Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimal Control of a Differentially Flat 2D Spring-Loaded Inverted
  Pendulum Model   This paper considers the optimal control problem of an extended spring-loaded
inverted pendulum (SLIP) model with two additional actuators for active leg
length and hip torque modulation. These additional features arise naturally in
practice, allowing for consideration of swing leg kinematics during flight and
active control over stance dynamics. On the other hand, nonlinearity and the
hybrid nature of the overall SLIP dynamics introduce challenges in the analysis
and control of the model. In this paper, we first show that the stance dynamics
of the considered SLIP model are differentially flat, which has a strong
implication regarding controllability of the stance dynamics. Leveraging this
powerful property, a tractable optimal control strategy is developed. This
strategy enables online solution while also treating the hybrid nature of the
SLIP dynamics. Together with the optimal control strategy, the extended SLIP
model grants active disturbance rejection capability at any point during the
gait. Performance of the proposed control strategy is demonstrated via
numerical tests and shows significant advantage over existing methods.

22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th