Technical information

develop the anti-collision radar system. When traveling around corners, trees can appear

as a possible collision; however, these are merely false warnings. Hence a false warning

suppression algorithm was developed and tested, in these areas, to eliminate false

warnings being indicated to operators.

2.5 Longitudinal Crack Sealing Machine (LCSM)

The Caltrans Equipment Service Center pulled the AHMCT Longitudinal Crack Sealing

Machine (LCSM) out of the field and assigned their Deployment and Development

Group the task of making alterations including the addition of a second crack sealant

melter. Support was provided during the development to explain mechanical design

considerations, electronic circuitry, and develop new control software to meet there

needs. During the initial startup and testing, it was determined that more flexibility was

needed to facilitate the system tuning. Additional software was developed to allow the

operator to monitor, via a digital display, which melter is active, each tanks pour time,

and change the tank timers from the display. The LCSM was initially deployed to

District 11 and is currently being used in District 6.

Additional work associated with the LCSM included providing training, to the primary

LCSM technician, in PLC logic theory, and troubleshooting automated process with

software, via a laptop interface. Software was backed up and provided along with

instruction on the use of the operator interface (Appendix C).

2.6 Automated Cone Machine (ACM)

The ACM has undergone a variety of field tests resulting in several changes in hardware.

The machine has been tested by Caltrans personnel and a private contractor, Granite

Rock Construction Company. Testing has included usage on busy high speed highways

and on inner city narrower roadways. In addition, extensive testing has been conducted

at the AHMCT facilities test road. Operators have been able to quickly adapt to the

operation of the machine and have all found it easy to use.

Originally the ACM used an opto-sensor on the drive shaft to sense vehicle displacement.

Testing revealed that the opto-sensor’s signal was unreliable at a vehicle speed over 10

mph. In addition, debris would often coat the sensor rendering it ineffective. Therefore,

modifications were made to use the vehicles OEM vehicle speed sensor (vss) to interface

with the embedded controller to measure vehicle displacement. Testing resulted in a

reliable signal in excess of 20 mph, which is effectively the maximum speed that cones

can be placed.

While testing the ACM in the central valley, a problem with low battery voltage was

detected. The problem was determined to be with an excessive electrical loading.

Running the ACM equipment, air conditioning, sign board, headlights, and electric

powered fans for the engine cooling exceeded the capacity of the existing electrical

system. However, the duty cycle of the excessive loading was fairly short. It was

determined that adding electrical storage capacity would be the optimal improvement.