A new kind of nonlinear control law is proposed for the purpose of improving servo platform tracking performance under condition of rapid movement. On the basis of linear ADRC, an arctangent function is selected, and ...
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ISBN:
(纸本)9781479936519
A new kind of nonlinear control law is proposed for the purpose of improving servo platform tracking performance under condition of rapid movement. On the basis of linear ADRC, an arctangent function is selected, and smoothly extended to an anti-S curve. The new method retains the feature of estimating and compensating the internal un-modeled dynamics and external disturbances. Simulation and comparison tests show that system using new control method has faster and more accurate tracking results.
A humanoid robot may suffer from slip since its two feet are not fixed on the ground. Slip occurrence may induce the loss of robot's balance. The previous literature focused on the detection or estimation of the s...
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A humanoid robot may suffer from slip since its two feet are not fixed on the ground. Slip occurrence may induce the loss of robot's balance. The previous literature focused on the detection or estimation of the slip occurrence, or only employed the translational acceleration regulation to overcome slip. This study proposes a slip prevention method by coordinating acceleration vector including the horizontal, vertical, and rotational acceleration components. The contribution of this paper is to regulate the translational and rotational acceleration together to prevent the slip occurrence. The effectiveness of our proposed method was verified by simulations and experiments on an actual humanoid robot.
In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for pie...
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In order to solve the linear variable differential transformer (LVDT) displacement sensor nonlinearity of overall range and extend its working range, a novel line-element based adaptively seg- menting method for piecewise compensating correction was proposed. According to the mechanical structure of LVDT, the output equation was calculated, and then the theoretic nonlinear source of output was analyzed. By the proposed line-element adaptive segmentation method, the nonlinear output of LVDT was divided into linear and nonlinear regions with a given threshold. Then the com- pensating correction function was designed for nonlinear parts employing polynomial regression tech- nique. The simulation of LVDT validates the feasibility of proposed scheme, and the results of cali- bration and testing experiments fully prove that the proposed method has higher accuracy than the state-of-art correction algorithms.
Uneven terrain walking is one of the important premises for biped robots to serve people. However, it is one of the key challenges for biped robots walking on a slope. In this paper, a universal method to generate pat...
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ISBN:
(纸本)9781479973989
Uneven terrain walking is one of the important premises for biped robots to serve people. However, it is one of the key challenges for biped robots walking on a slope. In this paper, a universal method to generate patterns for biped robot walking on a three-dimensional (3D) slope is proposed. Different from most researches, which only focused on the specific walking directions on a slope as across or along a slope, the proposed method is applied to biped robots for all directions walking on a slope. First, unification of parameters for biped walking on a 3D slope is designed. Second, walking patterns based on dual linear inverted pendulum method (DLLIPM) on a 3D slope are generated. Finally, the effectiveness of the universal pattern generator is verified through simulations.
This paper aims to present a robust attitude control strategy with guaranteed transient performance. Firstly, a Lyapunov-based control law is designed to achieve high-performance attitude control in the absence of dis...
This paper aims to present a robust attitude control strategy with guaranteed transient performance. Firstly, a Lyapunov-based control law is designed to achieve high-performance attitude control in the absence of disturbance and parameter variation. The proposed control law uses small feedback gains to suppress the control torque at large attitude error, and increases those gains with the convergence of attitude error to accelerate the system response. The overshooting phenomenon is also avoided by imposing a restriction on the parameter selection. Then, the integral sliding mode control technique is employed to improve the robustness, where the Lyapunov-based control law is used as the equivalent control part. Theoretical analysis and simulation results verify the effectiveness of the proposed strategy.
Considering the uncertainties parameters and unknown dynamics of permanent-magnet synchronous motors in real applications, a composite controller strategy for electromechanical actuator is proposed in this paper. The ...
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Considering the uncertainties parameters and unknown dynamics of permanent-magnet synchronous motors in real applications, a composite controller strategy for electromechanical actuator is proposed in this paper. The composite strategy consists of a disturbances observer based on linear extended state observer that suppresses disturbances by feedforward compensation and a Lyapunov stability-based position controller. A non-singular terminal sliding mode position controller is used here due to its good performance, under which state errors would converge to zero in finite time. Besides, special forms of load torque, hinge moment, and sinusoidal torque disturbances have been taken into consideration in this paper. The proposed control strategy is verified via simulation. High performance with respect to position tracking and robustness to load disturbances and parametric uncertainties of the motor have been demonstrated.
This paper describes our preliminary development of a virtual robot teleoperation platform based on hand gesture recognition using visual information. Hand gestures in images captured by a camera are recognised to con...
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ISBN:
(纸本)9781479920747
This paper describes our preliminary development of a virtual robot teleoperation platform based on hand gesture recognition using visual information. Hand gestures in images captured by a camera are recognised to control a virtual iCub. We employ two methods to realise the classification: Adaptive Neuro-fuzzy Inference systems (ANFIS) and Support Vector Machines (SVM). We realise the teleoperation of a virtual robot using iCubSimulator. The technique in the paper will enable us to teleoperate a physical robot in the future work. In addition, a video server is set up to monitor the real robot. By using the parallel system we are able to improve the robot's performance. Based on the techniques presented in this paper, the virtual iCub can perform the specified actions remotely in a natural manner.
In this paper, a sliding mode control using LESO coupled with an inverse hysteresis compensator is proposed for the motion tracking control of a microposition system with piezoelectric actuator(PEA). The inverse hyste...
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In this paper, a sliding mode control using LESO coupled with an inverse hysteresis compensator is proposed for the motion tracking control of a microposition system with piezoelectric actuator(PEA). The inverse hysteresis compensator is involved in eliminating the hysteresis nonlinearity reducing the nonlinear system to a linear system. Then, a sliding mode controller combining with LESO is adopted to handle all the unmodeled dynamics and disturbances, with an intention of improving and enhancing the dynamic performance and the robustness of system. The feasibility of the proposed control scheme is verified by experiment of a PEA. The result shows that when faced with a fast-rate control input, the proposed method can also ensure the system a good performance.
An adaptive unscented Kalman filter (AUKF) and an augmented state method are employed to estimate the timevarying parameters and states of a kind of nonlinear high-speed objects. A strong tracking filter is employed...
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An adaptive unscented Kalman filter (AUKF) and an augmented state method are employed to estimate the timevarying parameters and states of a kind of nonlinear high-speed objects. A strong tracking filter is employed to improve the tracking ability and robustness of unscented Kalman filter (UKF) when the process noise is inaccuracy, and wavelet transform is used to improve the estimate accuracy by the variance of measurement noise. An augmented square-root framework is utilized to improve the numerical stability and accuracy of UKF. Monte Carlo simulations and applications in the rapid trajectory estimation of hypersonic artillery shells confirm the effectiveness of the proposed method.
This paper is concerned with the controller design for networked controlsystems(NCSs). A novel eventtriggered networked predictive control scheme is proposed to compensate for the network-induced delay and save netwo...
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ISBN:
(纸本)9781479947249
This paper is concerned with the controller design for networked controlsystems(NCSs). A novel eventtriggered networked predictive control scheme is proposed to compensate for the network-induced delay and save network bandwidth. The closed-loop system is modeled as a switched system with time-varying delay. By constructing a common Lyapunov function, a sufficient stability condition is derived and presented in terms of linear matrix inequalities(LMIs). In order to prove the validity of the proposed method, both a simulation and an experiment are carried out. Both simulation results and experimental results show that this method can compensate for the network-induced delay actively and reduce the burden of the network significantly.
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