Engineering topics

Kuo, C.-P.

Publications and source records attributed to Kuo, C.-P..

5 records

NASA NTRS1990

Adaptive structures in space

Future NASA missions will need large (20 to 100m) structural systems with precision position (few microns to submicron) requirements. Data are presented which indicate the technology deficiencies of previous programs and analyses in current state-of-the-art structural design approaches, analytical prediction capabilities, control of structure capabilities, and ground test technologies to meet the performance requirements of future large precision structural systems. Test results on laboratory truss structures that demonstrate static displacement control, active damping, and on-orbit system identification are described. It is shown that for large precision structures, adaptive structures provide not only a means to achieve the precision and characteristics required in space, but can also significantly alleviate the ground test requirements for flight-validating the hardware.

Wada, B. K.↗

NASA NTRS1989

Adaptive structures for precision segmented optical systems

An adaptive structures approach for a large segmented optical system with a 20-meter primary reflector made of lightweight hexagonal composite panels is considered. This approach makes it possible to vary the static and dynamic characteristics of a structural system through actuators and sensors integrated within the structure. Topics discussed include quasi-static shape adjustment and active damping augmentation of the primary backup truss structure, deformable panels for long spatial wavelength quasi-static figure correction, and an on-orbit identification system for large segmented optical systems.

Chen, G.-S.↗

NASA NTRS1986

Multiple boundary condition test (MBCT) approach to update mathematical models of large flexible structures

A major challenge to the structural dynamicist is to validate mathematical models of large space structures which cannot be ground tested because of its size and/or flexibility. The paper presents a Multiple Boundary Condition Test (MBCT) approach which allows a systematic validation of the mathematical model by performing a number of ground tests on a large structure with variable boundary conditions. A numerical simulation is presented which illustrates the validity of the MBCT including some of the potential limitations.

Wada, B. K.↗

NASA NTRS1985

Direct computation of optimal control of forced linear system

It is known that the optimal control of a forced linear system may be reduced to that of tracking the system without forces. The solution of the tracking problem is available via the costate variables method. This procedure is computationally expensive for large order systems. It requires solution of matrix Riccati equation and two final value problems. An alternate approach is outlined for the direct computation of the optimal control. Instead of Riccati equation, a matrix Volterra integral must be solved. For this purpose two computational schemes are described, and an illustrative example is given. The results compare favorably with the classical solution. This alternative approach may be especially useful for the control of large space structure where large order models are required.

Utku, S.↗

NASA NTRS1983

Direct structural parameter identification by modal test results

A direct identification procedure is proposed to obtain the mass and stiffness matrices based on the test measured eigenvalues and eigenvectors. The method is based on the theory of matrix perturbation in which the correct mass and stiffness matrices are expanded in terms of analytical values plus a modification matrix. The simplicity of the procedure enables real time operation during the structural testing.

Chen, J.-C.↗