Oriental Motor CVD Stepper Drives Provide Accuracy and Repeatability

Oriental Motor, long known for reliable, high-precision motor and control hardware, has recently announced the latest addition to an extensive catalog of stepper motor drive units. The CVD series stepper motor drives provide closed-loop and EtherCAT-compatible control, designed for multi-axis robotics.

CVD series stepper motor drive with EtherCAT technology. Image used courtesy of Oriental Motor

Stepper Motor Drivers

Often overlooked, stepper motor drives provide control and protection to the stepper motors that accurately position machine tools, assembly lines, robotics, and other automation equipment. A high-quality stepper motor drive will include a positioning mechanism that can move the motor a certain number of degrees, repeatedly. This “step” may also be divided into micro-steps for high-precision motion. The finer the step resolution, the tighter control is required to ensure accurate positioning. Both the motor and the driver factor into this accuracy calculation; a motor with fine resolution will not be able to position properly if the motor driver is of poor quality.

Besides the drive mechanism, a good stepper motor drive will provide numerous protection mechanisms to protect the motor. It may include a current limiter to prevent the motor from overheating, surge protection, thermal relays, and other such devices. The driver will also need a way to communicate with the outside world so that it can be used in control loops and larger automation systems.

CVD Series Stepper Motor Drivers

The CVD Series stepper motor drive can be integrated with a five-phase stepper motor drive for the best results. In this system, feedback from an external sensor, such as a linear encoder, helps ensure that the object of interest has moved the proper distance. If it has not, the drive will adjust the position.

The motor, sensor, controller, and driver can form an open-loop or closed-loop system. At first, it performs open loop control to get the object close to its target position. Then, it automatically switches from open to closed loop control to perform the finer motion control. Once the item has been positioned, open loop control can be used to maintain the position.

A diagram of position versus time in closed-loop control mode. Image used courtesy of Oriental Motor

The drives are EtherCAT capable, and available with one of two standard power connections, making them easy to integrate with industry-standard hardware. This series can be paired with either two-phase or five-phase stepper motors, and provides control for up to four axes. Position accuracy in closed-loop mode is within 0.15 μm.

CVD motor controls are available at a low price point, at around $1100, and are available with a lead time of less than a month.

Precision Motion Applications

How accurately must objects be positioned to ensure an industrial process is repeatable? Oriental Motor has a great video that shows how the size of small objects are positioned and examined. In particular, semiconductor manufacturing requires accurate positioning down to the micron level to ensure that wafers are ready for the next processing stage. Registration between semiconductor layers from accurate positioning leads to higher yields.

Outside of manufacturing, research and development labs dealing with small items also benefit. Consider a biological research lab where the microscope stage is driven by precision stepper motors. A high-resolution stepper motor paired with an accurate stepper driver means research can be performed far more quickly and accurately than in a lab with manual controls.