Date of Award


Degree Name

MS in Mechanical Engineering


Mechanical Engineering


Hemanth Porumamilla


An Advanced Controller for a Semi-Active Wheelchair Suspension was designed, built and tested. The suspension consisted of a Goodyear 1S3-011 air spring, IQ Valves high speed proportional solenoid valve, and a custom made accumulator. Several controller designs specific to semi-active suspensions were designed and tested. The controllers investigated were skyhook, acceleration driven damping, and a combined control law employing both a dual and single sensor version. The implementation of skyhook control suffered performance degradation from the idealization due to particular elements of hardware, however acceleration driven damping showed a marked and statistically significant improvement over skyhook control, in hardware, by 14%. The combined control laws exhibited as yet unexplained transient behavior that produced results with low confidence in their veracity. All controllers proposed performed better than a conventional oil damper and spring type suspension.