Quantifying fruit quality affected by mechanical impact for selected apple varieties

Proceedings, IFAC Conference on Bio-Robotics Beijing, China,6th July 13-15, 2018 Proceedings, 6th IFAC Conference on Bio-Robotics Proceedings, IFAC Conference on Beijing, China,6th July 13-15, 2018 Proceedings, IFAC Conference on Bio-Robotics Bio-Robotics Beijing, China,6th July 13-15, 2018 online at www.sciencedirect.com Beijing, China, July 13-15, 2018 Proceedings, 6th IFAC Conference onAvailable Bio-Robotics Beijing, China,6th July 13-15, 2018 Proceedings, IFAC Conference on Bio-Robotics Beijing, China, July 13-15, 2018 Beijing, China, July 13-15, 2018

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IFAC PapersOnLine 51-17 (2018) 250–255 Quantifying fruit quality affected by mechanical impact for selected apple varieties Quantifying fruit quality affected by mechanical impact for selected apple varieties Quantifying fruit quality affected by mechanical impact for selected apple varieties Quantifying fruit quality affected by mechanical impact for selected apple varieties Quantifying fruit quality affected by mechanical impact for selected apple varieties Han Fu*, Jieli Duan**, Manoj Karkee***, Long He****, Du Chen*****, Daozong Sun******, Qin Zhang*** Quantifying fruit quality affected by mechanical impact for selected apple varieties Quantifying fruit quality affected by mechanical impact for selected apple varieties Han Fu*, Jieli Duan**, Manoj Karkee***, Long He****, Du Chen*****, Daozong Sun******, Qin Zhang*** Han Fu*, Jieli Duan**, Manoj Karkee***, Long He****, Du Chen*****, Daozong Sun******, Qin Zhang***

Han Duan**, Manoj Long He****, Chen*****, Daozong Sun******, * College of Engineering, South China (e-mail: [email protected]) Han Fu*, Fu*, Jieli Jieli Duan**, Manoj Karkee***, Karkee***, LongAgricultural He****, Du DuUniversity. Chen*****, Daozong Sun******, Qin Qin Zhang*** Zhang*** * College of Engineering, South China Agricultural University. (e-mail: [email protected]) Han Duan**, Manoj Karkee***, Long He****, Du Chen*****, Daozong Sun******, Qin Zhang*** * College of Engineering, South China Agricultural University. (e-mail: [email protected]) Han Fu*, Fu*, Jieli Jieli Duan**, Manoj Karkee***, Long He****, Du Chen*****, Daozong Sun******, Qin Zhang*** ** Engineering Fundamental Teaching and Training Center, South China Agricultural University (Corresponding author; College South China Agricultural (e-mail: ** Engineering Engineering* Fundamental Teaching and and Training Center, SouthUniversity. China Agricultural Agricultural University (Corresponding (Corresponding author; author; * Fundamental College of of Engineering, Engineering, South China Center, Agricultural University. (e-mail: [email protected]) [email protected]) ** Teaching Training South China University Tel: 020-85286120; e-mail: [email protected];) College South China Agricultural University. (e-mail: ** Teaching and Training South China University * Fundamental College of of Engineering, Engineering, South China Center, Agricultural University. (e-mail: [email protected]) [email protected]) Tel: 020-85286120; e-mail: [email protected];) ** Engineering Engineering* Fundamental Teaching and Training Center, South China Agricultural Agricultural University (Corresponding (Corresponding author; author; Tel: 020-85286120; e-mail: [email protected];) *** Center forFundamental Precision and Automated Agricultural Systems, Washington State University; Department of Biological ** Engineering Teaching and Training South China University (Corresponding author; Tel: e-mail: [email protected];) ***** Engineering Fundamental Teaching andAgricultural Training Center, Center, South China Agricultural Agricultural University (Corresponding author; Center for Precision and Automated Systems, Washington State University; Department of Biological Tel: 020-85286120; 020-85286120; e-mail: [email protected];) *** Center for Precision and Automated Agricultural Systems, Washington State University; Department of Biological Engineering, Washington State University (e-mail: [email protected]; [email protected] ) Biological Tel: 020-85286120; e-mail: [email protected];) *** for Precision and Automated Agricultural Systems, Washington State University; Department of Tel: 020-85286120; e-mail: [email protected];) Washington State University (e-mail: [email protected]; [email protected] ) *** Center CenterEngineering, for Precision and Automated Agricultural Systems, Washington State University; Department of Biological Engineering, Washington University (e-mail: [email protected]; [email protected] ) ****Department of Agricultural and State Biological Engineering, Fruit ResearchState and Extension Center, Pennsylvania State *** for and Agricultural Systems, Washington University; Department of Washington State University (e-mail: [email protected]; [email protected] *** Center CenterEngineering, for Precision Precision and Automated Automated Agricultural Systems, Washington State University; Department of)) Biological Biological ****Department of Agricultural and Biological Engineering, Fruit Research and Extension Center, Pennsylvania State Engineering, Washington State University (e-mail: [email protected]; [email protected] ****Department of Agricultural and Biological Engineering, Fruit Research and Extension Center, Pennsylvania State University (e-mail: [email protected]) Engineering, Washington State University (e-mail: [email protected]; [email protected] ) ****Department of Agricultural and Biological Engineering, Fruit Research and Extension Center, Pennsylvania State Engineering, Washington University (e-mail: [email protected]; [email protected] ) University (e-mail: [email protected]) ****Department of Agricultural and State Biological Engineering, Fruit Research and Extension Center, Pennsylvania State University (e-mail: [email protected]) *****College of Engineering, China Agricultural University (email: [email protected]) ****Department of Agricultural and Biological Engineering, Fruit Research and Extension Center, Pennsylvania State University (e-mail: [email protected]) ****Department of Agricultural and Biological Engineering, Fruit Research and Extension Center, Pennsylvania State *****College of Engineering, China Agricultural University (email: [email protected]) University (e-mail: [email protected]) Engineering, China University (email: [email protected]) ******College*****College of Electronic of and Engineering, SouthAgricultural China Agricultural University. (e-mail: [email protected]) University (e-mail: [email protected]) *****College of Engineering, China Agricultural University (email: [email protected]) University (e-mail: [email protected]) ******College of Electronic and Engineering, South China Agricultural University. (e-mail: [email protected]) *****College of Engineering, China Agricultural University (email: [email protected]) ******College*****College of Electronic of and Engineering, SouthAgricultural China Agricultural University. (e-mail: [email protected]) Engineering, China University (email: ******College of Electronic and Engineering, South China University. (e-mail: [email protected]) *****College of Engineering, China University (email: [email protected]) [email protected]) ******College of To Electronic and Engineering, South China Agricultural Agricultural University. (e-mail:localized [email protected]) Abstract: obtain baseline information forAgricultural providing sufficient protection during shake-and******College of Electronic and Engineering, South China Agricultural University. (e-mail: [email protected]) Abstract: To obtain baseline information for providing sufficient protection during localized shake-and******College of Electronic and Engineering, South China Agricultural University. (e-mail: [email protected]) Abstract: To obtain baseline information for on providing sufficient protection during localized shake-andcatch harvesting, the potential of fruit quality top, middle and bottom surface zones of ‘Jazz’, ‘Granny Abstract: To baseline for providing sufficient protection during localized shake-andcatch harvesting, the potential of fruit quality top, middle and bottom surface zones of ‘Jazz’, ‘Granny Abstract: To obtain obtain baseline information information for on providing sufficient protection during localized shake-andcatch harvesting, the potential of fruit quality on top, middle and bottom surface zones of ‘Jazz’, ‘Granny Smith’ and ‘Envy’ apples was assessed when respectively impacted by aluminum and three different Abstract: To‘Envy’ obtain baseline information for on providing sufficient protection during localized shake-andcatch harvesting, the potential of fruit top, and bottom surface zones of ‘Granny Abstract: To obtain baseline information for providing sufficient protection during localized shake-andSmith’ and was when respectively impacted by aluminum and three different catch harvesting, theapples potential ofassessed fruit quality quality on top, middle middle and bottom surface zones of ‘Jazz’, ‘Jazz’, ‘Granny Smith’ and ‘Envy’ apples was assessed when respectively impacted by aluminum and three different cushioned materials using a developed pendulum-type device.bysurface Three types of 12.7 thick catch harvesting, the potential of fruit quality on top, middle bottom zones of ‘Jazz’, ‘Granny Smith’ andsurface ‘Envy’ apples was assessed when respectively impacted aluminum and threemm different catch harvesting, thematerials potential ofassessed fruit quality on respectively top, middle and and bottom zonesand ‘Granny cushioned surface using aa developed pendulum-type device. Three types of 12.7 mm thick Smith’ and ‘Envy’ apples was when impacted bysurface aluminum three different cushioned surface materials using developed pendulum-type device. Three types of ‘Jazz’, 12.7 mm thick Polyurethane foam pieces with 2.1 (Foam 1), 4.8 respectively (Foam 2), and 9.7-11 (Foam 3) kPa deformation pressure Smith’ and ‘Envy’ apples was assessed when impacted by aluminum and three different cushioned surface materials using a developed pendulum-type device. Three types of 12.7 mm thick Smith’ andsurface ‘Envy’ appleswith was assessed when respectively impacted byThree aluminum and threemm different Polyurethane foam pieces 2.1 (Foam 1), 4.8 (Foam 2), and 9.7-11 (Foam 3) kPa deformation pressure cushioned materials using a developed pendulum-type device. types of 12.7 thick Polyurethane foam pieces with 2.1 (Foam 1), 4.8 (Foam 2), and 9.7-11 (Foam 3) kPa deformation pressure were selected as thepieces cushioning materials. Based on USDA Grades and(Foam Standards fordeformation fresh marketpressure apples, cushioned surface materials aa developed pendulum-type device. Three types of thick Polyurethane foam with 2.1 (Foam 1), 4.8 2), 9.7-11 3) cushioned surface materials using developed pendulum-type device. Three types of 12.7 12.7 mm mm thick were selected as the cushioning materials. Based on USDA Grades and Standards for fresh apples, Polyurethane pieces withusing 2.1 (Foam 1), 4.8 (Foam (Foam 2), and and 9.7-11 (Foam 3) kPa kPa deformation pressure werecategories selected foam as the cushioning materials. Based on Extra USDA Grades and Standards for fresh market market apples, the of the Extra Fancy Class 1 (no bruising), Fancy andand Fresh-market percentages were used Polyurethane foam pieces with 2.1 (Foam 1), 4.8 (Foam 2), and 9.7-11 (Foam 3) kPa deformation pressure were selected as cushioning materials. Based on USDA Grades Standards for fresh market apples, Polyurethane foam pieces withClass 2.1 (Foam 1), 4.8 (Foam 2),Fancy and 9.7-11 (Foam 3) kPa deformation pressure the categories of Extra Fancy 1 (no bruising), Extra and Fresh-market percentages were used were selected as the cushioning materials. Based on USDA Grades and Standards for fresh market apples, theevaluate categories ofquality Extra Fancy Class 1impact (no bruising), bruising), Extra Fancy andand Fresh-market percentages were used to fruit with varying levels. According to equivalent principle of energy, equivalent were selected as the cushioning materials. Based on USDA Grades Standards for fresh market apples, the categories of Extra Fancy Class 1 (no Extra Fancy and Fresh-market percentages were used were selected as the cushioning materials. Based onAccording USDAFancy Grades and Standards for fresh market apples, to evaluate fruit quality with varying impact levels. to equivalent principle of energy, equivalent the categories of Extra Fancy Class 1 (no bruising), Extra and Fresh-market percentages were used to evaluate fruit quality with varying impact levels. According to equivalent principle of energy, equivalent drop heights of fruits were converted from impact forces created by surface materials impacting fruits. The the categories of Extra Fancy Class (no Extra Fancy and Fresh-market were to evaluate fruit quality with varying levels. According to equivalent principle of energy, the categories offruits Extrawere Fancy Class 11impact (no bruising), bruising), Extracreated Fancy andsurface Fresh-market percentages were used used drop heights of from impact materials impacting fruits. The to evaluate fruit quality withconverted varying impact levels.forces According to by equivalent principlepercentages of energy, equivalent equivalent drop heights of fruits were converted from impact forces created by surface materials impacting fruits. The fruit quality patterns with varying equivalent drop heights were determined for each of the three apple to evaluate fruit quality with varying impact levels. According to equivalent principle of energy, equivalent drop heights of fruits were from forces created surface impacting fruits. The to evaluate fruit quality withconverted varyingequivalent impact levels. According to by equivalent principle of energy, equivalent fruit quality patterns with varying drop heights were determined for each of the three drop heights of fruits were converted from impact impact forces created by surface materials materials impacting fruits.apple The fruit quality patterns with varying equivalent drop heights were determined for each of the three apple varieties. The results showed that Extra Fancy Class 1 grade was maintained within the equivalent drop drop heights of fruits converted from impact forces created by surface impacting fruits. The fruit quality patterns with varying equivalent drop heights were for each of the drop heights of fruits were were converted fromFancy impact forces created bydetermined surface materials materials impacting fruits.apple The varieties. The results showed that Extra Class 11 grade was maintained within the drop fruit quality patterns with varying equivalent drop heights were determined for each of equivalent the three three apple varieties. The results showed that Extra Fancy Class grade was maintained within the equivalent drop heights ofThe 24,patterns 50 and with 54 cm for ‘Jazz’ apples, 8,Class 18 heights and 38 cm fordetermined ‘Granny Smith’ apples, andthree 7, 26apple and fruit quality varying equivalent drop were for each of equivalent the varieties. results showed that Extra Fancy 1 grade was maintained within the drop fruit quality patterns with varying equivalent drop heights were determined for each of the three apple heights of 24, 50 and 54 cm for ‘Jazz’ apples, 8, 18 and 38 cm for ‘Granny Smith’ apples, and 7, 26 and varieties. The results showed that Extra Fancy Class 1 grade was maintained within the equivalent drop heights ofThe 24, apples 50 and when 54 cmcatching for ‘Jazz’ apples, 8,Class 18 and 38Foam1, cmwas for2maintained ‘Granny Smith’ apples, and 7, 26 and 34 cm ‘Envy’ surface cushioned by and 3 respectively. Toequivalent achieve better varieties. results showed that Extra Fancy 1 grade within the drop heights of 24, 50 and 54 cm for ‘Jazz’ apples, 8, 18 and 38 cm for ‘Granny Smith’ apples, and 7, 26 and varieties. The results showed that Extra Fancy Class 1 by grade was maintained withinapples, theToequivalent drop 34 cm ‘Envy’ apples when catching surface cushioned Foam1, 2 and 3 respectively. achieve better heights of 24, 50 and 54 cm for ‘Jazz’ apples, 8, 18 and 38 cm for ‘Granny Smith’ and 7, 26 and 34 cm ‘Envy’ apples when catching surface cushioned by Foam1, 2 and 3 respectively. To achieve better protection for higher drop heights, it surface would be reasonable toFoam1, suggest the deformation pressure of 7, the series heights of 50 54 for apples, 8, cm Smith’ and and 34 cm apples when catching cushioned and 3 To better heights of 24, 24, 50 and anddrop 54 cm cm for ‘Jazz’ ‘Jazz’ apples, 8, 18 18 and andby 38 cm for for2 ‘Granny Smith’ apples, apples, and 7, 26 26 and protection for heights, it would be reasonable to suggest the pressure of series 34 cm ‘Envy’ ‘Envy’ apples when catching cushioned by38 2‘Granny anddeformation 3 respectively. respectively. To achieve achieve better protection for higher higher drop heights, itbesurface would be reasonable toFoam1, suggest the deformation pressure of the theSmith’ series of cushioning material used could it 4.8-11be kPa for ‘Jazz’ apples2whereas the samepressure forTo ‘Granny 34 cm ‘Envy’ apples when catching surface cushioned by Foam1, and 3 respectively. achieve better protection for higher drop heights, would reasonable to suggest the deformation of the series 34 cm ‘Envy’ apples when catching surface cushioned bytoFoam1, 2whereas anddeformation 3 respectively. To achieve better of cushioning material used could be 4.8-11 kPa for ‘Jazz’ apples the same for ‘Granny Smith’ protection for higher drop heights, it would be reasonable suggest the pressure of the series of cushioning cushioning material used could be 4.8-11 kPa kPa for ‘Jazz’ apples whereas the samepressure for ‘Granny Smith’ and ‘Envy’for apples could beheights, over 11itbe kPa. protection higher drop would reasonable to the of series of material used could 4.8-11 for apples the for protection for higher drop heights, itbe would bekPa reasonable to suggest suggest the deformation deformation of the theSmith’ series and ‘Envy’ apples could be over 11 kPa. of cushioning material used could 4.8-11be for ‘Jazz’ ‘Jazz’ apples whereas whereas the same samepressure for ‘Granny ‘Granny Smith’ and ‘Envy’ apples could be over 11 kPa. of cushioning material used could be 4.8-11 kPa for ‘Jazz’ apples whereas the same for ‘Granny Smith’ and ‘Envy’ apples could be over 11 kPa. Keywords: fresh market apples; mechanical impact; fruit quality; catching device; cushioning materials of cushioning material used could be 4.8-11 kPa for ‘Jazz’ apples whereas the same for ‘Granny Smith’ and ‘Envy’ apples could be over 11 kPa. Keywords: fresh market apples; mechanical impact; fruit catching device; cushioning materials Keywords: fresh market apples; mechanical impact; Control) fruit quality; quality; catching device; cushioning and ‘Envy’ apples could be 11 © 2018, IFAC (International Federation of Automatic Hosting by Elsevier Ltd. All rights materials reserved. and ‘Envy’ apples could apples; be over over 11 kPa. kPa. Keywords: fresh market mechanical impact; Keywords: fresh market apples; mechanical impact; fruit fruit quality; quality; catching catching device; device; cushioning cushioning materials materials Keywords: catching cushioning Keywords: fresh fresh market market apples; apples; mechanical mechanical impact; impact; fruit fruit quality; catching device; device; cushioning materials In quality; a shake-and-catch harvesting system,materials the catching surface is In aa shake-and-catch harvesting system, the catching surface is In shake-and-catch harvesting system, catching surface is aIncritical component harvesting for protecting fruit the from harvest-induced 1. INTRODUCTION a shake-and-catch system, the catching surface is aaIncritical component for protecting fruit from harvest-induced 1. INTRODUCTION a shake-and-catch harvesting system, the catching surface is critical component for protecting fruit from harvest-induced 1. INTRODUCTION damages. Researchersharvesting found thatsystem, different types of cushioning In a shake-and-catch the catching surface a critical component for protecting fruit from harvest-induced 1. INTRODUCTION a shake-and-catch harvesting system, the catching surface is is damages. Researchers found that different types of cushioning aIn critical component for protecting fruit from harvest-induced 1. INTRODUCTION Researchers found that different types of cushioning on the catching surfaces played an important role in China has the largest1. areas and production of apples materials aadamages. critical for protecting fruit harvest-induced INTRODUCTION damages. Researchers found that different different types of cushioning cushioning critical component component for protecting fruit from from harvest-induced materials on the catching surfaces played an important role in 1.planting INTRODUCTION damages. Researchers found that types of China has the largest planting areas and production of apples materials on the catching surfaces played an important role in better fruit quality (Chen and Yazdani, 1991; Zhou China the largest areas and production of apples achieving in the has world. In 2016,planting it produced over 43 billion kilograms damages. Researchers found that different types of cushioning materials on the catching catching surfaces played an important role in China has the largest planting areas and of damages. Researchers found that different types of1991; cushioning achieving better fruit quality (Chen and Yazdani, Zhou on the surfaces played an important role in in the world. 2016, it produced 43 billion kilograms China has the In largest planting areasover and production production of apples apples materials achieving better fruit quality (Chen and Yazdani, 1991; Zhou et al, 2016). De Kleine and Karkee (2015) also dropped in the world. In 2016, it produced over 43 billion kilograms apples (NBS), most of which were consumed for fresh market. materials on the catching surfaces played an important role in achieving better fruit quality (Chen and Yazdani, 1991; Zhou China has the largest planting areas and production of apples in the world. In 2016, it produced over 43 billion kilograms materials on the catching surfaces played an important role in et al, al, 2016). 2016). Defruit Kleine and(Chen Karkee (2015) also dropped better quality and (2015) Yazdani,also 1991; Zhou China the In largest planting areas and production ofmarket. apples achieving apples (NBS), most of which were consumed for fresh in the has world. 2016, it produced over 43 billion kilograms et De Kleine and Karkee dropped apples (NBS), most of which were consumed for fresh market. varieties of apple on cushioning surfacesalso and showed However, these fresh market apples are still manually picked different achieving better fruit quality (Chen and Yazdani, 1991; Zhou et al, 2016). De Kleine and Karkee (2015) dropped in the world. In 2016, it produced over 43 billion kilograms apples (NBS), most of which were consumed for fresh market. achieving better fruit quality (Chen and Yazdani, 1991; Zhou different varieties of apple on cushioning surfaces and showed et al, 2016). De of Kleine andcushioning Karkee (2015) also dropped in the world. In 2016, it produced over 43 billion kilograms However, these fresh apples are still manually picked apples (NBS), most ofmarket which were consumed for fresh market. different varieties apple on surfaces and showed However, these fresh market apples are still manually picked varieties of apple could varying sensitivity by seasonal workers. The increasing production cost and that et al, al,different 2016). De of Kleine andcushioning Karkeehave (2015) also dropped apples (NBS), most of which were consumed for market. different varieties of apple on cushioning surfaces and showed However, these fresh apples are still picked et 2016). De Kleine and Karkee (2015) also dropped that different varieties of apple could have varying sensitivity apples (NBS), most ofmarket which were consumed for fresh freshcost market. varieties apple on surfaces and showed by seasonal seasonal workers. The increasing increasing production cost and different However, these fresh market apples are production still manually manually picked that different varieties of apple could have varying sensitivity by workers. The and to bruise. They found that 14% of ‘Jazz’ apples bruised when shrinking workforce promote the development of mechanical different varieties of apple on cushioning surfaces and showed that different varieties of apple could have varying sensitivity However, these fresh market apples are still manually picked by seasonal workers. The increasing production cost and different varieties of apple on cushioning surfaces and showed to bruise. They found that 14% of ‘Jazz’ apples bruised when However, these fresh market apples are still manually picked that different varieties of apple could have varying sensitivity shrinking workforce promote the development of mechanical by seasonal workers.promote The increasing production cost and dropping shrinking workforce the development of mechanical to bruise. They found that 14% of ‘Jazz’ apples bruised when onto a non-Newtonian surface from 1.2 m whereas harvesting solutions. that different varieties of apple could have varying sensitivity to bruise. They found that 14% of ‘Jazz’ apples bruised when by seasonal workers. The increasing production cost and shrinking workforce promote the development of mechanical that different varieties of apple could have varying sensitivity dropping onto a non-Newtonian surface from 1.2 m whereas by seasonal workers. The increasing production cost and to bruise. They found that 14% of ‘Jazz’ apples bruised when harvesting solutions. shrinking workforce promote the development of mechanical harvesting solutions. dropping onto a non-Newtonian surface from 1.2 m whereas up to 36%onto of ‘Pacific Rose’ apples bruised in 1.2 the same drop to bruise. They found that 14% of ‘Jazz’ apples bruised when dropping a non-Newtonian surface from m whereas shrinking workforce promote the development of mechanical harvesting solutions. to bruise. They that 14% ofsurface ‘Jazz’ apples bruised when to 36% of ‘Pacific Rose’ apples bruised in the same drop dropping onto afound non-Newtonian from 1.2 m whereas shrinking the development of mechanical up There are workforce two major promote fruit removal approaches for harvesting solutions. up to 36% of Rose’ apples bruised in the same drop conditions. In ‘Pacific drop tests, apples were considered as isotropic There are two major fruit removal approaches for mechanical dropping onto a non-Newtonian surface from 1.2 m whereas up to 36% of ‘Pacific Rose’ apples bruised in the same drop harvesting solutions. dropping onto a non-Newtonian surface from 1.2 m whereas conditions. In drop tests, apples were considered as isotropic There are two major fruit removal approaches for mechanical up to 36% of ‘Pacific Rose’ apples bruised in the same drop harvesting solutions. of tree fruit crops: i) mass harvesting (e.g. shakeThere are two major fruit removal approaches for mechanical conditions. In drop tests, apples were considered as isotropic materials and thus the targeted impact areas didn’t be harvesting of tree tree fruit crops: i) mass mass harvesting (e.g. shake- up There are two major fruit removal approaches for (e.g. mechanical to 36% of ‘Pacific Rose’ apples bruised in the same drop conditions. In drop tests, apples were considered as isotropic harvesting of fruit crops: i) harvesting shakeup to 36% and of Rose’ apples bruised in theassame drop materials thus the targeted impact areas didn’t be In ‘Pacific drop tests, apples were considered isotropic harvesting), and ii)i) individual fruit picking (or conditions. and-catch There are two major fruit removal approaches for mechanical harvesting of tree fruit crops: mass harvesting (e.g. shakematerials and thus the targeted impact areas didn’t be controlled. In fact, the targeted impact area on fruit surface was There are two major fruit removal approaches for mechanical and-catch harvesting), and ii) individual fruit picking (or harvesting harvesting), of tree fruit crops: i) individual mass harvesting (e.g. shakeconditions. Infact, drop tests, apples were considered as isotropic materials and thus the targeted impact areas didn’t be and-catch and ii) fruitsuccesses picking (or materials conditions. In drop tests, apples were considered as isotropic controlled. In the targeted impact area on fruit surface was and thus the targeted impact areas didn’t be robotic harvesting). Despite some important has controlled. In fact, the targeted impact area on fruit surface was harvesting of tree fruit crops: i) mass harvesting (e.g. shakeand-catch harvesting), and ii) ii) individual fruitsuccesses picking (or very difficult to control in drop tests. Additionally, Studman et harvesting of tree fruit crops: i) mass harvesting (e.g. shakerobotic harvesting). Despite some important has and-catch harvesting), and individual fruit picking (or materials and thus the targeted impact areas didn’t be controlled. In fact, the targeted impact area on fruit surface was robotic harvesting). Despite some important successes has materials and thus the targeted impact areas didn’t be very difficult to control in drop tests. Additionally, Studman et controlled. In to fact, the targeted impact area on fruit surface was been achieved in robotic harvesting, certain critical problems, very difficult control in drop tests. Additionally, Studman et and-catch harvesting), and ii) individual fruit picking (or robotic harvesting). Despite some important has (1997) found that the extent of bruising was different and-catch harvesting), and ii) individual fruitsuccesses picking (or al. been achieved in robotic harvesting, certain critical problems, robotic harvesting). Despite some important successes has controlled. In fact, the targeted impact area on fruit surface was very difficult to control in drop tests. Additionally, Studman et controlled. In fact, the targeted impact area on fruit surface was al. (1997) found that the extent of bruising was different been achieved in robotic harvesting, certain critical problems, very difficult to control in drop tests. Additionally, Studman et such as inadequate accuracy, low speed and limited robustness al. (1997) found that the extent of bruising was different robotic harvesting). Despite some important successes has been achieved in robotic harvesting, certain critical problems, thefound blush and non-blush sides of an apple when they robotic harvesting). Despite some important successes has between such as inadequate accuracy, low speed and limited robustness been achieved in robotic harvesting, certain critical problems, very difficult to control in drop tests. Additionally, Studman et al. (1997) that the extent of bruising was different very difficult to control in drop tests. Additionally, Studman et between the blush and non-blush sides of an apple when they such as inadequate accuracy, low speed and limited robustness al. (1997) found that the extent of bruising was different environment, remain to be collided in picking apples in orchard been achieved in harvesting, certain critical problems, such as inadequate accuracy, low speed and limited robustness between the blush and non-blush sides of an apple when they each other,that which indicates that the surface fruit zone been achieved in robotic robotic harvesting, certain critical problems, in picking apples in orchard environment, remain to be such as inadequate accuracy, low speed and limited robustness al. (1997) found the extent of bruising was different between the blush and non-blush sides of an apple when they al. (1997) found that the extent of bruising was different collided each other, which indicates that the surface fruit zone in picking apples in orchard environment, remain to be between the blush and non-blush sides of an apple when they addressed (Karkee and Zhang, 2012; Silwal et al., 2017). Mass such as accuracy, low speed and limited robustness in picking apples in orchard environment, remain to be collided other, which indicates that the surface fruit zone beeach oneblush of the major factors affect impact such as inadequate inadequate accuracy, low speed and et limited robustness addressed (Karkee 2012; Silwal al., 2017). Mass in picking apples and in Zhang, orchard environment, remain to be could between the and non-blush sides an apple when they collided each other, which indicates thatof the surface fruitbruise zone between the blush and non-blush sides ofthe ansurface apple when they could be one of the major factors affect impact bruise addressed (Karkee and Zhang, 2012; Silwal al., 2017). Mass collided each other, which indicates that fruit zone harvesting (shake-and-catch) techniques for et fresh market fruits in picking apples in orchard environment, remain to be addressed (Karkee and Zhang, 2012; Silwal et al., 2017). Mass could be one of the major factors that affect impact bruise damage. in picking(Karkee apples and in Zhang, orchard environment, remain to be could harvesting (shake-and-catch) techniques for fresh market fruits addressed 2012; Silwal et al., 2017). Mass collided each other, which indicates that the surface fruit zone be one of the major factors affect impact bruise collided each other, which indicates that the surface fruit zone damage. harvesting (shake-and-catch) techniques for fresh market fruits could be one of the major factors affect impact bruise has been studied widely for several decades and have shown addressed (Karkee and 2012; Silwal al., 2017). Mass harvesting (shake-and-catch) techniques for fresh fruits addressed (Karkee and Zhang, Zhang, 2012; decades Silwal et al., market 2017). Mass damage. has been been studied studied widely for several several decades and have shown shown harvesting (shake-and-catch) techniques for et fresh market fruits could one of major that impact bruise damage. has widely for and have could be be one might of the theoccur majorinfactors factors that affect affect impact bruise Apple impact any possible surface zone on the damage. promise tostudied achieve a high fruit removal efficiency (Peterson harvesting (shake-and-catch) techniques for fresh market fruits has been widely for several decades and have shown Apple impact might occur in any possible surface zone on the harvesting (shake-and-catch) techniques for fresh market fruits promise to achieve a high fruit removal efficiency (Peterson has beentostudied widely forfruit several decades and have shown fruit damage. promise achieve a high removal efficiency (Peterson Apple impact might occur in any possible surface zone on the damage. during mass harvesting. However, the current results and Wolford, 2003; Zhou et al., 2014; He et al., 2017; He et Apple impact might occur in any possible surface zone on the has been studied widely for several decades and have shown promise to achieve aaZhou high fruit removal efficiency (Peterson fruit during mass harvesting. However, the current results has been studied widely for several decades and have shown Apple impact might occur in any possible surface zone on the and Wolford, 2003; et al., 2014; He et al., 2017; He et promise to achieve high fruit removal efficiency (Peterson and Wolford, 2003; Zhou et al., 2014; He et al., 2017; He et fruit during mass harvesting. However, the current results obtained by mass dropping fruit onto cushioned surfaces are al., 2018). However, no commercial success hasal., been achieved Apple impact might occur in any possible surface zone on the fruit during harvesting. current results However, the promise to achieve a high fruit removal efficiency (Peterson and Wolford, 2003; Zhou et al., 2014; He et 2017; He et Apple impact might occurfruit in any possible surface zone results on are the obtained by dropping onto cushioned surfaces fruit during harvesting. However, the current promise toHowever, achieve high (Peterson al., commercial success has been achieved and2018). Wolford, 2003; ano Zhou etfruit al., removal 2014; Heefficiency et al., 2017; He et insufficient obtained bytomass dropping fruit onto onto cushioned surfaces are provide adequate protection forcurrent fresh market al., 2018). However, no commercial success has been achieved for mass harvesting technology either, primarily due to the fruit during mass harvesting. However, the results obtained by dropping fruit cushioned surfaces are and Wolford, 2003; Zhou et al., 2014; He et al., 2017; He et al., 2018). However, no commercial success has been achieved fruit during mass harvesting. However, theforcurrent results insufficient to provide adequate protection fresh market by dropping fruit onto cushioned surfaces are and2018). Wolford, 2003; no Zhou et al., 2014; He et al., 2017; Hethe et obtained for mass harvesting technology either, primarily due to al., However, commercial success has been achieved insufficient toshake-and-catch provide adequate protection forstudy fresh market for mass harvesting technology either, primarily due to the apples during harvesting. This aimed at unacceptable level ofno harvest-induced fruit damage. obtained by dropping fruit onto cushioned surfaces are provide protection for fresh market al., 2018). However, commercial success has achieved for mass technology either, primarily due to obtained byto dropping fruit harvesting. onto cushioned surfaces are apples during This aimed at insufficient toshake-and-catch provide adequate adequate protection forstudy fresh market al., 2018). However, no commercial success has been been achieved unacceptable level of harvest-induced fruit damage. for mass harvesting harvesting technology either, primarily due to the the insufficient apples during shake-and-catch harvesting. This study aimed at unacceptable level of harvest-induced fruit damage. insufficient provide protection for fresh market during harvesting. This at for mass either, primarily unacceptable level harvest-induced fruit damage. insufficient toshake-and-catch provide adequate adequate protection forstudy freshaimed market for mass harvesting harvesting technology either, primarily due to to the the apples apples duringto shake-and-catch harvesting. This study aimed at unacceptable level of of technology harvest-induced fruit damage.due shake-and-catch harvesting. This Copyright © 2018 IFAC 250 apples unacceptable level of fruit apples during during shake-and-catch This study study aimed aimed at at unacceptable level of harvest-induced harvest-induced fruit damage. damage. 2405-8963 © IFAC (International Federation of Automatic Control) by Elsevier Ltd. All rights harvesting. reserved. Copyright © 2018, 2018 IFAC 250Hosting Copyright 2018 responsibility IFAC 250Control. Peer review©under of International Federation of Automatic Copyright 250 Copyright © © 2018 2018 IFAC IFAC 250 10.1016/j.ifacol.2018.08.166 Copyright © 2018 IFAC 250 Copyright © 2018 IFAC 250

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quantitatively evaluating fruit quality on different surface zones for selected apple varieties to provide sufficient baseline information for design of localized shake-and-catch system. The experimental implementation was conducted by exerting different levels of impact force respectively on different locations with varying surface materials using a developed pendulum-type device. Impact bruise sensitivity was therefore assessed for different surface zones on the fruit. For better understanding of the effect of impact forces on fruit quality, approximate equivalent drop heights were converted from the impact forces. The fruit quality patterns with varying equivalent drop heights were thus determined for varying surface zones for the selected apple varieties.

251

Fig. 1. Schematic of the pendulum-type device used to impact targeted fruit zones. Before each impacting, an apple sample was placed on the sample supporting platform with targeted zone normal to impact surface. In the test, the impactor was pulled manually to a desired position limited by a steel rod using a cotton string and then released to create normal impact force. 2.2 Sample Preparation In this study, three varieties of apples, namely ‘Jazz’, ‘Envy’ and ‘Granny Smith’ were tested. ‘Jazz’ and ‘Envy’ apples were randomly hand-picked from a commercial orchard near Prosser, WA, USA; ‘Granny Smith’ apples were randomized picked near Othello, WA, USA. All picked apple samples were carefully transported and stored in a cold room (~3 °C with ~60% RH, force-air) within ~5 hours after harvest to avoid any possible non-harvest induced bruising and other damages.

2. MATERIALS AND METHODS 2.1 Pendulum-Type Impact Test Device In fruit drop tests, drop heights could be taken into account directly, however, it is very difficult to control the targeted impact zone on fruit surface. A pendulum-type impact device was therefore developed; the schematic was shown in Fig. 1. This device mainly consists of a pendulum arm, a mechanism to position the pendulum arm at a designated location to create a desired level of impact force applying to a test specimen, and an optical encoder (E6B2-CWZ3E, YUMO, Yueqing, China) mounted at pendulum arm hinge to measure the angle of arm swinging. A computer data acquisition system was also included in the device to capture dynamic impact parameters, such as impact force and swing angle. The system primarily were composed of a NI 9234 analog input module, a NI 9401digital input module, a NI 9178 Compact DAQ chassis and a computer with software. Detail specifications of the pendulum impact device could be referred in our publication (Fu et al., 2017), in which ‘Jazz’ apple impact bruise responses were determined when impacted by different cushioning surface materials with varying levels of impacts. In this study, similar tests were completed for ‘Granny Smith’ and ‘Envy’ apples and sampled rate for impact force and swing angle was respectively set at 25.6 kHz and 62.5 Hz.

In the impacting test, total 200 bruising-free apple samples of each of the three varieties were divided into 4 groups of 50 each. One group was impacted by the bare aluminium impactor (as control group) whereas other three groups were impacted by the impactor covered by three cushioning materials (Foams 1-3). Table 1 lists the specifications of the cushioning materials used. These materials provide gentle cushioning support, thus are being used commonly for fruit packing (McMaster-Carr, 2016). The average weights of all samples were 197 g for ‘Jazz’ apples, 214 g for ‘Granny Smith’ apples and 251 g for ‘Envy’ apples. The corresponding standard deviations were 24, 25 and 30 g. Table 1. Specifications of cushioning materials used in this research Cushioning Materials Foam 1 Foam 2 Foam 3 Firmness 2.1 4.8 9.7-11 (25 % deformation, kPa) Density (kg·m-3) 44.9 44.9 48.1 Thickness (mm) 12.7 12.7 12.7 Fruit firmness and surface radius of curvature were also measured for sample fruit for all varieties. To measure flesh firmness, 30 specimens of each variety were randomly chosen from the same pool of hand-picked apples. A total of 360 points (four different locations in each test zone of each fruit specimen) were measured for each variety using a McCormick fruit pressure tester with an 11-mm-diameter probe (FDK30, WAGNER Instruments, Greenwich, CT). The circumferential radius (refer to R1) and meridian radius (refer to R2) of curvature at each impact location of all three zones were measured using a digital radius gauge with a 30 mm jaw (542313, Sanhe Measuring Instrument, Wenzhou, China). A total of 72 randomly selected samples (18 samples selected from each group) were measured for each variety to get the average R1 and R2. Due to imperfect spherical shape of apples, the radius of curvature was calculated using harmonic average of curvature radius (R), as shown in Equation (1). The measured firmness and radius of curvature are shown in Table 2.

R=

251

2 × R1 × R2 R1 + R2

(1)

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Fruit quality assessment for the tested samples was carried out after 24 hours of storage in the room temperature (~22℃). Bruised areas were identified manually, slice open and measured using a digital Vernier caliper.

Table 2. Firmness and radius of curvature of apples at three different zones on the fruit. Apple Test Firmness Radius of Variety Zones (kPa) [a] Curvature (mm) Top 577 ± 43b 32.0 ± 4.7f ‘Jazz’ Middle 579 ± 44b 39.5 ± 6.1c Bottom 603 ± 46a 33.9 ± 5.3e d 37.4 ± 4.2d Top 453 ± 30 ‘Granny Middle 440 ± 27e 46.5 ± 5.3b Smith’ Bottom 463 ± 41d 38.9 ± 4.4c c Top 559 ± 50 37.1 ± 4.0d ‘Envy’ Middle 570 ± 54bc 47.5 ± 6.5a Bottom 611 ±54a 36.8 ± 4.1d

Fruit quality was evaluated using the percentages of apples classified to Extra Fancy Class 1, Extra Fancy and Freshmarket (Extra Fancy + Fancy) categories based on USDA Grades and Standards (USDA-AMS, 2002; Peterson et al., 2010). As per this standard, no bruising is permitted for Extra Fancy Class 1 quality level whereas a bruise of ≤ 12.7 mm and ≤ 19 mm in diameter respectively are permitted for Extra Fancy and Fresh-market grade level. Percentage of fruit in each quality level was calculated using Equation (2) and similar equations.

= Pe

Duncan’s multiple range test was used to analyze the variation in each column (each variable). For a given variable (column), different alphabets (a, b, c, d, e and f) represent that there is a significant difference at a 95% level of confidence. [a]

Ne ×100% N

(2)

where, Pe is the percentage of Extra Fancy Class 1 fruit, Ne is the number of samples in Extra Fancy Class 1 category, and N is the total number of tested samples in a group.

2.3 Experimental Design

2.5 Impact Force and Equivalent Drop Height

Because fruit bruising might occur in any possible location on the fruit surface during shake-and-catch harvesting, impact analysis was complete with apple surface separated into three zones, e.g. top, middle and bottom. Each zone was further separated into seven smaller areas, which were marked and labelled as impact locations along circumferential direction. In the impact tests, seven different levels of impact force exerted on these seven locations in each zone separately by varying surface materials. Fig. 2 shows the separation of impact zones, impact locations, and impact points on each sample surface.

For better understanding of the effect of impact forces on fruit quality, approximate equivalent drop heights were converted from impact forces according to equivalent principle of energy. Here the positon where the pendulum arm was free standing was supposed as the balance. The swing kinetic energy (E) of the pendulum arm with θ (shown in Fig. 1) as the swing angle to the balance could be calculated using the Equation (3).  mp  E=  + mh  glp (1 − cos θ ) 2  

(3)

where mp was the equivalent mass of pendulum arm; mh was the equivalent mass of impactor; lp was the equivalent length of pendulum for the pendulum arm and impactor; g was the gravitational acceleration (9.8 m s-2). According to equivalent principle of energy, the equivalent drop height (h) of the fruit corresponding to the kinetic energy of the pendulum arm could be determined by Equation (4). h=

E mg

(4)

where m was the mass of fruit. Substituting Equation (3) into Equation (4), then the equivalent drop height could be given by Equation (5).

Fig. 2. Illustration of impact zones and impact points in each impact location on the fruit surface. During test, stationary samples were individually impacted at seven different locations by the pendulum impactor. The impact test was repeated with seven different impact forces. After each impact, the apple sample was caught to avoid it from landing on the floor and bear unexpected bruising damage. A catching box covered with a thick cushioning material was placed underneath the hand to provide further protection.

h=

 mp  + mh  glp (1 − cos θ )   2 

(5)

mg

The swing angle θ was calculated by Equation (6) based on the output pulses of the encoder. θ = 360

2.4 Fruit Quality Assessment 252

No xN b

(6)

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where No was the number of pulses generated by the encoder; Nb was the number of pulses generated by the encoder per shaft revolution; x was encoding type (here was the number 2). 3. RESULTS AND DISCUSSION 3.1 Impact Zones and Bruise Sensitivity For ‘Jazz’ apple, it was found that the percentages of fruit in the Extra Fancy and Fresh-market grades declined most rapidly with increasing impact force when impacted on top zones (Fu et al., 2017). The top fruit zone was thus the most sensitive to impact bruise damage. Similar results were found for ‘Granny Smith’ and ‘Envy’ varieties in this study. Therefore, it could be recommended that a catching surface designed for shake-and-catch harvesting should depend on the possible impact on top zones of the fruit to achieve the desired level of fruit quality. In this study, only the results on top zone were presented and analysed hereafter. The fruit mass used for calculation of equivalent drop heights were 197, 214 and 251 g respectively for ‘Jazz’, ‘Granny Smith’ and ‘Envy’ apples.

(c) Fig. 3. Percentages of Extra Fancy Class 1 apples with varying equivalent drop heights resulted in with the impact tests involving the top fruit zone. Four tests were repeated for aluminium and three different cushioned surfaces and for three different apple varieties: (a) ‘Jazz’; (b) ‘Granny Smith’; (c) ‘Envy’. The results (Fig. 3a) showed that Extra Fancy Class 1 quality was maintained for ‘Jazz’ apples with the equivalent drop height within 24, 50 and 54 cm for surfaces cushioned respectively with Foam 1 (2.1 kPa deformation pressure), Foam 2 (4.8 kPa deformation pressure), and Foam 3 (9.7-11 kPa deformation pressure). When the drop heights increased to over 45, 80 and 88 cm with respective cushioning, none of the fruit maintained the quality desired for Extra Fancy Class 1. Similar patterns could be found when the impact was applied to “Granny Smith” and “Envy” apples, as shown in Fig. 3b and 3c. For “Granny Smith” apples, the corresponding equivalent drop heights for Extra Fancy Class 1category were 8, 18 and 38 cm respectively (Fig. 3b) whereas the same for ‘Envy’ apples were 7, 26 and 34 cm respectively (Fig. 3c). These results indicated that the bruising resistant capability of foams with 4.8 and 11 kPa deformation pressure is only marginal when being used to catch ‘Jazz’ apples. However, this capability increased substantially for ‘Granny Smith’ and ‘Envy’ apples when the foam pressure was increased from 2.1 to 11 kPa.

3.2 Equivalent Drop Height and Fruit Quality 3.2.1 Fruit in Extra Fancy Class 1 Grade Fig. 3 shows the percentage of Extra Fancy Class 1 (no bruising) with varying equivalent drop heights for the three different impact zones of an apple when respectively exerted by the impactor of aluminium surface and covered with different foams. Regression curves showed that a linear model can represent the relationship between impact levels and bruise percentages. In order to precisely present the relationship between impact level and fruit quality, the data points between 0 and 100% of bruising was used to fit the curve, even though all the test points were shown in the Figures.

To achieve no-bruising protection for greater drop height, it would be reasonable to suggest using the series of cushioning material with deformation pressure over 11 kPa as the catching surface for ‘Granny Smith’ and ‘Envy’ apples. These results also reveal that fruit quality varies among different apple varieties under certain impact levels, which agreed with findings of the previous researchers (De Kleine and Karkee, 2015). Among the three tested apple varieties, ‘Jazz’ tolerated the maximum drop height to maintain the same percentage of Extra Fancy Class 1 fruit on the tested cushioning surfaces; The drop heights tolerated for ‘Granny Smith’ and ‘Envy’ apples were close when impacted by cushioning surfaces except for Foam 2. The fruit radius of curvature, firmness, and weight might play a role in achieving different levels of fruit quality in similar impact and cushioning conditions. For example, as shown in Table 2, compared to ‘Jazz’ apple, ‘Granny Smith’ and ‘Envy’ apples consisted of relative large radius of curvature which potentially allowed these foams to absorb more energy and tolerate greater impact (Baritelle and Hyde, 2001; Zarifneshat et al., 2010). However, firmness of

(a)

(b)

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‘Jazz’ apples was generally higher than that for the other two varieties, which could potentially allow the fruit to maintain relatively better quality at larger drop heights (Garcı́a et al., 1995; Mohammad Shafie et al., 2015).

equivalent drop heights respectively. For the ‘Granny Smith’ apples, the maximum equivalent drop heights to maintain Extra Fancy grade were 9, 20 and 40 cm respectively for Foam 1, Foam 2 and Foam 3 whereas the same for ‘Envy’ apples were 7, 28 and 38 cm. No fruit maintained the Extra Fancy grade when the corresponding equivalent drop heights increased to over 50, 86 and 92 cm for ‘Jazz’ apple, 16, 34, and 66 cm for ‘Granny Smith’ apples, 20, 53, and 67 cm for ‘Envy’ apples. These results indicated that, similar to the trends for Extra Fancy Class 1 fruit, ‘Jazz’ apples could tolerate higher drop height to maintain specific level of Extra Fancy quality grade on the tested cushioning materials compared to ‘Granny Smith’ and ‘Envy’ apples.

3.2.2 Fruit in Extra Fancy Grade Fig. 4 shows the patterns of Extra Fancy (i.e. all impacted fruit samples sustained no bruising or bruising with a diameter of ≤12.7 mm) fruit with varying impacting levels. Regression curves showed that a linear model can represent the relationship between impact level and percentage of Extra Fancy fruit.

3.2.3 Fruit in Fresh-market Grade According to the USDA Grades and Standards, the lowest Fresh-market grade permits impacted fruit samples a bruise diameter of ≤19 mm. The percentage of Fresh-market fruit was counted for the test apple varieties. The results showed that a 100% of ‘ Jazz ’ apples maintained Fresh-market grade when impacted by impactor cushioned by Foams 1, 2 and 3 within 47, 73 and 76 cm of equivalent drop heights respectively. For the ‘Granny Smith’ apples, the maximum equivalent drop heights to maintain Fresh-market grade were for, 13, 30 and 53 cm respectively for Foam 1, Foam 2 and Foam 3 whereas the same for ‘Envy’ apples were 16, 36 and 50 cm.

(a)

Currently, apple orchards in Washington State are being planted increasingly in trellis-trained, high density architectures, which can achieve significantly higher yield compared to the yield in traditional orchard systems (Marshall and Andrews, 1994). Those modern orchards also simplify the canopy structure and offer a greater potential for developing and adopting mechanical harvesting solutions to increase profitability and long term sustainability. These modern orchards include trellis-trained architectures, such as vertical fruiting wall ‘Jazz’ and ‘Granny Smith’ trees, and V-trellis ‘Envy’ trees, in which limbs horizontally grow. The ready access to the limbs and fruit provides a potential for localized shake-and-catch harvesting system to control fruit removal at the limb level and keep fruit quality to the desired level for fresh market. The distance between two adjacent trellis wires is about 0.4 m but the actual catching height between dropped fruit and catching surface ranges from 0.1 to 0.3 m depending on the actual opening between two layers of canopy, actual fruit position in the canopy and depth of the catching mechanism. Based on the findings in this study, it was recommended to select the series of cushioning material with deformation pressure 4.8-11 kPa as the cushioning surface of the catching device for ‘Jazz’ apples whereas the deformation pressure could be over 11 kPa for ‘Granny Smith’ and ‘Envy’ apples.

(b)

(c) Fig. 4. Percentage of Extra Fancy apples with varying equivalent drop heights resulted in with the impact tests involving the top fruit zone. Four tests were repeated for aluminium and three different cushioned surfaces and for three different apple varieties: (a) ‘Jazz’; (b) ‘Granny Smith’; (c) ‘Envy’.

The findings from this study could provide some baseline information for designing low-energy impact catching devices for localized shake-and-catch system, and will be evaluated in the harvesting tests and expanded investigations will be applied to more apple varieties in future study.

The results presented in Fig. 4 showed that ‘Jazz’ apples maintained Extra Fancy grade when impacted by impactor cushioned by Foams 1, 2 and 3 within 30, 51 and 60 cm of 254

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4. CONCLUSION

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Fu, H., He, L., Ma, S., Karkee, M., Chen, D., Zhang, Q., and Wang, S. (2017). ‘Jazz’Apple Impact Bruise Responses to Different Cushioning Materials. Transactions of the ASABE, 60(2), 327-336. Garcı́a, J. L., Ruiz-Altisent, M., and Barreiro, P. (1995). Factors influencing mechanical properties and bruise susceptibility of apples and pears. Journal of agricultural engineering research, 61(1), 11-18. He, L., Fu, H., Sun, D., Karkee, M., and Zhang, Q. (2017). Shake-and-catch harvesting for fresh market apples in trellis-trained trees. Transactions of the ASABE, 60(2), 353-360. He, L., Fu, H., Xia, H., Manoj, K., Zhang, Q., and Whiting, M. (2018). Evaluation of a localized shake-and-catch harvesting system for fresh market apples. Agricultural Engineering International: CIGR Journal, 19(4), 36-44. Karkee, M. and Zhang, Q. (2012). Mechanization and automation technologies in specialty crop production. Resource Magazine, 19(5), 16-17. Marshall, D. W. and Andrews, P. K. (1994). Trends in Washington State's apple industry. HortTechnology, 4(1), 6-15. McMaster-Carr. (2016). Foam firmness. www.mcmaster.com. Mohammad Shafie, M., Rajabipour, A., Castro-García, S., Jiménez-Jiménez, F., and Mobli, H. (2015). Effect of fruit properties on pomegranate bruising. International Journal of Food Properties, 18(8), 1837-1846. NBS-Tea and Fruit Production. : http://data.stats.gov.cn/easyquery.htm?cn=C01 Peterson, D. L. and Wolford, S. D. (2003). Fresh–Market Quality Tree Fruit Harvester Part II: Apples. Applied engineering in agriculture, 19(5), 545. Peterson, D. L., Tabb, A. L., Baugher, T. A., Lewis, K., and Glenn, D. M. (2010). Dry bin filler for apples. Applied engineering in agriculture, 26(4), 541. Silwal, A., Davidson, J. R., Karkee, M., Mo, C., Zhang, Q., and Lewis, K. (2017). Design, integration, and field evaluation of a robotic apple harvester. Journal of Field Robotics, 34(6), 1140-1159. Studman, C. J., Brown, G. K., Timm, E. J., Schulte, N. L., and Vreede, M. J. (1997). Bruising on blush and non-blush sides in apple-to-apple impacts. Transactions of the ASAE, 40(6), 1655-1663. USDA-AMS. (2002). USDA Quality Standard: 51.316-51.318. United States Standards for Grades of Apples. Zarifneshat, S., Ghassemzadeh, H. R., Sadeghi, M., Abbaspour-Fard, M. H., Ahmadi, E., Javadi, A., and Shervani-Tabar, M. T. (2010). Effect of impact level and fruit properties on golden delicious apple bruising. American Journal of Agricultural and Biological Sciences, 5(2), 114-121. Zhou, J., He, L., Zhang, Q., and Karkee, M. (2014). Effect of excitation position of a handheld shaker on fruit removal efficiency and damage in mechanical harvesting of sweet cherry. Biosystems engineering, 125, 36-44. Zhou, J., He, L., Karkee, M. and Zhang, Q. (2016). Effect of catching surface and tilt angle on bruise damage of sweet cherry due to mechanical impact. Computers and Electronics in Agriculture, 121, 282-289.

In this study, the potential of fruit quality on top, middle and bottom surface zones of ‘Jazz’, ‘Granny Smith’ and ‘Envy’ apples was assessed when respectively impacted by aluminum and three different cushioned surface materials using a developed pendulum-type device. The fruit quality patterns with varying equivalent drop heights were determined for the three apple varieties. A few conclusions were summarized up as follows. 1. It could be recommended that a catching surface designed for localized shake-and-catch system should depend on the possible impact on top zones of the tested apple varieties to achieve the desired level of fruit quality. 2. It was found that Extra Fancy Class 1 could be maintained within the equivalent drop heights of 24, 50 and 54 for ‘Jazz’ apples, 8, 18 and 38 cm for ‘Granny Smith’ apples, and 7, 26 and 34 cm for ‘Envy’ apples by using a catching surface cushioned by 2.1 kPa, 4.8 kPa and 9.7-11 kPa deformation pressure foam respectively. 3. To achieve better protection for higher drop height, it would be reasonable to suggest using the series of cushioning material with deformation pressure 4.8-11 kPa for ‘Jazz’ apples whereas deformation pressure of the cushioning materials could be over 11 kPa for ‘Granny Smith’ and ‘Envy’ apples. ACKNOWLEDGEMENTS This research was supported in part by Innovative Research Team of Guangdong Province Agriculture Research System (2017LM2153), United States Department of Agriculture (USDA)’s Hatch and Multistate Project Funds (Accession No 1005756 and 1001246), USDA National Institutes for Food and Agriculture competitive grant (Accession No 1005200), Washington State University (WSU) Agricultural Research Center (ARC), Guangdong Provincial Science and Technology Program (2017A020208049) and Liuzhou City Science and Technology Program (2017BE10303). Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture and Washington State University. The authors would also like to express our gratitude to Drs. Jintao Yao, Lingxiao Quan, Zhibin Zhang, Tao Wu, and Weizu Wang for their help in experimental data collection. REFERENCES Baritelle, A. L. and Hyde, G. M. (2001). Commodity conditioning to reduce impact bruising. Postharvest biology and technology, 21(3), 331-339. Chen, P. and Yazdani, R. (1991). Prediction of apple bruising due to impact on different surfaces. Transactions of the ASAE, 34(3), 956-961. De Kleine, M. E. and Karkee, M. (2015). Evaluating a NonNewtonian Shear-Thickening Surface During Fruit Impacts. Transactions of the ASABE, 58(3), 907-915. 255