Redirected walking (RDW) and omnidirectional treadmill (ODT) are two effective solutions to the natural locomotion interface in virtual reality. ODT fully compresses the physical space and can be used as the integration carrier of all kinds of devices. However, the user experience varies in different directions of ODT, and the premise of interaction between users and integrated devices is a good match between virtual and real objects.
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December 2023
The natural locomotion interface is critical to the development of many VR applications. For household VR applications, there are two basic requirements: natural immersive experience and minimized space occupation. The existing locomotion strategies generally do not simultaneously satisfy these two requirements well.
View Article and Find Full Text PDFWe deal with the linear controllability of two underactuated multi-link robotic systems in this paper. First, for a general n-link inverted pendulum mounted on a cart in a vertical plane, we prove that it is linearly controllable around the equilibrium point with the cart in a desired position and each link of the pendulum in the upright position regardless of its physical parameters, if and only if the cart is actuated. Second, for an n-link underactuated planar robot with its first joint mounted on a fixed base in a horizontal plane, we prove that it is linearly controllable around the trajectory where each link of the robot stretches straight out and rotates with a constant angular velocity, if and only if its first joint is actuated, regardless of its physical parameters and regardless of the actuation or underactuation of its rest joints.
View Article and Find Full Text PDFThis paper considers an adaptive fault-tolerant control problem for a class of uncertain strict feedback nonlinear systems, in which the actuator has an unknown drift fault and the loss of effectiveness fault. Based on the event-triggered theory, the adaptive backstepping technique, and Lyapunov theory, a novel fault-tolerant control strategy is presented. It is shown that an appropriate comprise between the control performance and the sensor data real-time transmission consumption is made, and the fault-tolerant tracking control problem of the strict feedback nonlinear system with uncertain and unknown control direction is solved.
View Article and Find Full Text PDFThis paper considers a three-dimensional trajectory design problem for horizontal well. The problem is formulated as an optimal control problem of switched systems with continuous state inequality constraints. Since the complexity of such constraints and the switching instants is unknown, it is difficult to solve the problem by standard optimization techniques.
View Article and Find Full Text PDFRadial basis function (RBF) networks are one of the most widely used models for function approximation and classification. There are many strange behaviors in the learning process of RBF networks, such as slow learning speed and the existence of the plateaus. The natural gradient learning method can overcome these disadvantages effectively.
View Article and Find Full Text PDFThis paper considers an optimal sensor scheduling problem in continuous time. In order to make the model more close to the practical problems, suppose that the following conditions are satisfied: only one sensor may be active at any one time; an admissible sensor schedule is a piecewise constant function with a finite number of switches; and each sensor either doesn't operate or operates for a minimum non-negligible amount of time. However, the switching times are unknown, and the feasible region isn't connected.
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