URIEL A. ROSA, Assistant Professor

Ph.D., Dept. of Agricultural and Bioresource Engineering, University of Saskatchewan, 1997
Department of Biological and Agricultural Engineering
3054 Bainer Hall
Phone: 530-752-1890
Email: uarosa@ucdavis.edu

Current Research

Professor Rosa has focused his research interests on engineering integration of electro-mechanical systems, sensing and control techniques for use in “in field” bioproduction systems conceived to reduce production costs, and to increase product quality.

The California tree fruit industry is a multibillion dollar industry in need of emerging technologies to help compete in the domestic and global markets. Development of horticultural engineering towards a more labor efficient production of fruits and nuts may require increasing participation of mechanized, automated and eventually robotic operations. Although, the industry displays many developments in control systems and actuators technology, science is in early development stages for the integration of the current technology into the complex and harsh environmental conditions frequently presented in operations involving fruitful tree structures. Off-road operations, as opposed to more controllable industrial conditions, simply add to the degree of complexity of the problems to be solved in this field.

Thus, Professor Rosa’s major long term research goal is to develop the science to assist the adoption of mechanized, automated, and/or eventually robotics harvesting, pruning and thinning operations of nut and fruit trees.

Since so much depends on the interaction of mechanical devices and actuators with biological materials such as fruits, tree limbs and branches, it is necessary to conduct experimental investigations, modeling, simulations, and analyzes of tool-plant/fruit interactions. The goal is to understand the interactions among machine components and actuating tools, or end-effectors, with biological material.

Along with academia and industry research collaborators and advisees Professor Rosa is currently working in the development of four distinct projects.

1) Precision Shaker: Clamp-less Actuation on Tree Limbs:

a) Development of precise tree limb shaker (Clamp-less Precision Shaker) used for thinning of peaches and precise harvesting of table fruits. The goal is to develop an electrodynamic servo controlled actuator to excite tree limbs by detecting and removing precise amount of fruits.

b) Experimental analysis and analytical modeling of incremental fruit removal of fruitful branches, by application of controlled pulsing techniques, is progressing towards the development of sensors that can detect and monitor tree limb fruit removal. Sensors that can accurately detect fruit removal are essential in the process of automatically controlling amount of thinning in orchard automation and in the future for robotic operations. This information can be fed back to computer boards to control shaker excitation and amount of thinning.

2) Development of a Pistachio Yield Monitoring System (PYM):

Yields vary dramatically from tree to tree within a pistachio orchard. A yield monitoring system is a basic tool required for the adoption of precision agricultural practices. The PYM has been used to investigate the causes of yield variability. Up to date more than 50,000 individual tree yields have been recorded and analyzed on commercial pistachio production farms with the use of three PYM prototypes developed and built in our Bio-Automation Lab and mounted on commercial pistachio harvesters. Data have been used to create per tree basis yield maps. Due to difficulties of GPS units to function properly inside orchards with dense canopy, an in row local navigation system has been developed based on “Integration of Sensor Data and Orchard Layout Characteristics for Tree Detection”.

3) Innovative Concepts in Robotic Citrus Harvesting for the Fresh Market:

Professor Rosa is actively investigating innovative research concepts in robotic citrus harvesting to overcome basic problems yet unsolved to efficiently and economically harvest citrus fruits for the fresh market.

4) Off-road Integration of Fuel Cell Applications:

Fuel cell systems provide clean energy, without noise and air pollution. Although in early stages of on-the-road commercial use, fuel cells may also have some future in off-road applications. Studies are in progress to determine the effects impact and vibration can cause on fuel cells working under intense off-road operations, such as those that occur in agricultural operations. Experimental and numerical modeling of impact and vibration have been started to create a design capable of mitigating impact and vibration effects on fuel cells stacks operating in off-road conditions.

Representative Recent Publications

Rosa, U. A., and D. Wulfsohn. 1999. Constitutive model for high speed tillage using narrow tools. Journal of Terramechanics 36:221-234.

Rosa, U. A., S. K. Upadhyaya, M. Josiah, M. Koller, M. Mattson, and M. G. Pelletier. 2000. Analysis of a tomato yield monitor. Transactions of the ASAE (American Society of Agricultural Engineers) 43(6):1331-1339.

Rosa, U. A., S. K. Upadhyaya, and P. Chen. 2000. Modeling and verification of an auto front-wheel-drive system. Transactions of the ASAE (American Society of Agricultural Engineers) 43(1):23-29.

Rosa, U. A., S. K. Upadhyaya, M. N. Josiah, and M. Koller. 2001. Effect of belt width and grouser wear on the tractive characteristics of rubber-tracked vehicles. Applied Engineering in Agriculture 17(3):267-271.

Rosa, U. A., P. Chen, and S. K. Upadhyaya. 2001. Modeling and verification of SuperSteer steering system. Transactions of the ASAE (American Society of Agricultural Engineers) 44(4):741-749.

Upadhyaya, S. K., U. A. Rosa, and D. Wulfsohn. 2002. Application of the finite element method in agricultural soil mechanics. Chapter 2 in Advances in Soil Dynamics, Volume 2, edited by Upadhyaya, S. K., W. J. Chancellor, J. V. Perumpral, R. L. Schafer, W. R. Gill, and G. E. VandenBerg. American Society of Agricultural Engineers Monograph. pp. 118-153.

Brown, P. H., U. A. Rosa, and S. K. Upadhyaya. Precision harvest and analysis techniques for crops. U.S. Patent Application #60/789,584.

Heidman, B. C., U. A. Rosa, P. H. Brown, and S. K. Upadhyaya. 2003. Development of a pistachio yield monitoring system. American Society of Agricultural Engineers Paper No. 03-1040, St. Joseph, MI.

Rosa U. A., J. Thompson, D. Slaughter, T. DeJong, K. Shackel, J. Tiamzon, and S. Johnson. 2004. Feasibility study of using electromagnetic shaker technology for peach thinning. Proceedings of International Conference AgEng2004. Leuven.

Diezma, B., and U. A. Rosa. 2005. Monitoring of fruit removal for mechanical thinning of peaches. Frutic05 - 7th Fruit, Nut and Vegetable Engineering Prod. Symposium, Montpellier, France.

Rosa, U. A., B. Diezma, B. S. Lee, and J. F. Thompson. 2005. Transient modal analysis of removed mass for mechanical thinning of fruits. Frutic05 - 7th Fruit, Nut and Vegetable Engineering Prod. Symposium. Montpellier, France.

Membership in Professional Societies

American Society of Agricultural Engineers
European Society of Agricultural Engineers

Courses Offered

EBS 75 – Properties of Materials in Biological Systems
EBS 275 – Physical Properties of Biological Materials
EBS 120 – Power Systems Design
EBS 189A – Special Topics - “Fluid Power Actuators and Systems”

Research Support

DOE US Department of Energy
CTFA California Tree Fruit Agreement
California Cling Peach Research Board
Pistachio Growers and Processors
UC New Faculty Startup Funds