Use of a computer algebra software in the functional validation of continuous simulations

Due to the numeric integration algorithms with multiple iterations and the coupling effects between variables, verification and validation of simulations of continuous systems is a complex task. A method involving a Computer Algebra Software (CAS) is presented that allows preparing general parameterized test cases that cannot be achieved by hand. It applies to flat systems that are causal systems, whose outputs and states can be expressed through derivation and algebraic operations by a set of given variables (mechanical systems for example). These variables are set as temporal expressions with no or few symbolic expansion through derivation such as trigonometric or polynomial functions. Formal expressions of the inputs and outputs are calculated by means of a CAS and coded into the environment test. In addition to the verification and validation, this test is useful to assess the precision level of the integration method with respect to the variability of the inputs.