Defining Paths for Driver Models with Hermite Parametric Curves
Abstract
In determining ground vehicle dynamic performance it is generally accepted that comparisons between simulated and test results will be compared for precision and accuracy. The test environment will define a particular course that will be used to define the excitation to the vehicle. In the simulation environment the same course must be replicated to excite the dynamics of the model. Each course used may have different characteristics that excite the dynamics in different ways to obtain a complete spectrum of inputs to the system. The broader the spectrum the better the characterization of the system. In the simulation environment, driver models are developed to ensure that the vehicle model is traversing the desired course in the same manner as in the test environment. A path must be defined for each course that represents the desired vehicle trajectory and will be used as a reference signal in the driver model for feedback control to maintain the vehicle parameters (speed, steering, etc.). Ideally, each position on the path should be uniquely identifiable. To satisfy these conditions, each position on the path is defined by a point. A parametric curve is then defined through these points that will allow one parameter to define a unique position on the path. This report provides a method (MATLAB function) to define continuous smooth and nonsmooth paths using Hermite parametric curves. The defined path can be used as a reference signal in a driver model for feedback control of vehicle position. Four input formats are allowed that encompass two- and three-dimensional paths. The formulation can account for path crossover and provides a method to deal with the nonlinear relationship relating path distance and path parameter values.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2002
- Accession Number
- ADA421758
Entities
People
- Wesley Bylsma
Organizations
- Tank-automotive and Armaments Command