Important Deployment Points
If you have any questions regarding the guidelines laid out below or how to implement them, please contact your local Universal Robots distributor or Universal Robots sales office for further support.
Disclaimer: This document does not replace Universal Robots standard user manual, it is instead intended to highlight the most critical points to new users deploying Universal Robots. This document does not guarantee completeness of all considerations for proper installation. The installation parameter values specified here are intended as starting point for an installation and should not be interpreted as specifications or limits. This approach is intended to provide a bare minimum set of requirements for deployment and should be complemented by further UR training. Ignoring the deployment point can lead to reduced overall lifetime of the robot system.
NOTE: The steps and method of programming can differ depending on the SW version your robot is running, we advise to always keep to the latest Polyscope version to benefit from the latest features.
A few examples of check-lists that can be used can found in the bottom of this article.
a) Mounting Surface
The robot must be mounted on a rigid surface capable of withstanding at least ten times the full torque of the base joint and at least five times the weight of the robot arm. Further, the surface mounting shall not introduce vibrations into the robot application. If the robot is mounted on a moving 7th axis, the acceleration and deceleration of that axis must be very low, causing minimal impact to the robot.
b) Protection from Environment
The Robot must be mounted in an environment suited for the IP54 rating. In environments where liquids such as machine coolants or fine powders are present and likely to interact with the surface of the robot arm or control box, additional measures should be taken, such as utilizing a protective robot suit.
c) Payload Configuration
The Mass and Center of Gravity of the payload (including end effector) at the end of the robot arm must be configured accurately at all times. For E-series robots, please use the Payload and Center of Gravity Wizard to estimate values. A warning will be issued if payload is not set in the Installation tab.
The Payload Mass and Center of Gravity must be updated each time the robot picks up or puts down a workpiece. This is achieved using the script command "set_payload(m, cog)" or with the “Set Payload” command for E-series robots on 5.10+. See Universal Robots script manual for more information on how to utilize the command.
d) Tool Center Point
A Tool Center Point (TCP) is a point on the robot’s tool. Each TCP contains a translation and a rotation relative to the center of the tool output flange.
When programmed to return to a previously stored waypoint, a robot moves the TCP to the position and orientation saved within the waypoint. When programmed for linear motion, the TCP moves linearly.
Tool center position should always be configured correctly. Incorrectly configured TCP can result in unwanted protective stops and unwanted movements as some features are calculated in relations to the TCP and not the tool mounting bracket flange.
Information about how to configure installations can be found in the Universal Robots user manual
2. Motion Programming
a) Blend Radii
A blend radius allows the robot to pass waypoints without needing to come to a complete stop, reducing stress on robot joints and decreasing cycle times. Adding blends should be the first method used to decrease robot cycle times before resorting to increasing speed or acceleration values.
Blends should be added wherever the robot does not need to stop to complete an action. A value of at least 15mm is recommended but must not be so large that it overlaps with other surrounding blends. This will cause the waypoint to be skipped and the blend will not be executed, which can have adverse effects on robot and application.
B) Acceleration Values
The robot should be programmed to move as slowly as possible while still meeting the cycle time requirements. Blends should be used to optimise paths wherever possible before increased acceleration values are considered. should be kept as low as possible when configuring the robot application.
It is recommended that acceleration values do not exceed 800°/s² for joint space movements or 2500mm/s² for linear movements. Exceeding these values can lead to reduced life time of the robot.
A singularity is a scenario in which the a set of joint position or speeds allowing the robot to move it’s TCP in the desired way cannot be found. Moving too close to a singularity can result in unexpected increased in joint speed and protective stops.
If a singularity is affecting robot motions try changing from MoveL to MoveJ, adjusting robot or surrounding equipment positions, or changing length or orientation of robot tool.
Information about motion programming can be found in the Universal Robots user manual
d) Protective Stops
The protective stop functionality in Universal Robots is intended to protect people working around the robot and prevent it from applying excess force to its environment. It is not acceptable for a deployed robot to experience protective stops during normal operation, as these can lead to damage to the robot.
Any occurrences of protective stops should be dealt with during testing phases of deployment. Common causes include incorrect payload configuration, excessive acceleration or collisions with workpieces during pick up or drop off.
3. Maintenance & Troubleshooting
a) Recommended Inspection Activities
Please go through recommended inspection activities in Service Manual and follow inspection plan. By doing this you can eliminate many possible failures and prolong the life of the product.
Use the command position_deviation_warning() to check whether your robot is struggling to maintain its planned path while running your program. No deviations over a threshold of 0.2 is recommended. For E-series robots, look out for C173 and C174 errors as they indicate the robot is experiencing high torques which can reduce expected life. The “pause_on_error_code()” command can be used in a “Before Start” sequence to identify where high-torque motions are occurring.
The Log Viewer can be used to view occurrences of errors and assess robot performance. Please visit the Support site for installation and startup instructions.
Information about maintenance and trouble shooting can be found in the Universal Robots service manuals