Parker set to shake motion control market with highly innovative all-digital intelligent servo drive

Citation

(2003), "Parker set to shake motion control market with highly innovative all-digital intelligent servo drive", Assembly Automation, Vol. 23 No. 1. https://doi.org/10.1108/aa.2003.03323aad.004

Parker set to shake motion control market with highly innovative all-digital intelligent servo drive

Parker set to shake motion control market with highly innovative all-digital intelligent servo drive

Keywords: Motion control

Advanced field-oriented control provides unprecedented dynamic performance and efficiency and powerful auto-configuring software even corrects motor or feedback wiring errors.

Parker Hannifin's Electromechanical Division has launched an all-digital intelligent servo drive that sets a radically new cost/performance standard in the low- to medium-power market sector (Plate 4). Combining leading-edge software and electronics technology, the company's latest-generation ViX servo drive packs an exceptionally powerful controller and 250/500VA output stage into an ultra-compact case, and provides truly outstanding acceleration performance. The new servo drive is specifically designed for ease of commissioning and tuning, using auto-configuring software that enables users to implement a fully tuned system within 15 min of unpacking the delivery box. Parker's ViX servo drives are suitable for a wide variety of single- and multi-axis motion control applications, especially those demanding very high levels of dynamic performance; they are also ideally suited to autonomous operation in decentralised control schemes.

ViX series servo drives are housed in an extremely compact case - measuring just 125 × 42 mm, with a depth of 85 mm - that is suitable for direct panel mounting or for attachment to a standard DIN rail using an optional adapter. The drives are available with a choice of power outputs, one rated at 2.5 A continuous, the other at 5 A continuous. Both versions accommodate motor bus voltages up to 80 V and have a peak current capability of three times their continuous rating, providing outstanding acceleration characteristics. When teamed with Parker's BE163 high performance brushless servo motor, for example, the ViX500 drive can accelerate to 5,000 rpm and back to rest in under 6 ms! The power stage features full pulse-width modulation control with sinusoidal commutation, and allows users to choose between resolver or encoder feedback.

Capable of operating in position-, velocity- or torque-control mode, ViX series drives are 100 per cent fully digital and use a number of innovative techniques to capitalise on the inherent power of their core processor. Advanced field-oriented control (FOC), using a special set of transforms to derive the power stage control signals, is used to overcome the inherent limitations of conventional servo amplifiers. Traditional servo amplifiers use independent low-pass filters and integrators to remove offsets and accommodate motor phase mismatches, which means that transient torque demands can cause instantaneous imbalance in the motor phase currents; the resultant change in torque angle and magnitude degrades response, increases motor heating and creates additional harmonics. FOC uses a digital amplifier structure that ensures optimum performance at all speeds and controls the torque magnitude directly. The required three-phase excitation is derived through transforms that repeatedly establish the instantaneous excitation to maintain the correct flux vector under all operating conditions. The system also incorporates sophisticated I²t protection for both drive and motor.

Plate 4 Parker's new ViX series all-digital intelligent servo drives set a radically new cost/performance standard in the low- to medium-power market sector

The drive optimises the FOC system according to motor parameters that are entered either directly or through selecting the appropriate motor model using Parker's EASI-V software. This enables a wide range of motors to be accommodated without compromising performance. The result is significantly improved bandwidth and dynamic performance - enabling higher useable torque figures to be achieved over a wide speed range - together with higher efficiency and reduced harmonic generation. By way of example, when used with Parker's latest-generation SMB82 "salient pole" brushless motor, the ViX500 drive can deliver a peak torque of 5 Nm at speeds up to 2,000 rpm.

All ViX drives are supplied with Parker's EASI-V software package, which provides a powerful and easy-to-use front-end tool for rapid system configuration and tuning. This Windows-based software makes extensive use of wizards, context-sensitive help and hierarchically-structured pull-down menus, to present a very clear and unambiguous user-interface. When the drives are used with Parker servo motors, users only need to select the motor from a menu to define the entire configuration; all set-up information is retrieved automatically from a built-in database. Simply entering the minimum and maximum load inertia guarantees stable performance right from power-up. Servo motors supplied by other vendors are also easy to integrate, thanks to the ViX drives' built-in auto-correction algorithms. If the motor or feedback sensor is incorrectly wired, during initialisation, the drive can determine the connections actually made and compensate for the error within software. EASI-V also provides an extremely useful oscilloscope function, enabling the servo response to be displayed on a PC screen for monitoring the effect of load and system changes during commissioning.

ViX series servo drives can be controlled directly from a PC, or operate autonomously from motion control programs stored within their built-in controller, which are executed in response to external events or signals from a host controller, such as a PLC. The built-in controller supports all standard motion control functions, as well as a number of advanced operations such as encoder following and registration. It is equipped with an RS232C interface as standard, and can optionally be fitted with a fieldbus module for CANopen and RS485 communications. The controller also offers industry-standard step-direction and ±10 V analogue velocity and torque demand control inputs, for users who wish to migrate existing machines to intelligent digital servo technology without changing host controllers. Standard I/O facilities include five digital inputs and three digital outputs, all of which offer software-configurable termination characteristics and 5 V or 24 V operation.

Parker's new ViX series servo drives are the first in a new series of high-performance motion control components that are currently under development. Subsequent products will include further servo drives, as well as stepper drives, power supplies, operator panels and I/O expansion units. Each of these products is being expressly designed to complement the industry-leading mechanical positioning systems produced by the company, which include precision tables, electric cylinders and linear actuators.