Soft robots offer a unique combination of flexibility, adaptability, and safety, making them well-suited for a diverse range of applications. However, the inherent complexity of soft robots poses great challenges in t...
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Soft robots offer a unique combination of flexibility, adaptability, and safety, making them well-suited for a diverse range of applications. However, the inherent complexity of soft robots poses great challenges in their modeling and control. In this letter, we present the mechanical design and data-drivencontrol of a pneumatic-driven soft planar robot. Specifically, we employ a data-enabled predictive control (DeePC) strategy that directly utilizes system input/output data to achieve safe and optimal control, eliminating the need for tedious system identification or modeling. In addition, a dimension reduction technique is introduced into the DeePC framework, resulting in significantly enhanced computational efficiency with minimal to no degradation in control performance. Comparative experiments are conducted to validate the efficacy of DeePC in the control of the fabricated soft robot.
The present work develops a DDPG-based path planning algorithm that integrates the artificial potential field method into reinforcement learning to learn and generate an obstacle-free path quickly and autonomously. Th...
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ISBN:
(纸本)9798350321050
The present work develops a DDPG-based path planning algorithm that integrates the artificial potential field method into reinforcement learning to learn and generate an obstacle-free path quickly and autonomously. The vehicle kinematic model is adopted to describe the motion of autonomous vehicles, and the potential field function of obstacles, road boundaries as well as reference waypoints are considered to construct rewards of reinforcement learning, which enables the vehicle to realize the tradeoff between avoiding obstacles, preventing driving off the road and following the reference route. In contrast to the existent path planning algorithms, the proposed approach is able to learn autonomously in different driving environments, which is more suitable to autonomous vehicles. Moreover, simulations are provided to further demonstrate the effectiveness and adaptability of the proposed algorithm.
High-intensity focused ultrasound (HIFU) is a surgical method commonly used to treat uterine fibroids, but not all patients are suitable for this treatment. Therefore, effective postoperative outcome prediction can im...
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ISBN:
(纸本)9798350321050
High-intensity focused ultrasound (HIFU) is a surgical method commonly used to treat uterine fibroids, but not all patients are suitable for this treatment. Therefore, effective postoperative outcome prediction can improve surgical success rate. In this study, a data-driven prediction model for HIFU treatment outcome was developed based on patients' MRI sequences and DenseNet network. We used N4 bias correction, SimpleITK intensity normalization, image registration and other preprocessing methods to improve image quality. We also introduced data augmentation and transfer learning methods to solve the problem of small dataset and integrated multimodal information through feature fusion method. In conclusion, the fusion model's Accuracy was 0.769, AUC value was 0.806, which was better than the prediction accuracy of single sequence, and the experimental results showed that the model had good predictive performance.
In order to improve tracking performance of a class of linear discrete time-invariant multi-agent systems, an adaptive optimal iterative learningcontrol strategy is designed. To design the control protocol, a paramet...
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In this article, we demonstrate the benefits of imposing stability on data-driven Koopman operators. The data-driven identification of stable Koopman operators (DISKO) is implemented using an algorithm [1] that comput...
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In this article, we demonstrate the benefits of imposing stability on data-driven Koopman operators. The data-driven identification of stable Koopman operators (DISKO) is implemented using an algorithm [1] that computes the nearest stable matrix solution to a least-squares reconstruction error. As a first result, we derive a formula that describes the prediction error of Koopman representations for an arbitrary number of time steps, and which shows that stability constraints can improve the predictive accuracy over long horizons. As a second result, we determine formal conditions on basis functions of Koopman operators needed to satisfy the stability properties of an underlying nonlinear system. As a third result, we derive formal conditions for constructing Lyapunov functions for nonlinear systems out of stable data-driven Koopman operators, which we use to verify stabilizing control from data. Finally, we demonstrate the benefits of DISKO in prediction and control with simulations using a pendulum and a quadrotor and experiments with a pusher-slider system. The paper is complemented with a video: https://***/view/learning-stable-koopman.
In the field of stochastic Iteration learningcontrol (ILC) people tend to treat channel fading and data quantization as two separate random disturbances. In this paper, we give an analysis of the convergence of quant...
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ISBN:
(纸本)9798350321050
In the field of stochastic Iteration learningcontrol (ILC) people tend to treat channel fading and data quantization as two separate random disturbances. In this paper, we give an analysis of the convergence of quantized ILC in the presence of channel fading. In addition, we design a dual quantized ILC, which can further reduce the deviation before and after channel fading while ensuring convergence. In the dual quantized ILC, two separate quantizers are set before and after the channel fading. The first quantizer is designed to relieve the transmission pressure;the second quantizer is designed to reduce the error caused by the channel fading. Here we use the multiplicative fading factor to describe the channel fading. We adjust the quantization interval of the quantizer to ensure that the dual quantized ILC has a greater probability of smaller errors than the quantized ILC. Illustrative simulations are provided to verify the theoretical results.
This article investigates a fixed-time nonsingular terminal sliding mode control (FNTSMC) method with disturbance observer (DO). Using the vehicle's acceleration information, a fixed-time DO is designed to estimat...
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ISBN:
(纸本)9798350321050
This article investigates a fixed-time nonsingular terminal sliding mode control (FNTSMC) method with disturbance observer (DO). Using the vehicle's acceleration information, a fixed-time DO is designed to estimate the external uncertain disturbance of the system. Considering the nonzero initial error, a modified constant time headway strategy is proposed to overcome the influence of the nonzero initial error on the vehicle controller. In addition, a new terminal sliding mode control method is introduced to avoid the nonsingular problem and ensure that the vehicle spacing error converges in a fixed time. Finally, a numerical simulation is presented to show the proposed method's effectiveness.
In this paper, an iterative algorithm based on differential dynamic programming (DDP) is developed to solve the finite-horizon multi-player non-zero-sum (NZS) games. By using the DDP, the coupled Hamilton-Jacobi (HJ) ...
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ISBN:
(纸本)9798350321050
In this paper, an iterative algorithm based on differential dynamic programming (DDP) is developed to solve the finite-horizon multi-player non-zero-sum (NZS) games. By using the DDP, the coupled Hamilton-Jacobi (HJ) equations are expanded from partial differential forms to higher-order differential forms. By approximating the value functions and optimal control policies through several finite sets of basis functions, the DDP expansions are transformed into algebraic matrix equations in integral forms. Then a policy iteration (PI) algorithm is provided to solve the feedback Nash equilibrium of above NZS games. Finally, two simulation examples are given to demonstrate the feasibility of the developed algorithm.
Robot systems, due to their unique flexibility and economy, are widely used in modern industry and intelligent manufacturing. The parameters of the system are unknown, and traditional parameter estimation methods are ...
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Robot systems, due to their unique flexibility and economy, are widely used in modern industry and intelligent manufacturing. The parameters of the system are unknown, and traditional parameter estimation methods are difficult to achieve fixed time convergence, which leads to extremely position tracking control problem. In addition, the transient and steady-state performance of the robot system is difficult to specify in advance. In this article, a novel composite learning fixed-time (FxT) control strategy is proposed for the robotic systems to deal with these issues. The funnel control (FC) is utilized to transform the original error system into a new error dynamics with transient performance constraints. The two-phase nonsingular FxT sliding mode surface is constructed to avoid the singularity problem. Then, the filter operation is introduced to obtain the expression of parameter estimation error and is used to design the composite learning law. To achieve parameter estimation, a FxT composite learning law based on online historical data and regression extension is proposed, where the interval excitation (IE) is considered in the adaptive law. Finally, the designed adaption is incorporated into the nonsingular FxT sliding mode control to achieve tracking control. Moreover, the comparison of three different controllers is made to demonstrate the benefits of the developed control strategy.
In this paper, a design method for PID control based on Gaussian reinforcement learning is proposed to find the optimal policy for linear quadratic tracking of an unknown system. Firstly, the mathematical model of the...
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