1. Dr Emma Rushforth (originally by Prof Ken Young/ Margret Low)
Robot Safety
Dr Emma Rushforth (originally by Prof Ken Young/ Margret Low)
University of Warwick

2. Hazard identification & Risk Assessment
Operational Characteristics of robots can be significantly different from other machines and equipment.
capable of high energy movements through a large operational space.
Initiation of movement & path of robot arm different to predict and can vary
Operating space can overlap other robots operating space or other machines work zones
Operators can be required to work in close proximity to the robot system.

3. Key Elements Fail safe Reliable Cheap
minimal down time
Cheap
Fast implementation / modification

4. How it is done traditionally
Relays
Redundancy
Physical barriers
Interlocks

5. Physical barriers Walls & interlocked gates
Barriers to material movement and maintenance
Impair view of process
Tend to cause large cells
Keep machine in as well as people out
machining spindles
lasers

6. inside

7. outside

8. Robot controller Internal E-stop Dead mans handle Mode Teach Automatic
Slow
Fast
Automatic
External

9. Large Cell / Multiple Access Points
Maintenance key
All personnel outside before system runs

10. Hardwired relay systems
Inflexible
Expensive to install
Limited reusability

11. Modern Method Modular hardware Modular software
Programmable / configurable systems
Networks
minimal wiring

12. Pilz SafetyBUS p and SafetyNET p

13. Light curtains Machine access guarding
Transmitter, receiver and two corner mirrors used for machine guarding

16. Radar detectors/Light curtains
Can be active or inactive
Programmable for coverage
Allow increased safety during certain parts of cycle
Require fast response to incursion

17. Radar/Light curtains Variable protection zones
Light curtain blanking/muting
Tool pallet/AGV variable protection zone

19. Programmable systems Function block based Dual/Triple redundant
Programming requires direct contact with a specialist tool & original program code for program development/alteration
Monitoring/maintenance software tool does not permit programming

22. What are the Dangers Functionality hidden in software
Easy to program could mean easy to bypass
software management (passwords, access, historical records)
What is the effect of a device or network failure
not all networks are safe & some will mix safe & unsafe devices together on a single network

23. Control Networks

24. Figure 1 Lathe E-stop Key Mill Robot door Key Pallet Pallet
Light curtain

25. Modular Safety System PNOZmulti PNOZmulti Configurator Getting Started
The XOR gate (Exclusive OR gate) is a digital logic gate that is, a true output (1/HIGH) results if one, and only one, of the inputs to the gate is true. If both inputs are false (0/LOW) or both are true, a false output results.
RS flip flop – A RS-flipflop is the simplest possible memory element. To understand the operation of the RS-flipflop (or RS-latch) consider the following scenarios:
S=1 and R=0: So SET, Q'=0 and Q=1, Hence, the input combination S=1 and R=0 leads to the flipflop being set to Q=1.
S=0 and R=1: Similar to the arguments above, the outputs become Q=0 and Q'=1. We say that the flipflop is reset.
S=0 and R=0: Assume the flipflop is set (Q=0 and Q'=1), then the output of the top NOR gate remains at Q=1 and the bottom NOR gate stays at Q'=0.
Similarly, when the flipflop is in a reset state (Q=1 and Q'=0), it will remain there with this input combination.
Therefore, with inputs S=0 and R=0, the flipflop remains in its state.
S=1 and R=1: This input combination must be avoided.

27. Key interchange
Internal
Laser
Estop
Robot K
Door switch
Door
Robot
Estop
Key interchange
external