Jeffrey H. Lang

TL;DR: A system to convert ambient mechanical vibration into electrical energy for use in powering autonomous low power electronic systems and an ultra low-power delay locked loop (DLL)-based system capable of autonomously achieving a steady-state lock to the vibration frequency is described.

TL;DR: A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems through the use of a variable capacitor, which has been designed with MEMS technology.

TL;DR: In this paper, a monolithic mechanically bistable mechanism that does not rely on residual stress for its bistability is presented, based on two curved centrally-clamped parallel beams, hereafter referred to as double curved beams.

TL;DR: In this paper, an experimental study of the acoustic noise emitted from an inverter-driven doubly salient variable-reluctance motor (VRM) is presented, and a list of possible noise sources is given.

Abstract: This paper presents the design principles for highly efficient legged robots, the implementation of the principles in the design of the MIT Cheetah, and the analysis of the high-speed trotting experimental results. The design principles were derived by analyzing three major energy-loss mechanisms in locomotion: heat losses from the actuators, friction losses in transmission, and the interaction losses caused by the interface between the system and the environment. Four design principles that minimize these losses are discussed: employment of high torque-density motors, energy regenerative electronic system, low loss transmission, and a low leg inertia. These principles were implemented in the design of the MIT Cheetah; the major design features are large gap diameter motors, regenerative electric motor drivers, single-stage low gear transmission, dual coaxial motors with composite legs, and the differential actuated spine. The experimental results of fast trotting are presented; the 33-kg robot runs at 22 km/h (6 m/s). The total power consumption from the battery pack was 973 W and resulted in a total cost of transport of 0.5, which rivals running animals' at the same scale. 76% of the total energy consumption is attributed to heat loss from the motor, and the remaining 24% is used in mechanical work, which is dissipated as interaction loss as well as friction losses at the joint and transmission.