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Transportation Automation
Reliability, Safety and Security in the Vehicle Industry
Stipendium Hungaricum
2017/2018 Spring Semester
Balázs Sághi P.hD, István Ferenc Lövétei
BMEKOKAM202
BMEKOKAM660
SAFETYLecture 7.
3
Depandability
• Depandability is a property of a system that justifies placing one’s reliance on it.
• RAMS - Depandability:
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4
Safety
• Safety (def) is a property of a system, that it will not endanger human life or the
environment.
• freedom from uneccaptable risk – in railway standards, EN 50126
• is freedom from accidents or losses,
• The state in which risks associated with aviation activities, related to, or in direct support of the
operation of aircraft, are reduced and controlled to an acceptable level. - ICAO (International
Civil Aviation Organization),
• freedom from unacceptable risk of harm - EUROCONTROL
• Safety - related (or critical) system is one by which the safety of equipment or plant is
assured.
09/04/2018 Safety, Hazard, Risk
Not exists a system that can be absolutely safe.
• our goal in a designing a system is to make it adequately safe for its given role……
• safety is subjective-ex. many people are afraid of flying…
09/04/2018 Safety, Hazard, Risk 5
Safety
6
Safety – Critical Processes
• transportation is a dangerous facility:
• it endangers the safety of:
• persons,
• objects,
• and the environment,
• by causing injuries.
• examples of other hazardous processes and systems:
• chemical processes, energy industry,
• manufacturing processes (production line, industrial robots),
• material handling, warehousing,
• medical tehnologies,
• a hazard is caused by one ore more source of hazard concerning the functions of thegiven process, appliance or system.
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Safety, Hazard, Risk 7
Expectations Against the Transportation System
Safety Capacity
• Problem:
• increased capacity
causes the decreasing
safety:
• increased speed,
• increased traffic density
• Expectations
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Safety, Hazard, Risk 8
Safety, Hazard, Accident
(Accident Chain of Events)
• The source of a hazardis not a direct danger. No hazards.
The source of threat is passive.
• The source of a hazardis a direct danger.
The source of a hazard is active.
• Occurence of an accident.
Injury
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Safety, Hazard, Risk 9
Safety, Hazard, Accident
(Accident Chain of Events)
• Safety:
probability, that there is no hazards
• Accident-free:
probability, that there is no injuries
P
A
I
safe state
dangerous state the source of a hazard is active
the source of a hazard is passive
injury
accident
technical error, faulty actiona*Δt
b*Δt 𝑃𝑃(𝑡 + ∆𝑡) = 𝑃𝑃(𝑡)-𝑃𝑃(𝑡)a∆𝑡𝑃𝐴(𝑡 + ∆𝑡) = 𝑃𝐴(𝑡)+𝑃𝑃(𝑡)a∆𝑡−𝑃𝐴(𝑡)b∆𝑡𝑃𝐼(𝑡 + ∆𝑡) = 𝑃𝐼(𝑡)+𝑃𝐴(𝑡)b∆𝑡
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Concept of the Risk
• risk expresses the significance of a hazardous effect
• can be described by:
• frequency,
• severity,
• other parameters (eg. possibility of the escape)
• Risk (def) is a combination of the frequency or a probability of a specified hazardous event, and itsconsequence.
Safety, Hazard, Risk09/04/2018 10
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Socially Tolerable Risk
• risk tolerance is influenced by subjective
standpoints:
• eg. responsability
• risk reduction means costs:
• absolutely safe state not exists…
• it’s needed to find the appropriate ratio of the
costs (efforts) and available results.
Ka
costs
risk reduction
risk
Ri
Ri
Ri4
Ri3
Ri2
Ri1
Kb
K1 K2 K3 K4
Safety, Hazard, Risk 12
Active and Passive RiskReduction
• The source of a hazardis not a direct danger. No hazards.
The source of threat is passive.
• The source of a hazardis a direct danger.
The source of a hazard is active.
• Occurence of an accident.
Injury
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safety-critical processcontrol systems
protection systems
passive risk reduction
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Traffic Rules
• Rules used continuously, applied in the same way:
• ex. right-hand rule, right-
keeping obligation,
• it is important to know the
rules, that’s why we limit the
access to the system (driver
license)
• Rules that vary depending on traffic or different situation:
• Traffic management systems
– permissions/instructions are given to the
vehicles for movements,
– vehicles may move according to the permit.
• Tasks of the traffic management:
– creating conditions for secure movements,
– achieving other management goals (eg.
reducing the energy consumption)
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Managing of the Instructions and Their Compliance
ProperInstructions
Complianceof the
InstructionsSafety
TrafficManagement
VehicleManagement
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Managing of the Instructions and Their Compliance
Road Traffic
• Automatically SupervisedInstructions, Indications (Lights)
• Control mechanisms esure, thatdangerous traffic situation does notappear due to the indications (lights).
• in a case of a failure too.
• Compliance of the instructions is based on a human decision.
• Controlled system-access.
• Nowdays: driver-assistence systems in the vehicles.
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• Handling instructions is a human
decision.
• Compliance of the instructions is a
human decision.
• With the aim of:
• supporting systems,
• high-quality education,
• continous training.
Managing of the Instructions and Their Compliance
Air Traffic
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Managing of the Instructions and Their Compliance
Rail Traffic
• Signalling systems – movement authority:
• automatically supervised signals,
• interlocking systems,
• Compliance of the signals:
• supervised by controlling mechanisms (since 1900s)
• train stopping, train controlling systems.
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Automated Systems in the Traffic Management
• Problem:
• How can these systems have the same „competence” like humans (eg. railwaysignallers, air traffic managers), that is ensured by continous training?
• In general:
• If the responsability of a human manager is big, it’s needed more stringenttraining requirements.
• In the case of technical systems:
• If the risk reduction role of a given system is big, it is strictly forbidden toallow to miss its given tasks,
• so we need a high-level of the safety.
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Inherent Safety of the Safety-Critical Process Control
Systems
• Safety Functions:
• Functionality of the safety-criticalprocess control and protection systems.
• The risk in the process controlled is reduced by safety functions.
• The safety functions protect against theexternal hazards.
• Safety Integrity:
• The inherent safety of the equipment.
• The process controlled has to be adequately protected from the internal hazards of the control system.
• How big has to be the degree of theprotection?
Summary
• The risks of the transportation systems are bigger, than the sociallytolerable risk,
• that’s why the application of the risk reducing systems is required.
• These systems are safety-critical systems, if it’s allow to miss itsgiven tasks, hazards will appear.
• It is needed to claim higher rquiremets against to the safety-criticalsystems.
• Other interesting chapters:– safety of the vehicle control systems,
– risks of the autonomous vehicles.
Safety, Hazard, Risk 2009/04/2018
Source of Hazards, Hazards
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Expectations Against the Transportation System
The importance of each factor is relative,
but safety is always in the first place.
Safety-Critical Process Control Systems in the Transportation
- vehicle – controlling systems
- traffic management systems
- other systems (eg. power supply management systems)
Expectations
• costs
• frequency
• speed
• travel speed
• safety
• reliability
• level of comfort
• etc..
compliance with expectations: efforts (costs)
attractiveness
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Safety-Critical Processes
• transport is a hazardous facility, it endangers the safety of:
• persons,
• objects,
• environment
• by causing injuries.
• other hazardous processes:
• chemical processes, energy industry,
• manufacturing processes (production line, industrial robots),
• material handling, warehousing,
• medical tehnologies.
A hazard (def.) is a situation in which there is actual or potential danger to people or to theenvironment.
Safety, Hazard, Risk 24
Safety, Hazard, Accident
(Accident Chain of Events)
• Safety:
probability, that there is no hazards (P)
• Accident-free:
probability, that there is no injuries (P, A)
P
A
I
safe state
dangerous state:• the subject of the hazard is exposed
to the danger
• it is a not safe state of the system,
that can lead to an accident.
the source of a hazard is active - „almost”
an accident
the source of a hazard is passive
injury
accident
technical error, faulty actiona*Δt
b*Δt
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09/04/2018 Safety, Hazard, Risk 25
Hazards in the Transportation
• in a case of a single vehicle:• track failure,
• persons, objects on the track, dangerous approach of the track,
• incorrect loading of cargo,
• inappropriate behaviour of passengers,
• vehicle failure,
• changing of the track-vehicle connection,
• driving error.
• in the case of multiple vehicles:• misjudgment of the traffic situation,
• dangerous approach:• from behind,
• frontwise,
• sidewards.
• longer braking distance than the foreseeable distance
• energy supply system of the vehicle
technical or
human error
human error(rarely technical error)
attributions
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Hazards in the Transportation
The rules and tools of the traffic management system exclude or
mitigate the effects of the hazards in some cases, thereby it enables
the travel with higher speed and the better exploitation of the track
capacity
Nonetheless, the errors connected to the traffic management
systems also imply hazards.
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Hazards in the Transportation
• the:
• insufficiency
• incorrect interpretations
• ignoring
• of the traffic control rules
• the:
• lack, deterioration, unnoticed
• incorrect interpretations
• ignoring
• of the traffic signs
• incorrect indication of traffic signalserrors of the traffic management systems
human error
technical errors
human error
human error
human error
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Possible Hazards (External and Internal)
• The
• systematic failure – human based:
• HW,
• SW
• random failure :
• HW,
• of a component of the system.
• The:
• functionality;
• normal operating mode;
• error states;
• emergency mode;
• misuse;
• interfaces;
• operation, maintenance and servicing;
• scrapping;
• of the system.
• Wrong human action during:
• the designing process,
• the operation:
• passengers,
• staff (operative, maintenance).
• Effects of the
• mechanical,
• electrical,
• meteorological, natural,
• environment.
-------------------------------------------------------
• Intentional hazards - security
09/04/2018 Safety, Hazard, Risk 29
Role of the Process Control Systems
controlled processes
(transportation, vehicle)
process control systems
environmental effects
control functions
safety functions
external hazards
internal hazards
09/04/2018 Safety, Hazard, Risk 30
Hazard Identification – (not the part of the curriculum!)
• Analytical techniques (systematic procedures)
• based on checklists,
• breakdown the system to smaller units,
• based on the functions.
• Based on the identified hazards:
• identification (eg. sequence number),
• designation of the hazards,
• causes of the hazards,
• possible outcome: accident
the source of a hazard is passive
the source of a hazard is active
P
A
a technical error, faulty action, environmental effects
Determination of the events that lead to a hazardous situation
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Hazard Analysis– (not the part of the curriculum!)
• Analytical techniques (systematic procedures):
• failure modes and effects analysis – FMEA - https://www.youtube.com/watch?v=BZWuUn93Sq4&t=735s
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Hazard Analysis– (not the part of the curriculum!)
• Analytical techniques (systematic procedures):
• failure modes effects and criticality analysis – FMECA – with criticality
09/04/2018 Safety, Hazard, Risk 33
Hazard Analysis– (not the part of the curriculum!)
• Analytical techniques (systematic procedures):
• hazard and operability studies– HAZOP – https://www.youtube.com/watch?v=AYtBUkjbVWc
09/04/2018 Safety, Hazard, Risk 34
Hazard Analysis– (not the part of the curriculum!)
• Analytical techniques (systematic procedures):
• event tree analysis – ETA – https://www.youtube.com/watch?v=mPC-CjCOrvs
09/04/2018 Safety, Hazard, Risk 35
Hazard Analysis– (not the part of the curriculum!)
• Analytical techniques (systematic procedures):
• fault tree analysis – FTA – https://www.youtube.com/watch?v=rg0CrfXk304
Safety Risk
09/04/2018 Safety, Hazard, Risk 37
Safety Risk
• The significance of a hazardous effect in an application is called „safety risk”.
• Safety risk is the combination of the :
• frequency or probability,
• and the consequence of
• a specified hazardous event.
• The safety risk can be influences other risk parameters.
• The risk can be determined by:
• quantitatively,
• or risk classification/qualitatively.
Severity
Frequency
Risk
End of Lecture 7.
Thank you for your attention!