Astrium is the world's third largest space transportation and satellite systems business and boasts some of the most advanced design, manufacturing and test facilities in the industry. With locations throughout Europe, the USA, Africa, and Asia, the group includes Portsmouth, UK based Astrium Ltd, specialising in advanced payloads for communications, navigation and Earth observation satellites.
Located some 50 miles northwards along the motorway network from Astrium's Portsmouth facility, motion control specialist, LG Motion was recently commissioned by the company to supply a custom-designed rig to automate the positioning of large satellite microwave components for testing, calibration and tuning purposes. The assembly, or 'PCT Support System', now forms part of Astrium's extensive satellite manufacturing process quality control systems at Portsmouth.
The mobile structure can support, as well as vertically position, off-centre loads of up to 20kg with high resolution over a travel range of 2,400mm at pre-set speeds of 0.1mm/s and 10mm/s. Much of the structure was completed with standard aluminium machine framing components from MiniTec UK, with whom LG Motion has worked very closely on similar projects for a variety of clients.
With an overall height of 3.6m and width/depth of 1.5m, the structure includes a custom designed micro-stepping, motor-driven linear actuator with a fine lead screw drive and two parallel linear rail bearings supporting a large test-piece mounting plate. Further aluminium framing components brace the assembly to ensure its overall stability, and outrigger supports with adjustable feet are also included to ensure stability of overhanging loads.
The control system is based on Arcus Technology’s ACE-SDE series intelligent micro-stepping drive, pre-programmed for manual pushbutton control. Arcus is exclusively represented in the UK by LG Motion. The single-axis controller and combined drive provides I/O interfacing and RS232/485 or Modbus communication with an easy-to-use interface and a programmable S-curve acceleration profile that suits large load positioning.
Astrium’s specification for this rig demanded an exceptional level of reliability, performance and safety. The 'PCT Support System assembly includes a lockable control cabinet, a dead man’s switch arrangement and an amber beacon that flashes when the rig is in use to ensure operator safety.
The lead-screw and bearings are lubrication free, which is essential in order to avoid any possibility of contamination of the sensitive equipment on test. With full EMC and LVD testing and documentation supplied, Astrium carried out a full on-site inspection of the assembly at LG Motion’s production site before accepting it for installation at the Portsmouth site.
Arcus Technology
LG Motion’s national distribution agreement with stepper motor specialist, Arcus Technology covers sales and technical support across the California based company’s entire range. Of note is the strong product design, the provision of multiple communications interfaces and a very competitive pricing structure.
Arcus Technology’s range includes the compact DMX series integrated stepper motor packages with a built-in micro-stepping driver and optional motion controller, plus an incremental encoder that provides closed-loop feedback for automatic position correction.
Available in NEMA 17 and 23 frame sizes, the controller includes multi-tasking BASIC-like programming and a full I/O count, including high speed position capture for product registration applications. An extremely compact and unusual NEMA size 11 version is also available with a square section of only 25mm.
DMX integrated steppers are complemented by ACE series stand-alone, single-axis stepper drive-controllers and PMX series stand-alone two- or four-axis stepper controllers. Across this wide range, communication interfaces include, USB 2.0, RS 485, Ethernet and Modbus and CANopen. This line-up also includes the VMX series touch-screen HMIs, cables, power supplies and other accessories, plus Arcus’ GUI based PC programming software.