Roadside Spraying System Reduces Chemical, Environmental Costs

SmartMotor actuates precision booms

Vegetation growing in cracks and under guardrails along the nation's roadways cause millions of dollars in damage each year. Designing a system that effectively and efficiently eradicates this growth, without overusing agricultural chemicals, was the challenge faced by engineers at Microphor in Willits, CA. Microphor designed a self-contained, mobile, highly-efficient roadside weed spraying system that incorporates a NEMA 56 SmartMotor by Animatics Corp., Santa Clara, CA, a stand-alone, brushless DC servomotor with built-in controller, drive and network capability.

The automated system mounts the motor, a 110-gallon spray tank and other hardware on the bed of a pick-up truck. Chemicals are sprayed from both a fixed boom underneath the truck, as well as a retractable boom, deployed and controlled by the SmartMotor, that rotates and extends five feet to each side of the vehicle, covering a range of 13 feet. As the truck operates, a light-sensing spray head activates when the light spectrum associated with chlorophyll is detected. Thirteen spray heads independently seek and spray individual plants, but do not spray bare surfaces. Compared to conventional systems, 50-80% of chemical cost savings are achieved.

The boom must operate quickly to spray weeds and avoid obstacles while the truck maintains a speed of 5 to 15 mph. The high torque of the SmartMotor is enough to extend and retract the boom in 0.5 seconds. Sensors at the front of the truck register obstacles such as utility poles and street signs, retracting the spray arm when an obstacle larger than 1/4- x 2-in. is within sensor range. The motor receives additional inputs from the truck's speedometer and optical sensors. As the various inputs are scanned, the controller constantly makes real-time calculations of acceleration and velocity needed to position the boom. A motion control program is stored on a memory module in the motor itself, and a built-in program employs a rich command set that includes motion control, arithmetic functions, Boolean operators and conditional logic. --KC

For more information: Circle 525 - Animatics, Santa Clara, CA, or connect directly to their website at http://www.OneRS.net/106df-525

Circle 526 - Microphor, Willits, CA. http://www.OneRS.net/106df-526