A load-dependent transmission friction model: theory and experiments

Dohring, Mark; Lee, E.; Newman, Wyatt S.

doi:10.1109/robot.1993.292210

Cited by 35 publications

(35 citation statements)

References 22 publications

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“…Gears introduce another subtlety of asymmetric friction loss, in which friction loss in the torque amplification direction is smaller than when energy flows back towards the motor [17]. This effect in spur gears has not been fully investigated; the full-gear model is part of the ongoing work of the MIT Cheetah project [18].…”

Section: Principle 3:low Impedance Mechanical Transmissionmentioning

confidence: 99%

Design Principles for Energy-Efficient Legged Locomotion and Implementation on the MIT Cheetah Robot

Seok

Wang

Chuah

et al. 2015

IEEE/ASME Trans. Mechatron.

443

228

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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 33kg robot runs at 22 km/h (6 m/s). The total power consumption from the battery pack was 973 watts and resulted in a total cost of transport of 0.5, which rivals running animals' at the same scale. The 76% of total energy consumption is attributed to heat loss from the motor, and the 24% is used in mechanical work, which is dissipated as interaction loss as well as friction losses at the joint and transmission.

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Section: Principle 3:low Impedance Mechanical Transmissionmentioning

confidence: 99%

Design Principles for Energy-Efficient Legged Locomotion and Implementation on the MIT Cheetah Robot

Seok

Wang

Chuah

et al. 2015

IEEE/ASME Trans. Mechatron.

443

228

View full text Add to dashboard Cite

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“…A device that shows this second characteristic is termed non-backdrivable. The fact that the transmission can support a load torque without any torque from the motor shows that the transmisive behavior of the worm drive is highly nonlinear [17], [18]. We draw heavily from [17] to derive the equations that describe our model.…”

Section: Modelmentioning

confidence: 99%

A passive-assist design approach for improved reliability and efficiency of robot arms

Brown

Ulsoy

2011

2011 IEEE International Conference on Robotics and Automation

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The purpose of this paper is to examine a passive-assist design approach for improving the performance of robot arms and unmanned ground vehicles (UGVs) with respect to reliability, utility, and efficiency. Specifically, a procedure that alters the mechanical design of a robot arm to incorporate springs optimized to reduce the maximum motor torque, or energy, required to perform a specified maneuver is proposed. By reducing the maximum motor torque required, the reliability and utility of the motors (and by extension the entire UGV) are increased. Our joint model includes both a non-backdrivable worm gear and a static DC motor. Initial results for a one link arm indicate that this procedure can reduce maximum required torque by 50.9% and energy consumed by 8.5%.

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“…For example, in [1] a load-dependent transmission friction model was developed for the potential use for constructing feed-forward compensation. The model presented therein is based on a wedge-like planar mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, the model in [1] contains implicit variables in the dynamic equations and thus can not be directly used for controller design. The classical and the QFT controllers respectively proposed in [2] and [3] are linear controllers.…”

Section: Introductionmentioning

confidence: 99%

Modeling and robust control of worm-gear driven systems

Yeh

IEEE International Conference on Mechatronics, 2005. ICM '05.

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This paper investigates modeling and control issues associated with worm-gear driven systems. In the modeling part, both static and dynamic analyses are conducted to investigate the characteristics of the worm-gear. The static analysis reveals not only the non-backdrivability but also the dependency of break-in torques ou the loading torque, direction of motion as well as crucial system parameters. The dynamic analysis generates four linear equations of motion, of which , at any particular instant, only one applies. The applicable equation at any given instant depends on the direction of motion and the relative magnitude between the input torque and the loading torque. In the control part, a sliding controner is designed based on the modeling results.The controner can provide robustness against variations of system parameters caused by the speed-dependent nature of the coefficient of friction. Because the dependency of the dynamic equation on the operating condition may render the controller ill-defined in some scenarios, a lemma is proved and can be used to select proper control parameters to guarantee the well-definedness of the controller.. The proposed control scheme is applied to a worm-gear driven positioning platform.Experimental results indicate the proposed control system achieves 20% of the tracking error of a conventional PID control.

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A load-dependent transmission friction model: theory and experiments

Cited by 35 publications

References 22 publications

Design Principles for Energy-Efficient Legged Locomotion and Implementation on the MIT Cheetah Robot

Design Principles for Energy-Efficient Legged Locomotion and Implementation on the MIT Cheetah Robot

A passive-assist design approach for improved reliability and efficiency of robot arms

Modeling and robust control of worm-gear driven systems

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