Mechatronics has contributed to progress in many industrial fields such as robotics, semiconductors, aerospace, automotive, consumer electronics, and medical. Well-known and well-established mechatronics systems include production systems, synergy drives, automated guided vehicles, automotive subsystems such as antilock braking systems, and commonly used spin-assist consumer products such as auto-focus cameras, hard disk drives, compact disc players, and washing machines. The main benefits that mechatronics has provided are an increased functionality and comfort level, energy savings, versatility, and flexibility.

So mechatronics is nothing new. It is the application of the latest techniques in precision mechanical engineering, controls theory, computer science, and electronics to the design process to create more functional and adaptable products. Many forward-thinking designers and engineers have been using and applying mechatronics for years.

The term mechatronics was first coined in Japan in 1969 as a portmanteau for mechanical engineering and electrical engineering (see Figure 1). Its origins are in precision mechanics, and informatics was also included later on as a core discipline. Today, mechatronics is defined as a holistic approach that merges both physical and logical processes. It denotes the multidisciplinary efforts to design a whole system by combining mechanics, actuators, sensors, electronics, and informatics. Such combined knowledge enables the development of the next generation of simpler, more economical, more reliable, and versatile systems, thus bringing more value than the mere sum of the individual components of a system.

Figure 1. The mechatronics approach concurrently combines various engineering fields.

Mechatronics has been a significant design trend that has greatly influenced the product development process, international competition in manufactured goods, and the nature of mechanical and electrical engineering education during the last few years. It has led to the emergence of many specialized engineering and manufacturing companies supporting industrial manufacturers through collaborations in mechatronics networks to use their knowledge in developing better products. Such specialized companies often solve technical challenges to make subsystems, submodules, or subfunctions perform according to the target performance goal through integration in a controlled architecture at a system level and achieving its technical effect by control algorithms.

Automation Trends in IVDs

One of the dominant demands in the IVD industry is to improve efficiency and consequently cut costs. Similar to individual hospitals merging more and more with large healthcare networks, labs are also joining forces to deal with the never-ending pressure on costs. This consolidation trend generates increased buying power, which compels IVD manufacturers to compete to offer full package deals with direct purchase and even leasing conditions. To complete such a package with all of the equipment that a group customer is asking for, manufacturers need to source their competitors’ analyzers and make sure they can be integrated in a fully automated lab.

The promised benefits of laboratory automation are increased efficiency of the sample handling processes and better machine integration. Moreover, automation should also offer a higher level of flexibility for future adaptations and upgrades to lab analyzers. However, many labs still rely heavily on technicians to process samples and monitor operations. As human involvement in the lab increases, so does the likelihood of improper liquid handling, sample contamination, and inefficiency. One way to make gains in efficiency is with automated laboratory equipment for handling liquids, along with uniform analysis and sample preparation that deliver reproducible test results.

The growing lab automation trend has been very clear for many years. In 2000, there were only two automation sites in Europe; in 2007, the number of automation sites in Europe grew to almost 600. On the cost side, the average savings as a result from switching to an automated lab are considerable, with a 20-40% reduction in staff, a 40-60% reduction in the number of analyzers, and a 17% decrease in cost per test (to 0.376 Euro per test).

IVD manufacturers have many reasons to reconsider and reexamine the designs of their lab analyzers. For example, the pressures to provide cost-effective equipment with increased sample throughput, the lack of educated laboratory personnel, the need to integrate equipment from diverse companies, and the increased complexity of sample motion through an analyzer are only but a few of the reasons. The circumstances and conditions for the IVD industry to embrace mechatronics, its specialist providers, and design processes are already evident and in place.

Is Automation the Solution?

The lab machines that have the typical applications for automation are hematology analyzers, automatic electrophores, microbiology analyzers, biomedical analyzers, hemostasis analyzers, and automatic dispensers. Such applications include syringe dispensing of tiny volumes of fluids, automatic dispensing and sampling of chemicals, DNA processing, and many other applications (see Figure 2). For the most part, the applications are Cartesian arrays of samples in small wells, and single or multiple dispensing devices on a moving head. The number of samples being managed can range from 1 to 96. The motion is often powered with small stepping motors and a variety of mechanical solutions, such as timing belts and pulleys, lead screws, and rack and pinion actuation solutions.

Figure 2. A close-up of a typical application for fluid dispensing with a pipette.

With automation being presented as the solution to the needs of the IVD marketplace, new technical challenges are emerging not only in the handling of sample data though information technology solutions but also on the physical transport of the sample through the chain of equipment while maintaining traceability.

For example, one such challenge is measuring liquid levels. Some labs still rely on technicians to monitor the presence and levels of fluids, an imprecise and expensive alternative to automated monitoring. But even automating this seemingly simple task of detecting liquid levels is problematic. Some equipment relies on conductive electrodes to measure levels when the liquid comes into direct contact with the switch. When that happens, the switch sends a signal to a conditioning instrument that converts it to a switching signal. But because such sensing probes come into direct physical contact with the liquids, labs run the risk of sample contamination and test failure. Even a single contaminated specimen can result in lost time, decreased efficiency, skewed test results, and flawed patient diagnoses.

To minimize sample contamination, the technicians monitoring the automated processes must interrupt lab operations to replace the disposable probe tips. These tips must be replaced with every test liquid change and for every patient sample analyzed. While assessing liquid levels in this manner is effective, disposable tips can be expensive, and replacing them requires costly downtime.

Ultrasonic sensors on automated laboratory equipment have emerged for detecting liquid levels quickly and accurately, and without touching the liquid. The ultrasonic sensors can be mounted to the top of the dispensing tubes to read the internal liquid levels. The X/Y table that moves the sensors above the sample tubes needs to deliver fast, stable, and repeatable positioning in the laboratory device. Although a component with standard lead screw or belt drive modules could accomplish this, an engineered solution with an integrated mechatronics approach is more likely to bring satisfactory performance levels at an acceptable cost.

But even though many specialized companies are providing the needed engineering and possibly manufacturing subcontracting services, many IVD manufacturers somehow have not yet discovered and implemented the combined discipline field of mechatronics.

Mechatronics Is the Solution

Laboratories designed for processing specimens (e.g., environmental research or medical laboratories with automated analyzers) could especially benefit from a mechatronics approach. Such analyzers are designed to measure different chemicals in a number of biological samples and tests. The first biochemistry analyzers were primarily used for routine repetitive medical laboratory analyses. However, they have been replaced during the past few years by discrete working systems that require lower reagent consumption. Such systems typically determine levels of albumin, alkaline, blood urea nitrogen, calcium, cholesterol, and glucoseuric acid in blood serum or other bodily samples (see Figure 3).

Figure 3. An automated analyzer for repetitive sample analysis.

Handheld pipettes, automation instrumentation, high-throughput robotic workstations, and chromatography systems for the drug discovery and biotechnology markets are very often composed of a Cartesian robot that is equipped with a multi-function X/Y/Z carriage that holds up to five tools at the same time. In general, these devices use high-accuracy motorized motion systems for high-speed and high-precision positioning. The motorized display positioning system improves the ease of performing display measurements. But although the required motions for automation are currently not very complex, the motion will be much more difficult as throughput demands increase. Components that are cantilevered tend to flex and oscillate, which can disturb the accuracy of the motion or require settling time between motions. No simple solutions for the kinetics of these systems will make them more efficient.

In the past, mechanical engineers have almost exclusively dealt with such machine and product design problems. After the mechanical engineers designed the machine, control and software engineers worked on solutions for control and programming problems. This sequential-engineering approach usually resulted in suboptimal designs. Machine design in general has been influenced by the evolution of microelectronics, control engineering, and computer science. What is needed as a solid basis for designing high-performance machines is a synergistic cross-fertilization between the different engineering disciplines. This is exactly what mechatronics tries to achieve: a concurrent engineering view of machine design.

An essential feature in the behavior of a lab or any machine is the occurrence of controlled and coordinated motion of one or more machine elements. The generation and coordination of the required motions, such that the increasingly growing performance and accuracy requirements are satisfied, are already the raison d’être of mechatronics in many other applications. Traditional mechanisms are limited in their flexibility in generating a wide variety of motions. Their potential for creating complex functional relationships between the motion of the actuator and the driven element is also restricted. Another limitation of purely mechanical drive systems is their inherent lack of accuracy, which is caused by friction, backlash, wind-up errors, resonances, dimensional errors, etc.

Such restrictions can be alleviated by eliminating or simplifying the forced-motion mechanism between the actuator and driven elements. Instead, each driven element is provided with a drive motor and a position sensor. A motion controller generates the required relationships between the motions of the different driven elements. The motion synchronization function is shifted from the error-prone hardware mechanism to the flexible software controller. By applying a mechatronics approach, a large number of motions can be synchronized, even those that are long distances away from each other.
As for external forces, a range of secondary effects such as vibration and noise can adversely affect the functional behavior of machine elements and instruments. While passive damping treatments are available, they have limited applicability. A mechatronics approach can provide more effective solutions. For example, based on the information about the vibration and noise levels that are captured by appropriate sensors, the vibrations can be counteracted by actuators distributed over the structure, and the machine elements become active and smart.

By taking a mechatronics approach, the next generation of lab equipment with increased throughput performance is going to be developed. Of course, this will require research and development, increased hardware costs, and the use of new design tools as described above. But the motion in lab analyzers is not mission critical such as for heart-lung machines or other systems that involve direct risk to human life, so conventional motion controls are still acceptable for now.

The main emphasis of the lab equipment is the data generated from the test processes, so a lot of care is taken to ensure that the right data is associated with the right sample. However, the motion control aspect of the IVD industry has not been a primary focus of its engineering efforts. Some companies are already experiencing limits in terms of what machine hardware can do. In order to get to the next performance plateau, the traditional mechatronics handbook that has been used up to now in other industries may need to be thrown out and start over on a clean slate. As with most mechatronics applications, the mechanical design of the IVD system has to be changed in order to achieve better throughput (see Figure 4). But it is not immediately obvious what that change is.

Figure 4. A mechatronics two-axes unit with an open frame design.

Virtual Prototyping

Virtual prototypes can help IVD manufacturers understand how to redesign their equipment without spending huge amounts on development cost and resources. These known engineering software tools can simulate the dynamic behavior of a high-demanding motion application.

Virtual prototyping is the process of using a virtual prototype, in lieu of a physical prototype, for testing and evaluating specific characteristics of a product design. A virtual prototyping environment is a multidisciplinary collection of models, simulations, and simulators that are focused on guiding product design from idea to prototype. In the development context, a virtual prototyping environment would address engineering design concerns of the developer, process concerns of the manufacturer, logistical concerns of the maintainer, and training and programming concerns of the operation.

Simulations are developed that enable the creation of a variety of realistic synthetic environments. Virtual prototypes are tested in such simulated operational environments. Once a concept is approved, design and manufacturing tradeoffs are conducted on the virtual prototype to enhance productivity and eliminate the need for a physical prototype. Virtual prototyping can accelerate production, help program managers identify program risks, help engineers visualize the interactive results of designs, and allow operational testers to conduct evaluations that aid in the design of tests performed during each phase of product development. Or to sum, virtual prototyping can provide an IVD company with a competitive edge.

Without having to build expensive prototypes and then test, redesign, rebuild, and retest them, virtual prototypes can be optimized with mechanical, electronic, and software building blocks to find the best design for the respective IVD automation task. Before even having worked out a design on a drawing board or in a 3-D CAD model, a multidisciplinary development team already knows the performance of their next-generation equipment.

Virtual prototyping can also allow for faster development of future IVD applications, enabling the cooperating partners to work simultaneously in different regions all over the world with an improved and better performing application, thus being more cost-efficient than before. At the same time, the complexity of such applications could be increased to a new level that could not be reached with the traditional engineering approach. In addition, such prototypes could be re-used for training purposes or act as remote diagnosis tools since they know very well how a final application functions.

Conclusion

The need for increased performance in efficiency, productivity, and flexibility through automation of lab equipment is more than obvious. Mechatronics has already improved existing products and developed new ones with better performance in other consumer and industrial areas and applications. The time has come for these two separate worlds to meet and allow mechatronics to bring lab equipment to the next performance level.

Leif Andersson is manager, strategic projects at SKF Linearsysteme GmbH (Schweinfurt, Germany). He can be reached at leif.a.andersson@skf.com.