This paper proposes a new cooperative projection neural network (CPNN), which combines automatically three individual neural network models with a common projection term. As a special case, the proposed CPNN can include three recent recurrent neural networks for solving monotone variational inequality problems with limit or linear constraints, respectively. Under the monotonicity condition of the corresponding Lagrangian mapping, the proposed CPNN is theoretically guaranteed to solve monotone variational inequality problems and a class of nonmonotone variational inequality problems with linear and nonlinear constraints. Unlike the extended projection neural network, the proposed CPNN has no limitation on the initial point for global convergence. Compared with other related cooperative neural networks and numerical optimization algorithms, the proposed CPNN has a low computational complexity and requires weak convergence conditions. An application in real-time grasping force optimization and examples demonstrate good performance of the proposed CPNN.variational inequality problems, general constraints, cooperative recurrent neural network, complexity, global convergence conditions Constrained optimization problems arise in a wide variety of scientific and engineering applications including signal and image processing, system identification, pattern recognition, optimal control, and so on [1−3] . In many practical applications, related optimization problems are of a timevarying parameter characteristic and thus have to be solved in real time. One example of such applications is the real-time signal processing in wireless communications [4] . Another example is the real-time optimal robot optimal control [5] . For such applications, conventional numerical methods such as the interior-point method [6] , the sequential quadratic programming method [7] , the projection type method [8] , may not be adequate due to the problem complexity and stringent requirement on the computational time. As a software and hardware-implementable approach [9] , recurrent neural networks, including single and cooperative recurrent neural networks, for solving linear and nonlinear constrained optimization problems have been developed in recent decade. By contrast with traditional numerical optimization algorithms, the neural network approach has potential advantages in real-time applications. Moreover, the dynamical analysis techniques with effective