In this paper, dynamic collision-free trajectory generation in a nonstation
ary environment is studied using biologically inspired neural network appro
aches, The proposed neural network is topologically organized, where the dy
namics of each neuron is characterized by a shunting equation or an additiv
e equation. The state space of the neural network can be either the Cartesi
an workspace or the joint space of multi-joint robot manipulators, There ar
e only local lateral connections among neurons. The real-time optimal traje
ctory is generated through the dynamic activity landscape of the neural net
work without explicitly searching over the free space nor the collision pat
hs, without explicitly optimizing any global cost functions, without any pr
ior knowledge of the dynamic environment, and without any learning procedur
es. Therefore the model algorithm is computationally efficient, The stabili
ty of the neural network system is guaranteed by the existence of a Lyapuno
v function candidate. In addition, this model is not very sensitive to the
model parameters, Several model variations are presented and the difference
s are discussed. As examples, the proposed models are applied to generate c
ollision-free trajectories for a mobile robot to solve a maze-type of probl
em, to avoid concave U-shaped obstacles, to track a moving target and at th
e same to avoid varying obstacles, and to generate a trajectory for a two-l
ink planar robot with two targets. The effectiveness and efficiency of the
proposed approaches are demonstrated through simulation and comparison stud
ies.