Experiment Control

Name

Experiment Control

Context

The pattern applies to a system with the following characteristics:

  • An experiment plan exists that lists the predetermined actions to be performed while running the experiment.

  • Actuators may exist to allow for moving or controlling something before, during and/or after running the experiment.

  • Sensors may exist to allow for measuring something before, during and/or after running the experiment.

  • Instruments may exist that contain sensors and potentially actuators.

  • Robots may exist that contain actuators and potentially sensors and that execute predetermined actions from the experiment plan in an automated or autonomous fashion.

Problem

Certain predetermined actions need to be performed while running an experiment.

Forces

Only pre-experiment conditions are considered in performing the predetermined actions while running an experiment. Only safety-related conditions during the experiment may be considered. Other changing conditions during the experiment or post-experiment conditions are not considered.

Solution

An experiment controller executes an experiment using a predetermined experiment plan (Fig. 7). The plan’s execution is automated, performed in an open loop control and may involve human interaction. The controller may monitor the experiment for safety reasons. The plan contains a complete description of the predetermined actions to be performed for running the experiment, including any safety-related responses.

Pattern components and control/data flow

Fig. 7 Experiment Control strategic pattern components and control/data flow

This pattern offers an open loop control with safety-related feedback on the experiment only. Experiment plan execution is automated, i.e., its list of actions is performed without external or human intervention that can unnecessarily hold up execution. Only 1 experiment is being controlled.

Resulting Context

An experiment is executed automatically using a predetermined plan.

Related Patterns

The Experiment Steering strategic pattern extends this strategic pattern with a closed loop control and feedback on experiment progress. The Design of Experiments and Multi-Experiment Workflow strategic patterns rely on this strategic pattern for automatically executing a predetermined experiment plan.

This strategic pattern is implemented by the Local Experiment Control and Distributed Experiment Control architectural patterns.

Examples

A robot-controlled chemistry laboratory science use case implements the Experiment Control strategic pattern, as a robot automates experiment execution. There is only safety-related feedback, such as to stop the robot in case of an emergency. The individual pattern components are as follows:

  • The experiment plan is the sequence of predetermined steps and associated parameters necessary to run the experiment. The predetermined steps include the parameters for synthesizing the chemical compound, route navigation instructions for the robot to move the sample between the different synthesis and characterization stations, parameters for characterizing the synthesized chemical compound, and safety related feedback instructions.

  • The experiment controller is a central workstation that is able to command and control the robot, synthesis equipment, analytical instruments, and any data and computing resources for analyzing the measurement data.

  • The test performed in an experiment characterizes the synthesized chemical compound.

  • The experiment result is a combination of the sample characterization results.

Known Uses

This strategic pattern is used in every experiment, where the predetermined experiment plan is automatically executed. The only feedback is related to safety, such as to perform an emergency stop of the experiment when a chemistry laboratory is on fire. This pattern is the starting point for any other pattern, as any feedback implemented by the Experiment Steering or Design of Experiment patterns and any orchestration of multiple experiments by the Experiment Workflow pattern require the automatic execution of a predetermined experiment plan.