Robust position control is the staple of navigation in mobile robotics. Tricycle robots are nonholonomic ground vehicles with three wheels. While actuated separately, traction and steering are processes coupled through nonlinearities generated by the kinematic model. During operation, environmental changes can cause the model parameters to vary through three unstable behaviors. This study presents a robust control system with modified P-D controllers tuned with real-coded genetic algorithms within a response matching scheme. Results show robustness for 2D trajectories under significant parameter variation, with respect to nonholonomic robot body limitations.