Magnets, sensors create paths for automated guided vehicles

12/19/2013


Script source

The source code below is written in Roboteq's MicroBasic language and runs inside the motor controller to perform the AGV functionality described in this article.

 

option explicit

' This script provide basic control for an AGV.

' Motor will turn on upon the presence of a track and stop when track disappears.

' The track position information is used to provide left/right steering.

' At forks, the AGV will follow the left or right track depending whether the last

' marker detected was on the left or right side of the track.

' Make sure you precede merges with a marker so that the AGV remains on the main track.

' The presence of a left and right marker simultaneously will cause the AGV to stop for

' 30 seconds or until the operator presses the button

' declare variables

dim Gain as integer

dim DefaultThrottle as integer

dim TapeDetect as boolean

dim MarkerLeft as boolean

dim MarkerRight as boolean

dim Throttle as integer

dim Tape_Position as integer

dim LineSelect as integer

dim Steering as integer

dim GoButton as boolean

dim RunState as boolean

dim NotOnStopMarker as boolean

dim PauseTime as integer

 

' initialize constants

Gain = -7 ' Use negative value to invert steering command

DefaultThrottle = 250 ' Motor power level while the AGV runs

LineSelect = 1 ' Use left track by default

PauseTime = 30000 ' in milliseconds

' main loop to repeat every 10ms

top:

wait(10)

' read sensor data

TapeDetect = getvalue(_MGD)

MarkerLeft = getvalue(_MGM, 1)

MarkerRight = getvalue(_MGM, 2)

 

' Read button state

GoButton = getvalue(_DI, 2)

 

if (GoButton) then SetTimerCount(1, 0) ' Pressing the button will clear the pause timer

if GetTimerState(1) then RunState = true ' When pause timer is cleared, AGV is allowed to run

 

' Use TapeDetect and Pause Timer to apply throttle or not

if (TapeDetect and GetTimerState(1))

                  Throttle = DefaultThrottle

else

                  Throttle = 0

end if

 

' Check Marker presence to select Left or Right track

if (MarkerLeft) then LineSelect = 1

if (MarkerRight) then LineSelect = 2

 

' Detect when transitioning onto stop markers

if (NotOnStopMarker and MarkerLeft and MarkerRight)

                  NotOnStopMarker = false ' Mark stop marker detection so that it is not detected again until AGV moved away

                  SetTimerCount(1, PauseTime) ' Load stop timer timeout value

                  RunState = false

else

                  NotOnStopMarker = true

end if

 

Tape_Position = getvalue(_MGT, LineSelect)

 

' use tape position multiplied with gain as steering

Steering = Tape_Position * Gain

 

' Send throttle and steering to controller Configured in Mixed mode

setcommand(_G, 1, Throttle)

setcommand(_G, 2, Steering)

 

' Log output. Useful for troubleshooting. Comment out when done.

print("\r", TapeDetect,"\t", Tape_Position,"\t", MarkerLeft,"\t", MarkerRight,"\t", Throttle,"\t", Steering,"\t",RunState,"\t",LineSelect)

 

goto top ' Loop forever

 

- Cosma Pabouctsidis is senior technologist, Roboteq Inc.  Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, mhoske@cfemedia.com.

ONLINE

www.roboteq.com

Search AGV at www.controleng.com for other AGV advice.


<< First < Previous 1 2 3 Next > Last >>

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
World-class maintenance: The three keys to success - Deploy people, process and technology; 2016 Lubrication Guide; Why hydraulic systems get hot
Your leaks start here: Take a disciplined approach with your hydraulic system; U.S. presence at Hannover Messe a rousing success
Hannover Messe 2016: Taking hold of the future - Partner Country status spotlights U.S. manufacturing; Honoring manufacturing excellence: The 2015 Product of the Year Winners
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Improving flowmeter calibration; Selecting flowmeters for natural gas; Case study: Streamlining assembly systems using PC-based control; CLPM: Improving process efficiency, throughput
Putting COPS into context; Designing medium-voltage electrical systems; Planning and designing resilient, efficient data centers; The nine steps of designing generator fuel systems
Warehouse winter comfort: The HTHV solution; Cooling with natural gas; Plastics industry booming

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me