4 results on '"Lin, Pei-Chun"'
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2. Legged Robot Running Using a Physics-Data Hybrid Motion Template.
- Author
-
Yang, Wen-Shan, Lu, Wei-Chun, and Lin, Pei-Chun
- Subjects
ROBOT motion ,INVERTED pendulum (Control theory) ,HYBRID systems ,ROBOTS ,GAUSSIAN processes ,RUNNING speed ,ROBOT control systems ,ROBOT design & construction - Abstract
We report on the methodology of developing a hybrid model and utilizing it as a template to initiate running behavior in a legged robot. The hybrid model is comprised of a physics-based, rolling, spring-loaded, inverted pendulum (R-SLIP) model, and a data-driven model that compensates for unmodeled dynamics using Gaussian process (GP) regression. The hybrid R-SLIP-GP model retains the R-SLIP's intrinsic running dynamics, as well as improves the template's accuracy without intensive data training and iteration efforts. The proposed hybrid model was evaluated via simulation and in empirical robot running experiments. The results confirm that the added GP-based model greatly improved the model's accuracy, especially discrepancies resulting from the originally difficult-to-model complex leg-ground interactions. In addition, the R-SLIP-GP model was utilized as a complete motion template to design and control the robot's running motion. The experimental results demonstrate that the hybrid template can initiate more stable and power-efficient running motion in the robot than using the R-SLIP template. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Clock-Torqued Rolling SLIP Model and Its Application to Variable-Speed Running in a Hexapod Robot.
- Author
-
Lu, Wei-Chun, Yu, Ming-Yuan, and Lin, Pei-Chun
- Subjects
ROBOT motion ,DEGREES of freedom ,DYNAMIC models ,RUNNING ,EQUATIONS of motion ,LAGRANGIAN functions - Abstract
In this paper, we report on the development of the clock-torqued rolling spring loaded inverted pendulum (CTR-SLIP) model. The new model, which adds clock-based torque control on the leg orientation of the previously developed R-SLIP model, has two advantages: first, regulating the model to follow its passive dynamic running (i.e., at a fixed point) significantly increases the model's basin of attraction; and second, formulating the model closer to the empirical robot enables the model to serve as the transient and steady-state running template of the robot as the anchor. These features enable the model/robot to perform speed transition from one fixed point profile to another, and the experimental validation confirms that the robot can successfully transition between two running speeds bidirectionally. The achievement of variable-speed running by the proposed method has a unique merit—it is purely model-based, and there is no need for further tuning, optimization, or learning processes. Regarding the robot, the proposed strategy only requires it to have simple position control to regulate its leg orientations, and there is no need for other sensory modules to provide information for feedback. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. Proprioceptive sensing for a legged robot.
- Author
-
Lin, Pei-Chun
- Subjects
- Legged Robot, Proprioceptive Sensing, Robots, Sensor Fusion, State Estimation
- Abstract
This thesis provides a methodology of sensory system development for a hexapod robot, working toward the development of dynamic behaviors utilizing feedback controllers. We develop an approach to utilizing strain gauges together with a simple data driven phenomenological model that simultaneously delivers information of leg touchdown, leg configuration, and ground reaction force suitable for robots with compliant legs. The strain gauges are implemented and models are constructed on two versions of RHex robot compliant legs. Leg configuration is further evaluated under realistic robot operating conditions by means of a high speed visual ground truth system. We then introduce a continuous time 6 degree of freedom (DOF) body pose estimator for a walking hexapod robot. Our algorithm uses six leg configurations together with prior knowledge of the ground and robot kinematics to compute instantaneous estimates of the body pose. We implement this estimation procedure on RHex and evaluate the performance of this algorithm at widely varying body speeds and over dramatically different ground conditions by means of a 6 DOF vision-based ground truth measurement system (GTMS). We also compare the odometry performance to that of sensorless schemes---both legged as well as on a wheeled version of the robot---using GTMS measurements of traversed distance. Finally, we report on a hybrid 12-dimensional full body state estimator for a jogging hexapod robot on level terrain with regularly alternating ground contact and aerial phases of motion. We use a repeating sequence of dynamical models switched in and out of an Extended Kalman Filter to fuse measurements from a body pose sensor and inertial sensors. Our inertial measurement unit supplements the traditionally paired 3-axis gyroscope/accelerometer with a set of three additional 3-axis accelerometer suites, thereby providing additional angular acceleration measurement (inertia torque), avoiding the need for localization of the accelerometer at the center of mass on the robot's body, and simplifying installation and calibration. We implement this estimation procedure offline, using data extracted from numerous repeated runs of RHex and evaluate its performance with reference to GTMS, also comparing the relative performance of different fusion approaches implemented via different model sequences.
- Published
- 2005
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