Safety Modes; Freedrive Mode - Universal Robots UR3/CB3 User Manual

10.6 Safety Modes

10.6 Safety Modes
Under normal conditions (i.e. when no protective stop is in effect), the safety system
operates in one of the following safety modes, each with an associated set of safety
limits:
Normal mode: The safety mode that is active by default;
Reduced mode: Active when the robot TCP is positioned beyond a Trigger Reduced mode
Recovery mode: When the robot arm is in violation of one of the other modes (i.e. Nor-
The subtabs of the Safety Configuration screen enable the user to define separate
sets of safety limits for Normal and Reduced mode. For the tool and joints, Reduced mode
limits regarding speed and momentum are required to be more restrictive than their
Normal mode counterparts.
When a safety limit from the active limit set is violated, the robot arm performs a Stop
Category 0. If an active safety limit, such as a joint position limit or a safety boundary,
is violated already when the robot arm is powered on, it starts up in Recovery mode.
This makes it possible to move the robot arm back within the safety limits. While in
Recovery mode, the movement of the robot arm is limited by a fixed limit set that is not
customizable by the user. For details about Recovery mode limits, see the Hardware
Installation Manual.

10.7 Freedrive Mode

When in Freedrive mode (see 13.1.5) and the movement of the robot arm comes close
to certain limits, the user will feel a repelling force. This force is generated for limits
on the position, orientation and speed of the robot TCP and the position and speed of
the joints.
The purpose of this repelling force is to inform the user that the current position or
speed is close to a limit and to prevent the robot from violating that limit. However,
if enough force is applied by the user to the robot arm, the limit can be violated. The
magnitude of the force increases as the robot arm comes closer to the limit.
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According to IEC 60204-1, see Glossary for more details.
Version 3.3.3
plane (see 10.12), or when triggered using a configurable input (see 10.13).
mal or Reduced mode) and a Stop Category 0 has occurred,
start up in Recovery mode. This mode allows the robot arm to be manually ad-
justed until all violations have been resolved. It is not possible to run programs
for the robot in this mode.
WARNING:
Note that limits for joint position, TCP position and TCP orientation are
disabled in Recovery mode, so take caution when moving the robot
arm back within the limits.
II-7
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the robot arm will
CB3