Safety Modes - Universal Robots UR3/CB3 User Manual

2.4 Safety Modes

Limiting Safety
Function
Joint position
Joint speed
TCP position
TCP orientation
TCP speed
TCP force
Momentum
Power
The system is considered de-energized when the 48 V bus voltage reaches an electrical
potential below 7.3 V. The de-energizing time is the time from a detection of an event
until the system has been de-energized.
2.4 Safety Modes
Normal and Reduced mode The safety system has two configurable safety modes:
Normal and Reduced. Safety limits can be configured for each of these two modes.
Reduced mode is active when the robot TCP is positioned beyond a Trigger Reduced
mode plane or when triggered by a safety input.
Version 3.3.3
Trueness Detection
Time
1.15 100 ms
1.15 / 250 ms
s
20 mm 100 ms
1.15 100 ms
50 mm / 250 ms
s
25 N 250 ms
3 kg m / 250 ms
s
10 W 250 ms
WARNING:
There are two exceptions to the force limiting function that are impor-
tant to notice when designing the work cell for the robot. These are
illustrated in Figure 2.1. As the robot stretches out, the knee-joint ef-
fect can give high forces in the radial direction (away from the base),
but at the same time, low speeds. Similarly, the short leverage arm,
when the tool is close to the base and moving tangential (around) the
base, can cause high forces, but also at low speeds. Pinching haz-
ards can be avoided, for instance, by removing obstacles in these ar-
eas, placing the robot differently, or by using a combination of safety
planes and joint limits to remove the hazard by preventing the robot
moving into this region of its workspace.
WARNING:
If the robot is used in manual hand-guiding applications with linear
movements, the joint speed limit must be set to maximum 40 degrees
per second for the base and shoulder joints unless a risk assessment
shows that speeds above 40 degrees per second are acceptable. This
will prevent fast movements of the robot elbow near singularities.
I-15
Worst Case
De-energizing Reaction Time
Time
1000 ms 1100 ms
1000 ms 1250 ms
1000 ms 1100 ms
1000 ms 1100 ms
1000 ms 1250 ms
1000 ms 1250 ms
1000 ms 1250 ms
1000 ms 1250 ms
UR3/CB3