Zhiyun Deng

Mr. Zhiyun Deng

University of Texas at Austin, Austin, Texas, USA
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 August 2023 in IEEE Internet of Things Journal
Verified
Journal Article
Open access
WLWei Liu
Wei Liu
MHMin Hua
Min Hua
ZDZhiyun Deng
Zhiyun Deng
ZMZonglin Meng
Zonglin Meng
YHYANJUN HUANG
YANJUN HUANG
XXXin Xia
Xin Xia
Vehicle control is one of the most critical challenges in autonomous vehicles (AVs) and connected and automated vehicles (CAVs), and it is paramount in vehicle safety, passenger comfort, transportation efficiency, and energy saving. This survey attempts to provide a comprehensive and thorough overview of the current state of vehicle control technology, focusing on the evolution from vehicle state estimation and trajectory tracking control in AVs at the microscopic level to collaborative control in CAVs at the macroscopic level. First, this review starts with vehicle key state estimation, specifically vehicle sideslip angle, which is the most pivotal state for vehicle trajectory control, to discuss representative approaches. Then, we present symbolic vehicle trajectory tracking control approaches for AVs. On top of that, we further review the collaborative control frameworks for CAVs and corresponding applications. Finally, this survey concludes with a discussion of future research directions and the challenges. This survey aims to provide a contextualized and in-depth look at the state of the art in vehicle control for AVs and CAVs, identifying critical areas of focus and pointing out the potential areas for further exploration.

18 January 2023 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
ZDZhiyun Deng
Zhiyun Deng
KYKaidi Yang
Kaidi Yang
Weiming ShenWeiming Shen
Weiming Shen
YSYanjun Shi
Yanjun Shi
This paper presents a Vehicle-Platoon-Aware Bi-Level Optimization Algorithm for Autonomous Intersection Management (VPA-AIM) to coordinate the merging of Connected and Automated Vehicles at unsignalized intersections. The constraint-coupled bi-level optimization is operated within a rolling horizon to balance traffic performance and computational efficiency. In each decision step, the platoon formation scheme is incorporated into an upper-level traffic scheduling model as decision variables to pursue an optimal schedule from a systemic view. Meanwhile, the passing sequence and timeslots of vehicles are jointly optimized with the platoon configuration scheme by virtue of real-time traffic states to improve operational efficiency and fairness. After that, a lower-level trajectory planning model will generate dynamically-feasible and energy-efficient trajectories according to the given schedule and coupling constraints with the objective of improving space utilization to prevent spillbacks. Moreover, the quantifiable connection between the makespan of traffic scheduling schemes and the occurrence of spillbacks is established, demonstrating that the cooperative platoon formation strategy is effective in avoiding and mitigating spillbacks in normal and saturated traffic states. Additionally, the proposed algorithm can be extended to mixed traffic scenarios. Numerical experiments are conducted on extensive scenarios with different arrival flows, where the Constraint Programming technique is employed to produce the optimal schedule. Experimental results indicate the superiority of the proposed approach in optimality and stability with reasonable sub-second computation time for real-life applications.

15 June 2023 in Sensors
Verified
Journal Article
Open access
PDF file
XYXianfeng Ye
Xianfeng Ye
ZDZhiyun Deng
Zhiyun Deng
Yanjun ShiYanjun Shi
Yanjun Shi
Weiming ShenWeiming Shen
Weiming Shen
This paper presents a multi-agent reinforcement learning (MARL) algorithm to address the scheduling and routing problems of multiple automated guided vehicles (AGVs), with the goal of minimizing overall energy consumption. The proposed algorithm is developed based on the multi-agent deep deterministic policy gradient (MADDPG) algorithm, with modifications made to the action and state space to fit the setting of AGV activities. While previous studies overlooked the energy efficiency of AGVs, this paper develops a well-designed reward function that helps to optimize the overall energy consumption required to fulfill all tasks. Moreover, we incorporate the e-greedy exploration strategy into the proposed algorithm to balance exploration and exploitation during training, which helps it converge faster and achieve better performance. The proposed MARL algorithm is equipped with carefully selected parameters that aid in avoiding obstacles, speeding up path planning, and achieving minimal energy consumption. To demonstrate the effectiveness of the proposed algorithm, three types of numerical experiments including the ϵ-greedy MADDPG, MADDPG, and Q-Learning methods were conducted. The results show that the proposed algorithm can effectively solve the multi-AGV task assignment and path planning problems, and the energy consumption results show that the planned routes can effectively improve energy efficiency.

4 August 2022 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
ZDZhiyun Deng
Zhiyun Deng
JFJiaxin Fan
Jiaxin Fan
YSYanjun Shi
Yanjun Shi
Weiming ShenWeiming Shen
Weiming Shen
This paper proposes a coevolutionary algorithm to optimize longitudinal trajectories of multiple vehicles with an energy-aware non-linear objective during the cooperative platoon formation process. In this work, an adaptive encoding scheme is adopted to represent trajectories as knot vectors of parametric cubic splines, and therefore the original problem is reformulated into a constrained numerical optimization version. The number of knots can be adjusted to trade-off between the shape flexibility and computation efficiency. Further, the proposed coevolutionary algorithm decomposes the initially high-dimensional problem into smaller subproblems, significantly reducing the complexity. A hybrid evolutionary algorithm is developed as an optimizer for subproblems. Additionally, a branch-and-bound strategy and a Tabu search component are integrated into the steepest ascent hill-climbing algorithm to speed up convergences within the local exploitation phase. Numerical experiments are conducted on extensive scenarios with different platooning sizes and initial separations. Experimental results indicate the superiority of the proposed approach in optimality and stability with reasonable sub-second computation time for real-life applications.

8 September 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
ZDZhiyun Deng
Zhiyun Deng
Yanjun ShiYanjun Shi
Yanjun Shi
QHQiaomei Han
Qiaomei Han
LLLingling Lv
Lingling Lv
Weiming ShenWeiming Shen
Weiming Shen
Previous studies on Connected and Automated Vehicles (CAVs) demonstrated the potential to coordinate the behaviors of multiple connected vehicles for traffic improvements. In this paper, we first propose a Conflict Duration Graph-based (CDG-based) coordination framework to resolve collisions and improve the traffic capacity of signal-free intersections. Secondly, a Speed Control-based Intersection Coordination Model (SICM) is developed to identify complex constraints in multi-vehicle collision scenarios. Thirdly, a geometric Translation-based Intersection Coordination Algorithm (TICA) is proposed to calculate the ideal location of time blocks in CDGs and then obtain the near-optimal design speed in the form of combinatorial optimization. Twelve groups of test scenarios with different traffic volumes were designed and tested on a MATLAB-based simulation platform. Simulation results showed that the proposed method can resolve all the collisions and instruct the vehicles to pass signal-free intersections collaboratively without stopping in low to medium level of congestion.

27 July 2023 in Transportation Research Part C: Emerging Technologies
Verified
Journal Article
Closed access
LLLingling Lv
Lingling Lv
ZDZhiyun Deng
Zhiyun Deng
CSChenyang Shao
Chenyang Shao
WSWeiming Shen
Weiming Shen