The CalTester tab has an option to determine the location of a force plate relative to the laboratory coordinate system based on a series of CalTester trials.
It will produce a written report detailing the force platform's location in your lab. This report can be saved as a text file and the values can be inputted into the data collection software that you use.
Download the example files for this tutorial here]
Instructions to Collect Data Trials to Locate the Force Platforms (click to expand)
In order to use the CalTesterPlus program you need a set of properly collected data for each force platform you wish to calibrate. To collect a useful static trial for CalTester follow the following process. - Set up your capture volume making sure that all force platforms and cameras are in the positions that they will remain in for following data collections. - Place the CalTester base plate on the force platform before you begining the collecting the trial. - Zero the force platform so that it will not record the force produced by the CalTester base. - Begin the trial with the CalTester Rod on the CalTester base plate OFF the force platform. - Press down firmly on the Rod with a load of at least 200 N. - Keep the Rod aligned vertically and motionless during the trial. - The trial needs to be at least 1 second long. - There should be a minimum of three trial collected per force platform. Ideally there should be 8 or more, with at least one near each corner of the force platform and one near the center of the force platform. |
Results (click to expand)
A sample of the output that should be created is provided below: Output for force platform 2 : ======== Corrected Locations (in mm): ======== Corner 1: 1364.9109, 620.7680, -30.1600 Corner 2: 1367.0836, -1.5241, -27.8853 Corner 3: 605.0885, -4.1823, -27.2197 Corner 4: 602.9156, 618.1097, -29.4944 Force platform Center: 984.9996, 308.2928, -28.6898 =============================================== Rotation Matrix (into lab space): -0.003492 0.999994 -0.000861 0.999987 0.003488 -0.003658 -0.003655 -0.000874 -0.999993 Cardan angles to rotate from lab to force platform Angle 1 (x): 179.790405 Angle 2 (y): -0.049318 Angle 3 (z): -89.799232 Cardan angles to rotate from force platform to lab space Angle 1 (x): 179.949951 Angle 2 (y): -0.209433 Angle 3 (z): -89.799232 Nexus orientation parameters: -0.203481 -0.125475 -89.799919 Visual3D Command Modify_One_Force_Platform /FP_SELECTED= 2 /FP_CORNER1= 1364.9109 + 620.7680 + -30.1600 /FP_CORNER2= 1367.0836 + -1.5241 + -27.8853 /FP_CORNER3= 605.0885 + -4.1823 + -27.2197 /FP_CORNER4= 602.9156 + 618.1097 + -29.4944 ; |