Research Article

Geometric Pseudospectral Method on SE(3) for Rigid-Body Dynamics with Application to Aircraft

Algorithm 1

4th-order geometric pseudospectral algorithm on SE(3).
Step 1. Initialization:
 Initialize time interval , step length , configuration , velocity , and let be 0;
Step 2. Main loop:
Step 2.1. Compute the Gauss points in , corresponding differentiation matrix
and quadrature weights ;
Step 2.2. Compute velocities and at the Gauss points:
    Step 2.2.1. Set the number of iterations, threshold of iterations deviation and let current step be 1;
    Step 2.2.2. Let initial value of both and be , that of both and be ;
    Step 2.2.3. Child loop:
  Step 2.2.3.1. According to the following equations, obtain ,
  
  Step 2.2.3.2. Update velocities at the Gauss point,
  
  Step 2.2.3.3. Compute 4th-order reduced truncated Magnus series expansion at the Gauss points,
  Step 2.2.3.4. Using the Cayley map, update configurations at the Gauss points,
  Step 2.2.3.5. Compute the configuration deviation and velocity deviation respectively between the adjacent steps,
  and let the larger one between them be iterative deviation at the current step,
,
  Step 2.2.3.6. Substitute and at and into and respectively, at the same time, let plus 1;
  Step 2.2.3.7. Compute the difference between iterative deviation and specified tolerance,
  so that determine whether or not to terminate the iterative process.
    Step 2.2.4. End child loop;
    Step 2.2.5. Use the final iterative results and in child loop to compute the velocity at the endpoint ,
    Step 2.2.6. Compute configuration at :
  Step 2.2.6.1. Compute 4th-order reduced truncated Magnus series expansion at ,
  Step 2.2.6.2. Use the Cayley map to update configuration ,
  
    Step 2.2.7. Compare with , so that determine whether or not to terminate the main loop;
Step 3. End loop.