We have been working on several control and actuation improvements applicable to the design of biomimetic robots and assistive (e.g. prosthetic or orthotic) devices. This paper focuses on the implementation of a joint-level impedance controller for series-elastic actuators that eliminates the use of joint angle sensor information, instead using information from co-located commutation sensors on the back of a brushless motor and a compression sensor on the series elasticity. This approach is both more robust than previous systems and less subject to instabilities due to stiction and backlash.