Swing-up of a rotating type pendulum from the pendant to the inverted state is known to be one of most difficult control problems, since the system is nonlinear, underactuated, and has uncontrollable states. This paper studies a time optimal swing-up control of the pendulum using bounded input. Time optimal control of a nonlinear system can be formulated by Pontryagin’s Maximum Principle, which is, however, hard to compute practically. In this paper, a new computational approach is presented to attain a numerical solution of the time optimal swing-up problem. Time optimal control problem is described as minimization of the achievable time to attain the terminal state under the bounded input amplitude, although algorithms to solve this problem are known to be complicated. Therefore, in this paper, it is shown how the optimal time swing-up control is formulated as an auxiliary problem in that the minimal input amplitude is searched so that the terminal state satisfies a specification at a given time. Through the proposed approach, time optimal control can be solved by nonlinear optimization. Its approach is evaluated by numerical simulations of a simplified pendulum model, is checked satisfying the necessary condition of Maximum Principle, and is experimentally verified using the rotating type pendulum.

1.
Mori
,
S.
,
Nishihara
,
H.
, and
Furuta
,
K.
,
1976
, “
Control Of Unstable Mechanical Control Of Pendulum
,”
Int. J. Control
,
23
, No.
5
, pp.
673
692
.
2.
Furuta, K., Yamakita, M., and Kobayashi, S., 1992, “Swing-up Control of Inverted Pendulum Using Pseudo-state Feedback,” Proc. of Institute of Mechanical Engineers, Vol. 206, pp. 263–269.
3.
Shiriaev, A. S., Ludvigsen, H., Egeland, O., and Fradkov, A. L., 1999, “Swinging up of Simplified Furuta Pendulum,” Proc. of ECC ’99.
4.
Åstro¨m, K. J., and Furuta, K., 1996, “Swing Up a Pendulum by Energy Control,” IFAC 13th Triennial World Congress, San Francisco.
5.
Yamakita, M., Iwashiro, M., Sugahara, Y., and Furuta, K., 1996, “Robust Swing Up Control of Double Pendulum,” Proceedings of the American Control Conference, Seattle, Washington.
6.
Yurkovich
,
S.
, and
Widjaja
,
M.
,
1996
, “
Fuzzy Controller Synthesis for an Inverted Pendulum System
,”
Control Engineering Practice
,
4
, No.
4
, pp.
455
469
.
7.
Pontryagin, L. S., Boltyanskii, V. G., Gamkrelidze, R. V., and Mischenko, E. F., 1962, The Mathematical Theory of Optimal Processes, Interscience Publishers.
8.
Kirk, D. E., 1970, Optimal Control Theory, Prentice-Hall, Englewood, NJ.
9.
Polak, E., 1971, Computational Methods in Optimization: A Unified Approach, Academic Press, New York.
10.
Canon, M. D., Cullum, C. D., and Polak, E., 1970, Theory of Optimal Control and Mathematical Programming, McGraw-Hill, New York.
11.
Lee
,
Y. D.
,
Kim
,
B. H.
, and
Gyoo
,
H.
,
1999
, “
Evolutionary Approach for Time Optimal Trajectory Planning of a Robotic Manipulator
,”
Information Sciences
,
113
, No.
3–4
, pp.
245
260
.
12.
Melikyan
,
A. A.
,
1994
, “
Necessary Optimality Conditions for a Singular Surface in the Form of Synthesis
,”
J. Optim. Theory Appl.
,
82
, No.
2
, pp.
203
217
.
13.
Meier
,
E. B.
, and
Bryson
,
A. E.
, Jr.
,
1990
, “
Efficient Algorithm for Time-Optimal Control of a Two-Link Manipulator
,”
Journal of Guidance
,
13
,
No. 5
No. 5
.
14.
Van Willigenburg
,
L. G.
, and
Loop
,
R. P. H.
,
1991
, “
Computation of Time-optimal Controls Applied to Rigid Manipulators With Friction
,”
Int. J. Control
,
54
, No.
5
, pp.
1097
1117
.
15.
Ga¨fert, M., Svensson, J., and Åstro¨m, K. A., Friction and Friction Compensation in the Furuta Pendulum, Proc. of ECC ’99.
16.
Arczewski
,
K.
, and
Blajer
,
W.
,
1996
, “
A Unified Approach to the Modelling of Holonomic and Nonholonomic Mechanical Systems
,”
Mathematical Modelling of Systems
,
2
, No.
3
, pp.
157
174
.
17.
Furuta, K., and Xu, Y., 1999, “Project of Super-Mechano Systems—Study on Single Pendulum,” Proc. of SMC ’99, Tokyo Japan, Vol. 3, pp. 123–128.
18.
Gabasov, R., and Kirillova, F. M., 1999, “Numerical Methods of Open-loop and Closed-loop Optimization of Linear Control Systems,” Report.
19.
Lewis, F. L., 1986, Optimal Control, Wiley, New York.
20.
Wu
,
C. J.
,
1995
, “
Minimum-time Control for an Inverted Pendulum Under Force Constraints
,”
Journal of Intelligent & Robotic Systems
,
12
, No.
2
, pp.
127
143
.
21.
Czogala
,
E. M.
, and
Pawlak
,
Z. A.
,
1995
, “
Idea of a Rough Fuzzy Controller and its Application to the Stabilization of a Pendulum-car System
,”
Fuzzy Sets Syst.
,
72
, No.
1
, pp.
61
73
.
22.
Gregory, J., and Lin, C., 1992, Constrained Optimization in the Calculus of Variations and Optimal Control Theory, Van Nostrand Reinhold.
23.
Eltohamy
,
K. G.
, and
Kuo
,
C. Y.
,
1998
, “
Nonlinear Optimal Control of a Triple Link Inverted Pendulum With Single Control Input
,”
Int. J. Control
,
69
, No.
2
, pp.
239
256
.
24.
Huang
,
S. J.
, and
Huang
,
C. L.
,
1996
, “
Control of a Sliding Inverted Pendulum Using a Neural Network
,”
International Journal of Computer Application
,
9
, No.
2–3
, pp.
67
75
.
25.
Liu, Y., and Kojima, H., 1994, “Optimal Design Method of Nonlinear Stabilizing Control System of Inverted Pendulum by Genetic Algorithm,” Nippon Kikai Gakkai Ronbunshu, C Hen, Vol. 60, No. 577, pp. 3124–3129.
26.
Lin
,
Z.
,
Saberi
,
A.
,
Gutmann
,
M.
, and
Shamash
,
Y.
,
1996
, “
Linear Controller of an Inverted Pendulum having Restricted Travel: a High-and-low Gain Approach
,”
Automatica
,
32
, No.
6
, pp.
933
937
.
You do not currently have access to this content.