Robert G. Hardin IV’s research while affiliated with Texas A&M University and other places

Weed competition is one of the most limiting factors affecting crop yield and profitability. Robotic weeding systems have demonstrated their potential to save herbicide usage and thereby minimize costs and adverse impacts on the environment. We introduce the software and hardware design of an automatic system for micro-volume herbicide spray using a mobile robot for early-stage weed control. The system is equipped with a stereo camera, one inertial measurement unit, and multiple linearly actuating spray nozzles. To enable the system, we propose a new scene representation from the perspective of spray operation. We represent the space occupied by weeds as candidate line segments for spray and then construct a directed acyclic graph (DAG) that embraces the feasible nozzle paths among weeds. Based on the new scene representation, we formulate an optimal K -nozzle assignment/motion planning problem and develop a binary linear programming-based algorithm to assign nozzles to the candidate line segments for optimal coverage. We built the system and conducted both simulation and field experiments. Evaluation on rough soil surfaces with artificial targets has shown that the lateral errors of herbicide spray are at sub-centimeter levels. Simulation results demonstrate that the proposed assignment algorithm can provide good coverage within the intra-row regions.

Cylindrical modules, also known as round modules, are becoming a more common method of seed cotton storage and transport. Increasing use of cylindrical modules has led to the development of new methods of field staging, transport, and handling at the gin. A low-cost smart cotton module tracking and monitoring system (SCMTM) was developed for recording module tag numbers, equipment location, and images of the modules automatically. The SCMTM system was mounted on a cotton module loader and module truck in a gin yard of Texas. Data was recorded automatically using the SCMTM system and used for analysis of cotton module handling logistics and wrap damage. Route and throughput rates of the loader were calculated, and the time required per module was estimated. The study found that the loader was idle more than 46% of the total working period. Analysis of module images indicated a module wrap damage rate of 4.4% in the studied cases.

Nine diverse Upland cotton cultivars and germplasm lines differing in seed size were planted at two locations at Stoneville, MS in 2015, 2016, and 2017. ‘AR 9317-26’ and ‘DP 555 BG/RR’ were classified as small with a seed index (SI) < 10 g. ‘FM 832’, ‘FM 966’, and ‘MD 15’ had SI ranging from 10 to 12 g and were classified as intermediate seed size. ‘TAM 182-34 ELS’ and three other breeding lines: ‘201-2’, ‘107-1’, and ‘152-1’ had large seeds with SI > 12 g. The seeds were planted in three replications at two sites at Stoneville, MS. Data were collected on ginning energy requirement (Wh kg-1 lint), ginning rate (g lint s-1), and other agronomic and quality traits. The objectives of the test were to determine the effect of seed size on the above parameters. Statistical analyses were performed using Proc GLM. Simple Pearson’s correlation tests and regression analyses were conducted to test the relationships between SI and these traits. Covariance estimates were calculated using Proc GLIMMIX to determine the direction of linear relationships. Differences in SI were highly significant among cultivars. SI was positively and significantly correlated with ginning rate but significantly and negatively correlated with ginning energy requirement. Significant and negative relationships were observed between SI and fiber uniformity, lint yield, lint turnout, and number of seeds per kg. Significant and positive relationships were observed between SI and fiber strength, fuzz percentage, and seed surface area. Relationships among SI and micronaire, fineness, and fiber length were minor.

Automation provides key benefits to production plants: increased speed of production, improved quality control, enhanced worker safety, and reduced production costs. Numerous types of systems use automated control throughout the world; in cotton gins, there are a few main systems that rely on some form of control: material flow, fire suppression, dryer temperature, press operation, and moisture restoration systems. This chapter provides an overview of control systems in general along with key examples of control systems in use in U.S. cotton gins.

A comprehensive gin maintenance program is critical to optimizing the efficiency of a ginning system and affects labor, energy, and maintenance costs; safety, downtime, daily throughput, fiber properties, and customer satisfaction. A comprehensive gin maintenance program includes a sound maintenance philosophy, downtime and repair documentation and guidelines, a dormant season repair program, ginning season preventive maintenance, and a ginning season repair program. Implementing a comprehensive gin maintenance program in dormant and ginning seasons will minimize the frequency and length of downtime. This will maximize throughput, reducing energy and labor costs per bale, benefitting both the gin’s customers and its owners. Example downtime, inspection, repair and preventive maintenance reports are provided.

Ginning practices affect both economic returns to cotton producers and quality of fiber produced for textile mills and, ultimately, consumers. Because of the shift from a primarily domestic to an export market for U.S. cotton and the loss of textile market share to synthetic fibers, production of high-quality cotton is critical to maintaining the competitiveness of the U.S. cotton industry. The objectives of this review are to summarize the effects of ginning on cotton quality, focusing on recent research, and provide best practices for gin managers to maximize bale value and fiber quality. Higher fiber moisture content at the gin stand, with an optimum of 6 to 7%, better preserves fiber length and strength, but this moisture level reduces both seed cotton and lint cleaning efficiency; therefore, a fiber moisture content of 5 to 6% might be needed for efficient cleaning. Seed cotton cleaners are effective at removing larger foreign matter particles and cause minimal fiber damage. Lint cleaners are efficient cleaners and necessary for removing seed-coat fragments and other small particles created in the gin stand. However, lint cleaners break some fibers, create neps, and remove some good quality fiber. To maximize fiber quality, gins should encourage producers to grow high-quality cultivars and follow recommended harvesting practices. Modules need to be stored and handled properly. Gins should use the minimum amount of drying and lint cleaning that maximizes bale value. Avoiding contamination is vitally important to uphold the U.S. cotton industry’s reputation as a supplier of high-quality cotton.

Gins have become more energy efficient. However, energy costs account for 25% of the total variable costs of ginning, including seasonal labor, increasing from 15% in 1994. Recent studies found that average electricity use at gins is approximately 35 kWh per bale, down from 53 kWh per bale reported in 1980. However, gins must continue to increase efficiency to remain profitable and consumers are increasingly concerned with the sustainability of textile products. This paper reviews recent research on energy use and conservation in cotton gins and offers suggestions on ways for gin managers to reduce energy use based on this research. Gins should focus on maximizing their ginning rate and sustaining this rate as much as possible during the ginning season. Increased ginning rates will reduce per-bale costs of not only electricity and fuel, but labor as well. Maintaining consistent material flow through the gin, matching equipment capacities, and minimizing downtime allows gins to produce more bales per shift. More than half the electricity at gins is used for material handling, primarily by the large centrifugal fans used to convey materials. The cost of conveying materials should be considered when designing or updating gins. Gins should use only the volume of air necessary for consistent conveying and adequate drying and need to eliminate unnecessary friction losses in conveying systems. To reduce fuel use, dryer control systems should be used to avoid excessive drying of cotton. Insulating drying systems might be economically feasible, particularly from the burner to the mixpoint. Gins also should consider strategies to reduce the prices paid for electricity and fuel.