A new dynamometer walker system for the measurement of handle reaction vector (HRV)

Abstract

The handle reaction vector (HRV) is commonly prescribed as an effective index for evaluating paraplegic walking efficiency assisted by functional electrical stimulation (FES). But up to now relevant studies on HRV have been limited because its direct measurement on walker handle is rather inconvenient. This paper reports the design of a new dynamometer walker to indirectly measure the HRV, which was based on 12 strain-gauge bridges instrumented on a walker frame. To adapt the data acquisition-analysis system of the dynamometer walker to quantitative and reliable measurement, a redundant-optimized technique was developed in instrumentation and calibration. The effect of its application was validated by the comparison of force measurement errors during the centrostigma shift of HRV. The measurement nonlinearity and crosstalk of the designed system were also investigated and were found to be better than 2.2% and 3.2%, respectively. One preliminary clinical trail was done to demonstrate the potential usefulness of this system in walking assessment. The results of the experiment and clinical trail showed that a practical dynamometer walker system was accomplished in this paper to measure the HRV without any impact on normal paraplegic walking training and might be employed further to guide the effective use of FES. © 2005 IOP Publishing Ltd.