Analysis Techniques For Man-Machine Systems Design

VNATO UNCLASSIFIED;-AC/243(Panel 8')TR/7Volume 26.2 CRITICAL DESIGN REQUIREMENTSWhat the technique doesThe technique identifies design requirements which are critical to the operation of the system. to provide a basis forinterface and workspace design. The technique identifies the following information (Morgan, Cook, Chapanis &Lund, 1963):the functions performed by the systemthe operator tasksthe outputs of each taskthe critical operating variables for each taskthe critical design requirements that affect thcsc variablesThe critical operating variables, or the design requirements identified by the analysis, may be weighted to facilitateevaluation of competing design concepts (Bishop & Guinncss. 1966; Woodson, 1981).Inputs to the techniqueOutputs of the techniqueA list of critical design requirements for the human-machine interface, workspace. and operatingenvironment, ordered by operator functions and tasks.The analyst requires a task analysis for the systemoperator(s) which identifies the critical operator tasks. Anannotated Operational Sequence Diagram (4.3),Information/Action analysis (4.4), or Critical TaskAnalysis (4.5) are suitable inputs.When to useCritical design requirements can only be identified once a detailed task analysis is available, either from the sequenceof analyses described in previous sections, or from the elaboration of an existing analysis. This limits the techniqueto application in the latter stages of concept development or preliminary design.RelatedtechniquesThe analysis of critical design requirements is related closely to several task analysis techniques. It is also related toDesign approach trade-off analyses (Woodson, 1981).Resources requiredThe analyst requires information on the operator tasks, critical tasks and operator outputs, and potential choices forcomponents of the human-machine interface. The analyst also requires knowledge of human engineering principlesand data in order to be able to identify the critical requirements.ftjNATO UNCLASSIFIED-122-