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In order to autonomously design the optimal descending trajectory for spacecraft soft landing on an asteroid, an onboard guidance based on the bidirectional extreme learning machine (B-ELM) is proposed. The optimization problem is formulated and transformed into a two-point boundary value problem (TPBVP). And then, based on the sample trajectories obtained off-line, a single-hidden layer feed-forward...
This paper presents an improved adaptive sliding mode control method for soft Landing on the Asteroid, and addresses the problems of the unknown parameter of the upper bound of interference uncertainty and over-adaptation of switching gain. First, a three-dimensional dynamic model of asteroid probe, in which considering the interference uncertainty of the third-body gravitational perturbation and...
Flexible double inverted pendulum system is a higher order, nonlinear and strong coupling unstable system. In order to achieve the steady control of the pendulum, an improved method of sliding mode control with boundary layer is put forward. Linear feedback is replaced with nonlinear feedback within the boundary layer. A mathematical model of flexible double inverted pendulum which is based on mechanism...
An asteroid landing trajectory optimization method is studied based on Gauss Pseudo-spectral. Firstly, we analyze the characteristics of probe landing on asteroid, and put forward the initial conditions, process constraints, terminal constraints and the optimization performance index. The probe's landing trajectory optimization should meet the index. Secondly, Gauss Pseudo-spectral Method is used...
At present, micrometer is used for measure the shape edge of automobile airbag. There are some shortcomings in this method. The number of test points is limited. Test data is not comprehensive. Detection speed is slow and a fixture can only test a kind of airbag. The method of airbag shape edge detection based on image processing is researched in this paper. The image of airbag is collected by CCD,...
In this paper, an exact dynamic model of manipulator handling a flexible payload is derived by Hamiton's principle. On the basis of the distributed parameter model, a position controller is designed by using Lyapunov function related to the total energy of the system. The controller can achieve the given desired link angles and suppress the vibrations of flexible payload. Using the LaSalle's invariance...
In order to reduce the influence of azimuth effect in multi-position strap-down north seeking system, its cause of formation is studied based on the precession principle of the dynamically tuned gyro. A detecting system, composed by true north prism, two Leica theodolites and benchmark prism fixed in the strap-down north seeking system, was designed to calibrate the azimuth effect. By two steps, many...
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