Developing a customized board for an ophthalmic device offered many advantages over the standard component solution for Visionix, combining two boards into one with the perfect fit.
A conventional eye test is a time-consuming affair that depends heavily on the patient’s subjective judgment as to whether or not the view improves with one lens or the other. The automatic diagnostic device L80 +, designed in 2008 by the Israeli company Visionix, overcomes this problem, delivering absolute, objective data within a few seconds after measuring the reflexes of a patient’s eye.
Using thousands of physicians’ assessments stored as diagnostic patterns, the device evaluates each objective result with far more experience and accuracy than is typically available to a single physician. While the medical knowledge and decision for the appropriate treatment are still needed, the diagnostic device provides a sound basis for consultation and treatment options. As such, the Vision80 L80 + can be used in medical practices as well as opticians shops.
Since the measurements are used as a basis for corrections, the level of precision is extremely high. To make sure this level of precision is reached, the manufacturer uses stepper motors and brushless DC motors for the movements of the chin rest and the laser. All six axes used to this end are controlled by a single control module, the custom TMCM-VI-802.
All components needed to control five stepper motors and one BLDC motor were packed on one single PCB – two of the stepper motor axes are designed as low-current axis for motors with up to 1A phase current, while two additional axes allow for driving motors with up to 3A phase current. This board, based on building blocks from a standard solution, is a typical example of the cost-effectiveness of a custom motor control and motion control solution resulting from the optimization of a standard solution to save time, money, and risk.
For the development of the ophthalmic device, five stepper motor and one BLDC motor axis were needed. The prototype was initially equipped with Trinamic’s standard solutions – the TMCM-610 for driving up to six stepper motors, and the TMCM-170 BLDC module, a round, stacked module that can be directly placed on the motor. However, as there was no need for the BLDC driver module to be mounted on the motor, they asked Trinamic to optimize their prototype in terms of production, combining the control of all axes on one single board.
During development, Trinamic and Visionix worked closely together on the customer’s request, ensuring the customer-specific solution was developed in parallel to the pre-series production with the standard products. This is a common method of operation, using standard products for the prototypes and pre-series before migrating to mass production using the cost-effective, optimized solution.
|Trinamic's TMCM-170||Trinamic's TMCM-610||The TMCM-VI-802 combines the TMCM-170 and TMCM-610|
What makes the tailor-made TMCM-VI-802 so special is that it combines stepper motor and BLDC motor control on one board. With one processor available per motor type, all connections and wiring only need to be made once, reducing cost, effort, and room for error. Moreover, the board is shaped to fit the application exactly, matching the space constraints Visionix’ Engineers are dealing with.
Most importantly, with Trinamic’s team of Engineers taking care of the motion control components for the applications, the customer’s own team of Engineers were free to focus their full attention to the core aspects of the L80 +, optimizing the application layer and software. As such, the team behind it turned the L80 + in a groundbreaking device, making eye tests easier to perform while increasing the accuracy.
These benefits offer not only potential to ophthalmic devices, it has the potential to free up engineering teams from the burgeoning constraints induced by the 4th Industrial Revolution. According to Klaus Schwab, “the speed of current breakthroughs has no historical precedent.” So in order to stay one step ahead of the competition, it’s necessary to keep innovating at a fast pace. For example by calling in the expertise of Trinamic to solve complex motion control puzzles within tight development cycles as Visionix did.
This not only reduces development time, cost, and risk, it also adds profitability to the product over its life cycle. Especially in medical, robotics, and space, being first to market boosts customer loyalty simply because the product is known to the customer. Of course, this also means the custom solution needs to be a reliable, turnkey solution. That’s why the individual elements such as low and high current axes or BLDC controls were not newly developed by Trinamic.
The solution is composed of individual blocks instead that have been battle-tested in many designs and applications. After adapting the software to the new layout, the team of Engineers created the perfect custom solution in as little as time possible.