When electric drives are used in vehicles, the masking effect of an internal combustion engine disappears, allowing the noise behavior of the transmission to take center stage. At the same time, peak power and torque increase, engine speeds increase, and power must be transferred optimally in both directions due to the regenerative braking system. Conventional design parameters remain important, however: The build space is limited, durability must not be compromised, and the product must still be cost-efficient. Optical metrology as part of a hybrid measurement concept helps to overcome all these challenges.

Tactile or contact probes are the most common metrology technique in the coordinate measurement world, including the more specialized gear measurement community. Tactile probes can be active or passive, scanning or touch only, and may vary in cost and performance depending on the system itself. They are offered by multiple industrial companies as standalone OEM products (e.g., Renishaw) or only included in their coordinate measuring machines (e.g., Zeiss, Klingelnberg, and Hexagon). Their overall performance, especially their robustness and flexibility, have led to a gold standard for most metrology tasks.