Canadian robotics software provider RoboDK has released TwinTool, an application that it says offers fully automated robot tool calibration for industrial robots.
The company pitches TwinTool as a cost-effective, quick, and easy solution for a wide variety of manufacturing applications. It added that the application is a competitive alternative to costly and complex robot calibration services currently available on the market.
Industrial robots are increasingly used for high-accuracy manufacturing tasks, such as assembly, soldering, and machining. However, new users are sometimes disappointed by the apparent low accuracy of their robots, the company argues. They invest in expensive robot calibration systems to try to improve the accuracy.
“Many users don't realize how important it is to calibrate the tool properly,” said Albert Nubiola, CEO of RoboDK. “They believe they need to calibrate the whole robot. However, properly calibrating the tool center point (TCP) can provide a significant improvement in accuracy.”
TwinTool helps improve industrial robot accuracy
Industrial robots have high repeatability, but low accuracy. This means they can move to the exact same position every time, but their position doesn't accurately match the world coordinate system.
There are two main types of calibration procedures for improving a robot's accuracy. Robot calibration requires precision laser systems to calibrate the robotic mechanism itself. Tool center point (TCP) calibration is a simpler procedure to ensure the programming system has an accurate model of the robot's tool.
The typical way of calibrating a robot tool center point (TCP) is by a four-point method, which consist of taking a series of at least for four joint readings when moving the tool to the same point with different orientations. This process is time consuming and less accurate as the user needs to move the robot in different position manually.
TwinTool calibration functionality is distributed as a RoboDK App, a plugin that extends the capabilities of RoboDK's highly popular robot programming software.
RoboDK TwinTool requires an off-the-shelf linear gauge sensor (or LVDT) to directly communicate with any robot and to calculate the robot tool center point (TCP) without human intervention. TwinTool automatically records an unlimited number of points, and the linear gage sensor offers great accuracy for tool definition.
The app is compatible with a wide range of sensors from major brands including Mitutoyo, KEYENCE, and Sylvac, allowing it to be versatile with any hardware. Other sensor brands can also be integrated on request.
RoboDK TwinTool supports more than 600 robot arms from 50 different robot manufacturers and is suited for many industrial environments.
This follows RoboDK's well-established philosophy of remaining brand-agnostic for hardware.
Ease of use and safety at the heart of the process
Equally important, RoboDK said is ease of use and safety of its products. TwinTool runs directly from RoboDK, making the bridge between the robot controller and the sensor. No programming skills are required, claimed the company.
Users only need RoboDK simulation software, a robot, its tool (spherical or conical), and a sensor. Singularities and collisions are avoided, and trajectories automatically calculated.
“We have created a user-friendly wizard to ensure that the calibration is done correctly and safely,” said RoboDK software developer Samuel Bertrand. “This is simple enough that it can be used by operators that don't have robotics knowledge.”
To calibrate a robot tool, the user simply follows this three-step procedure in RoboDK’s software:
- Select their robot model from RoboDK's extensive robot library.
- Connect RoboDK to the robot and to the sensor.
- Move the robot on the sensor and start the calibration.
“The procedure is fully automated and does not require any manual intervention,” Nubiola said. “It automatically avoids collisions and does not require users to write a single line of code.”
Accurate to 0.25 mm
With TwinTool, users can quickly and automatically improve the accuracy of their tool by up to 0.25 mm (0.009 in.) with some robot setups, according to the company. This provides an accuracy improvement by two to 10 times, depending on the robot and the tool.
“Without this calibration, robot errors can be in the range of 2 to 5 mm,” Nubiola said. “ With this tool calibration, you can usually reduce robot errors up to 0.25 to 1 mm, depending on your application.”
This accuracy improvement is more than enough for most robot applications, even those that require precision. This can save users a lot of money on unnecessary robot calibration services.
RoboDK plans to build marketplace
Users can now request to add TwinTool to their copy of the RoboDK software as an optional RoboDK App.
Bertrand said the company will continue to improve TwinTool's functionality.
“Currently, the tool is oriented towards maintenance modes,” he says. “However, we are working towards a mode that will run the calibration procedure automatically during production.”
RoboDK also plans to extend its app interface by creating a RoboDK App Marketplace. It said it will invite companies to develop and publish their own apps for the software.
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