MIT researchers develop Affective Intelligent Driving Agent

MIT researchers and designers are developing the Affective Intelligent Driving Agent (AIDA) – a new in-car personal robot that aims to change the way we interact with our car. The project is a collaboration between the Personal Robots Group at the MIT Media Lab, MIT’s SENSEable City Lab and the Volkswagen Group of America’s Electronics Research Lab.

AIDA communicates with the driver through a small robot embedded in the dashboard.   AIDA is developed to read the driver’s mood from facial expression and other cues and respond in a socially appropriate and informative way.

AIDA communicates in a very immediate way as well: with the seamlessness of a smile or the blink of an eye. Over time, the project envisions that a kind of symbiotic relationship develops between the driver and AIDA, whereby both parties learn from each other and establish an affective bond.

To identify the set of goals the driver would like to achieve, AIDA analyses the driver’s mobility patterns, keeping track of common routes and destinations. AIDA draws on an understanding of the city beyond what can be seen through the windshield, incorporating real-time event information and knowledge of environmental conditions, as well as commercial activity, tourist attractions, and residential areas.

It merges knowledge about the city with an understanding of the driver’s possible priorities and needs, and based on these learned facts, AIDA can make important inferences. Within a week AIDA will have figured out your home and work location. Soon afterward, the system will allegedly be able to direct you to your preferred grocery store, suggesting a route that avoids a street fair-induced traffic jam. On the way AIDA might recommend a stop to fill up your tank, upon noticing that you are getting low on gas. AIDA is also said to also be able to give you feedback on your driving, helping you achieve more energy efficiency and safer behavior.

http://web.mit.edu/

Motors and Electronics

I have been involved in the motors and controls industry for quite some time.  Most recently, I worked for a company exploring the possibilities that new generations of RISC based microcontrollers offer for lower cost and improved performance motor applications. This effort has caused me to review all the major motor segments, DC, AC, Brushless and stepping motor, to re-examine my assumptions about what goes on and what brings us to where we are today.

Each motor family has it’s own properties due to the basic physics of the motor’s design.  DC motors which were first proposed by Faraday, actually evolved into workable machines, but electric power was not commonly available.  DC motors are intrinsically variable speed, all you have to do is vary the voltage.

AC motors which came later, proved to be more versatile when AC power distribution became widespread.  AC motors are constant speed and require no control, just a switch to turn them on and off.  As a result of the simplicity of the motor’s construction and implementation, the are very popular and found in lots of applications.

But for every application of a standard motor, there are dozens of applications where there is a need for something a little different.  And oddly, the more rules that we try to apply to how things work in the motor industry, the more exceptions there are to deal with.  The Small Motor Manufacturers Association has a motor family tree with 60+ categories.  And we keep coming up with new ones.

But the really strange thing that keeps coming up is the fact that motor manufacturers are really mechanically oriented.  Motors are machines that convert electricity to mechanical power.  So it makes sense to be focused on how much starting torque there is, what happens the load is stalled and things of that nature.

Ironically, the mechanical focus on motors is often to the exclusion of the control electronics.  Nowadays, all variable speed motors require some type of electronic control, from the variable frequency AC drive to the advanced brushless DC drive.   So for the most part, you buy a motor from one company and controls from another company.  Of course, in the modern marketing era, a lot of companies source the product they are missing and private label it.  But the real expertise may be somewhat harder to get at.

And there’s nothing wrong with this situation.  I just think it’s odd.  Clearly it’s difficult to master two different fields of engineering.  And from the standpoint of the technical competency itself, there would seem to be little in common between power electronics and the electromechanical issues of motor manufacturing.  But there is something of an imperative in the case of electrically controlled motors.  The problem being that the performance of the motor is closely linked to the electronics.

Variable frequency drive suppliers are more apt to be in the motor business, as Reliance, Baldor and some others are.  But in general, motor suppliers and drive electronics suppliers are two completely different activities.  As I have reviewed many of the large market applications, I believe there are opportunities for collaboration that will offer significant improvements in sizem weight, performance and economic opportunities for for cost reduction that would provide adequate incentive for those willing to work toward common goals.

Tax the Internet?

Tax the Internet?  Once again government is looking for new ways to generate revenue.  And it should come as no surprise that once again the topic of generating tax revenue from the Internet has come up.

If the unemployment rate reflects the fact that 5 million Americans who were working a year ago, now are no longer working, then it stands to reason that state sales tax revenues have also decreased.  State sales tax revenue has been off between 15% to 25% in some states his most hard by the recession.

But rather than make appropriate budget cuts to reduce expenses, some state government are responding by passing laws to raise new tax revenues.  What an option!  Run out of money?  Pass a law and take more from someone else.   That seems to be the new version of Democracy in Action at all levels of government, state, local and Federal.

So the latest innovation in creative tax legislation is a proposal that State sales taxes should be collected on Internet sales.  Even if your company doesn’t own property in the state to which the merchandise is shipped.  In conventional retail sales,  when you sell outside the state your business is located in, the business is not required to collect state sales taxes.

But what makes the current legislative situation really peculiar is that the legislature in say, New York, can pass a law that compels a company in Georgia to collect taxes for sales and shipments made to New York.  Since the taxing authority is outside the state that the business operates in, it’s not clear what the basis is for being able to enforce such a requirement.

Consumers increasingly use the Internet for retail transactions.  The Internet provides the convenience of shopping without getting in the car and driving around from store to store.  Translates as lower cost.   Sometimes Internet shopping also provides access to hard-to-find items.  Less time wasted running around, translates as lower cost.  Since retail sales taxes are not collected, this also translates as lower cost.  Maybe that’s why Internet sales are doing so well,.

But Internet retailers must ship products to their customers.  Which adds cost.  And to some extent, the real innovation of Amazon.com was the efficiency of their logistics, translate as low cost.  So collecting taxes on Internet transactions has the unintended consequence of increasing costs to the consumer.

The logistics piece, by the way, requires companies like Fedex and UPS to move freight.  So there are real people moving your purchase from a warehouse to your home or office.  And there are complex material handling systems, bar code scanning systems, PLC controls, fork lifts, battery controls and computer data systems required to achieve all this performance.  Mechatronics being a large part of the technology that enables this cost efficiency.

So the current debate is an ethical problem.  Do state legislatures or does the federal government have the authority to tax transactions made on the Interntet?  Does the proposed legislation represent a public safety concern?  Does legislation of this kind open the door to further control of what will and will not be considered “legal” about the internet.

All weighty matters.  And matters that must be considered sooner rather than later.  Without public response, the trend is toward more government, more government control and rising costs.  None of which will get the US economy going in the direction we need to be going.

Guitar Hero® Playing Robot

Minneapolis, MN — Banner Engineering Corp. partnered with a Minnesota West Community and Technical College engineering student and robotics instructor to develop a robot designed to play the Guitar Hero® video game—responding to each note as it appears onscreen. Pete Nikrin, who graduated from Minnesota West in 2008 and now works as a manufacturing engineer at Meier Tool & Engineering, designed the robot to compete with a friend that Nikrin had introduced to the game and, after playing for two weeks, had surpassed Nikrin in his ability.

Bill Manor, robotics instructor at Minnesota West, suggested Nikrin incorporate a PresencePLUS® P4 OMNI vision sensor with a right-angle lens from Banner Engineering. Manor had such a vision system in his possession, as Minnesota West had purchased it at a discount through Banner as a start-up education kit.

“Students have used Banner vision sensors in many projects over the years—to inspect containers, for example, as they come down a conveyor,” Manor said.

To develop his Guitar Hero robot, Nikrin used a mannequin—complete with Minnesota West sweatshirt, hat and painted fingernails—and installed the camera lens as the robot’s left eye, which would be positioned toward the TV or computer screen. The robot, named Roxanne, identified the notes to be played by using an Edge vision tool, which detects, counts and locates the transition between bright and dark pixels in an image area.

Roxanne plays Guitar Hero® using Banner vision sensor

“We set-up five Edge tools that ran horizontally across the screen, one for every fret, and positioned the tools to focus on the notes at the bottom of each,” Nikrin said. “The Edge tools sent a constant signal as the five vertical fret lines progressed, and when a bright white dot appeared in the middle of a dark colored circle, the Edge tool allowed the sensor detect it.”

Jeff Curtis, Senior Applications Engineer at Banner, worked with Nikrin and Manor to ensure the robot’s processing time was fast enough to keep up with the video game. Once a note was identified, communicating this signal efficiently depended upon a heavy amount of programming, as well as Ethernet technology applied through a Modbus register. A PLC was programmed so that it constantly looked at the vision sensor’s register. Once the Edge tool senses a note, the PLC notices the change in the register, and the logic in the PLC fires a solenoid that activates the robot’s finger. Just as a human player would react, the robot’s finger then presses down on the appropriate note on the guitar. This set-up resulted in 9 ms processing speed.

To ensure consistent, accurate operation, the team needed to ensure Roxanne could play within a range of lighting conditions—as she would be relocated from classrooms to gymnasiums for demonstrations—as well as confirm the robot was correctly oriented with the monitor displaying the video game. They solved this problem by using a Locate tool, an edge-based vision tool that finds the absolute or relative position of the target in an image by finding its first edge.

PresencePLUS® P4 OMNI

“We honed a Locate tool and gave it a fixed point—a piece of reflective tape on the PC monitor—to focus on,” Curtis said. “This ensures the Edge tools are in the proper location to detect each note as it comes along and allows for any slight vibration in the application environment that could result in some deviation. If the robot starts to sag a bit, for example, it can still play.”

Using this technique, Roxanne has, on Medium mode, hit 100 percent accuracy at times, and it averaged 98 percent accuracy during the remainder of Nikrin’s tenure at Minnesota West. She could achieve up to 95 percent accuracy on Hard mode and 80 percent accuracy on Expert mode, due to the increased mechanical requirements of the robot’s fingers required. Today, Roxanne still engages current and prospective Minnesota West engineering students, and Nikrin looks back on it with both a sense of accomplishment and a hefty dose of gratitude.

“Throughout the process, I was impressed with Banner’s dedication to their products and customers,” he added. “Bill and I both thought that they went above and beyond to help with a school project, which might seem trivial to some companies.”

Banner Engineering

www.bannerengineering.com

::Design World::

Make the Right Design Moves with Mechatronics

By Mark D. Hinckley, Director-Mechatronics, SKF USA Inc.

Many electro-mechanical systems can qualify as mechatronic systems. Don’t agree? Take a look at these application examples that demonstrate both the power and potential of mechatronics in action.

Mechatronics integrates mechanical and electronic technologies with application-specific software to perform a particular task. Engineers who use mechatronic components and systems do so to focus on:
• improving precision, repetition, and flexibility in movement;
• saving energy;
• expanding function;
• reducing system size, weight, and footprint;
• and minimizing both the physical and audible environmental impact.
Mechatronic designs can be as elementary as “building block” components or as sophisticated as fully integrated systems. The basic building blocks are represented by individual components, such as linear bearings and guides, bearings integrated with sensors, or ball and roller screws.  You can specify these components individually in an application to help control movement, reduce friction, create a mechanism for driving linear motion, and even provide feedback on how fast equipment is rotating and in what position.

The next level combines components into a sub-system that serves as a self-contained unit to deliver more in terms of speed, strength, accuracy, reliability, or other measurement compared with basic building block components. Depending on application needs, sub-systems can include feedback devices to ascertain position or special configurations that can support structural loading. Some sub-systems will accommodate unique operating conditions while others fit more universal specifications.

Beyond sub-systems, fully integrated mechatronic systems offer “complete package” approaches that independently respond to inputs and offer real-time feedback and actions.  For example, an electric parking brake engineered as a mechatronic system can receive specific input about the
current operating condition from a CANbus network. In effect, the brake “knows” when it should activate or release, based upon programming in the integrated actuator specific to that vehicle.

Our applications casebook describes a range of examples demonstrating both the power and potential of mechatronics in action.

Linear ball bearings in stretcher-mounting system
Space is scarce inside ambulances, so placing and securing a stretcher can become an issue.  One mechatronic approach is to use linear ball bearings to guide the horizontal movement of a stretcher in and out of the ambulance.

The benefits here include high load-carrying capacity (to accommodate all sizes of patients), robustness and reliability, and the delivery of smooth, low-friction movement (greatly assisting EMTs).  In addition, the patient bed remains tightly secured during the ride in the ambulance.

Actuators onboard “factory on wheels”
In agricultural harvesting, the combine essentially serves as a “factory on wheels.”  Raw material is brought into this “factory” (harvested with the header) and proceeds through the machine where the crop (such as wheat) is separated from the chaff (waste) by the threshing mechanism.  The grain from the wheat passes over a sieve mechanism where it is sifted out of the waste and collected.  The chaff can then be reprocessed for complete threshing and then ejected from the rear of the combine.

Each of these processes requires movement. Since there is only one source of power (the engine), how and where to deliver that power is critical to machine function.  The prerequisite for any component is that it must be mechanically robust and able to survive in the dirty and dusty environment usually encountered.

Traditional components used to perform the necessary functions include belts, chains, or hydraulics.  Each presents its own challenges in delivering power to each point.  Applying tailored actuators for some operations, such as the threshing mechanism, cleansing fan, secondary separation system, sieve table, and auger, can improve the overall efficiency and reliability of the machine.

Electro-hydraulic steering system for off-road vehicles
Some applications can benefit from a combination of technologies, mechatronics and otherwise.  Electric steering offers flexibility and hydraulics delivers the necessary power density.  Combined, the two parts replace the traditional steering column with a more ergonomic design; reduce the number of parts; simplify assembly procedures and processes; and use less space.  Without the steering column operators experience less noise, better safety, and avoid hydraulic leaks in the cab.

One example of a closed-loop system integrates: a mechanical/electronic (mechatronic) steering module; a controller regulating all steering functions; high resolution kingpin bearing sensors for steering position input and actual steered wheel feedback; and an electrically actuated proportional valve.  Each component “talks” to the next using CANbus protocols.

When the operator turns the wheel, a signal travels to the controller with data indicating the angle of the turn and the desired position of the wheels.  The controller takes the signal and commands the proportioning valve to actuate the hydraulic cylinder, which forces the steered wheels to move to the desired position.  The position sensor integrated into the kingpin measures the position of the steered wheels and returns feedback data to the controller, which are compared to the desired position input to correct any discrepancies.

This system can be programmed to adjust the number of turns for the steering wheel from lock-to-lock.  Programming software governs steering sensitivity changes through vehicle speed.  This feature is especially useful in operating off-road vehicles, where it is often necessary to steer quickly at lower speeds and slowly at higher speeds.

Depending on the vehicle requirements, steer-by-wire modules with a constant, non-programmable torque may be preferred.  These plug-and-play systems send an electronic signal on the speed, acceleration, and direction of the steering wheel movement; and can increase cabin design flexibility and enhance operator ergonomics.

Mast height control unit for forklifts
A mechatronic system can automatically position the mast on industrial vehicles, such as forklifts.  Integrated sensor bearings detect mast height and convey rotational speed and direction feedback from the ac motor.

Accurate mast height control is important when forklifts quickly move from place to place, placing or retrieving pallets or containers to and from bin locations. Through a simple readout of the mast’s height compared to a pre-programmed shelf height, sensor bearings on the mast will automatically position it to the desired height with the push of the button or the flip of a switch.

The control unit mounts on the mast to monitor its location as it travels up or down and sends a continuous signal to the controller.  These signals are interpreted into precise measurements.  Using either a pre-programmed mast height system or a simple digital readout system, the vehicle “knows” the height of the load and can trigger other safety systems.

For example, the forklift’s safety controls can be programmed to limit speed or turning radius, depending on the height of the load, reducing the possibility of the vehicle tipping over.

Alternatively, the safety system can prevent the mast from rising beyond a specified height when the load exceeds a predetermined weight.

Two different designs have been created for mast control units.  A spring-loaded cam arrangement uses spring force to press the sensor bearing against the mast.  This unit is driven directly by the moving frame of the mast.  Pulley arrangement units are driven by either a wire or belt incorporated into the design of the mast-positioning system.

Both the cam and pulley control units respond directly to a designer’s need for smaller components, simpler assembly, and reliable performance.

Surgical and patient tables
Surgical equipment must meet stringent hygiene standards and perform reliably and consistently.  In medical applications, electro-mechanical actuation systems have distinct advantages over conventional hydraulics.  Without hydraulic fluids, there are no leaks to contaminate operating or patient rooms. The usually quiet electro-mechanical systems foster a lower stress environment for patients.

Electro-mechanical systems move telescopic pillars, or lifting columns, on surgical tables quickly and silently.  For structural support, rigid aluminum profiles and precision glide pads in the columns lift offset loads without deflection.  Combinations of screws and gears feature high push force capabilities and low noise levels.  Telescopic pillars can satisfy other applications, including patient-positioning tables for medical imaging, treatment, and ophthalmic examination, among others that require vertical action and structural support.

As part of the system, guiding actuators extend or retract the telescopic pillars.  Columns can run quietly and with minimal vibration at maximum speeds up to 45 mm/sec, depending on the model.  Stroke lengths can be up to 700 mm.

Control boxes synchronize and control multiple actuators for a flexible system.  The proper combination of control boxes and actuators ensure component compatibility and help reduce time spent in design, production, and assembly.

Interest among OEMs for fully integrated medical equipment systems has led to the design and development of subsystem medical tables.  In one application example, these tables (one is mobile and the other is “fixed”) are incorporated into machines for urology.  Through mechatronics components for multi-axis positioning, doctors can precisely, easily, and comfortably move patients for specific treatment.

Patient beds
Mechatronics has found a home in hospital rooms and in similar patient-care settings. Modular, power-driven actuation systems let caregivers precisely, safely, and securely adjust and position patient beds.  Other applications include couches, stretchers, and physiotherapy and examination tables in various healthcare settings.  Specialized actuators, recliners, and control units integrate
easily into standard bed platforms.

Beds equipped with such actuation systems can offer variable height adjustment; an adjustable backrest with CPR function; special positioning with auto-contour for comfortable sitting; and adjustable elevation of legs and knee-fold.  Full electrical control comes from handsets, bilateral pedals, and selective function limiters.  A manual quick-release mechanism safeguards in case of emergency.

Final Note: Regardless of application, an understanding of particular requirements and the operating environment will help guide your choices.  Partnering early in the design stage with a knowledgeable engineering resource can help identify the best components or systems for the job.

SKF USA
www.skfusa.com

Contact Mark D. Hinckley at 267-436-6510 or email Mark.D.Hinckley@SKF.com

Increased Sensing Accuracy with Signal conditioning

By Brett Burger, National Instruments, Austin, TX

Signal conditioning provides a distinct advantage because it enhances both performance and measurement accuracy.

For many real-world applications, you must measure environmental or structural parameters, such as temperature or vibration, with sensors. These sensors, in turn, require signal conditioning before a data acquisition device can effectively and accurately measure the signal. Signal conditioning provides a distinct advantage over data acquisition devices alone because it enhances both the performance and measurement accuracy of data acquisition systems.

Data acquisition systems
With the speed and accuracy of modern data acquisition devices, it is easy to overlook the need for signal conditioning. While plug-in DAQ devices specifically and accurately measure voltage signals, voltage is only one of many I/O types required by modern measurement and automation applications.

Many of today’s data acquisition systems must also measure signals from sensors that detect physical, chemical, or mechanical phenomena. While several of these sensors, such as RTDs and strain gauges, must have signal conditioning to return any measurement, they all require conditioning to return accurate measurements.

While data acquisition devices have become progressively more intricate, the basic principles of data acquisition remain the same — you must connect to the signal, apply the necessary signal conditioning, digitize the signal, and display the data (see Fig. 1). With this in mind, the three vital components of all data acquisition systems are as follows:
• Signal conditioning (to condition the signal/sensor).
• Data acquisition device (to digitize the conditioned signal).
• Software (to analyze, record, and display the acquired signal data).

The component most often forgotten, yet fundamentally important, is signal conditioning. A large portion of the world’s measurable signals must be detected with sensors, most of which require some sort of signal conditioning for the data acquisition device to accurately read them. Thus, a data acquisition system must not only incorporate the digitizer and application software, but also tightly integrated signal-conditioning hardware.

Improving accuracy
Data acquisition devices are used in a variety of applications. In laboratories, in field services, and on manufacturing plant floors, these devices act as general-purpose measurement tools well suited for measuring voltage signals.

However, for many real-world applications, you must measure environmental or structural parameters, such as temperature or vibration, with sensors. These sensors, in turn, require signal conditioning before a data acquisition device can effectively and accurately measure the signal. Signal conditioning provides a distinct advantage over data acquisition devices alone because it enhances both the performance and measurement quality of data acquisition systems.

To illustrate the necessity of signal conditioning, consider a thermocouple. To accurately measure thermocouple signals, you must provide amplification, filtering, and cold-junction compensation.

Amplification is required because of the small magnitude of the signal, and you must apply it as close to the thermocouple as possible to increase your signal-to-noise ratio. While this amplification help reduces the noise effect on your signal, you must also provide filtering to eliminate environmental noise from power lines and other electric devices.

Cold-junction compensation is also necessary to offset any temperature difference that exists between the measurement junction of the thermocouple and the junction with the data acquisition device. The net effect of this signal conditioning is dramatically improved accuracy.

The graph compares thermocouple measurements taken at 25°C using a National Instruments SCXI-1112 thermocouple signal-conditioning module and an SCB-68, a screw terminal connector block with a temperature sensor for cold-junction compensation (see Figs. 2 and 3). The SCXI-1112 module achieved an accuracy of 0.3°C, compared to 5.0°C accuracy with the SCB-68 (see Fig. 4). Thus, the SCXI-1112 signal-conditioning module provides a thermocouple measurement with accuracy more than 10 times greater than that of the terminal block because of preamplification, low-pass filtering, and a more accurate temperature sensor.

There are several critical signal conditioning technologies that enhance the accuracy and performance of the data acquisition system:

Amplification. Amplifiers improve the accuracy and sensitivity of your small signal measurements by boosting the amplitude of the input signal to better match the input voltage range of the digitizer, thereby increasing the resolution and sensitivity of the measurement. While many data acquisition devices include onboard amplifiers for this reason, many sensors, such as thermocouples,
require more amplification than a data acquisition device alone can provide. Using signal conditioning to amplify the signal near the source also reduces the environmental noise effect on your measurement.

Attenuation. Attenuation diminishes your input signal’s amplitude to fall within the digitizer’s input range so you can measure high-voltage signals with your data acquisition system.

Isolation. Signal-conditioning devices with isolation pass input signals to the measurement device by using transformer, optical, or capacitive coupling techniques rather than a physical connection. Isolation prevents ground loops. With isolation, you can measure signals with high common-mode voltages while protecting the expensive measurement equipment in your data acquisition system from any high-voltage surges that may occur.

Filtering. Filtering improves your measurement accuracy by removing unwanted frequency components from your signal. In addition to eliminating noise from your measurement, filtering prevents signal aliasing (a phenomenon that occurs when frequencies higher than half of the sampling rate appear in your measured signal, corrupting your measurement).

Excitation. Many sensors, such as RTDs, strain gages, and accelerometers, require some form of power to return a measurement. Excitation provides this power, in the form of either voltage or current, so you can use these types of sensors in your data acquisition system.

Calibration. Calibration improves your measurement accuracy by adjusting your data acquisition system to compensate for any imbalances in your sensor or measurement hardware. For example, strain gage measurements require both null (or zero) and shunt (or gain) calibrations to ensure accurate linearization.

Cold-junction compensation. Thermocouples measure temperature as the difference in voltage between two dissimilar metals. Based on this concept, another voltage is generated at the connection between the thermocouple and connector (or terminal) block of your data acquisition device.

Cold-junction compensation improves your temperature measurement accuracy by providing the temperature at this connection, which you can then subtract from the reading.

Simultaneous sampling. When you must measure two or more signals at the same instant in time, you need simultaneous sampling. Using signal conditioning with track-and-hold circuitry can be a much more cost-effective simultaneous sampling solution than purchasing a digitizer for each channel. Typical applications that might require simultaneous sampling include vibration measurements and phase-difference measurements (see Table 1).

DAQ system considerations
The number of available data acquisition system devices and options can make the process of choosing the proper components very complex. But this process is crucial because the type of components you use can have a dramatic effect on the overall performance and accuracy of your system. Couple this with the fact that your development and time to first measurement also can be drastically impacted, and it quickly becomes evident that component choice is one of your most important decisions in selecting the right data acquisition system.

There are nine essential considerations for your data acquisition system that can help you take full advantage of the latest advances in computer-based data acquisition.

Breadth of signal types. Selecting signal conditioning hardware that accepts a large breadth of signal types is critical to protecting your data acquisition system investment. In addition, the ability to incorporate all of these measurements into a single data acquisition system can dramatically reduce your development time because you can focus on implementing your tests rather than learning and configuring multiple measurement systems. To illustrate, consider an application where you must validate the design of an automobile engine. To accurately characterize the engine, you must measure a variety of signal types — including temperature, vibration, frequency (rpm), and torque — each with unique conditioning requirements. Traditionally, this meant that you needed an individual stand-alone instrument or custom data acquisition device for each type of measurement, which required you to configure multiple devices. With modern, high-performance signal-conditioning hardware, you can easily incorporate all of these measurements into a single, rugged chassis and configure them from a single software interface, such as NI-DAQ. This capability reduces your current application’s development time and cost while still protecting your data acquisition system investment and providing the flexibility to address future applications.

Connectivity. With the diverse range of sensor connectors available, your signal-conditioning hardware must not only offer a variety of connectivity options but also, more importantly, the specific options you need. Whether you are using a strain gage with a D-Sub connector or an accelerometer with a BNC interface, your signal-conditioning platform should offer easy connection to all of your sensors to simplify your system setup. Some signal-conditioning hardware offers direct connectivity options on a per-channel basis so you can match each channel to the required connector. With sensor-specific connectors, you can easily remove and replace individual sensors while your data acquisition system is still running, making it easier to troubleshoot your system and minimizing system downtime. On the other hand, the most flexible type of connector is the screw terminal. Consider a data acquisition system with screw terminals for voltage and current measurements or if your sensor connection type is likely to change often. When you can connect your data acquisition system to any sensor, you greatly enhance your measurement capabilities.

Expandability. As your test evolves and your measurement requirements change, you must have a data acquisition system that provides the flexibility to expand and change with your application. Expanding your data acquisition system should not require a complete overhaul of your signal-conditioning platform. Using modular signal-conditioning hardware, you can very quickly increase the number and variety of signals in your system by simply plugging in another module. This feature protects your data acquisition system investment because you can expand your channel count in a matter of minutes, dramatically reducing the time before your modified system is up and running. This flexibility, in turn, reduces the total cost of ownership for your data acquisition system.

Integration. To realize the full productivity potential and value of your data acquisition system, all of its components must integrate seamlessly. Specifically, your signal-conditioning hardware should be capable of incorporating mixed-signal types in a single system, while still maintaining quick and easy connection to your data acquisition device. With this capability, you can dramatically reduce your setup time. Furthermore, by selecting signal-conditioning hardware that tightly integrates with your data acquisition device, you can easily upgrade the speed and resolution of your entire data acquisition system as your application requirements evolve by simply upgrading the data acquisition device. Thus, tightly integrated signal-conditioning hardware can reduce both current and future system development costs.

Packaging. Your signal-conditioning hardware packaging is most often dictated by the size and environmental constraints of your application. Because space is at a premium on most laboratory and test floors, it is important to choose a data acquisition system that packs more channels into less space. Signal conditioning with high-channel density minimizes the space requirement of your data acquisition system while reducing per-channel cost. In portable applications, your signal-conditioning hardware must be compact and lightweight, while still offering a high level of performance and functionality. Alternatively, applications running in harsh, industrial environments require signal conditioning with rugged mechanical packaging. To operate effectively in such extreme environments, hardware must be capable of enduring a wide operating temperature range in addition to severe shock and vibration.

Software. A large portion of the total cost of a test and measurement system is application development. To keep these costs to a minimum, you must use software tools that maximize productivity. In particular, driver software should provide a single interface for configuring and testing your entire data acquisition system, while also tightly integrating with your application development environment (ADE). Driver software should also provide the ability to scale and calibrate your sensor measurements. These capabilities dramatically reduce your overall development time and cost because you can quickly incorporate new sensor measurements into your data acquisition application.

Isolation. Isolation can dramatically increase the overall value of your data acquisition system by improving overall safety, accuracy, and performance. By creating an insulation barrier, isolation permits the ground reference of the input and output of a measurement device to be at different voltage levels, protecting both the operator and equipment from any transient voltage spikes. Isolation also improves system accuracy by physically preventing ground-loop currents, a common source of measurement noise and inaccuracy; ground loops result when a data acquisition system and its input signal have separate grounds at different potentials. Lastly, isolation improves the performance of your data acquisition system by increasing its common-mode rejection ratio (CMRR), or ability to reject common-mode voltage. Common-mode voltage, another frequent source of error, is voltage that is present on both the positive and negative input of your measurement device, but it is not part of the signal you wish to measure. While isolated devices are often more expensive, their additional cost is easily justified when you consider the amount of troubleshooting time isolation saves you by eliminating hard-to-find sources of error, such as ground loops and
common-mode voltage.

Calibration. One of the most critical technologies that a signal-conditioning system should incorporate is the ability to be easily and accurately calibrated. Most measurement devices are calibrated at the factory, but the accuracy immediately starts to drift with time and temperature changes. To make the most accurate measurements possible, you must periodically calibrate your entire data acquisition system. If your system has precision onboard voltage references, you can adjust your measurement system to compensate for temperature changes. In addition, you must have access to external calibration services to keep your system performing up to the manufacturer’s specifications year after year. It is very important to understand the calibration capabilities and requirements for any signal-conditioning system under consideration because this is the only way to ensure that your investment contains the technology you need to make accurate and reliable measurements.

Switching. In today’s demanding test environments, the ability to route signals easily throughout your measurement system is a technology that can lead to huge improvements in test times. As an example, consider a case where you must subject a unit under test (UUT) to four separate measurements in the testing process. Without the proper technology, you must reconnect the UUT to each different measurement device for each test. With state-of-the art switching technology, not only can you route the UUT leads automatically to each measurement device in turn, but also you can test several UUTs at the same time. You thus achieve more efficient use of your test equipment, faster test times, and less user intervention. Your selection of a signal-conditioning system that offers this technology can have a huge impact on the overall performance and cost of your system.

Bandwidth. Bandwidth is an often overlooked but extremely important technology to consider when selecting a signal-conditioning system. Modern signal-conditioning hardware should have the bandwidth to handle data throughput from a high-channel-count system and to accommodate any future growth in channel count. System bandwidth is typically expressed in samples/second (Hz), and often reaches several hundred kilohertz for large systems even at modest acquisition rates.

Overall, signal conditioning defines the measurement capabilities and is a critical component of any complete data acquisition system. Furthermore, signal conditioning is required for accurate sensor measurements. To protect your data acquisition system investment, you must invest in modular, easily expandable signal-conditioning hardware that accepts a wide variety of signal types and offers a broad range of connectivity options, while still meeting your size and environmental constraints and tightly integrating with your development software and data acquisition device.

The types of hardware listed in Table 2 are examples of National Instruments offerings. They serves as an example of the types of choices available to users when selecting signal-conditioning hardware capable of interfacing a signal or sensor to a data acquisition system.

Front-end signal conditioning (SCXI)
SCXI is a signal-conditioning and data acquisition system for PC-based instrumentation applications (see Fig. 5). It consists of a shielded chassis that houses a combination of signal-conditioning input and output modules that perform a variety of signal-conditioning functions. You can connect many different types of transducers, including thermocouples, directly to the modules. The system is a high-performance USB plug-and-play data acquisition system, and it can also operate as a front-end signal-conditioning system for PCI, PXI, or PCMCIA data acquisition devices.

Integrated DAQ and signal conditioning (SC series)
SC Series data acquisition (DAQ) devices (see Fig. 6) expand the measurement capability of PXI by integrating measurement-specific signal conditioning onto a 16-bit PXI data acquisition device. With this tight integration of signal-conditioning and data-acquisition functionality, the SC Series delivers high-performance sensor-specific measurements at a lower cost per channel than leading solutions, such as SCXI DAQ systems, for low- to medium-channel counts.

Distributed DAQ with signal conditioning
CompactDAQ (see Fig. 7) and CompactRIO are modular embedded control and distributed I/O systems for measurement, control, and data logging. They are intended for applications that demand industrial-grade hardware with easy installation and configuration. Both systems feature built-in signal conditioning for direct connectivity to sensors and actuators. Modules are available for connecting to thermocouples, RTDs, strain gauges, 4 to 20-mA signals, high-voltage sources, and many other signals.

They offer embedded control by running LabVIEW Real-Time on a dedicated embedded processor, and can connect to a PC through a variety of industrial buses (Ethernet, serial, CAN, and Foundation Fieldbus) or even wirelessly (see Fig. 8). They can operate in harsh environments with electromagnetic noise, wide temperature ranges, and high shock and vibration.

National Instruments
www.ni.com

Hope For the Future

By Richard Comerford, Editor, Electronic Products

One of the most frustrating things that we experience in our day-to-day existence is not being understood. As engineers, we’ve all run into people who have no idea what it is we actually do, and seem totally ignorant of the basic scientific principles and techniques we use every day. And those of us who have been around awhile may be tempted to tell those who are experiencing this frustration for the first time that it won’t be the last time they run into the situation.

But recently I was given hope that the aforementioned situation may really be changing – that in the future, what we do as engineers will be less foreign to the world in general. The occasion was NIWeek, an annual meeting in Austin, TX, sponsored by National Instruments.

For those of you who haven’t attended this event – and if you really want to keep up with what’s happening in mechatronics you really should go to this show – the program includes opening keynotes each day that are a significant departure from the usual. Instead of someone just talking to you about technology developments, keynote speakers provide live demos of what the technology they’re working on can do. (You can see these keynotes at National Instruments’ Web site, http://www.ni.com/niweek/.) One of the keynote speakers, Ray Almgren, NI Vice President of Academic Marketing, made the following observations: “Through our work with LEGO, we’ve learned that kids are born with an innate sense of creativity. They are innovators; they are engineers – from the time they are born.”

Acting on that realization, NI is actively going about encouraging the development of engineering abilities, not only at the university level, but in high schools and elementary education institutions. They are a major contributor to FIRST (www.usfirst.org), a not-for-profit organization, founded by Dean Kamen, that aims to inspire young people to be leaders in science and technology; it does so by sponsoring robotics competitions that are like scientific Olympics, complete with team uniforms and a large stadium for competitions.

NI has also been working with LEGO to create toys that preschoolers and kindergarten kinds can use to build and program simple robotic systems. And they are backing a competition called Moonbots (www.moonbots.org) in which small teams composed of children and adults compete to design, program, and construct robots that perform simulated lunar missions similar to those required to win the $30 million Google Lunar X PRIZE, a private race to the Moon to encourage commercial exploration of space.

The dedication of  all those involved with these projects gave me hope that perhaps that feeling of being misunderstood just might disappear in future generations. “We are creating a new generation of engineers and scientists,” said Almgren, and that generation may not only make me feel more comfortable, they just may solve a lot of the world’s problems. As Almgern noted, “they are the real stimulus package.”

Robots created by high schoolers compete in a FIRST event.

Will Solar Make It?

Solar Power is here in a big way.   It may not make the front pages of the paper, but it is huge.  The rate of new installations is breathtaking.

Large retailers like Target and Walmart are putting solar arrays on the roof of their stores to reduce energy costs over the long term. British Petroleum may have been one of the first companies to consider the implication of eliminating the cost of electrical power from their operating expenses.  The long term benefit of converting the unused roof space on local gas stations are staggering, and may have been the incentive for BP to enter the solar manufacturing business.

And why wouldn’t businesses be interested in reducing their costs?  Especially when the costs are paid for by subsidy programs from the power companies, incentive programs from the Federal government and in many states, programs from the state level to help pay for the technology.

I don’t even know how to do the math on this one.  The utility contribution is often 30% or more of system cost paid directly to the contractor.  The Federal contribution is another 30% plus 5 year accelerated depreciation.  Some states have subsidies of 20 and 30 percent.  So 80 to 90 percent of the direct cost is paid by others, plus the depreciation value.

What a great deal!  It’s not surprising that the solar industry is booming.

But is this how American businesses run?  I thought that the incentive to start a business is the opportunity to make a profit.  To earn money for goods and services, pay a living wage to employees and hopefully return a profit after everything ia accounted for.

Well not in New United States.  We underwrite new businesses with Tax dollars when the government decides the situation is important enough.

But the utiliity companies are running out of money to pay for the incentive programs and are having to cut back.  And the Federal and State subsidies must eventually follow suit.  What then?  Will the needed jobs be created or will the industry stall?

We come back to the Absolute Value of the technology.  Actual ROI’s for the standard photovoltaic systems going into today’s projects are in the range of 9 years without the discounts and subsidies.  If  Solar Power is going to make it as an industry it has to achieve better rates of return, especially as subsidies become less available.

Silicon based photovoltaics are falling in price.  Which would seem to be a problem, but in fact, falling cost should lead to more sales.  As the technology becomes less expensive, it’s rate of return increases.  If panel prices are falling, then the balance of system costs, labor and installation, will be under pressure to find means of cost reduction..

There is a lot of work to be done to get solar energy to stand on it’s own.  I say, let’s get to it!

Something New in Electric Motors

In the electric motor field, everyone generally accepts that integral horsepower motors are 3 phase.  This is done to increase the amount of power that can be output from the motor.  By putting three electrical phases in, staggered 120 degrees apart, it is possible to put more electrical power through the motor and get more mechanical work out of approximately the same space.  Of course this is limited by the motor’s efficiency since all systems have energy conversion loses which are manifested as heat.

Smaller motors, most often referred to as single phase devices, are generally split phase or, more literally 2 phase with the second phase being turned off when a speed threshold is met.  The second phase is required in order to start the motor and to determine which direction the motor will turn.

Another attribute of the AC motor is the starting current required to bring the motor and load to operating speed.  The typical starting characteristic can be as much as 6 times the running current.  In fact, AC motors will pull in more and more current until either the motor starts or it burns up.  This is the reason for the use of thermal overload devices.

But the difference between starting and running power creates significant problems when applying solid state technology.  Solid state starters and variable frequency drives, which depend on  power semiconductors to control motor speed, are limited to the inrush current profile of the power device.  This limit is usually double the running current and in fact is better defined by the dI/dt or current rate over time in addition to the temperature rating of the device.

But when you have to pump water for irrigation in remote locations, the cost of bringing 3 phase wiring is very expensive.  Most of the time remote powered pumping has been powered with diesel engines.  It is estimated that over 200,000 IC engines are in use in rural applications.  And with rising fuel costs and high maintenance expenses, these IC engine solutions are threatening to close down many small farmers.

But John Roesel had a better idea.  And in the mid 1990’s Precise Power Corporation was started, building integral horspeower motors based on a new single phase design called the Written Pole motor.  These motors that produce 125% of full load torque with only 150% current, with efficiencies from 92-95% and 85% power factor.  These results have been verified by stringent testing at motor labs like Manitoba Hydro.

And it only take 2 wires.  So the cost for the utility to pull power to a remote location is reduced proportionately.  This makes a lot of new applications cost effective, quieter and cleaner by far.  Some ranchers are saving in excess of $10,000 per month compared with IC engine operation.

For something completely different in electric motor technology check out www.precisepw.comr

E-Gear Drive on All Electric Sedan

AUBURN HILLS, Mich., Sept. 24 /PRNewswire-FirstCall/ — BorgWarner announces another eGearDrive transmission application on the all-electric CODA sedan, scheduled for introduction in California in 2010. Ideally suited for full performance electric vehicles on either front-wheel drive or rear-wheel drive transverse driveline applications, the BorgWarner 31-03 eGearDrive(TM) single-speed transmission delivers high torque capacity, high efficiency, and low noise, vibration and harshness (NVH) in a compact package. Paired with a UQM TECHNOLOGIES, INC. (NYSE Amex: UQM) PowerPhase(R) electric propulsion system, the BorgWarner eGearDrive(TM) transmission will propel the five-passenger CODA sedan at highway speeds while providing maximum powertrain efficiency.

“BorgWarner’s 31-03 eGearDrive is a purpose built, high performance transmission that can be broadly adapted to a variety of electric propulsion systems,” said John Sanderson, President and General Manager, BorgWarner Drivetrain Systems. “Designed for fast-to-market implementation, we expect this eGearDrive transmission to accelerate growth in the all-electric and hybrid electric vehicle segments.”

In addition to providing primary drive for front-wheel drive and rear-wheel drive electric vehicles and hybrid electric vehicles, BorgWarner eGearDrive systems enable launch assist, energy recovery, and AWD performance for the secondary-driven axle on any type of vehicle. Also available is an optional electronically actuated park lock system as well as various electronic driveline disconnect systems.

Headquartered in Santa Monica, Calif., CODA Automotive is an all-electric car and battery company. The company designs, brands, markets and distributes electric vehicles utilizing a strategy that allows CODA Automotive to develop vehicles rapidly in a flexible manner, avoiding the traditionally capital-intensive nature of the automobile business. Through its exclusive transportation battery joint venture with Lishen Power Battery, China’s main state-owned battery manufacturer, CODA is also a leading designer and large-scale manufacturer of power battery systems.

“BorgWarner’s commitment to excellence and leadership position in the powertrain component business made the company an ideal transmission supplier for the all-electric CODA,” said Kevin Czinger, President & CEO CODA Automotive. “We’re looking forward to working with BorgWarner.”

BorgWarner Drivetrain Systems produces highly engineered drivetrain technologies for the global vehicle industry. Key product segments include: Dual clutch modules; wet friction clutch components and systems; mechatronic transmission control modules; electro-hydraulic solenoid valves; mechanical clutch assemblies; all-wheel drive couplings, transfer cases and software/controls; and electric vehicle transmissions. These systems improve fuel economy and performance while enhancing vehicle stability. BorgWarner Drivetrain Systems is a trusted supplier to virtually every major light vehicle and automatic transmission producer in the world today.