Testbed design from TTE Systems
At TTE Systems we specialise in the development of deeply-embedded applications, including automotive systems, aerospace system, medical devices, factory automation, and many other areas. In such designs, the system under development must often interact with other equipment (for example, the vehicle wheel in an automotive braking design) and / or with a user (for example, taking measurements from a patient in an ECG monitoring system) in a manner which can make it very difficult and / or dangerous to test and debug the system. When developing such systems, a “hardware-in-the-loop” (HIL) testbed is often a key part of the development environment.
We can provide a wide range of specialised “Hardware-in-the-Loop” testbeds. Such testbeds are typically used during product development and testing and / or as a means of performing product demonstrations to customers.
We provide further information about custom testbeds on this page. In addition, some of the off-the-shelf platforms discussed in our education pages may also be of interest. These cover process control, robotics and elevator control (for example).
For further information about any of our testbeds, please contact us.
What is HIL simulation?
The use of HIL simulation with an embedded control system is illustrated in the figure below (figure by Dr. Michael Short, Embedded Systems Laboratory, University of Leicester). The embedded system outputs are fed directly to the simulation, where they are sampled and used as input variables. A dynamic simulation model, acting on these input variables, is evaluated (normally in real-time, but this is not always the case). The outputs from the simulation are synthesised from the dynamic model(s): these are then fed back into the system under test as outputs, thereby closing the control loop.
HIL simulations of this nature have been used successfully in a variety of applications, including verification of new machine tool designs, aircraft autopilot system design, numerous military applications and testing of automotive ECUs.
Script-based testbeds (ACCS)
One example of a custome testbed testbed from TTE Systems is the adaptive cruise-control system (ACCS), illustrated below. This testbed (which has 10 nodes, linked by the dual CAN bus) reproduces the system architecture involved in an ACCS design for a passenger car. Using this testbed, developers can investigate the use (for example) of different processors, different network architectures and different control algorithms.
As illustrated, the ACCS design runs test scripts (without user interaction) to support long periods of system testing: during the test period, the HIL testbed allows the injection of faults (for example, reproducing the impact of electromagnetic interference on one or more processor nodes) and records the system response in detail.
Testbeds with a “human in the loop” (Driving simulator)
The ACCS testbed is able to run over long periods, without user intervention.
Other testbeds require interactive designs, with a more complex user interface. One example — a driving simulator — is illustrated in the photograph below. In this case, the interface is produced by XPI Simulation: TTE Systems provide the embedded architecture and test framework.
The driving simulator and some other testbeds appear in a recent interview by British Satellite News.