Balancing Control of a Self-driving Bicycle
T. J. Yeh, Hao-Tien Lu and Po-Hsuan Tseng
Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
Keywords:
Balancing Control, Bicycle, Convex Combination, Linear Matrix Inequality.
Abstract:
In this research, a self-driving bicycle is constructed and the balancing control using the handlebar is stud-
ied. The controller is designed based on a model which characterizes the bicycle’s lateral dynamics under
speed variations. As the model can be decomposed into a convex combination of four linear subsystems
with time-varying coefficients, the proposed controller also consists of a convex combination of four linear,
full-state feedback controllers. It is proved that if the full-state feedback controllers satisfy a set of linear
matrix inequalities, the bicycle can maintain its lateral stability regardless of speed changes. Both simulations
and experiments verify that the proposed controller can achieve robust balancing performance under various
operating conditions.
1 INTRODUCTION
As the least expensive means of wheeled transporta-
tion, bicycles are widely used for many activities such
as commute, sport, recreation and so on. Bicycles
are considered to be environmentally friendly because
they can reduce the traffic congestion and air pollu-
tion in urban areas. The recent introduction of elec-
tric bicycles can further enhance the range and mo-
bility of bicycles. From system dynamics perspec-
tive, bicycles are in the category of wheeled-inverted-
pendulum vehicles and exhibit interesting dynamic
behavior. Modeling, analysis, and control of bicycles
thus have attracted significant attention in research
community ever since they were invented.
Whipple(Whipple, 1899) pioneered his work on
bicycle modeling by firstly deriving the equations of
motion of the bicycle. His model, which consid-
ered the bicycle as an assembly of four rigid bod-
ies, is both rigorous and complete. However, it is
not suitable for control system studies because it is
is highly nonlinear and complex. For this reason,
several simplified models have been proposed. For
example, Sharp(Sharp, 1971) used a four-degree-of-
freedom model to analyze the forward stability of
a bicycle. Lowell et.al.(Lowell and McKel, 1982)
lumped the whole bicycle as a point mass and used an
inverted pendulum to describe the lateral dynamics.
K. J. Astrom(Astrom et al., 2005) further augmented
the inverted pendulum model by incorporating steer-
ing angle as the input to the front fork assembly. In
(Meijaard et al., 2007), a benchmark model for the bi-
cycle was presented by Meijaard et. al.. This model,
which is a linear time-varying system parameterized
by the bicycle speed, is obtained by linearizing the
motion equations for small perturbations around the
constant-speed straight-ahead upright trajectory.
Regarding the control studies for bicycles, the re-
cent advances in digital computers, sensor and ac-
tuator technologies have drawn significant research
interests on developing self-balancing bicycles. For
instance, Beznos et al.(Beznos et al., 1998) con-
trolled the precession of the gyroscopes to gener-
ate a gyroscopic torque to counteract the destabiliz-
ing gravitational torque so as to balance a bicycle.
In (Cerone et al., 2010), the authors exploited the
linear-parameter-varying (LPV) nature of the bicycle
model proposed in (Meijaard et al., 2007) to design
a control system that automatically balances a rid-
erless bicycle in the upright position. Their control
problem is formulated as the design of an LPV state-
feedback controller that guarantees stability when the
speed varies within a given range and its derivative
is bounded. While the steering torque is treated as
the control input in (Cerone et al., 2010), Tanaka and
Murakami(Tanaka and Murakami, 2004) applied PD
control to modulate the steering angle to stabilize the
roll motion of the bicycle. In (Huang et al., 2017), the
authors developed a miniaturized humanoid robot to
ride and pedal a bicycle of comparable size. The robot
balances and steers the bicycle via controlling the an-
gle of the handlebar. The controller, which is de-
signed based-on a constant-speed bicycle model, can
automatically counteract the mass imbalance in the
34
Yeh, T., Lu, H. and Tseng, P.
Balancing Control of a Self-driving Bicycle.
DOI: 10.5220/0007810600340041
In Proceedings of the 16th International Conference on Informatics in Control, Automation and Robotics (ICINCO 2019), pages 34-41
ISBN: 978-989-758-380-3
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