Modeling and design of geared DC motors for energy efficiency: Comparison between theory and experiments

Abstract Energy efficiency is a growing concern in today’s mechatronic designs. In recent years, many works have emerged presenting energy-efficient actuators with electrical motors. However, there is little consistency in the way energy consumption is calculated. Drive inertia, motor efficiency and controller efficiency are often neglected in optimizations, and so are the load- and speed-dependency of the losses and other non-linearities. While this approach works well in stationary circumstances, it can lead to significant errors in highly dynamic tasks with a wide range of operation, such as the ones faced by actuators in the field of robotics. This paper discusses the losses occurring in an actuator consisting of a DC motor and gearbox as it is forcing a swinging motion on a pendulum. From this simple case study, some general recommendations on the modeling of energy losses are formulated. Combining data from manufacturer’s datasheets with empirical data, the approach presented in this paper was able to predict the energy consumption for this specific case with an error of less than 10%.

[1]  Hugh M. Herr,et al.  Powered ankle-foot prosthesis , 2008, IEEE Robotics & Automation Magazine.

[2]  Antonio Bicchi,et al.  Soft-actuators in cyclic motion: Analytical optimization of stiffness and pre-load , 2013, 2013 13th IEEE-RAS International Conference on Humanoid Robots (Humanoids).

[3]  J. Stevens,et al.  A study of lead-acid battery efficiency near top-of-charge and the impact on PV system design , 1996, Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996.

[4]  Sheng Li,et al.  Prediction of mechanical gear mesh efficiency of hypoid gear pairs , 2010 .

[5]  Simone Cinquemani,et al.  Effects of transmission mechanical characteristics on the choice of a motor-reducer , 2010 .

[6]  J. Schuy,et al.  Conception and evaluation of a novel variable torsion stiffness for biomechanical applications , 2012, 2012 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob).

[7]  Manuel G. Catalano,et al.  Variable impedance actuators: A review , 2013, Robotics Auton. Syst..

[8]  Stuart H. Loewenthal,et al.  Spur-Gear-System Efficiency at Part and Full Load , 1980 .

[9]  Hai Zhou,et al.  A reduction ratio for minimizing dissipated energy in a mechatronic system with a gear train , 2008 .

[10]  André Seyfarth,et al.  A comparison of parallel- and series elastic elements in an actuator for mimicking human ankle joint in walking and running , 2012, 2012 IEEE International Conference on Robotics and Automation.

[11]  Valeriy Stavytskyy,et al.  LOAD-INDEPENDENT POWER LOSSES OF GEAR SYSTEMS: A REVIEW , 2010 .

[12]  Leonid B. Freidovich,et al.  Parallel Elastic Actuators as a Control Tool for Preplanned Trajectories of Underactuated Mechanical Systems , 2010, Int. J. Robotics Res..

[13]  Ahmet Kahraman,et al.  Prediction of Mechanical Efficiency of Parallel-Axis Gear Pairs , 2007 .

[14]  Oskar von Stryk,et al.  Power-optimized stiffness and nonlinear position control of an actuator with Variable Torsion Stiffness , 2013, 2013 IEEE/ASME International Conference on Advanced Intelligent Mechatronics.

[15]  George Ellis,et al.  Control System Design Guide , 2012 .

[16]  William Bolton.  Mechatronics: Electronic Control Systems in Mechanical and Electrical Engineering , 2004 .

[17]  Bram Vanderborght,et al.  Exploiting Natural Dynamics to Reduce Energy Consumption by Controlling the Compliance of Soft Actuators , 2006, Int. J. Robotics Res..

[18]  Matthew A. Holgate,et al.  The SPARKy (Spring Ankle with Regenerative kinetics) project: Choosing a DC motor based actuation method , 2008, 2008 2nd IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics.

[19]  Shiqian Wang,et al.  Spring uses in exoskeleton actuation design , 2011, 2011 IEEE International Conference on Rehabilitation Robotics.

[20]  Bram Vanderborght,et al.  Comparison of Mechanical Design and Energy Consumption of Adaptable, Passive-compliant Actuators , 2009, Int. J. Robotics Res..

[21]  John Kenneth Salisbury,et al.  A New Actuation Approach for Human Friendly Robot Design , 2004, Int. J. Robotics Res..

[22]  Albert Duan Wang.  Directional impedance of geared transmissions , 2012 .

[23]  Oskar von Stryk,et al.  Analysis of system dynamic influences in robotic actuators with variable stiffness , 2014 .

[24]  Sheng Li,et al.  Prediction of Spur Gear Mechanical Power Losses Using a Transient Elastohydrodynamic Lubrication Model , 2010 .

[25]  C. Rydh,et al.  Energy analysis of batteries in photovoltaic systems. Part I: Performance and energy requirements , 2005 .

[26]  Nikolaos G. Tsagarakis,et al.  How design can affect the energy required to regulate the stiffness in variable stiffness actuators , 2012, 2012 IEEE International Conference on Robotics and Automation.

[27]  André Seyfarth,et al.  Effects of unidirectional parallel springs on required peak power and energy in powered prosthetic ankles: Comparison between different active actuation concepts , 2012, 2012 IEEE International Conference on Robotics and Biomimetics (ROBIO).

[28]  Martin Otter,et al.  Modeling and Simulating the Efficiency of Gearboxes and of Planetary Gearboxes , 2002 .

[29]  Jan Wikander,et al.  Optimal selection of motor and gearhead in mechatronic applications , 2006 .

[30]  Hugh M. Herr,et al.  Clutchable series-elastic actuator: Design of a robotic knee prosthesis for minimum energy consumption , 2013, 2013 IEEE 13th International Conference on Rehabilitation Robotics (ICORR).

[31]  A. Galip Ulsoy,et al.  A passive-assist design approach for improved reliability and efficiency of robot arms , 2011, 2011 IEEE International Conference on Robotics and Automation.

[32]  Michael R. Tucker,et al.  Mechanical damping with electrical regeneration for a powered transfemoral prosthesis , 2010, 2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics.

[33]  Pier Paolo Valentini,et al.  A Review of Formulas for the Mechanical Efficiency Analysis of Two Degrees-of-Freedom Epicyclic Gear Trains , 2003 .

[34]  Philipp Beckerle,et al.  Human-Machine-Centered Design and Actuation of Lower Limb Prosthetic Systems , 2014 .

[35]  Yeau-Ren Jeng,et al.  Modeling and Analysis of the Meshing Losses of Involute Spur Gears in High-Speed and High-Load Conditions , 2013 .