AGV — Automated Guided Vehicle

An AGV is a driverless industrial vehicle used in man-

facturing plants and warehouses to transport material.

The first AGV was introduced in 1953 using tactile safety

sensors and simple wire guidance. Since the mid-1990s,

the industry has boomed, now offering multiple navi-

gation technologies and sophisticated software controls.

Objective

Examine the available and relevant AGV technology

Identify the opportunities and challenges to

implementing AGVs for material supply on the

manufacturing floor in Volvo Cars Final Assembly.

Author:

Sten Björn ANDERSSON

Academic Supervisor EPFL: Industry Supervisor:

Prof. Philippe Wieser Kristoffer Mann, Volvo Cars

Opportunities and Challenges

for AGV-Technology in Material Supply

for Automotive Final Assembly

Methodology Industry 4.0

Manufacturing industries are moving towards

increased automation and digitalisation under

the Industry 4.0 paradigm with more decentrali-

sed control, modularity and real-time capabili-

ties.

Fig. 3 a-e: Navigation Technologies [Top-to-bottom, left-to-right] 3a: Inductive wire, 3b: Magnetic tape, 3c: Magnetic spot,

3d: laser navigation using artificial landmarks, 3e: natural landmark / contour laser navigation (Transbotics.com, 2018)

Whilst AGVs currently can be considered

”intelligent but not autonomous”. AGVs are

currently becoming increasingly autonomous enabling the vehicle fleet to reconfigure

to the needs of the production system. The future of the AGV industry is conjectured to

be enhancing the vehicle and fleet ability to share traffic information and redistribute

transportation assignments to ultimately provide flexibility and logistical efficiency.

Fig 1: Smart Connected AGVs (Sickinsight-online.com, 2018)

Fig. 4e: Underride AGV configuration (Savant Automation, 2018)

Fig. 4b: Piggyback (conveyor-loaded) AGV

(Hilelectro.net, 2018) Fig. 4a: Forklift AGV (Rocla, 2018)

Fig. 4c: Towing Tractor AGV (Robotic Automation, 2018)

Fig. 4d: Underride AGV (Wiscolift, 2018)

The most common AGV vehicle types

Acknowledgements:

Volvo Cars: Manufacturing Engineering Department

Mats Hultman, Veikko Turunen, Morgan Ericsson,

Ola Fogelmark & Jonathan Legat-Odin, Volvo Cars.

Yang Yaqing, Lynk & Co. Jakob Dannemark, AGVE

Pär Knutsson, Jernbro. FlexSim

Fig. 2 a [top]: Protective Fields of a Safety Sensor

Fig. 2b [bottom]: Laser Safety Sensor (Ullrich, p.120, 2015)

Energy Supply:

Virtually all indoor AGVs are electrified. The most common solution for logistic

AGVs, as opposed to assembly-fixture AGVs, is a battery solution. The battery can

either be replaced or charged on-board.

Manual battery exchange: suitable for smaller fleets in continuous operation.

Automatic battery exchange: suitable for larger fleets in continuous operation.

Automatic on-board charge: scheduled charging, suitable for cyclic applications

Opportunity on-board charge: non-scheduled charging, suitable for appli-

cations with varying workload.

Safety:

Personal detection: the vehicle must be

able to detect pedestrians and plant infra-

structure and avoid collision by braking.

Laser sensors, see Fig. 2b, is the industry-

standard with different protective fields

set as shown in Fig. 2a.

Industry standards limit the operating

speed to 1-2 m/s. The AGV path should

also feature a 0.5 m margin on either side.

Sten Björn ANDERSSON Master Thesis MSc Mechanical Engineering

Navigation

Fixed-path navigation

- Inductive wire

- Magnetic/Optical track

Open-path navigation

- Magnetic Spot

- Laser (Artificial landmark)

- Natural / Contour laser

Impact of AGVs

Improved labour efficiency

Improved plant safety

Real-time tracking of material

Reduced damaged goods

Improved energy efficiency

Longer lifetime than manual

trucks

Space-efficient

Significant initial investment

Less flexible compared to

manual vehicles

Slower speed and loading

compared to manual trucks

Sources Images:

Hilectro.net. (2018). Piggyback AGV-Piggyback AGV. [online] Available at: http://www.hilectro.net/Piggyback%20AGV_149_745.html [Accessed 9 Aug. 2018].

Roboticautomation.com.au. (2018). ECO Z Towing AGV | Robotic Automation. [online] Available at: http://www.roboticautomation.com.au/agvs/industrial-agvs/dedicated-agvs-

eco-series/eco-z-towing-agv [Accessed 12 Aug. 2018].

Rocla. (2018). Fork Over Lift AGV. [online] Available at: https://www.rocla-agv.com/en/products/fork-over-lift-agv [Accessed 7 Aug. 2018].

Savant Automation (2018). [online] Agvsystems.com. Available at: http://www.agvsystems.com/wp-content/uploads/2018/07/AGV-AGC_Model_DC10_180701.pdf

[Accessed 3 Jun. 2018].

Sick.com. (2018). Protecting automated guided vehicles (AGV) | SICK. [online] Available at: https://www.sick.com/us/en/industries/industrial-vehicles/automated-guided-systems/

automated-guided-vehicles/protecting/protecting-automated-guided-vehicles-agv/c/p360745 [Accessed 15 Jul. 2018].

Sickinsight-online.com. (2018). Thinking ahead intelligently. [online] Available at: http://www.sickinsight-online.com/thinking-ahead-intelligently/ [Accessed 16 Jul. 2018].

Transbotics.com. (2018). Guidance and Navigation for AGV and AGC automatic guided vehicle manufacturer. [online] Available at: https://www.transbotics.com/learning-center/

guidance-navigation [Accessed 10 Aug. 2018].

Ullrich, G. (2015) Automated Guided Vehicle Systems: A Primer with Practical Applications. 2nd ed.

Wiscolift (2018). AGV, Model E3500 Tunnel Style Automated Guided Vehicle. [online] WiscoLift, Inc. Available at: https://www.wiscolift.com/products/e3500-tunnel-style-

automated-guided-vehicle [Accessed 12 Aug. 2018].

Fig. 5: Simulation Engine Delivery using Flexsim

Fig. 7: Process Plan Dashboard Delivery

Fig. 6: Process Plan Windshield Delivery

Conclusion:

It is recommended to use open-path navigation as it permits smaller modifications to

the route network to be done virtually. The most relevant technologies were judged to

be laser navigation, using artificial or natural landmarks, and magnetic spot navigation

because of their high reliability and flexibility. These technologies could advantageously

be used in hybrid as their flaws complement each other.

The most relevant energy supply option was seen to be automatic or opportunity on-

board charging to eliminate manual intervention and take advantage of often naturally

occuring idle time.

The main opportunities were identified as reducing labour costs and improving plant

safety. The key challenges were identified as operating in an environment shared with

manual traffic, identifying suitable processes, where de-facto rationalisation can be

made, and setting an adequate level of automation

Case Studies & Simulation:

3 specific case studies were selected and analysed further including the supply of

windshields, dashboards and engines.

A sophisticated simulation model was developed, using Flexsim and their AGV-module,

to model the engine material flow. This was done to discover how AGV application

could handle a varying workloads using a simple dispatching algorithm essentially assig-

ning transportation assignments in the order of appearance. The conclusion drawn

from this simulation is that for varying workloads the AGV system must be granted a

maximum lead-time.

Moreover, it was concluded that for certain processes some modification to exisiting

loading and unloading station layout configuration may be required.

Based on the case studies, the conclusion was made that it should (in select processes)

be possible to rationalise one manual truckdriver with 2-3 AGVs.

Based on the site visits, interviews and case studies, it was estimated that an AGV-

system could be implemented with the initial investment offset by the reduced labour

cost in 3-4 years.

Logistics, Economy and Management Chair (LEM)