The current automated fiber place machines can only produce large, open-surface parts, which cannot meet the growing interest in small complex structures from industry. By employing a rotational stage, a parallel robot, and serial robots, the dexterity of a fiber placement machine can be significantly improved for manufacturing complex composite parts. Demonstrating the procedure will be Pengcheng Li, a PhD student from my lab.
Begin by loading the frame definition file through the software of the optical CMM. Click Positioning and Detect targets, and select the targets that are attached on the motors of the parallel robot. Click Accept to use those targets as the positioning reference of the whole system, and, in the Entities list, click Base Frame, and select Make this reference frame the origin.
To define the tracking model of the end-effector platform frame, select Tracking models, click Detect model, and select the targets fixed on the end-effector platform of the parallel robot. Click Accept, and click Tracking models. Select UpPlatform in the drop-down, and click Up Frame.
Then click Apply and File, Export, and Tracking model, and enter a file name to save the tracking model. To define the tracking model of the tool frame, select Tracking models and Detect model, and select the targets fixed on the tool frame of the serial robot. Click Accept, and click the Tracking models and SerTool.
Then, select SerToolFrame in the drop-down list, click Apply, save the defined tracking model. To prepare the rotational stage, load the integrated control interface programmed by event-driven programming language on computer A, and click Connect to connect the controller of the rotational stage. Click Enable to connect the motor of the rotational stage, and click Home to move the rotational stage to the home position.
To prepare the serial robot, power on the serial robot controller, and click Connect on the integrated control interface to connect the robot server. To prepare the optical CMM, power on the optical CMM controller, and wait until the screen of the controller shows Ready. Click Connect on the integrated control interface to connect the optical CMM via the application programming interface, and import the models built in section one, which include the base model, the upper platform model, and the end-effector model of the serial robot.
Click Add Sequence, and add the relative sequence between the models as necessary. Then click Start Tracking to track the pose of the models. To prepare the parallel robot, power on the parallel robot controller.
Load the SerialPort_Receive program, and select Normal mode. Load the Para Remote Control program, and select External mode. Then click Incremental Build to connect to the target, and click Start Simulation of the two programs to initialize the controller of the parallel robot.
To generate the offline path, load the path planning interface through the numerical computing software, and click Import STL to select the part file. Click Segmentation and Add Work Region, and select the region on the extraction of cylinders. Adjust the slider to 100%and click Extract Cylinders and Add Work Region to select the starting branch of the path.
Click Generate Path, and select Constant Placement Angle in the popup window. Then set the desired placement angle to 90 degrees, and select the red dot. To display the generated path, in the Select a Path dropdown menu, select the path, then save the file.
To initiate a trajectory decomposition, run the Methode Jacobienne function in the numerical computing software, and open the desired path file. Enter the desired path number. The first point of the trajectory will be calculated.
Then select the configuration of interest for the manipulator to reach this pose. When the configuration is complete, a graph showing the evolution of the joint values will be displayed, and a file containing the trajectory for the serial robot and the rotational stage will be generated. To run an offline path without a path modification algorithm, press Select on the teach pendant, and select the name of the imported file.
Press Enter to load the path file, and turn the switch of the robot controller to Auto mode. Turn the teach pendant On/Off switch to Off, and press Cycle Start on the controller of the serial robot to run the path. Then click Cooperative Move in the cooperative control panel.
To run an offline path with the path modification algorithm, set the serial robot to run the path as just demonstrated, and click DPM Connect in the cooperative control panel to add the online path modification ability for the system. Then click Cooperative Move in the cooperative control panel. As demonstrated, the generated 90-degree ply can cover two branches without any interruption, and the overlaps and gaps between the tapes can be minimized.
To cover branch C, branches B and C are considered to generate the second trajectory. Another 90-degree ply will then be generated to cover branches A and C.Here, the decomposing process of continuously wrapping two branches of the Y-shaped mandrel with a constant 90-degree placement angle is illustrated. The mandrel can be decomposed to the trajectory of the serial robot and the rotary movement of rotational stage with a constant 90-degree placement angle as illustrated.
In this experiment, an offline planning path was generated for manufacturing the Y-shape composite part, in which joint wrist singularity occurs. These experimental results demonstrate that the proposed method can create a pose correction for the parallel robot and adjust the offline path of the serial robot based on the optical coordinate measuring machine feedback. In this way, the system can smoothly pass the singularity and lay up the fiber along the path without termination, confirming that the proposed CCM system can successfully accomplish the manufacturing process of the Y-shape structure.
The most important thing to remember is to operate the subsystems in the correct sequence. This collaborative system has the potential to manufacture small composite components of complex geometry by cooperating six degree of freedom, serial and parallel robots, and the optical coordinate measurement machine.
