Andrew A. Frank

On the Stability of Biped Locomotion

The stability of legged machines in locomotion is considered. The general machine has a rigid body to which legs are attached. Locomotion is performed on level smooth surfaces.

Conceptual design and simulation of a small hybrid-electric unmanned aerial vehicle

Parallel hybrid-electric propulsion systems would be beneficial for small unmanned aerial vehicles used for military, homeland security, and disaster-monitoring missions involving intelligence, surveillance, or reconnaissance (ISR). The benefits include increased time on station and range as compared to electric-powered unmanned aerial vehicles and reduced acoustic and thermal signatures not available with gasoline-powered unmanned aerial vehicles. A conceptual design of a small unmanned aerial vehicle with a parallel hybrid-electric propulsion system, the application of a rule-based controller to the hybrid-electric system, and simulation results are provided. The two-point conceptual design includes an internal combustion engine sized for cruise speed and an electric motor and lithium-ion battery pack sized for endurance speed. A rule-based controller based on ideal operating line concepts is applied to the control of the parallel hybrid-electric propulsion system. The energy use for the 13.6 kg (30 Ib) hybrid-electric unmanned aerial vehicle with the rule-based controller during one-hour and three-hour ISR missions is 54% and 22% less, respectively, than for a four-stroke gasoline-powered unmanned aerial vehicle.

2005 Special Issue: The control of a parallel hybrid-electric propulsion system for a small unmanned aerial vehicle using a CMAC neural network

A Simulink model, a propulsion energy optimization algorithm, and a CMAC controller were developed for a small parallel hybrid-electric unmanned aerial vehicle (UAV). The hybrid-electric UAV is intended for military, homeland security, and disaster-monitoring missions involving intelligence, surveillance, and reconnaissance (ISR). The Simulink model is a forward-facing simulation program used to test different control strategies. The flexible energy optimization algorithm for the propulsion system allows relative importance to be assigned between the use of gasoline, electricity, and recharging. A cerebellar model arithmetic computer (CMAC) neural network approximates the energy optimization results and is used to control the parallel hybrid-electric propulsion system. The hybrid-electric UAV with the CMAC controller uses 67.3% less energy than a two-stroke gasoline-powered UAV during a 1-h ISR mission and 37.8% less energy during a longer 3-h ISR mission.

Dynamic Simulation of Legged Machines Using a Compliant Joint Model

A computerized simulation of the dynamics of multilegged walking machines is presented. The simulation includes the effects of leg mass and compliance, joint compliance and friction, as well as the effects of leg contact with the ground. An approach is presented in which the Newton-Euler formu lation is used to develop the dynamic equations of each link. Kinematic constraints are not imposed explicitly. Instead, a compliant joint model is used to relate the dynamic reaction forces between neighboring links. The approach can handle multiloop devices with a combination of closed and open kinematic chains. Simulation results for the Ohio State Uni versity Hexapod walking machine are presented and shown to be in close agreement with previously published experi mental data.

The Continued Design and Development of the University of California, Davis FutureCar

The UC Davis FutureCar Team has redesigned a 1996 Ford Taurus as a parallel hybrid electric vehicle with the goals of tripling the fuel economy, achieving California ultra low emissions levels (ULEV), and qualifying for partial zero emissions vehicle (ZEV) credits in California. These goals were approached using a highly efficient powertrain, reducing component weight, and improving stock aerodynamics. A charge depletion driving strategy was chosen to maximize energy economy and provide substantial all-electric operating capabilities. The UC Davis FutureCar couples a Honda 660 cc gasoline engine and a UNIQ Mobility 48 kW-peak brushless permanent magnet motor within a compact, lightweight, and reliable powertrain. The motor is powered by a 15.4 kWh Ovonic Nickel Metal Hydride battery pack. The body of the vehicle has been reshaped using carbon fiber composite panels to improve airflow characteristics and reduce weight. At the 1997 FutureCar Challenge, the vehicle achieved an equivalent fuel consumption of 5.64 L/100 km (41.7 mpg) on the federal urban driving schedule and 3.74 L/100 km (62.8 mpg) on the federal highway driving schedule for a combined fuel consumption of 4.79 L/100 km (49.1 mpg). This represents a doubling of the stock vehicle’s fuel economy. Driving range exceeded 400 km on the combined driving schedules. The vehicle accelerates from 0 to 100 kph in 14.4 seconds and has an all-electric range of 105 km.

Application of a CMAC neural network to the control of a parallel hybrid-electric propulsion system for a small unmanned aerial vehicle

Optimizing and controlling the energy use of a hybrid-electric propulsion system is difficult due to the interaction of nonlinear mechanical, thermodynamic, and electromechanical devices. An optimization routine for the energy use of a parallel hybrid-electric propulsion system for a small unmanned aerial vehicle (UAV), the application of a cerebellar model arithmetic computer (CMAC) neural network to approximate the optimization results and control the hybrid-electric system, and simulation results are presented. The small hybrid-electric UAV is intended for military and homeland security missions involving intelligence, surveillance, or reconnaissance (ISR). The flexible optimization routine allows relative importance to be assigned between the use of gasoline, electricity, and recharging. The CMAC controller saves on the required memory compared to a look-up table by two orders of magnitude. The hybrid-electric UAV with the CMAC controller uses 37.8% less energy than a two-stroke gasoline-powered UAV during a three-hour ISR mission.

On the stability of an algorithmic biped locomotion machine

Abstract There has been recent activity in the constructed of biped locomotion machines. One class of such machines is designed to move “slowly”. If the motion is slow enough the dynamics of the machine can be ignored. The various joints of the biped are then related by an algebraic expression. The stability of such a machine can be considered in a very special manner. The paper provides an approach to the analysis of the stability problem when a biped operates in this mode.

A Moving Base Robot

This paper introduces the concept of a moving base robot and presents the preliminary work on its kinematics and stability. The objective of a moving base is to give robots a semi-infinite work space. The stability criteria is shown to lead to infinite solution boundaries which means optimization can be applied.

EVALUATION OF THE FLYWHEEL DRIVE CONCEPT FOR PASSENGER VEHICLES

A flywheel to manage energy between a prime mover and a load has been used in many engineering applications. Automotive applications, however, pose a number of difficult problems which can be overcome only with proper design. Substantial mileage and performance improvements while meeting emission constraints can then be accomplished with the concept. An experimental flywheel car has been designed and built at the University of Wisconsin that has demonstrated a mileage improvement of about 50% over a corresponding production vehicle on the EPA/FUDC. With continued research and development gains of 100% appear feasible.

CONTINUOUSLY VARIABLE TRANSMISSIONS: THEORY AND PRACTICE

The five basic principles that can be used in the design of continuously variable transmissions (CVT) for motor vehicles are examined and compared. These include: hydrostatic, traction drive (V-belt and rolling contact), overrunning clutch, electric, and multispeed gearbox with slipping clutch. Appendix A discusses commercially available CVTs suitable for motor vehicles, and Appendix B describes research and development programs for CVTs.