The current versions of software available in the DX100 controller have an important reminder about the need for correct Tool Data. When no Tool Data has been entered into the controller, this message will scroll near the bottom of the Teach Pendant screen:
Input correct tool information. Using robot with wrong tool information may result in premature failure of the robot.
The tool information is entered into a Tool Data file. The controller allows users to enter the actual end of arm tool mass (weight), center of gravity (where that weight would balance) and moment of inertia (how hard it is to get the tool moving based on its size and shape). When all this information is entered correctly, the controller will adapt the way it accelerates to perform tool motion as quickly as possible, while not overstressing internal components of the robot beyond their design limits. When the tool information is not entered, the robot will use some default data that is intended to represent a typical tool. These values will likely never be 100% correct for a real tool and could even be very far off. The greater the difference between the entered Tool Data and the actual tool used, the greater potential for premature failure of the robot.
Using the Tool Data to improve the robot motion was named Advanced Robot Motion control, or ARM control for short. ARM control is not new with the DX100 controller; it actually started with the XRC controller. It is important to understand that correct Tool Data will also improve the motions and life expectancy of the XRC and NX100 robots.
Sometimes, we see a Tool Data file that has the mass and center of gravity values entered, but not the moment of inertia. This is probably because finding the correct values for moment of inertia can require some math that not everyone is familiar with. Also, the robot can automatically estimate the mass and center of gravity for you fairly well, but cannot estimate the moment of inertia*. It may seem that entering two of the three properties correctly is better than nothing, but that is not always correct. Sometimes, entering only part of the correct Tool Data can cause earlier failure than if there was none at all. The solution for correct motion and long robot life is always achieved by entering the complete and correct Tool Data each and every time.
* To correctly calculate moment of inertia, we suggest customers review their Controller instruction manual (section on ARM control) or contact their Regional Sales Manager (RSM) or Regional Technical Manager (RTM).
By Mike Ondrasek, Senior Project Engineer