| Stepping and Servo Motor Commutation | White Paper | Multi-phase motors need to switch among phases as they move, which is referred to as commutation. Most systems with incremental encoders require an initial commutation phase finding step upon power-up. Depending on the specifics of the application, this can range from quick and easy to problematic. This white paper provides a solid grounding on the subject of commutation, and includes a robust algorithm that ensures accurate commutation under even challenging conditions. |
| Adjustable passive magnetic constant | Publication | This publication presents an adjustable passive magnetic system that provides constant force along its stroke. Gravity is an undesirable force in most linear stages that operate in non-horizontal and specifically in vertical directions. Active systems consume extra energy to compensate for this force. In addition, they impose complexity, heat and cost to the systems. Pneumatic counterbalance systems have been proposed for the past two decades; however they need compressed air and are not reliable. This design provides a passive, reliable and adjustable counterbalance that works based on shear magnetic force. |
| Slow Down to Speed Up | Publication | It may not seem logical, but you can boost the productivity of a servo system by slowing down its operation. This publication explains this paradox |
| Quantifying Velocity Stability: Optimizing Sample Rate for Effective Measurement | White Paper | This whitepaper contrasts two distinct approaches to specifying and quantifying velocity stability. Limitations and common missteps are enumerated and a recommendation is made on a preferred approach. Real-world examples reinforce the presented theory and relationship to practical applications is provided. |
| A Constant Velocity Scanning Stage with Resolution of 31 Picometers | Publication | This publication describes a constant velocity scanning stage with a resolution of 31 picometers. |
| A High Performance X-Y Stage with a Novel Topology (Delta Stage) | Publication | This publication describes a 350 mm travel X-Y positioning system with a novel topology, high dynamic performance, and an advanced real- time controller. While the initial implementation positions a 300 mm semiconductor wafer under a stationary laser system, the design can be scaled upwards or downwards in travel to suit a wide range of potential applications. The Delta Stage described below provides substantially higher performance than traditional X-Y stages, and its advantages become even more compelling as the travel is increased. |
| Accuracy in Positioning Systems | White Paper | The state of the art in precision positioning systems has undergone continuing improvement, with the result that modern positioning systems can now achieve unprecedented levels of accuracy. These gains have come about due to specific technical advances (most notably, the availability of coherent light sources) as well as inexorable pressure from high-tech applications which depend on dimensional accuracy for their existence. Notwithstanding the gains that have been made, there are gaps between levels of accuracy which are perceived as achievable, and those levels which can actually (and/or affordably) be met. This paper will attempt to address the realistic accuracy levels which various positioning technologies can meet, as well as the nature of the limitations which restrict accuracy. |
| Force Generation and Measurement | White Paper | Our broad product offerings in miniature, high performance, air bearing linear motor stages have, by virtue of their design, some interesting secondary capabilities of particular value in photonic automation applications. In addition to their traditional roles as point-to-point motion stages and constant velocity systems, the completely non-contact nature of their three primary design elements
– motor, bearing, and encoder – permit these stages to function as both high performance generators and measurers of force. Central to this capability is the complete absence of friction in the bearing ways, the perfectly linear relationship between motor coil current and the resulting force, and the availability of high resolution optical encoder position feedback. Together, these make the creation and measurement of milliNewton-level forces a reality in your application, as an added benefit above and beyond the substantial value that they already provide in high precision movement, and short move and settle times. |
| Positioning Systems Overview | White Paper | Divide and conquer! To help in understanding positioning systems, it is useful to employ a classically reductionistic approach, breaking such systems down into their constituent assemblies. In this paper, we will divide the overall function of positioning systems into categories and discussing their attributes. |
| The Air Bearing Throughput Edge | White Paper | Air bearings have an additional edge over conventional bearing systems that is not generally appreciated. When compared with rolling steel bearing systems, air bearings offer a throughput advantage of up to 10 times, which is a substantial productivity improvement |
| Trigger On Position | White Paper | In precision motion applications, it is frequently necessary to trigger a device in a way that is synchronized with the position of a moving stage. In this white paper, we will explore this functionality, as well as its implementation in Dover Motion products. |
| Position Accuracy Compensation | White Paper | Discover the concept of Abbe error and its effects on the accuracy of direct-drive stages using high accuracy linear encoders. In this whitepaper, we will cover the Position Accuracy Compensation (PAC) as a powerful method to address these inaccuracies by utilizing laser interferometer measurements, resulting in substantial improvements in precision, up to 10X to 20X. |
