Page 28 - ASME DSCC 2015 Program

Technical Program

Sliding Mode Control for Heart Rate Regulation of Electric Bicycle
InVITED SESSIon
2-9-1 WM2 Human Robot Interaction 1 Riders
George Bellows B 1:30pm–3:30pm Invited session paper. DSCC2015-9712
Daniel Meyer, Technische Universität München, München, Germany,
Session Organizer: Jun ueda, Georgia Tech. Wenlong Zhang, Masayoshi Tomizuka, University of California, Berkeley,
Session Organizer: Jingang Yi, Rutgers University CA, United States
Session Organizer: ashish deshpande, University of Texas, Austin In this paper a new controller for electric bicycles is proposed to maintain
Session Chair: Venkat Krovi, University at Buffalo a desired heart rate level and improve the riding experience of cyclists.
Session Co-Chair: Te Tang, University of California, Berkeley The controller achieves this by adequately adjusting the motor assistance
without affecting the cycling velocity. First, a human heart rate model is fitted
Impedance Behavior of Controllers for Compliant Positioning of a
to experimental data to model the heart rate response of cyclists during dif-
Pneumatically Actuated System
ferent exercises. Then, a sliding mode controller is designed to keep the hu-
Invited session paper. DSCC2015-9691
man heart rate at a predefined level. Furthermore, a feedforward controller
Hannes Daepp, Wayne J. Book, Georgia Institute of Technology, Atlanta, is introduced into the system to improve both the tracking performance and
GA, United States riding experience. The feedforward controller consists of an inverse human
Pneumatic actuators are frequently selected for use in machines intended heart rate response model, which estimates the necessary rider torque for
for human interaction because of their clean operation and natural a desired heart rate level. The controller is implemented with a commercial
compliance. However, the compliance, coupled with friction, can also electric bicycle. Simulation and experimental results are presented to assess
make motion control difficult, leading to the use of more aggressive the validity of the controller. Whereas the sliding mode controller itself
controllers, such as high-gain PID or sliding mode control, which result in achieves good tracking performance, the sliding mode control combined
stiff closed-loop system behavior. Model-based options are needed to with the feedforward control additionally reduces the maximal exerted rider
obtain behavior that provides a better trade-off of compliance and torque and improves the riding experience.
accurate position control. In particular, Model Predictive Control (MPC) is passive control of a hydraulic human power amplifier using a
suggested; through the use of constrained optimal control, it offers a Hydraulic Transformer
framework for minimizing tracking error while enforcing force constraints Invited session paper. DSCC2015-9734
that ensure low impedance behavior.
Sangyoon lee, Perry Y. li, University of Minnesota, Minneapolis, MN,
This paper assesses the suitability of controllers for pneumatic systems to
United States
positioning applications in which human-machine interaction is anticipated.
MPC is compared against commonly-used alternatives for such scenarios: The hydraulic human power amplifier is a tool that uses hydraulic actuation
sliding mode, PID, and impedance control. Results are shown in simula- to amplify the force that the human exerts on it. Our control objective and
tion, and use spectral analysis of the impedance and closed loop tracking framework are to make the system behave like a passive mechanical tool
to characterize the balance of compliance and accuracy for each of the when interacting with the human and with the work environment with a
controllers. specified power scaling factor. A virtual velocity coordination control
approach casts the human power amplifier problem into one of velocity
A learning-Based framework for Robot Peg-Hole-Insertion
coordination by generating a fictitious reference mechanical system.
Invited session paper. DSCC2015-9703
Force amplification becomes a natural consequence of velocity
Te Tang, Hsien-Chung lin, Masayoshi Tomizuka, University of California, coordination. This control has been previously demonstrated using servo
Berkeley, CA, United States valves which is a major contributor to energy loss in hydraulic system. In
Peg-hole-insertion is a common operation in industry production, but this paper, a hydraulic transformer, which does not rely on throttling to
autonomous execution by robots has been a big challenge for many years. accomplish its control function is used instead of a servo valve to achieve
Current robot programming for this kind of contact problem requires tremen- human power amplification.
dous effort, which needs delicate trajectory and force tuning. However, hu- This controller was experimentally validated with good force amplification
man may accomplish this task with much less time and fewer trials. It will be and velocity coordination performance on a single degree of freedom
a great benefit if robots can learn the human skill and apply it autonomously. hydraulic human power amplifier.
This paper introduces a framework for teaching robot peg-hole-insertion
from human demonstration. A Dimension Reduction and Recovery method is
proposed to simplify control policy learning. The Gaussian Mixture Regres-
sion is utilized to imitate human skill and a Dual Stage Force Control strategy
is designed for autonomous execution by robots. The effectiveness of the
teaching framework is demonstrated by a series of experiments.

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