Robotics

I have been working on different robot platform. Most of them are underactuated balance robot. I develop/test/modify the hardware, develop the algorithm, run the experiment and write the paper.

1. Ski-stunt Maneuvering Control of Racing Truck

A ski-stunt maneuver is a type of aggressive vehicle motions in which a four-wheel vehicle runs on two wheels on one side, and the other two wheels are lifted in the air. It is a challenging task even for skilled car drivers to perform a ski-stunt maneuver. We present the safety-guaranteed motion control of autonomous ski-stunt maneuvers. Inspired by bicycle dynamics, a vehicle dynamic model is first built for ski-stunt motion. To prevent possible rollovers, a control barrier function is used in a model predictive control formulation to plan a safe motion trajectory. A motion controller is then designed to follow the safe trajectory with guaranteed balance. Ski-stunt maneuver initiation and switching strategies are also analyzed and designed. Extensive experiments are conducted using a scaled truck platform to demonstrate the control design. The experimental results confirm that the vehicle can successfully initiate the ski-stunt maneuver to safely navigate among obstacles and narrow passes and then switch to normal driving.

(a) Indoor experiment setup. (b) Vehicle runs on a narrow bridge by performing a ski-stunt maneuver. (c) Snapshots of ski-stunt maneuver initiation process by steering. The labels in (c) illustrate the stages in four-wheel to two-wheel transition process.

2. Autonomous Bicycle Robot Control for Crossing Obstacles With Impulsive Actuation

As a single-track mobile platform, bikebot (i.e., bicycle-based robot) has attractive capability to navigate ,through narrow, off-road terrain with high speed. However, running crossing step-like obstacles creates challenges for intrinsically unstable, underactuated bikebots. This work presents a novel autonomous bikebot control with two assistive legs to navigate crossing obstacles. The proposed design integrates the external/internal convertible form based motion control with leg-assisted impulse actuation. The leg–terrain interaction generates impulsive torques to help maintain navigation and balance when running across obstacles. The control performance is analyzed and guaranteed. The experimental results confirm that under the control design, the bikebot can smoothly run crossing multiple step-like obstacles with heights more than one-third of the wheel radius. The comparison results demonstrate the superior performance than those under only the velocity and steering control without leg assistive actuation.

Autonomous bikebot with assistive legs

Proposed Impulse assistive control strategy

Highlights of design

Unstable moving bicycle robot
Impact between the tire and stairs
Leg cannot touch down on ground for long time, leading to impulse effect
Integrations of continuous system and discontinuous system
Necessary conditions are identified for balance

Video showing the effectiveness of the proposed control scheme.

3. Coordinated Control of A Manipulator On a Bicycle Robot Control

Bikebot manipulation has advantages of the single-track robot mobility and manipulation dexterity. We present a coordinated pose control of mobile manipulation with the stationary bikebot. The challenges of the bikebot manipulation include the limited steering balance capability of the unstable bikebot and kinematic redundancy of the manipulator. We first present the steering balance model to analyze and explore the maximum steering capability to balance the stationary platform. A balancing equilibrium manifold is then proposed to describe the necessary condition to fulfill simultaneous platform balance and posture control of the end-effector. A coordinated planning and control design is presented to determine the balance-prioritized posture control under kinematic and dynamic constraints. Extensive experiments are conducted to demonstrate the mechatronic design for autonomous plant inspection in agricultural applications. The results confirm the feasibility to use the bikebot manipulation for plant inspection with end-effector position and orientation errors about 5mm and 0.3 degs, respectively.

Block diagram of the balance-prioritized trajectory planning and control scheme.

Related Work

F. Han, and J. Yi, Safe Motion Control of Autonomous Vehicle Ski-Stunt Maneuvers. IEEE/ASME Transactions on Mechatronics, 2023. (Under Review) Video
P. Wang, F. Han, and Yi, Jingang, “Gyroscopic Balancer-Enhanced Motion Control Of An Autonomous Bikebot,” in Journal of Dynamic Systems, Measurement, and Control, pp. 1-15, 2023. PDF
F. Han, X. Huang, Z. Wang, J. Yi and T. Liu, “Autonomous Bikebot Control for Crossing Obstacles With Assistive Leg Impulsive Actuation,” in IEEE/ASME Transactions on Mechatronics, vol. 27, no. 4, pp. 1882-1890, Aug. 2022. Concurrent Submission to 2022 AIM Conference. PDF Video 2022 Finalist of Best Transaction Paper.
F. Han, A. Jelvani, J. Yi and T. Liu, “Coordinated Pose Control of Mobile Manipulation With an Unstable Bikebot Platform,” in IEEE/ASME Transactions on Mechatronics, vol. 27, no. 6, pp. 4550-4560, Dec. 2022. PDF Video
T. Zheng, F. Han, and J. Yi, Design and Control of An Agricultural Robot for Turf Grass Inspection. 2023 Modeling, Estimation and Control Conference (MECC). (Accepted)
M. Mihalec, F. Han, and J. Yi, “Integrated inverted pendulum and whole-body control design for bipedal robot with foot slip,” IFAC-PapersOnLine (2022 MECC Conference), Volume 55, Issue 37, pp. 376-381, 2022. PDF
X. Huang, F. Han, Y. Han, S. Wang, T. Liu and J. Yi, “Motion Control of an Autonomous Wheel-Leg Bikebot,” 2022 IEEE 18th International Conference on Automation Science and Engineering (CASE), Mexico City, Mexico, 2022, pp. 2341-2346. PDF

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