Hardware in the loop: Ensuring proper integration

The complexity of modern smart devices is increasing due to new functionalities and new areas where connected devices are being developed. In smart home devices, for example, Com-module device is responsible for interacting with a number of subsystems and sensors to provide online monitoring and communication with the user. Another example is the industrial IOT where the Com-module needs to receive data from machines and drones to control them.

The integration of all the subsystems like motors, sensors and other complexes mechanisms is not feasible in development laboratories and workbenches. Even when those sensors and subsystems are available from the beginning of development, trigger events or set sensor’s values to specific values might not be straightforward.

Apart from the complexity, checking all possible usage scenarios and ensuring that all conditions specified for the system is an important key to guarantee that the user will have the best experience — the most important requirement of any system.

Integrated HiL on the rails

To ensure all possible system behaviors, Concept Reply has been developing integration tests with Hardware in the Loop (HiL). The Hardware in the Loop (HiL) is an approach that segregates the device under test (DUT), connects it to real-time simulators supporting the same protocols used in the real HW.

While making sure that the timing response of all of the simulation corresponds to the real specification, it is possible to introduce not only a multiple combination of the values in the system but also failures not easily triggered in the real hardware like loss of communication and internal failures.

A key feature of the approach used by Concept Reply is the Integration of all simulations by HiL Manager. This component triggers the transmission of data over necessary interface, simulating test scenarios and checking the outputs of DuT, comparing whether the behavior is compliant with the requirements.

This architecture combined with the continuous integration strategy ensures the most reliable software release to the customer.

Stress Test approach

The development of systems with a restricted amount of memory demands an analysis of the worst-case execution and the worst-case memory consumption. It is important to identify behavior of the system under the load. The stable execution when the user is interacting with the device over BLE and cloud is triggering commands or updates, which is a feasible scenario where the peak of the memory usage can be reached. To prevent resets and failure to respond in devices, Concept Reply has also used the HiL architecture to force the worst usage scenarios in long term tests. Those tests provide triggering of the commands to the DuT in parallel and the periodic monitoring of free memory, identification of memory leaks, generating reports and logs for further analysis.

Concept Reply has been executing those long term tests for at least four weeks, monitoring the main points of the device stability that have impact in user experience:

● Memory Consumption

● Latency

● Stability of BLE connection

● Stability of WIFI connection.