Jiajun Xu

Michigan State University | MSU · Department of Biosystems and Agricultural Engineering (BAE)

Green asparagus is a labor-intensive vegetable crop for harvesting. Rising labor costs and seasonal labor shortages are threatening the sustainability and profitability of the asparagus industry in the United States (U.S.), making harvesting automation more urgently needed than ever. A multitude of challenges, however, exist in developing practical...

Automated quality grading and sorting of fresh market sweetpotato roots have not been achieved at packing facilities, which consequently requires significant labor to manually grade the products and sort them by hand. Given an increasing shortage of labor and rising labor costs, there is a pressing need to develop automated grading and sorting tech...

Automated sorting of sweetpotatoes is necessary to reduce labor dependence and costs that are significant at today’s sweetpotato packing sheds. Although optical sorters have been widely adopted in commercial packing lines for many horticultural commodities, there remains an unmet need to develop dedicated technology for the automated grading and so...

Weed management impacts crop yield and quality. Machine vision technology is crucial to the realization of site-specific precision weeding for sustainable crop production. Progress has been made in developing computer vision algorithms, machine learning models, and datasets for weed recognition, but there has been a lack of open-source, publicly av...

Rapid advances in machine vision and artificial intelligence (AI) technologies have generated high interest in developing automated grading and sorting solutions for fresh produce of specialty crops. Sweetpotatoes are an economically important crop in the United States and beyond, but grading and sorting the commodity, especially for surface defect...

Weeds are a major threat to crop production. Automated innovations for reducing herbicides and labor needed for weeding have become a high priority for sustainable weed management. The current state-of-the-art weeding systems still cannot reliably recognize weeds in changing field conditions for precision weed control. Enhancing weed recognition ac...

Weeds are a major thread to crop production. Automated innovations for reducing herbicides and labor needed for weeding have become a high priority for sustainable weed management. The current state-of-the-art weeding systems still cannot reliably recognize weeds in changing field conditions for precision weed control. Enhancing weed recognition ac...

Sweetpotato is an economically important specialty crop in the United States (U.S.), but it is significantly labor-intensive in many production activities such as postharvest packing. Currently, grading and sorting of sweetpotato storage roots for quality is still performed manually. In addition to incurring high labor costs, manual grading is subj...

Volume is an important phenotype and shape descriptor of sweetpotato storage roots for postharvest quality assessment and breeding programs. The standard water displacement method for measuring fruit volume is laborious, subject to human observation errors, and often destructive. Three-dimensional (3D) imaging-based machine vision provides an alter...

Mobile cable-driven parallel robots (MCDPRs) offer expanded motion capabilities and workspace compared to traditional cable-driven parallel robots (CDPRs) by incorporating mobile bases. However, additional mobile bases introduce more degree-of-freedom (DoF) and various constraints to make their motion planning a challenging problem. Despite several...

Graphical user interfaces (GUIs) interacting with hardware, data, and models, are beneficial for accelerating the deployment and adoption of machine vision technology in precision agriculture. They are particularly important for end users without the necessary technical expertise in computer programming. Making GUIs open-source and public is furthe...

Mobile cable-driven parallel robots (MCDPRs) is a novel concept of cable-driven parallel robots (CDPRs) developed by mounting several mobile bases to discrete the conventional fixed frame. However, the additional mobile bases introduce more degree-of-freedom (DoF), thereby causing the kinematic redundancy. Moreover, mobile bases are susceptible to...

The ability to avoid the moving obstacle is critical to cable-driven parallel robots (CDPRs) operating in real-world environments. However, the moving obstacle raises extraordinary challenges for CDPRs due to various constraints introduced by cables. In this article, an adaptive sampling-based path planning method is presented for CDPRs to find col...

Mobile cable-driven parallel robot (MCDPR) is a variant of cable-driven parallel robots (CDPRs) by mounting several mobile bases to replace the conventional fixed frame. The novel modification of adding mobile bases leads MCDPRs being highly flexible and have great potential for complex environments. However, the issue of coupled mobile bases intro...

Volume is an important phenotype and quality attribute of sweetpotato storage roots. Conventionally the volume of most agricultural products is measured by water displacement. This method, which requires submerging the products in a container of water and measuring the displacement of water in the container, is time-consuming and tedious. It would...

Cable-driven parallel robots (CDPRs) have demonstrated a remarkable potential for a wide range of applications over the past few decades. However, multiple cables introduce various interferences, which is a challenging task for the path planning of CDPRs. In this study, an adaptively optimal rapidly exploring random tree (RRT*) is proposed for CDPR...

This article establishes a mechanical‐electrical‐hydraulic vertical torsional coupling vibration mathematical model, and investigates its vibration suppression control strategy with time varying full state constraints for the rolling mill vertical torsional coupling vibration system. Firstly, the mechanical‐electrical‐hydraulic vertical torsional c...

In the past decades, cable-driven parallel robots (CDPRs) have been proven the extraordinary performance for various applications. However, the multiple cables lead the robot easy to interfere with environments. Especially the large workspace of CDPR may introduce unknown moving obstacles. In this study, a sampling-based path planning method is pre...

Moving obstacle avoidance is one of the most challenging problems for cable-driven parallel robots (CDPRs) due to various constraints. In this work, the improved rapidly exploring random tree (RRT) method is proposed to address moving obstacle avoidance for CDPRs. Compared with the conventional RRT method which mainly focused on the static environm...

This paper deals with the collision-free path planning of cable-driven parallel robots (CDPRs) in a dynamic three-dimensional environment. The proposed algorithm is based on the artificial potential field (APF) approach which provides a simple and effective path planning method. However, the APF approach is easy to cause the robot oscillation and h...

In this study, the improved vision-based rapidly exploring random tree (RRT) algorithm is proposed to address moving obstacle avoidance for cable-driven parallel robots (CDPRs). The improved RRT algorithm is goal-biased with dynamic stepsize makes it possible to implement in dynamic environments. For the implementation of algorithm on CDPRs, the im...

In this study, a method was proposed to change the surface roughness of Polydimethylsiloxane (PDMS) membrane, a hydrophobic material coated on circular steel substrates, using ultrasonic vibration with frequency above 20 kHz to control the surface tension of water droplet on the PDMS membrane. Ultrasonic vibration applied from piezo actuator was tr...