The customer required precision rotary axis control in the lowest profile form factor for multiple sequential robot arm joints. Key additional requirements included minimal movement at start-up to report absolute position...
Celera Motion Case Study – Precision Rotary Axis Control
Contributed by | Celera Motion
The Challenge
The customer required precision rotary axis control in the lowest profile form factor for multiple sequential robot arm joints. Key additional requirements included minimal movement at start-up to report absolute position, and minimal signal cabling keep the overall arm size as small as possible.The Solution
A series of custom-sized PCB-based encoder modules with FPGA control and BiSS communication interfaces was developed by MicroE, each featuring two standard ChipEncoder™ readheads and a Micro Motion Absolute™ (MMA) rotary grating disk. MMA grating technology employs a standard 40 micron pitch incremental counting track, coupled with a reference track where each index is uniquely spaced. With only a small movement at start-up, multiple index marks are detected, and the measured spacing is compared to a lookup table in firmware to determine the absolute position.The Benefit
The output of the two encoders are averaged for improved rotational accuracy, and absolute position is determined at start-up with minimal axial rotation. BiSS serial communication protocol allows each successive robot joint to be connected in a daisy-chain arrangement, rather than having dedicated bus cables for each axis, which along with the small size of the ChipEncoder helps reduce the overall size of the each joint. High speed serial communication (32MHz clock, 1µsec update rate) assures high robot responsiveness to the operator’s commands.Specifications
| PCB Diameter | 20mm |
| Scale Diameter | 15mm |
| Total Module Height | 13.8mm |
| Serial Interface | BiSS C |
| Clock Rate | 32 MHz |
| Position Update Rate | 1µsec |
| Resolution | 85,280 CPR (15.2 arc-sec; 73.7µrad) |
| Cable Wire Count | 5 twisted pairs, 32AWG |
The content & opinions in this article are the author’s and do not necessarily represent the views of ManufacturingTomorrow
Comments (0)
This post does not have any comments. Be the first to leave a comment below.
Featured Product
FLIR Si1-LD - Industrial Acoustic Imaging Camera for Compressed Air Leak Detection
The FLIR Si1-LD is an easy-to-use acoustic imaging camera for locating and quantifying pressurized leaks in compressed air systems. This lightweight, one-handed camera is designed to help maintenance, manufacturing, and engineering professionals identify air leaks faster than with traditional methods. Built with a carefully constructed array of MEMS microphones for high sensitivity, the Si1-LD produces a precise acoustic image that visually displays ultrasonic information, even in loud, industrial environments. The acoustic image is overlaid in real time on a digital image, allowing you to accurately pinpoint the source of the sound, with onboard analytics which quantify the losses being incurred. The Si1-LD features a plugin that enables you to import acoustic images to FLIR Thermal Studio suite for offline editing, analysis, and advanced report creation. Field analysis and reporting can also be done using the FLIR Acoustic Camera Viewer cloud service. Transferring of images can be managed via memory stick or USB data cable. Through a regular maintenance routine, the FLIR Si1-LD can help facilities reduce their environmental impact and save money on utility bills.
