Luke Metcalfe
Servo Motor Test Rig
April 2021
Seecor Blowmoulding Solution’s latest machines are all-electric, meaning they have no hydraulic or pneumatic actuators, as traditional machines would. Instead, movements are controlled by electric motors and actuators and their corresponding motor drives, giving us finer control and improved efficiency.
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Some of these motions need to be incredibly precise, and their position, speed and acceleration curves are carefully calculated. On one project, we were having an issue with the timing of a specific motion, and so we needed to develop a test rig to determine whether the output of the motor matched the trajectories that were calculated and set as the setpoint.
To do this, I connected a Yaskawa J1 servo motor and drive to a Siemens IPC477E HMI, a collection of analogue/digital input/output cards and an encoder. I modified an existing program to run a motor calibration process and record the position, speed and acceleration of the motor. This data was output to a CSV file and Excel spreadsheet which allowed us to compare the output to the pre-calculated setpoints and quantify any error.
The test is run using touch input from the Siemens HMI, and a snippet of the testing procedure is shown below:
This proved to be a valuable tool and in solving the timing issue we were experiencing, validated the calculations of several movements of our machines, and will no doubt be used in tests and validations going forward.