Artificial Knee Joint Controller Characterisation and Condition Diagnosis
Abstract
The development of the hydraulic artificial knee joint controller has significantly improved the quality of life for many people who have suffered above the knee amputations. While these devices are extremely reliable, lasting up to 3 years before servicing is required, gradual deterioration does take place. Minor deterioration of the knee controller performance can be compensated for using adjustments on the device, however, changing performance has largely been left to the user to detect qualitatively during use. Given the wide range operating conditions that the controller may regularly be used within and the continuous usage of the device, it is not surprising that gradual deterioration of the performance is difficult to detect. Sudden failures of hydraulic knee controller units are known to occur and can result in oil leakage and loss of support, bringing about embarrassing and dangerous situations for the user. At present there is no simple quantitative test which allows for early detection of performance deterioration. The work reported on in this paper was carried out to establish clear performance characteristics for the controller. Various controller settings were used for simulated normal operating condition tests and full flexion relaxation tests. All the operating and test parameters, including performance test results are presented for a new and known to be significantly deteriorated controller. It was found that the time for the unit to return unassisted to its equilibrium position from full displacement (full flexion), varied greatly between the new and old units, suggesting a simple quantitative method for the early detection of controller deterioration.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1996
- Accession Number
- ADP010212
Entities
People
- C. K. Mechefske
- J. T. Davenport