The seeding of solution alternatives

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practical work scopes of different specialists; the mechanists follow the specification derived from requirements as “gantry travel speed is 45 m/min and acceleration time from zero to full speed is 5 seconds”. Once the required acceleration force has been defined and converted to motor torque, the electricians choose the correct sizing for the power supply and inverter. Finally, the automation specialist programs the PLC code for particular function and related interactions.

103 Figure 8.10 Two problem solving dimensions; linear optimization within a discipline

and integration over disciplines.

The dimension along a discipline provides the traditional development route, resulting in a linear process and sub-optimization. As stated earlier, with static concepts the development has gone through optimization within disciplines and obviously reached its limits. The other dimension across disciplines provides a platform for identifying seeds for alternative solutions. The integration across disciplines follows the function execution chain and enables developers to escape from a linear axiomatic design strategy.

The integration dimension also illustrates the root cause path for identified deviations from the ideal (designed) transformation process. Accordingly, it can be concluded that the integration dimension across different disciplines with multi-disciplinary products presents a path for a functional response including interactions and impacts. Through this event chain the experienced behaviour is performed in the reality domain.

Experienced behaviour is the qualitative aspect of how function is delivered and received during the execution process. In other words, it is the response to the system, its sub- systems, user and environment when the mode of action is being performed. However, the measurement of this aspect is challenging – often the deviation from the designed ideal process can be recognized, but the measuring is either relative or indirect. For example, an increase in a vibration level can be measured, but the perception is relative to the situation, location or person and impacts on performance indirectly.

Experienced behaviour, the response, has a dynamic nature. A function in a transformation process expresses the change in an operand’s state and obviously is a time related activity.

However, this is not well considered by functional and process structures or other conceptual approaches. With incremental development, the dynamic relationship during a function execution can be identified when:

• The timescale or time aspect is included with the function mode and changes in state.

• The time related impacts (deviations from the ideal transformation process) within and between the sub-systems are identified.

The time dependent interactions expand the complexity of the functional modelling.

However, it is obvious to add this dimension to the general interface logic between subsystems. The time dependency represents and visualizes different views on the design and reality domains [Figure 8.11].

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Figure 8.11 Time dependency of different systems through functional execution chain.

Differences in Design and Reality Domains when multiple events occur before the physical function activation and response.

The time dependency chart, even on a very rough level widens the understanding about the system behaviour within the design team. The sub-system interactions are not sequential, because depending on the type of transformation process, the activity and response period of each sub-system varies. More specifically, this is concretized by the difference between the internal functions and external effects. On the basis of the case studies, typically ignored differences between the design and reality domains during the conceptual design phase are those where:

• The function activation input reference is assumed to be linear and continuous and can be used as such for control purposes. Cases which involve human controlled equipment or analogical sensors, the reference signal includes a lot of noise and requires programmed filtering.

• The activation reference signal transmission to give a reference for a power train system consists of several sequences; status check, function initiation and start- up, function acceleration, constant function mode, function deceleration, function stop and deactivation. During each sequence various interlocks and interruptions from other sub-systems are active and may influence the sequence.

• Each power train system has its own capability to respond to the reference signal. Depending on the type of energy conversion necessary for the function mechanism, the activation delay and form of force and speed varies. This causes a differentiation between the reference and actual status of the mechanism. At this stage of a function activation event chain, a physical movement in the function exists.

• The mechanical system carries the physical functions and is designed for external and internal requirements. However, when the design parameters and criteria are derived from the functional requirements and specification, all earlier mentioned events in other sub-systems are ignored. Accordingly the functional

105 response and experienced behaviour in the reality domain differ from the ideal in the design domain.

Each technical transformation process is unique and two-dimensional search for seeds for solution alternatives and possible innovative solutions are strongly dependent on the system configuration. However, even different maturity levels within products in companies can be identified. Therefore, a similar type of approach can be utilized with various multi-disciplinary products.