robotic harvesting. It was concluded that further research would be conductedinto the application of such sensors into a commercially viable harvester.
Publisher: Emerald
Date: 15-05-2020
Abstract: This paper aims to investigate if a Cartesian robot system for kiwifruit harvesting works more effectively and efficiently than an articulated robot system. The robot is a key component in agricultural automation. For instance, multiple robot arm system has been developed for kiwifruit harvesting recently because of the significant labor shortage issue. The industrial robots for factory automation usually have articulated configuration which is suitable for the tasks in the manufacturing and production environment. However, this articulated configuration may not fit for agricultural application due to the large outdoor environment. The kiwifruit harvesting tasks are completed step by step so that the robot workspace covers the canopy completely. A two-arm, Cartesian kiwifruit harvesting robot system and several field experiments are developed for the investigation. The harvest cycle time of the Cartesian robot system is compared to that of an articulated robot system. The difference is analyzed based on the workspace geometries of these two robot configurations. It is found that the kiwifruit harvesting productivity is increased by using a multiple robot system with Cartesian configuration owing to its regular workspace geometry. An articulated robot is a common configuration for manufacturing because of its simple structure and the relatively static factory environment. Most of the agricultural robotics research studies use single articulated robot for their implementation. This paper pinpoints how the workspace of a multiple robot system affects the harvest cycle time for kiwifruit harvesting in a pergola style kiwifruit orchard.
Publisher: Inderscience Publishers
Date: 2011
Publisher: Wiley
Date: 02-12-2012
DOI: 10.1002/NME.3283
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.41
Abstract: The development of new composite materials requires analysis and experimentation spanning scales from nanometres to metres, from “atoms to assemblies”. In this paper, concerned primarily with fibre reinforced epoxy composites, a methodology is presented which allows continuum level structural simulation to account for nanoand micro-scale size effects in composites. The novelty of this approach is the modular hierarchical nature of the simulation which ensures computational tractability, regardless of the length scales considered. Linking the nanoscale to the macroscopic scale in a single simulation allows for holistic materials development, including the addition of nanoadditives to polymer resin systems.
Publisher: IEEE
Date: 17-05-2021
Publisher: Elsevier BV
Date: 11-2021
Publisher: IEEE
Date: 17-05-2021
Publisher: Elsevier BV
Date: 03-2023
Publisher: IEEE
Date: 08-2020
Publisher: Elsevier BV
Date: 11-2023
Publisher: MDPI AG
Date: 09-09-2022
Abstract: The rejection rate of tree stock in a forestry nursery can be as high as 35%. This is attributed to plant physiology, poorly trained seasonal workers and unsophisticated equipment. It is estimated that approximately 5% of seedling rejection in the pilot nursery (approximately 220,000 per year) is due to poorly dibbled holes. These holes are typically dibbled using a spiked wheel, which produces crooked and imprecise holes. The poor-quality holes cause bends in the stems, resulting in rejection. This article presents a tractor-drawn mechatronic dibbling machine that can produce precise vertical holes of a specified depth, spacing and diameter. Both hole quality and dibbling efficiency are greatly improved. The machine was tested at a nursery and produced 98% of the holes at the desired angle and 94% at the desired depth. The unwanted stem bends were eliminated with a subsequent reduction in rejects. Furthermore, it was found that worker productivity increased, as they did not have to spend time setting seedlings vertically.
Publisher: IEEE
Date: 11-2010
Publisher: Trans Tech Publications, Ltd.
Date: 08-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.884.86
Abstract: Researchers at the University of Waikato visit caves on a periodic basis to collect s les of drip water, which over geological timeframes form stalagmites and other formations. However, most caves are remotely located, which makes it an arduous task to reach the study site and is economically unfeasible for frequent visits. This paper presents the position control aspect of the cave auto-s ler, which is a crucial operation to store water s les in an airtight container. The primary challenge was to position airtight s le vials under the needles for s le collection, within 3.5mm from the centre of the silicone septa. Various methods and makes of stepper motors were tested to find the balance between precision and power saving. A high gear ratio stepper motor was chosen as the primary drives due to its high precision and its ability to hold position when power is turned off between operations. Testing in lab conditions showed satisfactory consistency regarding position control and is integrated into the auto-s ler.
Publisher: Trans Tech Publications, Ltd.
Date: 08-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.884.23
Abstract: Orientation of fibre preforms is an important factor that affects the properties of short natural plant fibre composites. In this paper, oriented short hemp fibre mats were produced using dynamic sheet forming and the fibre orientation distribution in the mats was analysed using ImageJ software as well as by a simple program developed on a MATLAB software package. The OrientationJ plug-in of ImageJ gave an orientation distribution curve with a peak at a predominant direction of 0° supporting alignment during dynamic sheet forming and from MATLAB software, a mean ratio of 0.64 was obtained for the oriented mats compared to 0.74 for an aligned bundles.
Publisher: IEEE
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 04-01-2020
Publisher: Trans Tech Publications, Ltd.
Date: 08-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.884.69
Abstract: The demand for high accuracy on automated harvesters is getting higher. While system accuracy is lowered by vibration resulted when a robot with sensors and arms is running on the field. Applying suspension system onto these automated harvesters is a solution to reduce the vibration effects and assure required accuracy. This paper presents a model of the suspension system for a robotic asparagus harvester. The simulation results showed that the peak value of vibration was reduced to an acceptable level. Most importantly, the peak deflection of a vibrated platform was decreased to a required range as well. At the end of this paper, a conclusion is drawn. A suspension system is suggested to reduce vibration effects and improve the accuracy of both sensors and picking arms for mobile manipulators. In the future, this suspension system will be fabricated and installed onto a robotic asparagus harvester to validate this proposed model.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 02-2020
Publisher: Inderscience Publishers
Date: 2008
Publisher: IEEE
Date: 11-2018
Publisher: Informa UK Limited
Date: 18-12-2016
Publisher: Elsevier BV
Date: 2019
No related grants have been discovered for Shen Hin Lim.