Stepper motor control limits

One of the fundamental questions that arose during the control and testing of the SCARA arm was what is the maximum speed achievable and the torque available at that speed. Some digging around in the world-wide-web revealed the following: The speed is limited by the torque availability from the stepper to rotate. For steppers, as the torque drops exponentially with …

Documentation

  Links to other reference files: GRBL and Protoneer stepper shield reference – Click here

PUPS 8

Completed the first draft of the 3D model. Write-up:   Spreadsheet:

PUPS 8

Completed the first draft of the 3D model. Write-up:   Spreadsheet:

Achieving rotational accuracy with steppers

For the SCARA (Selective Compliance Articulated Robot Arm) that I’m building for the course project, the rotation accuracy at the joints is critical to achieving overall accuracy. The stepper motors that I have are 200 steps per revolution which amounts to 1.8 deg per step. The accuracy is +/- 5% which means a rotational angle uncertainty of 0.18 deg (best possible). …

PUPS-7 Machine Design Concept Detail Exploration

Discussions with the PREP team was done and each of us explained our concepts on the blackboard and gave feedback.   PUPS-7 document:   Error budgeting spreadsheet:   Engineering calculations spreadsheet:  

PUPS-7 Machine Design Concept Detail Exploration

Discussions with the PREP team was done and each of us explained our concepts on the blackboard and gave feedback.   PUPS-7 document:   Error budgeting spreadsheet:   Engineering calculations spreadsheet:  

Harmonic Drives

Harmonic drives (also called strain wave gear) was invented in 1957 by C.W. Musser. They offer several advantages over conventional gear systems, especially for high precision and high torque applications. Hence, they are commonly used in many industrial robots. High gear reduction ratios are possible in a small volume from 30:1 up to 100:1 in some cases! The patents regarding this …