Heason builds EtherCAT-controlled hexapod demonstration rig

The automated hexapod uses the Stewart Platform system to full effect with six Thomson PC-series high-precision linear actuators arranged in pairs and fixed by flexible ball-joint linkages to the mechanism's rigid base and moving top. The actuators have large diameter ballscrew transmission with a preloaded nut arrangement for high repeatability, smooth motion and excellent repeatability. They are regularly specified for applications ranging from packaging machinery to conveying and pick-and-place systems where they replace the limited positioning capability of pneumatic actuators and their extended life, high repeatability and quiet operation provide much improved production throughput and parts accuracy.

Fitted with Kollmorgen AKM series brushless motors with incremental encoder feedback, the actuator's fully synchronised servo control combines Elmo Motion's "Gold' series Solo Whistle drives and the Maestro EtherCAT master controller. As a Gold Partner with Kollmorgen Europe, Heason Technology regularly specifies AKM series permanent magnet servomotors. The range offers unprecedented choice and flexibility with eight frame sizes and a wide variety voltage, feedback, braking and interfacing options to choose from.

Elmo Motion Control's Gold Line is an unprecedented and wide range of servo drives that spans 6 to 780V DC for DC-brushed, and brushless sinusoidal and trapezoidal commutated motors. In particular, the network-based Solo Whistle servo drive is an ultra-compact, integrated digital servo drive that offers up to 1.6kW of continuous power or 3.2kW of peak power. With support for a wide variety of feedback sensors and multiple communication options, Heason's hexapod rig utilises the EtherCAT network option which marries this impressive drive with Elmo's Maestro motion controller. The controller has a great deal of flexibility, enabling multi-axis control with a choice of CANopen or EtherCAT masters for distributed drive networking - saving installation costs and reducing wiring tasks over control cabinet drives.

For this application, Heason chose the industry standard EtherCAT option which is fast becoming the number one choice for high speed motion systems requiring tightly synchronised motion. The Maestro has up to 100 axis control capability and a 50 microsecond servo update rate specified for up to 16-axes. It also boasts advanced features such as motion blending, PVT and spline support, Delta robot kinematics and more.

Easy-to-use graphical environment

As part of a wide choice of programming environment options for the Maestro which includes PLCopen, .NET, and both Native and Win C/C++, the industry standard IEC 61131-3 with PLC function block coding was chosen for the hexapod's sequence and manual modes. The advanced EASII (Elmo Application Studio II) programming, configuration and application development tool was used to bring all aspects of the hexapod demonstration rig together in one easy-to-use graphical environment.

The manually controlled "joystick hexapod' has the same geometry as the motorised version with a fixed base and moving top with a simple control arm fitted. Visitors are invited to position the larger unit using the improvised joystick control. Six VLPSC series linear sensors, supplied by Variohm EuroSensor - Heason's sister company in the Variohm Holdings Group - each have a stroke length of 50mm and include self-aligning pivot bearing mountings as standard. Well proven in harsh industrial environment, agricultural/construction machinery or challenging motorsports applications, the durable sensor design is based on conductive plastic potentiometric technology with an integrated signal conditioning module for 0...10V DC voltage or 4"20mA current output.

The West Sussex-based motion specialist combines its own design and build systems integration expertise with motion products, components and systems from a small but select group of globally recognised distribution partners. Heason Technology's comprehensive range includes servo and stepper motors with associated drives and motion controls, linear and rotary positioning mechanics, linear and rotary encoders, ceramic servo motors and positioning stages, high-precision gearboxes, rotary actuators and slip ring assemblies.

To learn more, go to www.heason.com, or see the EtherCAT controlled 6-axis hexapod (parallel robot) demonstration rig at DSEI at the ExCel, London, or the Engineering Design Show at the Ricoh, Coventry.