Integrated motors, also called smart motors, include a motor rotor and stator (in a brushless dc, servomotor or stepper motor form) paired with other motion components. About half of all integrated motors incorporate a brushless motor with permanent magnets on the rotors, though other formats exist. The most basic integrated motors consist of just a motor and drive or a motor and controller. Other add-ons can include an encoder for feedback, power supplies, cabling, and communication ports. For the latter, common communication options include serial communication links such as RS232 or RS485 and advanced network topologies for complex motion control tasks—CANopen, DeviceNet, or Ethernet protocols.
The pre-engineered nature of smart motors lets application engineers use motor-based motion control with less effort. With fewer parts, integrated motors also boost reliability and minimize cabling, wiring, and overall design cost. Most integrated motors also program easily and quickly, which cuts development time.
For machine builders, integrated motors help reduce machine size and complexity. That’s because smart motors significantly reduce the amount of space required for a machine by consolidating components, eliminating cabling, and possibly the need for entire enclosures. Integrated motors can also eliminate external controllers such as PLCs.
With the increased use of decentralized motion-control architectures, applications using integrated motors have only proliferated. As an alternative to centralized motion control, decentralized architectures distribute motion control to a number of individual motion axes (in this case, to individual integrated motors), eliminating the need for a central controller. This means that individual motors can execute the control closer to the actual axis of motion or load, thereby taking the computational burden off of a central controller and distributing it to individual integrated motors.
Integrated motors central to fast bottling machine
Creating a fast bottle labeling (or cupping) machine requires the design and execution of complex and dynamic ECAM movements — especially with more than 60 integrated motor/drives on a rotating platform, transferring high power and high-speed EtherCAT communication through slip rings.
This type of design would require tackling manipulators using rapid and complex control of rotating mechanics with motors and drives that operate in a vibrating, humid and extreme temperature environment. In addition, there is the requirement of transmitting deterministic and signal-integrity- sensitive communication via the slip ring media. This could involve substantial time and many weeks of intensive work, requiring high-level expertise with considerable experience. But smart motors from Elmo shorten design time to less than three days.
Integrated into the motors are Gold Whistle servodrives. This simplifies the indexing table and minimizes cabling to only dc bus plus EtherCAT communication cables. So the electrical cabinet is smaller too — for less EMI. The servodrive is tuned for wide bandwidth and fast response by overcoming the non-linearity of the mechanical load, making operation more stable for higher throughput. All 60 servodrives run off a Maestro multi-axis controller that controls and supervises the whole bottling process.
Bottles feed into a machine and transfer to the rotating platform, which consist of 60 small integrated drive/motor components called DUETs. The DUETs fit in the rotating platform’s limited footprint. They all directly drive bottles, which ensure precision of rotation during camera image capturing.
Engineers designed the compact motor/high power drive for limited machine space using high-resolution absolute feedback for precision and servo control performance. The DUETs must be rugged enough to withstand the mechanical vibrations of the rotating platform. The minimum cabling used here results in minimal external noise and low EMI and RFI.
Four cameras take snapshots of the bottles for a host computer to process and verify exact label position using an algorithm. Bottle rotation is controlled by the Maestro, which sets the initial target labeling position and waits for the ECAM execute operation to start. All subordinate units operate in the DS-402 standardized cyclic synchronized position mode of operation. The Maestro and EASII feature high interpolation levels for smooth motion trajectories with a minimum number of ECAM points. It enables fast dynamic table calculations, execution, table switching, multi-hierarchy topology building and virtual axis synchronization. The advanced EASII, Elmo Application Studio ECAM tool combined with Elmo’s Motion Block Libraries (EMBLs), make testing of the ECAM trajectories faster to get machines up and running in a couple of days.
Filed Under: Slip rings + rotary unions, Motors • stepper, Motion Control Tips