title: The Barracuda: An investigation of a novel cane pruning technology for avoiding wires in structured vineyard environments

authors: Harvey, Scott

subjects: Robotic

abstract: The viticulture industry, among many others, is trying to improve their product quality whilst facing labour supply challenges and increasing labour costs. The Maaratech research group has been developing human assist technology and an autonomous, prototype grape vine pruning machine to alleviate these issues. The machine is an arched “straddle” platform, containing a camera array, PC, UR5 manipulator, and end-effector. The canes of the grapevine are wrapped around guide wires, making it very difficult for cuts to be made – whether by human or robot. This thesis presents the process of developing and testing a novel technology called the Barracuda, to enable cuts to be made where the wire interferes with a cut. The wire also puts high accuracy requirements on the vision system and manipulator movements if a secondary mechanism was used to separate the wire and cane. The Barracuda was developed as an end effector to alleviate these issues by allowing passive wire separation from the cane. It works by exploiting the diameter difference between the smaller wire, and larger canes. The wire falls into slots, evading the blade, while the cane is cut.

Two Barracuda configurations were tested by making cuts on canes wrapped around the guide wire. Config 1 was a single row of teeth, with larger recesses, flat teeth and a blade-guiding chamfer. Config 2 used two rows of teeth either side of smaller recesses and included rounded teeth tips. The components are CNC machined or laser cut. Results showed for both configurations, the 0° position was most effective. The 0° position is where the wire was below the cane, relative to the handpiece. In this position, Config 1 was effective 40.7% of the time, and config 2, 94.5% of the time. Damage to the wire was caused 8.9% of the time for config 1, and config 2 just 2.6% of the time. Both blades received the same rate of blade damage, however the damage was visibly more significant on config 1. From these results, config 2 was the preferred design, but integrating a chamfer from config 1 should reduce blade damage further.

It also benefits human assist goals. By allowing cuts on the wire, pruners are able to make cuts quickly and easily with Barracuda-modified secateurs or loppers, removing the need to separate the cane from the wire. The design works around the environment, increases the number of points available for decision making, and allows some inaccuracy in the rest of the robotic system by offering passive wire avoidance with the teeth. The performance of the Barracuda in cut situations involving a wire proved it valuable for integration with current manual pruning methods, and as a cornerstone for robotic pruning development, providing further opportunities for the greater system.

text: The Barracuda: An investigation of a novel cane pruning technology for avoiding wires in structured vineyard environments The viticulture industry, among many others, is trying to improve their product quality whilst facing labour supply challenges and increasing labour costs. The Maaratech research group has been developing human assist technology and an autonomous, prototype grape vine pruning machine to alleviate these issues. The machine is an arched “straddle” platform, containing a camera array, PC, UR5 manipulator, and end-effector. The canes of the grapevine are wrapped around guide wires, making it very difficult for cuts to be made – whether by human or robot. This thesis presents the process of developing and testing a novel technology called the Barracuda, to enable cuts to be made where the wire interferes with a cut. The wire also puts high accuracy requirements on the vision system and manipulator movements if a secondary mechanism was used to separate the wire and cane. The Barracuda was developed as an end effector to alleviate these issues by allowing passive wire separation from the cane. It works by exploiting the diameter difference between the smaller wire, and larger canes. The wire falls into slots, evading the blade, while the cane is cut.

Two Barracuda configurations were tested by making cuts on canes wrapped around the guide wire. Config 1 was a single row of teeth, with larger recesses, flat teeth and a blade-guiding chamfer. Config 2 used two rows of teeth either side of smaller recesses and included rounded teeth tips. The components are CNC machined or laser cut. Results showed for both configurations, the 0° position was most effective. The 0° position is where the wire was below the cane, relative to the handpiece. In this position, Config 1 was effective 40.7% of the time, and config 2, 94.5% of the time. Damage to the wire was caused 8.9% of the time for config 1, and config 2 just 2.6% of the time. Both blades received the same rate of blade damage, however the damage was visibly more significant on config 1. From these results, config 2 was the preferred design, but integrating a chamfer from config 1 should reduce blade damage further.

It also benefits human assist goals. By allowing cuts on the wire, pruners are able to make cuts quickly and easily with Barracuda-modified secateurs or loppers, removing the need to separate the cane from the wire. The design works around the environment, increases the number of points available for decision making, and allows some inaccuracy in the rest of the robotic system by offering passive wire avoidance with the teeth. The performance of the Barracuda in cut situations involving a wire proved it valuable for integration with current manual pruning methods, and as a cornerstone for robotic pruning development, providing further opportunities for the greater system.

year: 2022

title: Hemicellulolytic and cellulolytic functions of the domains of a β-mannanase cloned from Caldicellosiruptor saccharolyticus

authors: Frangos, Tracy

subjects: mannanase

abstract: Various combinations of the four domains of the multifunctional mannanase from Caldicellosiruptor saccharolyticus have been cloned and expressed in Escherichia coli. The four domains comprise two catalytic domains (1 and 4), and two putative cellulose binding domains (2 and 3). Each of the six gene products (Man1, Man123, Man1234, Man23, Man234 and Man4) was partially purified by heat treatment.
The enzymes Man1234, Man123 and Man1 exhibited activity on mannans, and Man1234, Man234 and Man4 exhibited activity on xylan and carboxymethylcellulose (CMC). For the complete enzyme (Man1234) all activities were of the same order of magnitude. Activities were additive against a mixture of mannan and xylan or mannan and CMC (but not xylan and CMC). The expression product Man23 exhibited activity on none of the substrates tested, nor did its presence influence thermostability or significantly reduce the Km value for any of the substrates. However, when expressed in combination with domains 1 or 4 it greatly increased their activity.
We conclude that domain 1 catalyses mannan hydrolysis and domain 4 catalyses xylan and CMC hydrolysis at the same active site: domains 2 and 3 have no obvious function, since they do not reduce substrate Km nor affect thermostability. However, their effect on rates of substrate hydrolysis may indicate a role influencing the conformation of the adjacent catalytic domains.

text: Hemicellulolytic and cellulolytic functions of the domains of a β-mannanase cloned from Caldicellosiruptor saccharolyticus Various combinations of the four domains of the multifunctional mannanase from Caldicellosiruptor saccharolyticus have been cloned and expressed in Escherichia coli. The four domains comprise two catalytic domains (1 and 4), and two putative cellulose binding domains (2 and 3). Each of the six gene products (Man1, Man123, Man1234, Man23, Man234 and Man4) was partially purified by heat treatment.
The enzymes Man1234, Man123 and Man1 exhibited activity on mannans, and Man1234, Man234 and Man4 exhibited activity on xylan and carboxymethylcellulose (CMC). For the complete enzyme (Man1234) all activities were of the same order of magnitude. Activities were additive against a mixture of mannan and xylan or mannan and CMC (but not xylan and CMC). The expression product Man23 exhibited activity on none of the substrates tested, nor did its presence influence thermostability or significantly reduce the Km value for any of the substrates. However, when expressed in combination with domains 1 or 4 it greatly increased their activity.
We conclude that domain 1 catalyses mannan hydrolysis and domain 4 catalyses xylan and CMC hydrolysis at the same active site: domains 2 and 3 have no obvious function, since they do not reduce substrate Km nor affect thermostability. However, their effect on rates of substrate hydrolysis may indicate a role influencing the conformation of the adjacent catalytic domains.

year: 1999-08

title: Wearing moko: Maori facial marking in today’s world

authors: Nikora, Linda Waimarie

subjects: moko

abstract: The early voyagers, missionaries, settlers all reacted to the pukanohi, to the marked faces of the Maori people, during the period of first contact, and the century following it. Their accounts are vivid, judgemental, revealing, telling us as much about them as they do about the people they described.
Curiosity and horror are mixed with a genuine
fascination; where sternly evangelizing words
failed, armed confrontation occurred; and we
now live with the results, te ao hou, a new world. In this world, today, wahine mau kauae, tangata mau moko, pukanohi – wearers – are speaking for themselves, about themselves, and commenting on how others view them. Unanimously, they insist that the decision to take the marking is about continuity, affirmation, identity and commitment. It is also about wearing those ancestors, carrying them into the future; as their moko become a companion, a salient being with its own life force, its own integrity and power, beyond the face.

text: Wearing moko: Maori facial marking in today’s world The early voyagers, missionaries, settlers all reacted to the pukanohi, to the marked faces of the Maori people, during the period of first contact, and the century following it. Their accounts are vivid, judgemental, revealing, telling us as much about them as they do about the people they described.
Curiosity and horror are mixed with a genuine
fascination; where sternly evangelizing words
failed, armed confrontation occurred; and we
now live with the results, te ao hou, a new world. In this world, today, wahine mau kauae, tangata mau moko, pukanohi – wearers – are speaking for themselves, about themselves, and commenting on how others view them. Unanimously, they insist that the decision to take the marking is about continuity, affirmation, identity and commitment. It is also about wearing those ancestors, carrying them into the future; as their moko become a companion, a salient being with its own life force, its own integrity and power, beyond the face.

year: 2004-04-04