Impedance Control with Energy Regeneration in Advanced Exercise Machines
American Control Conference (ACC), 2015
This paper shows how a controls-oriented approach can be used to improve the functionality, energy efficiency and bulk/weight requirements of advanced exercise machinery. Exercise devices for the space environment are the motivation for this research, but other applications are certainly possible. The paper introduces a design concept involving a user force/velocity port, a mechanical transmission, a DC motor/generator a regenerative servo amplifier and an ultracapacitor as the sole electric energy storage device. The intrinsic capability of the design concept to realize any desired force/velocity relationship at the user port (controllability of port impedance) is verified first using an inverse model approach. As an example, design parameters are selected to match the force/velocity characteristic of a typical gym rower. A feedback implementation is then developed based on the author's semiactive virtual control strategy. The validity of the approach is demonstrated with a laboratory prototype of a scaled rowing machine. The results show that the system can be operated entirely on human power, while simultaneously attaining the impedance control objective.
Richter, H., and Selvaraj, D., 2015, "Impedance control with energy regeneration in advanced exercise machines," American Control Conference (ACC), 2015, pp. 5890-5895.