Belief Space Planning for Risk Signal Temporal Logic via Mixed-Integer Convex Programming
Authors: Shaohang Han, Joris Verhagen, Kaier Liang, Jana Tumova
Organizations: Division of Robotics, Perception and Learning, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden · Digital Futures
Signal Temporal Logic (STL) specifies robot tasks with spatio-temporal requirements, and its robustness semantics allow planning by trajectory optimization. In practice, robots estimate their state from noisy measurements, and when the information gained from a measurement depends on the state, the robot can actively reduce its uncertainty by planning in the belief space. The resulting problem is, however, generally non-convex, for which gradient-based methods are neither complete nor globally optimal. In this paper, we consider Risk STL (RiSTL) planning in Gaussian belief space and show that an information-form parameterization of the belief, together with a convex relaxation of the belief dynamics, yields a mixed-integer convex program (MICP). We prove that the MICP is sound and complete, and that the relaxation preserves the globally optimal input trajectories. We validate the effectiveness of our method in numerical simulations.
Figures & tables
Fig. 1 : Optimal belief trajectories. The background shows m , where brighter means more informative measurements. The blue line is the mean trajectory with 95% confidence ellipses. Stars mark the time step at which a goal is reached and, in (b), at which punc first holds.
reach-avoid
cautious-motion
MICP
NLP
MICP
NLP
First feasible [ s ]
2.1
–
1.9
–
Runtime [ s ]
83.0
170.1
5.6
204.1
Robustness ρφ
0.146
0.129
0.0047
−0.057
Cost αJu−ρφ
−0.065
−0.041
0.059
0.120
TABLE I : Comparison of the MICP and the NLP baseline on the exact belief trajectories. First feasible is the time to the first feasible solution of the MICP, which satisfies the specification.
We present a unified trajectory planning and control framework for the satisfaction of Signal Temporal Logic (STL) specifications defined over convex predicates. At the planning layer, STL tasks are encoded as time-varying convex sets in configuration space, specifically designed so that forward invariance of the system with respect to these sets implies satisfaction of the specification with a prescribed robustness margin. This representation is then lifted to the joint time--configuration space and combined with the Graphs of Convex Sets (GCS) framework, yielding a shortest-path formulation of the planning problem over convex spatio-temporal sets. Trajectories are parameterized by B-splines, which enable continuous-time enforcement of STL satisfaction, collision avoidance, and smoothness constraints. At the control layer, the same time-varying sets used for planning are exploited to design a feedback controller that tracks the planned trajectory while prioritizing satisfaction of the STL specification during execution in the presence of tracking errors and model mismatch. We validate the proposed approach in simulation and in real-world experiments on space robotic platforms.
Nicola De Carli, Gregorio Marchesini, Dimos V. Dimarogonas
This paper investigates continuous-time motion planning under Signal Temporal Logic (STL) specifications. The goal is to generate smooth robot trajectories that satisfy high-level logical and timing requirements while respecting low-level motion constraints. To this end, we propose an efficient framework that combines timed-automata reasoning with graphs of convex sets (GCS). An STL specification is first represented by a timed automaton, which is then coupled with a convex decomposition of the configuration space to form a joint transition system encoding both task progress and region occupancy. Based on this joint transition system, the STL motion-planning problem is reformulated as a shortest-path problem over a GCS, whose solution induces a smooth Bézier-spline trajectory satisfying the STL specification, smoothness requirements, and velocity bounds. We establish the soundness of the proposed formulation and analyze its computational complexity, showing that, once the timed automaton and convex decomposition are fixed, the convex relaxation scales polynomially with the configuration-space dimension and the Bézier degree. We further develop a compact timed-automaton construction for an expressive STL fragment using dedicated templates and Boolean composition. Numerical experiments on low-dimensional benchmarks, a 3-D quadrotor, a 30-DoF humanoid, and a hardware experiment on a UR-3 robot arm demonstrate that the proposed method efficiently solves complex STL motion-planning problems and produces smooth executable trajectories.
Yu Chen, Ancheng Hou, Mingyang Feng +2
School of Automation & Intelligent Sensing, Shanghai Jiao Tong University, Shanghai 200240, China · Institute of Artificial Intelligence, Xiamen University, Xiamen, China
Safety-aware motion planning remains a challenge in robotics, especially when missions are time-critical and are under complex specifications. In this paper, we propose safety-aware-stl-mppi, a computationally efficient sampling-based receding-horizon planning framework designed to promote satisfaction of constraints expressed in Signal Temporal Logic (STL). Our approach encodes discrete-time STL formulas into candidate time-varying control barrier functions (CBF), which are integrated into a model predictive path integral (MPPI) controller. Our method inherits the benefits of low computational cost from an efficiently parallelizable sampling based planner and utilizes CBF for constraints expressed in STL. We compare against several MPPI baselines using four artificial Mars Rover planning case studies with a diverse environment and cost setups, where we show our method consistently achieving high safety and efficiency. We show a quadcopter planning experiment with NVIDIA Isaac Lab.
Yiqi Zhao, Taekyung Kim, Hideki Okamoto +4
Thomas Lord Department of Computer Science, University of Southern California, Los Angeles, CA 90089, USA · Department of Robotics, University of Michigan, Ann Arbor, MI 48109, USA · Toyota Motor North America R&D, Ann Arbor, MI 48105, USA +1