Machine Safety

Machine assessment

Contents

• Basic machine description
• Machine control description
• Machine specifications
• Hazards
• Required performance levels

Introduction

This document is based on ISO 12100, ISO 10218-1, ISO 10218-2, ISO 13849-1 and ISO 13482

Safety measures are taken using the procedure as displayed in the figure below, which is taken from ISO 13482.

Safety measures are evaluated according to the image below, which is also taken from ISO 13482.

Basic machine description

Intended use

The robot is intended to be used in a group of similar robots to cooperate with. After deployment, all machines will autonomously explore an environment in order to build a map of this environment. The map will be exported and regularly updated to any monitoring device running Linux 14.04 with ROS Indigo installed.

Machine components

The machine consists of a metal base. It is made portable by four wheels, two of which motorised. An additional frame is attached to the machine to support a 3D vision camera. A LIDAR sensor is attached to the base of the machine. The machine also consists of an ECU, an accu pack and a charger.

Figure 1: Rosbee robot with laser- and depth sensor

Machine control system description

The microcontroller has two motor controllers sending -10V to +10V power supply to the motors.

Figure 2: Rosbee microcontroller

Machine specifications

Machine limits
Machine Name/Type	Rosbee
Intended Environment:	Indoors, University corridors Restrictions: the robot should not be used during crowded times (e.g. use only during classes) Use robot only in environments without a possibility of altitude drops (e.g. staircase). Or place fences around, or doors towards staircase.
Required Training Level:	Basic Training
Operated by:	Operator, Maintenance Technician
Intended Use:	Exploration and surveillance
Machine Lifetime:	5 years
Machine Dimensions:	400mm x 350mm x 400mm (l x w x h)
Machine Environment:	Indoors, dry, clean, non-explosive, non-flammable.

Operational and maintenance information
Operational information
No. of Operators:	1
Maintenance information
Maintained by:	Operator, Maintenance Technician
Maintenance Frequency:	Daily
Cleaning:	Operator
Jamming Repair:	Operator

Power sources
Main Feed, Elec. Supply:	11.1V DC (+-10%)
Pneumatic Supply:	Not Applicable
Hydraulic Supply:	Not Applicable

Hazards

The Evaluation methodology is based on Pilz criteria and experience, an evaluation of the factors, Degree of Possible Harm (DPH), Probability of Occurrence of a Hazardous Event (PO), Possibility of Avoidance

(PA) and Frequency and/or duration of Exposure (FE), and has been performed on the risk related with

each hazard. A Pilz Hazard Rating has then been calculated from the following formula:

PHR = DPH x PO x PA x FE

Degree of Possible Harm (DPH)

                            0.25     Scratch / Bruise

                            0.5       Laceration / cut / mild ill health effect/ minor burns

                            3           Fracture minor bone – fingers, toes

                            5           Fracture major bone – hand, arm, leg

                            8           Loss of 1 or 2 fingers/ toes or major burns

                           11          Leg / hand amputation, partial loss of hearing or eye

                           15          Amputation of 2 legs/hands, total loss of hearing/sight in both ears/eyes

                           25          Critical injuries or permanent illness/condition/injury

                           40          Single Fatality

                           65          Catastrophe

Possibility of Occurrence of Hazard Event (PO)

                          0.05         Almost impossible

                          1.25         Unlikely

                          2.5           Possible

                          4               Probable

                          6               Certain

Possibility of Avoidance (PA)

                          0.75         Possible

                          2.5            Possible under certain circumstances

                          5                Not Possible

Frequency of Exposure (FE)

                         0.5           Annually

                         1              Monthly

                         2              Weekly

                         3              Daily

                         4             Hourly

                         5             Constantly

The maximum and minimum numerical values that could be assigned to each factor for every hazard are

shown in the following table.

PHR		Risk		Comment
	1-10	Negligible Risk		Presents practically no risk to health and safety, no further risk reduction measures are required.
	11-20	Very Low Risk		Presents very little risk to health and safety, no significant risk reduction measures are required, may necessitate the use of personal protective equipment and/or training.
	21-45	Low Risk		Risk to health and safety is present, but low. Risk reduction measures must be considered.
	46-160	Significant Risk		The risk associated with the hazard is substantial enough to require risk reduction measures. These measures should be implemented at the next suitable opportunity.
	161-500	High Risk		Potentially dangerous hazard, which requires risk reduction measures to be implemented urgently.
	501+	Very high Risk		Risk reduction measures should be implemented immediately, corporate management should be notified.

Hazard Identification			Hazard No.	1.1 a
Title	Tripping over an immobile robot	Tripping over Robot
Location	Robot
Target	Feet, shins
Activity	Normal operation
Task	Navigating
Sub Task	Mapping
Hazard Type	Hazard with the consequence of
Sub Type	Tripping, falling
Description	The Rosbee is standing somewhere in an environment and is overlooked by a person. The person trips over the robot.
References:
Risk Estimation and Evaluation
Degree of Possible Harm:	5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	1.25	Frequency And/or Duration of Exposure:		5
Pilz Hazard Rating (PHR):	23.4375	Summary Level:	Low Risk
Risk Reduction			Reference
Use bright coloured markers on the robot + a bright coloured flag. The robot can make a continuous warning sound for surrounders.
Risk Estimation and Evaluation
Degree of Possible Harm:	5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	0.05	Frequency And/or Duration of Exposure:		5
Pilz Hazard Rating (PHR):	0.9375	Summary Level:	Negligible Risk

Hazard Identification			Hazard No.	1.1 b
Title	Tripping over a moving robot	Tripping over Robot
Location	Robot
Target	Feet, shins
Activity	Normal operation
Task	Navigating
Sub Task	Mapping
Hazard Type	Mechanical Hazard with the consequence of
Sub Type	Tripping, falling
Description	The Rosbee navigates through an environment and is overlooked by a person. The person trips over the robot.
References:
Risk Estimation and Evaluation
Degree of Possible Harm:	5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	2.5	Frequency And/or Duration of Exposure:		5
Pilz Hazard Rating (PHR):	46.875	Summary Level:	Significant Risk
Risk Reduction			Reference
Use bright coloured markers on the robot + a bright coloured flag. Add collision avoidance software. The robot can make a continuous warning sound for surrounders.
Risk Estimation and Evaluation
Degree of Possible Harm:	5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	1.25	Frequency And/or Duration of Exposure:		5
Pilz Hazard Rating (PHR):	23.4375	Summary Level:	Low Risk

Hazard Identification			Hazard No.	1.2
Title	Falling	Altitude drop
Location	E.g. staircase or other sudden altitude drop
Target	Human
Activity	Normal operation
Task	Navigating
Sub Task	Mapping
Hazard Type	Mechanical Hazard with the consequence of
Sub Type	Impact, crushing
Description	The Rosbee navigates through an environment, overlooks an altitude drop (e.g. staircase) and falls/accelerates
References:
Risk Estimation and Evaluation
Degree of Possible Harm:	40	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	1.25	Frequency And/or Duration of Exposure:		1
Pilz Hazard Rating (PHR):	37.5	Summary Level:	Low Risk
Risk Reduction			Reference
Use robot only in environments without a possibility of altitude drops (e.g. staircase). Or place fences around, or doors towards staircase.
Risk Estimation and Evaluation
Degree of Possible Harm:	40	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	0.05	Frequency And/or Duration of Exposure:		1
Pilz Hazard Rating (PHR):	1.5	Summary Level:	Negligible Risk

Hazard Identification			Hazard No.	1.3
Title	Voltage Adapter	Connect the wrong adapter
Location	Battery
Target	Robot, Environment
Activity	Charging Battery
Task	Charging
Sub Task	-
Hazard Type	Thermal Hazard with the consequence of
Sub Type	Burn, fire, explosion, inhalation of toxic fume.
Description	Connect the wrong voltage adapter to the battery in order to charge it.
References:
Risk Estimation and Evaluation
Degree of Possible Harm:	0.5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	1.25	Frequency And/or Duration of Exposure:		4
Pilz Hazard Rating (PHR):	1.875	Summary Level:	Negligible Risk
Risk Reduction			Reference
Not necessary

Hazard Identification			Hazard No.	1.4
Title	Sharp Edges	Getting cut by a sharp edge
Location	Top of the robot
Target	A human body part
Activity	Normal operation
Task	Any
Sub Task	-
Hazard Type	Mechanical Hazard with the consequence of
Sub Type	Cutting
Description	If someone bumps the robot or grabs the robot in the wrong place the sharp edge can cut the person.
References:
Risk Estimation and Evaluation
Degree of Possible Harm:	0.5	Possibility of Avoidance:		0.75
Probability of Occurance of a Hazardous Event:	1.25	Frequency And/or Duration of Exposure:		4
Pilz Hazard Rating (PHR):	1.875	Summary Level:	Negligible Risk
Risk Reduction			Reference
Not necessary