A time domain method for estimating forces applied to an unrestrained structure

A new method for the estimation of forces applied to a structure is present ed. This time domain technique uses the structures response time history an d returns tin estimate of the applied force time history. This technique al lows near-real-time estimation of input forces for non-collocated sensor/ac tuator pairs for multi-input/multi-output systems. Two examples are present ed. The first is a single-input/single-output one-dimensional spring/ mass chain in which a remote accelerometer is used to estimate an input force at one end. In the second example, the technique is used to estimate six dock ing fim-es and moments between the Space Shuttle and the Russian MIR Space Station during el numerical simulation of a docking event.