Mechanical Design and Initial Performance Testing of an Apple-Picking End-Effector

2015 ◽  
Author(s):  
Joseph R. Davidson ◽  
Changki Mo
Keyword(s):  
Normal Force ◽  
Performance Testing ◽  
Open Loop ◽  
Labor Costs ◽  
Fresh Market ◽  
Damage Development ◽  
Fruit Removal ◽  
End Effector ◽  
Position Errors ◽  
Tree Fruit

The fresh market apple industry currently relies on manual labor for all harvesting activities. The lack of mechanical harvesting technologies is a serious concern because of rising labor costs and increasingly uncertain labor availability. Researchers have been working for several decades to develop mechanical harvesters for tree fruit. The two fruit removal methods considered include mass mechanical harvesters and selective harvesting with robotics technology. Whereas mass mechanical harvesters have demonstrated unacceptable damage rates, robotic systems have been limited by insufficient speed and robustness. This paper describes the design and analysis of a novel underactuated end-effector fabricated for the robotic harvesting of tree fruit. The device has been optimized around a set of target tasks, the most critical being speed, low complexity, suitability for a highly variable field environment, and the replication of hand picking so as to minimize fruit damage. Development of the end-effector has been facilitated by a thorough study of the dynamic forces involved during the manual harvesting of apples. The end-effector produces a spherical power grasp with a normal force distribution and picking sequence replicating selected human patterns. An underactuated, tendon-driven device with compliant flexure joints has been adopted to improve system performance in the presence of position errors as well as enhance robustness to variable fruit size, shape, and orientation. The prototype end-effector also uses minimal sensors and incorporates open-loop control to reduce complexity and improve picking speed. This paper presents the theoretical analysis of the end-effector kinematics and discusses the selection of key geometric parameters. Experiments have been conducted to determine the normal forces developed during grasping of the apple. Results indicate that open-loop, feedforward control can be used to produce optimal normal force patterns.

Evaluation of Shake-and-Catch Methods on Harvesting of Tall Spindle Apples

2020 ◽  
Vol 63 (4) ◽  
pp. 857-863
Author(s):  
Haiqian Xing ◽  
Shaochun Ma ◽  
Ming Liu ◽  
Menglong Wang ◽  
Yi Wei ◽  
...  
Keyword(s):  
Physical Properties ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Test System ◽  
List Type ◽  
Labor Costs ◽  
Fresh Market ◽  
Fruit Removal ◽  
Apple Trees ◽  
Fruit Damage

HighlightsBoth frequency and amplitude were influencing factors in analyzing the fruit removal efficiency and fruit damage.This research focused on tall spindle ‘Fuji’ apple trees, which enriched the study of the variety and architecture resources of apple trees.The advice for shake-and-catch harvesting was based on the analysis of amplitude and frequency from the perspective of energy consumption.Abstract. Almost all fresh-market apples are picked manually, and these apples rank among the most labor-intensive fruit crops to produce. Due to declining labor supply and rising labor costs, fresh-market apple growers are seeking mechanical harvesting solutions. Shake-and-catch is a potential method that has been well studied. However, because of fruit damage, this method cannot be widely used for fresh-market apples. The primary goal of this study was to investigate how the physical properties of the fruit tree and the shaker parameters affect fruit removal efficiency and fruit damage in an effort to help growers find solutions to the above-mentioned issues. A test system was developed, and its performance was evaluated in certain shaking modes. Based on the experimental results, the physical properties of the tree (length and diameter of limb, length and diameter of twig, and apple weight) and the frequency and amplitude of the shaker influenced the effectiveness of fruit detachment. When the amplitude of the shaker was 14.3 mm and the frequency was less than 15 Hz, the length of the twig had the greatest effect on fruit harvesting. However, with increasing frequency and amplitude, the effect of tree properties on fruit harvesting declined, and amplitude had a more significant effect on fruit harvesting than frequency. Moreover, the fruit removal rate reached 91.43% when the amplitude was 14.3 mm and the frequency was 20 Hz. The results of this study contribute to the development of an effective mechanical harvester that is adapted to tall spindle apple trees. Keywords: Amplitude, Apple fresh market, Frequency, Physical properties, Shake-and-catch, Tall spindle.

A Precision Pruning Strategy for Improving Efficiency of Vibratory Mechanical Harvesting of Apples

2018 ◽  
Vol 61 (5) ◽  
pp. 1565-1576 ◽  
Author(s):  
Xin Zhang ◽  
Long He ◽  
Yaqoob Majeed ◽  
Matthew David Whiting ◽  
Manoj Karkee ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Fruit Quality ◽  
Negative Relationship ◽  
Fresh Market ◽  
Fruit Removal ◽  
Vibratory System ◽  
Significant Difference ◽  
Labor Requirements ◽  
Lateral Branches ◽  
Canopy Management

Abstract. The state of Washington is the biggest fresh market apple ( Borkh.) producer in the U.S., and the state’s annual apple production has exceeded 60% of the national production. Due to the extensive labor requirements for harvesting fresh market apples, there is burgeoning demand for mechanical harvest solutions. Our transdisciplinary studies on mechanical harvest systems for apples have shown that fruit removal efficiency (FRE) with a vibratory system can be improved with precision canopy management. In this study, we evaluated the effect of precision pruning strategies on FRE in two groups (106 and 107, respectively) of randomly selected horizontal branches of ‘Jazz/M.9’ apple trees in a commercial orchard. Fruiting lateral branches were pruned to either shorter than 15 cm (guideline 1, G1) or 23 cm (guideline 2, G2). Harvest tests were conducted using a shake-and-catch harvester prototype developed by Washington State University with a fixed vibrating frequency of 20 Hz and shaking duration of 5 s. FRE for branches treated with G1 was significantly higher (91%) than FRE for branches treated with G2 (81%). We recorded a negative relationship between FRE and lateral shoot length. FRE was up to 98% when shoots were shorter than 5 cm, and FRE was only 56% for shoots of 25 cm or longer. We developed a shoot diameter-to-length index (S-index) to better understand the effect of shoot size on FRE. FRE was as high as 98% when the S-index was greater than 0.15. In addition, mechanically harvested fruit quality was assessed by categorizing the fruit into Extra Fancy, Fancy, and Downgrade fresh market classes based on USDA standards; however, no significant difference was found between the two treated groups. These results suggest that pruning lateral fruiting branches to less than 15 cm or to an S-index greater than 0.03 is required to achieve FRE of 85% with no negative impacts on fruit quality. Keywords: Canopy management, Fresh market fruit, Fruit removal efficiency, Mechanical harvest, Shoot pruning severity.

Analytic Geometric Design of Spatial R-R Robot Manipulators

2000 ◽  
Author(s):  
Constantinos Mavroidis ◽  
Munshi Alam ◽  
Eric Lee
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulators ◽  
Open Loop ◽  
Geometric Design ◽  
Sixth Order ◽  
Design Parameters ◽  
End Effector ◽  
Revolute Joints ◽  
Order Polynomial ◽  
Spatial Locations

Abstract This paper studies the geometric design of spatial two degrees of freedom, open loop robot manipulators with revolute joints that perform tasks, which require the positioning of the end-effector in three spatial locations. This research is important in situations where a robotic manipulator or mechanism with a small number of joint degrees of freedom is designed to perform higher degree of freedom end-effector tasks. The loop-closure geometric equations provide eighteen design equations in eighteen unknowns. Polynomial Elimination techniques are used to solve these equations and obtain the manipulator Denavit and Hartenberg parameters. A sixth order polynomial is obtained in one of the design parameters. Only two of the six roots of the polynomial are real and they correspond to two different robot manipulators that can reach the desired end-effector poses.

scholarly journals Workspace and Stiffness Analysis of 3D Printing Cable-Driven Parallel Robot with a Retractable Beam-Type End-Effector

Robotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 65
Author(s):  
Jinwoo Jung
Keyword(s):  
3D Printing ◽  
Natural Frequencies ◽  
Parallel Robot ◽  
Good Alternative ◽  
Construction Time ◽  
Single Plane ◽  
End Effector ◽  
Stiffness Analysis ◽  
Position Errors ◽  
Beam Type

3D printing is a widely used technology that has been recently applied in construction to reduce construction time significantly. A large 3D printer often uses a traditional Cartesian robot with inherent problems, such as position errors and printing nozzle vibrations, due to the long, heavy horizontal beam carrying it and a large amount of power required to actuate the heavy beam. A cable-driven parallel robot (CDPR) can be a good alternative system to reduce the vibrations and necessary power because the robot’s lightweight cables can manipulate the printing nozzle. However, a large 3D printing CDPR should be carefully designed to maximize the workspace and avoid cable interference. It also needs to be stiff enough to reject disturbances from the environment properly. A CDPR with a retractable beam-type end-effector with cables through the guide pulleys in a single plane is suggested for avoiding cable interference while maximizing the workspace. The effects of using the retractable end-effector on the workspace were analyzed relative to the cable connection points’ location changes. Static stiffness analysis was conducted to examine the natural frequencies, and the geometric parameters of the end-effector were adjusted to improve the lowest natural frequencies. Simulation results show that a retractable beam-type end-effector can effectively expand the wrench-feasible workspace.

scholarly journals Blueberry Producers’ Attitudes toward Harvest Mechanization for Fresh Market

2018 ◽  
Vol 28 (1) ◽  
pp. 10-16 ◽  
Author(s):  
R. Karina Gallardo ◽  
Eric T. Stafne ◽  
Lisa Wasko DeVetter ◽  
Qi Zhang ◽  
Charlie Li ◽  
...  
Keyword(s):  
Fruit Quality ◽  
New Technologies ◽  
Cost Effective ◽  
The United States ◽  
Limiting Factor ◽  
Primary Concern ◽  
Agricultural Labor ◽  
Labor Costs ◽  
Fresh Market ◽  
Specialty Crop

The availability and cost of agricultural labor is constraining the specialty crop industry throughout the United States. Most soft fruits destined for the fresh market are fragile and are usually hand harvested to maintain optimal quality and postharvest longevity. However, because of labor shortages, machine harvest options are being explored out of necessity. A survey on machine harvest of blueberries (Vaccinium sp.) for fresh market was conducted in 2015 and 2016 in seven U.S. states and one Canadian province. Survey respondents totaled 223 blueberry producers of various production sizes and scope. A majority (61%) indicated that their berries were destined for fresh markets with 33% machine harvested for this purpose. Eighty percent said that they thought fruit quality was the limiting factor for machine-harvested blueberries destined for fresh markets. Many producers had used mechanized harvesters, but their experience varied greatly. Just less than half (47%) used mechanical harvesters for fewer than 5 years. Most respondents indicated that labor was a primary concern, as well as competing markets and weather. New technologies that reduce harvesting constraints, such as improvements to harvest machinery and packing lines, were of interest to most respondents. Forty-five percent stated they would be interested in using a modified harvest-aid platform with handheld shaking devices if it is viable (i.e., fruit quality and picking efficiency is maintained and the practice is cost effective). Overall, the survey showed that blueberry producers have great concerns with labor costs and availability and are open to exploring mechanization as a way to mitigate the need for hand-harvest labor.

scholarly journals Effects of Machine-Harvest Interval on Fruit Quality of Fresh Market Northern Highbush Blueberry

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 245
Author(s):  
Yixin Cai ◽  
Fumiomi Takeda ◽  
Brian Foote ◽  
Lisa Wasko DeVetter
Keyword(s):  
Fruit Quality ◽  
Titratable Acidity ◽  
Vaccinium Corymbosum ◽  
Soluble Solids ◽  
Highbush Blueberry ◽  
Labor Costs ◽  
Fresh Market ◽  
Harvest Intervals ◽  
Northern Highbush Blueberry

Machine harvesting blueberry (Vaccinium sp.) alleviates labor costs and shortages but can reduce fruit quality. Installation of softer catching surfaces inside modified over-the-row harvesters (modified OTR) and adjusting harvest intervals may improve fruit quality and packout. The objective of this study was to determine the effect of harvest interval on fruit quality of fresh market northern highbush blueberry (Vaccinium corymbosum L.) harvested using a modified OTR. ‘Liberty’ blueberry bushes were harvested by hand or using a modified OTR at 3-, 10-, and 14-day intervals in 2019 and at 7-, 11-, and 14-day intervals in 2020. Hand-harvested ‘Liberty’ had greater packout and firmness than machine-harvested fruit. Machine harvesting at the 3-day interval in 2019, and the 14-day interval in 2020 reduced packout from 70–80% to 60% and 54%, respectively. In 2019, machine harvesting at a 3-day interval overall resulted in fruit with greater firmness, higher titratable acidity (TA), and lower total soluble solids (TSS) and SS/TA, compared to other harvest intervals. In 2020, the 7-day machine-harvest interval had a greater TA and lower TSS/TA, compared to the 11- and 14-day intervals. Overall, modified OTR machine-harvest intervals can be extended to 10–11 days for fresh market northern highbush cultivars such as ‘Liberty’ grown in northwest Washington.

scholarly journals AUTOMATIC ESTIMATION OF SIZE PARAMETERS USING VERIFIED COMPUTERIZED STEREOANALYSIS

2011 ◽  
Vol 24 (1) ◽  
pp. 41 ◽  
Author(s):  
Peter R Mouton ◽  
Joel Durgavich ◽  
Donald K Ingram
Keyword(s):  
Biomedical Research ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Performance Testing ◽  
High Signal ◽  
High Contrast ◽  
Size Estimation ◽  
Labor Costs ◽  
Biological Objects ◽  
Novel Approach

State-of-the-art computerized stereology systems combine high-resolution video microscopy and hardwaresoftware integration with stereological methods to assist users in quantifying multidimensional parameters of importance to biomedical research, including volume, surface area, length, number, their variation and spatial distribution. The requirement for constant interactions between a trained, non-expert user and the targeted features of interest currently limits the throughput efficiency of these systems. To address this issue we developed a novel approach for automatic stereological analysis of 2-D images, Verified Computerized Stereoanalysis (VCS). The VCS approach minimizes the need for user interactions with high contrast [high signal-to-noise ratio (S:N)] biological objects of interest. Performance testing of the VCS approach confirmed dramatic increases in the efficiency of total object volume (size) estimation, without a loss of accuracy or precision compared to conventional computerized stereology. The broad application of high efficiency VCS to high-contrast biological objects on tissue sections could reduce labor costs, enhance hypothesis testing, and accelerate the progress of biomedical research focused on improvements in health and the management of disease.

Combining Motion Primitives and Image-Based Visual Servo Control

2020 ◽  
Author(s):  
Ghananeel Rotithor ◽  
Ashwin P. Dani
Keyword(s):  
Feedback Control ◽  
Open Loop ◽  
Servo Control ◽  
Visual Servo ◽  
Motion Generation ◽  
End Effector ◽  
Visual Servo Control ◽  
Dynamic Movement ◽  
Motion Primitive ◽  
Dynamic Movement Primitives

Abstract Combining perception feedback control with learning-based open-loop motion generation for the robot’s end-effector control is an attractive solution for many robotic manufacturing tasks. For instance, while performing a peg-in-the-hole or an insertion task when the hole or the recipient part is not visible in the eye-in-the-hand camera, an open-loop learning-based motion primitive method can be used to generate end-effector path. Once the recipient part is in the field of view (FOV), visual servo control can be used to control the motion of the robot. Inspired by such applications, this paper presents a control scheme that switches between Dynamic Movement Primitives (DMPs) and Image-based Visual Servo (IBVS) control combining end-effector control with perception-based feedback control. A simulation result is performed that switches the controller between DMP and IBVS to verify the performance of the proposed control methodology.

scholarly journals ANALISA FORWARD KINEMATIC PADA SIMULATOR ARM ROBOT 5 DOF YANG MENGINTEGRASIKAN MIKROKONTROLER ARDUINO-UNO DAN LABVIEW

ROTASI ◽  
2013 ◽  
Vol 15 (2) ◽  
pp. 37
Author(s):  
Munadi Munadi
Keyword(s):  
Robot Manipulator ◽  
Angular Position ◽  
Servo Motor ◽  
End Effector ◽  
Position Errors ◽  
Position And Orientation ◽  
The Individual ◽  
Forward Kinematic ◽  
The Relationship ◽  
Numerical Program

An arm robot simulator has been developed, that capable in simulating a 5 degree of freedom robot manipulator, in which it was equipped with two-finger gripper mechanism at end-effector. This simulator is designed for educational purposes so that many students can easily understand when learning about robot manipulator. The simulator was developed using Ardiuno Uno with LabVIEW through the Firmata interface for controlling the actuators (servo motors). Ardiuno Uno was chosen because it can interact with LabVIEW that will be able to control the angular position of servo motor easily. Angular position errors that occur on the servo motor can be solved by using a numerical program functions and numerical multiply divided on LabVIEW. For analysis, this paper presents the forward kinematics problem which is concerned with the relationship between the individual joints of the arm robot simulator and the position and orientation of the tool or end-effector. The analysis result is carried out in MATLAB.

A New Polynomial Solution to the Geometric Design Problem of Spatial R-R Robot Manipulators Using the Denavit and Hartenberg Parameters

1999 ◽  
Vol 123 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Constantinos Mavroidis ◽  
Eric Lee ◽  
Munshi Alam
Keyword(s):  
Design Problem ◽  
Degrees Of Freedom ◽  
Robot Manipulators ◽  
Polynomial Solution ◽  
Open Loop ◽  
Geometric Design ◽  
New Method ◽  
Design Parameters ◽  
End Effector ◽  
Spatial Locations

This paper presents a new method to solve the geometric design problem of spatial two degrees of freedom, open loop robot manipulators with revolute joints that perform tasks, which require the positioning of the end-effector in three spatial locations. Tsai and Roth [3] solved this problem first using screw parameters to describe the kinematic topology of the R-R manipulator and screw displacements to obtain the design equations. The new method, which is developed in this paper, uses Denavit and Hartenberg parameters and 4×4 homogeneous matrices to formulate and obtain the kinematic equations. The loop-closure geometric equations provide eighteen design equations in eighteen unknowns. Polynomial Elimination techniques are used to solve these equations and obtain the manipulator Denavit and Hartenberg parameters and the manipulator base and end-effector geometric parameters. A sixth order polynomial is obtained in one of the design parameters. Only two of the six roots of the polynomial are real and they correspond to two different robot manipulators that can reach the desired end-effector poses.

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