understanding integrated motion control systems
TRANSCRIPT
www.zaber.com • s impl i fy ing mot ion control
Understanding Integrated Motion Control Systems
Zaber Technologies
www.zaber.com • s impl i fy ing mot ion control
You have a task to automate
Say you have a simple task you’d like to automate.
For example, let’s say you want to move a camera back and forth and take photos at specific intervals.
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What next?
How do you accomplish that task?
If you break it out, a simplified view might look something like this:
USER TASK?? ?? ??
I want to move a camera back and forth and take photos at specific intervals.
We don’t know what this might entail yet.
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What next?
And you might break out the task into greater detail, like so:
I want to move a 2 kg camera linearly at 75 mm/s speed. Stop it every 17.250 mm, and trigger the shutter.
USER TASK?? ?? ??
I want to move a camera back and forth and take photos at specific intervals.
We don’t know what this might entail yet.
www.zaber.com • s impl i fy ing mot ion control
How to get from A to B?
So, how do you get from USER to TASK?
Or, more specifically, how do you find/design the best possible automation solution that will meet your requirements?
I want to move a 2 kg camera linearly at 75 mm/s speed. Stop it every 17.250 mm, and trigger the shutter.
USER TASK?? ?? ??
I want to move a camera back and forth and take photos at specific intervals.
We don’t know what this might entail yet.
www.zaber.com • s impl i fy ing mot ion control
First, a little information about us
Who are we?
Zaber is a Vancouver-based company that designs precision positioning devices.
We were founded in the 1990’s, and our first product was the T-LA linear actuator. The first prototype of the T-LA had a built-in controller, which set it apart from other actuators on the market at the time.
The very first prototype of our T-LA actuator featured all control and drive electronics in one small, compact package.
We’ve grown since then...
We now offer over 56 series of devices and hundreds of models, which are distributed
around the world. Many of our products are designed to be integrated, all-in-one solutions.
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Our focus continues to be on
Simplifying motion control »
Advancing our inhouse design and »assembly capabilities
Continuously improving our »products based on customer feedback and suggestions
Our research and production facilities in Vancouver, Canada!
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AUTOMATIONMOTION CON
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Our area of expertise
Precision Positioning
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AUTOMATIONMOTION CON
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Precision positioning is...
Precision positioning is a specific area of the motion control market, which is itself part of the larger automation industry.
www.zaber.com • s impl i fy ing mot ion control
AUTOMATIONMOTION CON
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Our area of expertise
While our focus is on precision positioning, what we’ll discuss here is applicable to the field of motion control, and any automation application.
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What is a motion control system?
Before we can start to identify possible solutions, we need to familiarize ourselves with what a motion control system is:
Motion control systems are ones where either the position or velocity of one or more components is controlled.
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What is a motion control system?
Motion control systems are ones where either the position or velocity of one or more components is controlled.
That can mean linear movement...
Rotation...
Or, often, multi-axis movement.
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What makes up a system?
Let’s take another step back and look at what makes up a motion control system. Nearly every system is comprised of 6 components:
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Controller
The controller defines the motion profile, including the positions, speeds, and accelerations based on settings, user input, and feedback.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Controller
The controller will coordinate at least one axis of the motion control system. It can coordinate two or more together, like the system displayed below, which shows two micro linear stages mounted in XY configuration.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Controller
The controller will interface with other components, such as software run on a computer, or other hardware via USB or RS-232 connection. Through this interface, the controller sends motion instructions to the driver.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Driver
The driver uses the controller signal to power and direct the actuator. The photo above shows a board that has a stepper motor driver. It incorporates a power connector for a 15 V power supply.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Actuator
The actuator drives the motion. Although actuators may use hydraulic or pneumatic pumps to generate power, many use motors, which are driven with electrical power. The photo below shows one of Zaber’s NM stepper motors.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Actuation Mechanics
The actuator will connect to the actuation mechanics, which may include lead screws, ball screws, nuts, gears, belts, or pulleys. These mechanics direct the actuator’s motion as required by the system.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Actuation Mechanics
Many of our devices are lead screw driven. The photo below shows a precision lead screw, which is attached to the motor by a coupler. The platform on the right contains a nut to translate the rotation of the lead screw to the linear motion of the stage.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Support Mechanics
While the actuation mechanics act in the direction of motion, the support mechanics allow loading in all the perpendicular directions. Support mechanics include components like rails, joints, bearings, and bushings.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
In the photo shown, a high load stage has been disassembled to show the supporting mechanics. Pre-loading of the bearings against the precision ground rails helps to achieve stiffness in all axes.
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The Support Mechanics
Zaber’s TSB translation slide is one of our few non-motorized products. It includes mechanics that support a load and allow linear translation. It uses precision ground rails with ball bearings for smooth and accurate motion.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Sensor Feedback
Many systems use sensors to provide feedback to the controller. There are many types of sensors that can give feedback such as force or pressure, strain, temperature, sound, vibration, magnetic fields, light, or motion.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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The Sensor Feedback
A hall affect sensor is pictured below. Hall affect sensors detect magnetic fields at close range. Zaber uses hall affect sensors on many of our products to provide position feedback.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
When placed at one or both ends of a travel length, the sensor is called a limit switch, and it serves to prevent over-travel, as well as create a reference (or home position) to base movements on.
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So, what does it all mean?
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
We went over each component in detail because it is necessary to consider each component and their specifications, and how they will perform together in an integrated system.
Putting it all together, when we understand what goes into a motion control system, we are in a better position to design it to our needs.
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So, what does it all mean?
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
As an example, when you consider potential inaccuracy in a system, there will be contributions from the controller, drive, actuator, and mechanics.
Looking at any single component in that list will only give you a partial indication of potential inaccuracy of the complete system. This is why it’s important to look at all of those components.
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A practical application
Let’s take another close look at our components, but this time, in the context of an actual positioning system that integrates all 6 components.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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Zaber’s positioning systems
Specifically, let’s look at one of Zaber’s positioning systems: the T-LSM miniature linear stage.
The T-LSM is designed for ease of use, high resolution positioning, and compact spaces. It suits applications that require accuracy and stiffness, but not necessarily load or speed. These requirements are common for many applications in the sciences.
The T-LSM linear stage is one of our most popular products, and it is used in many markets and industries for many different purposes.
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Our controllers
Let’s take a closer look at each of the components used in our devices. We’ll look at the controller first.
Many of our devices, like the T-LSM, have built-in controllers, although some are designed to be used with an external controller. Those products are called peripherals, and they are intended for use with any of Zaber’s controllers or any third party 2-phase stepper motor driver and controller.
Controller and driver
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Our controllers
Our controllers are built to use trapezoidal motion profiles for their predictable and easy to specify positions.
We use RS-232 serial communication; some of our external controllers can connect directly to a computer with just a data cable.
Our controllers can be directly connected to a USB or RS-232 port of a computer with a data cable. The two controllers shown in the photo are also daisy-chained together.
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Our actuation type
We use a microstepping drive controlling high resolution stepper motors with current capacity up to 2.5 A/phase. This actuation type offers direct position control, stability and repeatability, and fine resolution movement.
The board in this photo has a stepper motor drive with microstepping that has a default of 64 microsteps per motor step.
One of our stepper motors.
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Our mechanics
The types of mechanics we’ll use largely depends on the requirements of the application.
However, for linear motion, we often use lead screws and anti-backlash nuts. This allows us to offer many device versions that have the same mechanics, but different pitches for different speed, accuracy, resolution, and force requirements.
Lead screw
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Our supporting mechanics
For supporting mechanics, we use a number of different bearing types based on the size and expected load capacity. Almost all are pre-tuned to achieve high stiffness, as that is often a requirement for precision positioning applications.
The components of a linear stage act to support the load. In the photo here, eight roller bearings ride on precision rails for smooth and accurate motion.
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Considering your costs
We can see that a lot goes into designing and building a motion control system. Each component that goes into the system will add a cost – not just related to parts, but also related to things like design time, purchasing, and potential parts failure.
The question then is: How do you control those costs while getting the best possible solution?
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A possible solution
One of the main ideas behind using an integrated system is that it reduces time and cost investments, while also providing a more reliable solution and
an overall better user experience.
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A possible solution
The integration of each of the 6 components means a reduction in considerations like number of suppliers, design work required, and issues with compatibility and/or failure. It also means increased confidence in the
performance of the system.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
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A complete solution
When all 6 motion control components are integrated, you have a complete solution. Referring back, you can now see how Zaber’s devices are
integrated, with the controller, actuator, and mechanics working together as a unified system.
Controller
Driver
Actuation Mechanics
Actuator
Support Mechanics
Sensor Feedback
www.zaber.com • s impl i fy ing mot ion control
Questions? Interested in more?
Visit www.zaber.com to learn more about our products and/or services.
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