ARS | Publication request: A miniature ultrasonic actuator-control system for plant stem diameter micro-variation measurements

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 22, 2011
Publication Date: August 24, 2011
Citation: Gao, G., Zhu, H. 2011. A miniature ultrasonic actuator-control system for plant stem diameter micro-variation measurements. ASABE Annual International Meeting. Paper No. 1110592. http://asae.frymulti.com/azdez.asp?search=1&JID=5&AID=39065&CID=loui2011&T=2.

Technical Abstract: Measurements of micro-variations in plant stem diameter are potentially useful to optimize irrigation decision support systems that are based on plant physiological responses. However, for this technology to be suitable for field applications, problems associated with stem softness and micro variations in the stem diameter due to water potential changes must be resolved. A real-time, non-destructive measuring system that uses a miniature ultrasonic linear actuator to precisely measure the deformation of stem surface was developed. The actuator employs a specially designed probe capable of a 0.8 µm travel per step and a 0.083 N maximum push force to avoid deforming the soft stem during the measurement. The travel motion of the probe is controlled with a custom-designed microcontroller. The plant stem was held in place by a fixture designed for the probe to precisely sense the contact of the stem surface. Tests with different plants under laboratory conditions verified the system accuracy and reliability, and provided prospects for the technology to be used for optimizing water utilization during plant growth.