Why the Closed Loop Stepping System has better performance than the Servo Systems?

Torque from Servo Motor is proportional to position Error. Torque from Step Motor has no relation to position error. Torque from Step Motor has only relation to Speed.

Motor revolution generate 62.8mm of linear movement so most of motion must be short pitch of movement. Due to less rigidity of load, shaking of load should be directly delivered to motor shaft when motion stops. In case of servo motor, when motor stops, servo motor has very tiny power to keep target position so shaking of load can be easily effected to motor shaft it’s own vibration

Reliable positioning without loss of synchronism. Holding stable position and automatically recovering to the original position even after experiencing positioning error due to external forces, such as mechanical vibration or vertical positional holding. Ezi-SERVO utilizes100% of the full range of rated motor torque, contrary to a conventional open-loop stepping driver that can use up to 50% of the rated motor torque due to the loss of synchronism. Capability to operate at high speed due to load-dependant current control, open-loop stepper drivers use a constant current control at all speed ranges without considering load variations.

No gain tuning (Automatic adjustment of gain in response to a load change.) Maintains the stable holding position without oscillation after completing positioning. Fast positioning due to the independent control by on-board DSP. Continuous operation during rapid short-stroke movement due to instantaneous positioning.

Ezi-SERVO is an innovative closed loop stepping motor and controller that utilizes a high-resolution motor mounted encoder to constantly monitor the motor shaft position. The encoder feedback feature allows the Ezi-SERVO to update the current motor shaft position information every 25 micro seconds. This allows the Ezi-SERVO drive to compen-sate for the loss of position, ensuring accurate positioning. For example, due to a sudden load change, a conventional stepper motor and drive could lose a step creating a posi-tioning error and a great deal of cost to the end user!

Conventional servo systems, to ensure machine performance, smoothness, positional error and low servo noise, require the adjustment of its servo s gains as an initial crucial step. Even systems that employ auto-tuning require manual tweaking after the system is installed, especially if more that one axis are interdependent. Ezi-SERVO employs the best characteristics of stepper and closed loop motion controls and algorithms to eliminate the need of tedious gain tuning required for conventional closed loop servo systems. This means that Ezi-SERVO is optimized for the application and ready to work right out of the box! The Ezi-SERVO system employs the unique characteristics of the closed loop stepping motor control, eliminating these cumbersome steps and giving the engineer a high performance servo system without wasting setup time. Ezi-SERVO is especially well suited for low stiffness loads (for example, a belt and pulley system) that some-time require conventional servo systems to inertia match with the added expense and bulk of a gearbox. Ezi-SERVO also performs exceptionally, even under heavy loads and high speeds!

Traditional servo motor drives overshoot their position and try to correct by overshooting the opposite direction, especially in high gain applications. This is called null hunt and is especially prevalent in systems that the break away or static friction is significantly higher than the running friction. The cure is lowering the gain, which affects accuracy or using Ezi-SERVO Motion Control System! Ezi-SERVO utilizes the unique characteristics of stepping motors and locks itself into the desired target position, eliminating Null Hunt. This feature is especially useful in applications such as nanotech manufacturing, semiconductor fabrication, vi-sion systems and inkjet printing in which system oscillation and vibration could be a problem.

Ezi-SERVO is a high-precision servo drive, using a high-resolution encoder with 32,000 pulses/revolution. Unlike a conventional Microstep drive, the on-board high performance DSP (Digital Signal Processor) performs vector control and filtering, producing a smooth rotational control with minimum ripples.

Similar to conventional stepping motors, Ezi-SERVO instantly synchronizes with command pulses providing fast positional response. Ezi-SERVO is the optimum choice when zero-speed stability and rapid motions within a short distance are required. Traditional servo motor systems have a natural delay between the commanding input signals and the resultant motion because of the constant monitoring of the current position, necessitating in a waiting time until it settles, called settling time.

Compared with common step motors and drives, Ezi-SERVO motion control systems can maintain a high torque state over relatively long period of time. This means that Ezi- SERVO continuously operates without loss of position under 100% of the load. Unlike conventional microstep drives, Ezi-SERVO exploits continuous high-torque operation during high-speed motion due to its innovative optimum current phase control.

The unit of the position command can be divided precisely. (Max. 32,000 pulses/revolution) The Ezi-SERVO functions well at high speed without the loss of Synchronism or positioning error. Ezi-SERVO’s ability of continuous monitoring of current position enables the stepping motor to generate high-torque, even under a 100% load condition. Since the drive controls the operating current depending on the variation of a load, it reduces the heat generation, improving efficiency.

Ezi-STEP Characteristics Ezi-STEP is an all in one unit incorporating the stepper drive into the motor housing. This helps eliminate wiring, ensuresreliability and provides a low cost compact package. Fastech’s unique integrated software provides sensor-less detection of the loss of step synchronization, dampening that provides smooth motion, and no vibration at the low speed range. High speed and precision are ensured by the high performance onboard DSP (digital signal processor) and proprietary algorithms constantly monitoring the motor s performance and making corrections. The DSP even detects missed steps during high speed operation(over 300 RPM) and built in damping provides smooth operation at low speeds. The resolution of the Ezi-STEP-BT can be adjusted from 1.8。motor step angle to 0.0072。step angle for super precision. Ezi- STEP also generates alarms and running signals to monitor its operation remotely.

Step-Out Detection (Patent pending) Ezi-STEP-BT can detect step loss of the stepping motor without the addition of an external sensor. This is achieved by the DSP in conjunction with proprietary estimation algorithm constantly monitoring and comparing the voltage, current, and the back-emf. This enables the drive to detect the loss-of-synchronization of the motor rotor (an impossible task for conventional stepping motor drives) and increase voltage to the motor to prevent the step loss. This feature provides higher torque in high speed applications without the loss-of-synchronization*. * effective only over 300 rpm

Ezi-STEP-BT features a High Precision Microstep function and Filtering (Patent pending) The high-performance Digital Signal Processor (DSP) and proprietary algorithms improves the basic motor resolution of 1.8。up to maximum 0.0072。(1/250 steps). Ezi-STEP adjusts the PWM control signal in every 25 ??sec, unlike conventional drivers, which makes it possible for more precise current control and provides high-precision microstep operation.

Vibration suppression and High-speed operation (Patent pending) Motor vibration is created by magnetic flux variations of the motor, lower current from the drive due to back-emf from the motor at high speeds, and lowering of phase voltages from the drive. Ezi-STEP?? drive detects these problems and the DSP adjusts the phase of the current according to the pole position of the motor, drastically suppressing vibration. This allows the smooth operation of the motor at high speeds.

Ezi-STEP provides loss of step, run/stop, over-current, over-heat, over-voltage, power, and motor connection alarms that can be monitored by the controller and visible by a motor-mounted flashing led indicator.

Depending on the speed of the stepping motor, Ezi-STEP automatically increases the supply voltage and prevents torque lowering due to low operating voltage to the motor caused by back-emf voltage, this enables high-speed operation. Additionally, the software damping algorithm minimizes the vibration and prevents the loss-of-synchronization at high-speed.

Ezi-STEP Characteristics Ezi-STEP is an all in one unit incorporating the stepper drive into the motor housing. This helps eliminate wiring, ensuresreliability and provides a low cost compact package. Fastech’s unique integrated software provides sensor-less detection of the loss of step synchronization, dampening that provides smooth motion, and no vibration at the low speed range. High speed and precision are ensured by the high performance onboard DSP (digital signal processor) and proprietary algorithms constantly monitoring the motor s performance and making corrections. The DSP even detects missed steps during high speed operation(over 300 RPM) and built in damping provides smooth operation at low speeds. The resolution of the Ezi-STEP-BT can be adjusted from 1.8。motor step angle to 0.0072。step angle for super precision. Ezi- STEP also generates alarms and running signals to monitor its operation remotely.

Step-Out Detection (Patent pending) Ezi-STEP-BT can detect step loss of the stepping motor without the addition of an external sensor. This is achieved by the DSP in conjunction with proprietary estimation algorithm constantly monitoring and comparing the voltage, current, and the back-emf. This enables the drive to detect the loss-of-synchronization of the motor rotor (an impossible task for conventional stepping motor drives) and increase voltage to the motor to prevent the step loss. This feature provides higher torque in high speed applications without the loss-of-synchronization*. * effective only over 300 rpm

Ezi-STEP-BT features a High Precision Microstep function and Filtering (Patent pending) The high-performance Digital Signal Processor (DSP) and proprietary algorithms improves the basic motor resolution of 1.8。up to maximum 0.0072。(1/250 steps). Ezi-STEP adjusts the PWM control signal in every 25 ??sec, unlike conventional drivers, which makes it possible for more precise current control and provides high-precision microstep operation.

Vibration suppression and High-speed operation (Patent pending) Motor vibration is created by magnetic flux variations of the motor, lower current from the drive due to back-emf from the motor at high speeds, and lowering of phase voltages from the drive. Ezi-STEP?? drive detects these problems and the DSP adjusts the phase of the current according to the pole position of the motor, drastically suppressing vibration. This allows the smooth operation of the motor at high speeds.

Ezi-STEP provides loss of step, run/stop, over-current, over-heat, over-voltage, power, and motor connection alarms that can be monitored by the controller and visible by a motor-mounted flashing led indicator.

Depending on the speed of the stepping motor, Ezi-STEP automatically increases the supply voltage and prevents torque lowering due to low operating voltage to the motor caused by back-emf voltage, this enables high-speed operation. Additionally, the software damping algorithm minimizes the vibration and prevents the loss-of-synchronization at high-speed.