Extraordinary design Towards an Integration of CAD tools
Extraordinary design Towards an Integration of CAD tools
Imagination, Inspiration, Instrumentation, Integration: The vibrant world of 4Is
Over the past years a lot of CAD tools have been developed for use in the design of hardware, devices and instruments. When it comes to the design of chemical instrumentation it is the advancement of subtractive manufacturing (CNC) and additive Manufacturing (3D printing) that makes a difference.
These technologies allow for fast prototyping and field testing in a continuous loop with the design phase that leads in efficient and high-performance prototypes. At T4i engineering we integrate these tools with CAD tools to reinforce and accelerate the production of prototypes.
In designing field detectors/analyzers we are using the following terms:
On-site analysis: In-situ or near the field measurements
Near-real time (online) measurements: data displayed by an instrument that depict an event or situation as it existed at the current time minus the processing time.
Concentration gradient: describes the vector of concentration change as a function of time.
Temporal resolution: describes the ability of measuring quantities identified at a specific sampling site of the field, as a function of time.
Spatial resolution: describes the ability of measuring quantities identified in a snapshot, as a function of the spatial coordinates of the different sites in the field.
Duty cycle: itis defined by the device (transducer/instrument) and it is the ratio of time needed for a device to complete sampling versus delivering a specific output. Usually, the term applies for one analysis.
Throughput: it is defined by the instrument and it is the number of samples per time unit acquired by the instrument.
Wearable instrument: an instrument that an individual can wear.
Hand-held instrument: an instrument designed to be carried by one hand.
On-board UAV (chemical) instrument: An instrument specifically designed to be carried by UAVs and be able to address all the challenges of the flight.
Portable (chemical) instrument: An instrument that is designed to be moved from one site to another. A portable instrument needs to be below 5 kg, or generally to have the capability to be carried by an individual.
Mobile (chemical) instrument: An instrument that can be transported to different sites in the field. Instruments can be categorized in transportable, portable, onboard, hand-held, wearable, fixed/standoff.
Speed platforms: Special designed platforms that can be used for mapping types of compounds and/or concentrations in the field: roving van, balloon, helicopter, unmanned aerial or ground or sea vehicle (UAV, UGV, USV).
Field data transfer: Data transfer is to communicate data or more broadly information from one site to the other in the field or from the site to a command-and-control center.
Power autonomy: Power autonomy is the ability of an instrument to operate independently in the field for a specific time duration.
Instrument ergonomics: The ergonomics of the accessories or of the entire instrument (pumps, batteries, screens, controls, etc.).
Techniques: Techniques are the different physical or chemical principles on which an instrument is based on (e.g., atmospheric instruments, vacuum instruments, photoionization sensors, electrochemical sensors, gas chromatography). Techniques can also be divided in those measuring concentration gradients in space (screening), in time (on-line monitoring), or in a combination of two.
Integration: Integration is a process of combining (synergism) or accumulating (sum) two or more individual techniques, technologies or principles of operation.
Payload: the maximum weight that can be safely added to a vehicle (e.g., UAV). The chemical detector/analyzer on-board UAV needs to have a weight that is equal to the max UAV payload.
Top-level design strategies: The path towards extraordinary design
A number of strategies are followed for efficient design. For example, user requirements are turned into specifications and then key-parameters become weighted factors. In the following diagram this selection refers to a specific application in which a chemical detector on-board a UAV was needed.
In field analysis, one sensor (one source of information) is not usually enough to achieve efficient inferences for a system due to:
Temporal and spatial variations
Malfunctions and noise of the sensors
Inherent limitations of technical features characterizing each sensor.
Addressing these challenges entails multisensor fusion. This refers to the synergistic combination of sensor data from multiple sensors to provide more reliable and accurate information. The potential advantages of multisensor fusion and integration are redundancy, complementarity, timeliness and cost of information.
The integration or fusion of redundant information can reduce overall uncertainty and thus serve to increase accuracy with which the features are perceived by the chemical detector/analyzer. Multiple sensors providing redundant information can also serve to increase reliability in the case of sensor error and failure. Multisensor chemical/detector for use on-board UAVs is an example of multisensor fusion and integration.
Complementary information from multiple sensors allows features in the environment to be perceived that are impossible to perceive using the information from each individual sensor operating separately. More timely information may be provided by multiple sensors due to either the actual speed of operation of each sensor, or the processing parallelism that may be possible to achieve as part of the integration process.
Standardization is also part of the design process. Adopting specific standards for field chemical calibrators/detectors/analyzers is critical for the reliability of measurements, instrument protection in the field, and environmental concerns such as recycling.