Papers by Keyword: Relative Motion

Abstract: This paper exploits the guidance algorithms to assembly multiple vehicle in close proximity. The objective is to move each vehicle in the assembly to its final location. The guidance laws are determined such that, each vehicle should attract to the others on long distances and avoid collision with them in short distances. These laws are based on Lyapunov’s second method that utilize the potential function theory to insure the stability of the assembly process. Numerical investigations were performed for different configurations of the assembly. The proposed algorithms may prove useful for future mission applications such as satellite formation flying, structures assembly in space and mobile robots control.

Abstract: This paper develops a relative position and velocity estimation approach for spacecrafts in proximity. A dynamical model is built at first to describe the relative motion between the chaser and target. In this approach a light detection and ranging (LIDAR) system is used to perform the range and angle measurements of the target relative to the chaser. The three-axis magnetometer (TAM) and gyro are installed on the chaser to measure the chasers attitude. An extended Kalman filter (EKF) is designed to estimate the relative state by combination of the measurements and dynamical model. Numerical simulations prove the validity of proposed filter.

Abstract: Relative motion of tendon limbs of a double tendon graft for the application of anterior cruciate ligament (ACL) reconstruction may affect the mechanical behaviour of a tendon graft structure. The biomechanical data derived from the standard tensile testing machines may not be able to show the relative motion of the graft limbs. This paper uses the non-destructive digital stereo imaging recording system, synchronized with the standard test machine, to precisely determine the biomechanical properties of 10 bovine flexor tendon grafts which hanged from the loop side to the rig and the other end was fixed in a bone block. The study showed there is a relative motion between graft limbs.

Abstract: The method to process measured data of ship model test with contact measurement to study the characteristics of relative motion between two side-by-side ships was investigated. The reference co-ordinate systems and the relative motions of two side-by-side replenishment ships were defined. Then the integration transform method which combines Fast Fourier Transform(FFT) with Empirical Mode Decomposition(EMD) self-adaptive filter was applied to transform measured acceleration signal into displacement. The EMD adaptive filter is designed, and the integration results from acceleration to displacement with and without EMD adaptive filter were compared, which shows that the EMD adaptive filter can effectively eliminate the noise embedded in the measured data. At last, the relative motions are acquired, which are consistent with the practical situation.